| Line 1... |
Line 1... |
////////////////////////////////////////////////////////////////////////////////
|
////////////////////////////////////////////////////////////////////////////////
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//
|
//
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// Filename: zipcpu.v
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// Filename: zipcpu.v
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//
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//
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// Project: Zip CPU -- a small, lightweight, RISC CPU soft core
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// Project: Zip CPU -- a small, lightweight, RISC CPU soft core
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//
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//{{{
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// Purpose: This is the top level module holding the core of the Zip CPU
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// Purpose: This is the top level module holding the core of the Zip CPU
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// together. The Zip CPU is designed to be as simple as possible.
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// together. The Zip CPU is designed to be as simple as possible.
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// (actual implementation aside ...) The instruction set is about as
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// (actual implementation aside ...) The instruction set is about as
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// RISC as you can get, with only 26 instruction types currently supported.
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// RISC as you can get, with only 26 instruction types currently supported.
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// (There are still 8-instruction Op-Codes reserved for floating point,
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// (There are still 8-instruction Op-Codes reserved for floating point,
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| Line 47... |
Line 47... |
//
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//
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// assign (n)_ce = (n-1)_valid && (!(n)_stall)
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// assign (n)_ce = (n-1)_valid && (!(n)_stall)
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//
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//
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//
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//
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// always @(posedge i_clk)
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// always @(posedge i_clk)
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// if ((i_rst)||(clear_pipeline))
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// if ((i_reset)||(clear_pipeline))
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// (n)_valid = 0
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// (n)_valid = 0
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// else if (n)_ce
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// else if (n)_ce
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// (n)_valid = 1
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// (n)_valid = 1
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// else if (n+1)_ce
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// else if (n+1)_ce
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// (n)_valid = 0
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// (n)_valid = 0
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| Line 66... |
Line 66... |
// (n)_variable = ... whatever logic for this stage
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// (n)_variable = ... whatever logic for this stage
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//
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//
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// Note that a stage can stall even if no instruction is loaded into
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// Note that a stage can stall even if no instruction is loaded into
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// it.
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// it.
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//
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//
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//
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//}}}
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// Creator: Dan Gisselquist, Ph.D.
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// Creator: Dan Gisselquist, Ph.D.
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// Gisselquist Technology, LLC
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// Gisselquist Technology, LLC
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//
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//
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////////////////////////////////////////////////////////////////////////////////
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////////////////////////////////////////////////////////////////////////////////
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//
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//
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// Copyright (C) 2015-2017, Gisselquist Technology, LLC
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// Copyright (C) 2015-2019, Gisselquist Technology, LLC
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//
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//{{{
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// This program is free software (firmware): you can redistribute it and/or
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// This program is free software (firmware): you can redistribute it and/or
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// modify it under the terms of the GNU General Public License as published
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// modify it under the terms of the GNU General Public License as published
|
// by the Free Software Foundation, either version 3 of the License, or (at
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// by the Free Software Foundation, either version 3 of the License, or (at
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// your option) any later version.
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// your option) any later version.
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//
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//
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| Line 88... |
Line 88... |
//
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//
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// You should have received a copy of the GNU General Public License along
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// You should have received a copy of the GNU General Public License along
|
// with this program. (It's in the $(ROOT)/doc directory. Run make with no
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// with this program. (It's in the $(ROOT)/doc directory. Run make with no
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// target there if the PDF file isn't present.) If not, see
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// target there if the PDF file isn't present.) If not, see
|
// <http://www.gnu.org/licenses/> for a copy.
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// <http://www.gnu.org/licenses/> for a copy.
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//
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//}}}
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// License: GPL, v3, as defined and found on www.gnu.org,
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// License: GPL, v3, as defined and found on www.gnu.org,
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// http://www.gnu.org/licenses/gpl.html
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// http://www.gnu.org/licenses/gpl.html
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//
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//
|
//
|
//
|
////////////////////////////////////////////////////////////////////////////////
|
////////////////////////////////////////////////////////////////////////////////
|
//
|
//
|
//
|
//
|
|
`default_nettype none
|
|
//
|
|
`define CPU_SUB_OP 4'h0 // also a compare instruction
|
|
`define CPU_AND_OP 4'h1 // also a test instruction
|
|
`define CPU_BREV_OP 4'h8
|
|
`define CPU_MOV_OP 4'hd
|
//
|
//
|
`define CPU_CC_REG 4'he
|
`define CPU_CC_REG 4'he
|
`define CPU_PC_REG 4'hf
|
`define CPU_PC_REG 4'hf
|
`define CPU_CLRCACHE_BIT 14 // Set to clear the I-cache, automatically clears
|
`define CPU_CLRCACHE_BIT 14 // Set to clear the I-cache, automatically clears
|
`define CPU_PHASE_BIT 13 // Set if we are executing the latter half of a CIS
|
`define CPU_PHASE_BIT 13 // Set if we are executing the latter half of a CIS
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| Line 115... |
Line 121... |
// Compile time defines
|
// Compile time defines
|
//
|
//
|
`include "cpudefs.v"
|
`include "cpudefs.v"
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//
|
//
|
//
|
//
|
module zipcpu(i_clk, i_rst, i_interrupt,
|
module zipcpu(i_clk, i_reset, i_interrupt,
|
// Debug interface
|
// Debug interface
|
i_halt, i_clear_pf_cache, i_dbg_reg, i_dbg_we, i_dbg_data,
|
i_halt, i_clear_pf_cache, i_dbg_reg, i_dbg_we, i_dbg_data,
|
o_dbg_stall, o_dbg_reg, o_dbg_cc,
|
o_dbg_stall, o_dbg_reg, o_dbg_cc,
|
o_break,
|
o_break,
|
// CPU interface to the wishbone bus
|
// CPU interface to the wishbone bus
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| Line 129... |
Line 135... |
i_wb_ack, i_wb_stall, i_wb_data,
|
i_wb_ack, i_wb_stall, i_wb_data,
|
i_wb_err,
|
i_wb_err,
|
// Accounting/CPU usage interface
|
// Accounting/CPU usage interface
|
o_op_stall, o_pf_stall, o_i_count
|
o_op_stall, o_pf_stall, o_i_count
|
`ifdef DEBUG_SCOPE
|
`ifdef DEBUG_SCOPE
|
, o_debug
|
, o_debug // , o_dcache_debug
|
`endif
|
`endif
|
);
|
);
|
|
// Parameters
|
|
//{{{
|
parameter [31:0] RESET_ADDRESS=32'h0100000;
|
parameter [31:0] RESET_ADDRESS=32'h0100000;
|
parameter ADDRESS_WIDTH=30,
|
parameter ADDRESS_WIDTH=30,
|
LGICACHE=8;
|
LGICACHE=12;
|
`ifdef OPT_MULTIPLY
|
`ifdef OPT_MULTIPLY
|
parameter IMPLEMENT_MPY = `OPT_MULTIPLY;
|
parameter IMPLEMENT_MPY = `OPT_MULTIPLY;
|
`else
|
`else
|
parameter IMPLEMENT_MPY = 0;
|
parameter IMPLEMENT_MPY = 0;
|
`endif
|
`endif
|
`ifdef OPT_DIVIDE
|
`ifdef OPT_DIVIDE
|
parameter IMPLEMENT_DIVIDE = 1;
|
parameter [0:0] IMPLEMENT_DIVIDE = 1;
|
`else
|
`else
|
parameter IMPLEMENT_DIVIDE = 0;
|
parameter [0:0] IMPLEMENT_DIVIDE = 0;
|
`endif
|
`endif
|
`ifdef OPT_IMPLEMENT_FPU
|
`ifdef OPT_IMPLEMENT_FPU
|
parameter IMPLEMENT_FPU = 1,
|
parameter [0:0] IMPLEMENT_FPU = 1;
|
`else
|
`else
|
parameter IMPLEMENT_FPU = 0,
|
parameter [0:0] IMPLEMENT_FPU = 0;
|
`endif
|
`endif
|
IMPLEMENT_LOCK=1;
|
|
`ifdef OPT_EARLY_BRANCHING
|
`ifdef OPT_EARLY_BRANCHING
|
parameter EARLY_BRANCHING = 1;
|
parameter [0:0] EARLY_BRANCHING = 1;
|
|
`else
|
|
parameter [0:0] EARLY_BRANCHING = 0;
|
|
`endif
|
|
`ifdef OPT_CIS
|
|
parameter [0:0] OPT_CIS = 1'b1;
|
|
`else
|
|
parameter [0:0] OPT_CIS = 1'b0;
|
|
`endif
|
|
`ifdef OPT_NO_USERMODE
|
|
localparam [0:0] OPT_NO_USERMODE = 1'b1;
|
|
`else
|
|
localparam [0:0] OPT_NO_USERMODE = 1'b0;
|
|
`endif
|
|
`ifdef OPT_PIPELINED
|
|
parameter [0:0] OPT_PIPELINED = 1'b1;
|
|
`else
|
|
parameter [0:0] OPT_PIPELINED = 1'b0;
|
|
`endif
|
|
`ifdef OPT_PIPELINED_BUS_ACCESS
|
|
localparam [0:0] OPT_PIPELINED_BUS_ACCESS = (OPT_PIPELINED);
|
|
`else
|
|
localparam [0:0] OPT_PIPELINED_BUS_ACCESS = 1'b0;
|
|
`endif
|
|
localparam [0:0] OPT_MEMPIPE = OPT_PIPELINED_BUS_ACCESS;
|
|
parameter [0:0] IMPLEMENT_LOCK=1;
|
|
localparam [0:0] OPT_LOCK=(IMPLEMENT_LOCK)&&(OPT_PIPELINED);
|
|
`ifdef OPT_DCACHE
|
|
parameter OPT_LGDCACHE = 10;
|
`else
|
`else
|
parameter EARLY_BRANCHING = 0;
|
parameter OPT_LGDCACHE = 0;
|
`endif
|
`endif
|
parameter WITH_LOCAL_BUS = 1;
|
localparam [0:0] OPT_DCACHE = (OPT_LGDCACHE > 0);
|
|
|
|
parameter [0:0] WITH_LOCAL_BUS = 1'b1;
|
localparam AW=ADDRESS_WIDTH;
|
localparam AW=ADDRESS_WIDTH;
|
localparam [(AW-1):0] RESET_BUS_ADDRESS = RESET_ADDRESS[(AW+1):2];
|
localparam [(AW-1):0] RESET_BUS_ADDRESS = RESET_ADDRESS[(AW+1):2];
|
input i_clk, i_rst, i_interrupt;
|
parameter F_LGDEPTH=8;
|
|
|
|
//}}}
|
|
// I/O declarations
|
|
//{{{
|
|
input wire i_clk, i_reset, i_interrupt;
|
// Debug interface -- inputs
|
// Debug interface -- inputs
|
input i_halt, i_clear_pf_cache;
|
input wire i_halt, i_clear_pf_cache;
|
input [4:0] i_dbg_reg;
|
input wire [4:0] i_dbg_reg;
|
input i_dbg_we;
|
input wire i_dbg_we;
|
input [31:0] i_dbg_data;
|
input wire [31:0] i_dbg_data;
|
// Debug interface -- outputs
|
// Debug interface -- outputs
|
output wire o_dbg_stall;
|
output wire o_dbg_stall;
|
output reg [31:0] o_dbg_reg;
|
output reg [31:0] o_dbg_reg;
|
output reg [3:0] o_dbg_cc;
|
output reg [3:0] o_dbg_cc;
|
output wire o_break;
|
output wire o_break;
|
| Line 177... |
Line 219... |
output wire o_wb_lcl_cyc, o_wb_lcl_stb, o_wb_we;
|
output wire o_wb_lcl_cyc, o_wb_lcl_stb, o_wb_we;
|
output wire [(AW-1):0] o_wb_addr;
|
output wire [(AW-1):0] o_wb_addr;
|
output wire [31:0] o_wb_data;
|
output wire [31:0] o_wb_data;
|
output wire [3:0] o_wb_sel;
|
output wire [3:0] o_wb_sel;
|
// Wishbone interface -- inputs
|
// Wishbone interface -- inputs
|
input i_wb_ack, i_wb_stall;
|
input wire i_wb_ack, i_wb_stall;
|
input [31:0] i_wb_data;
|
input wire [31:0] i_wb_data;
|
input i_wb_err;
|
input wire i_wb_err;
|
// Accounting outputs ... to help us count stalls and usage
|
// Accounting outputs ... to help us count stalls and usage
|
output wire o_op_stall;
|
output wire o_op_stall;
|
output wire o_pf_stall;
|
output wire o_pf_stall;
|
output wire o_i_count;
|
output wire o_i_count;
|
//
|
//
|
`ifdef DEBUG_SCOPE
|
`ifdef DEBUG_SCOPE
|
output reg [31:0] o_debug;
|
output reg [31:0] o_debug;
|
|
// output wire [31:0] o_dcache_debug;
|
`endif
|
`endif
|
|
//}}}
|
|
|
|
|
// Registers
|
// Registers
|
//
|
//
|
// The distributed RAM style comment is necessary on the
|
// The distributed RAM style comment is necessary on the
|
| Line 200... |
Line 244... |
// optimizes logic away, to where it no longer works. The logic
|
// optimizes logic away, to where it no longer works. The logic
|
// as described herein will work, this just makes sure XST implements
|
// as described herein will work, this just makes sure XST implements
|
// that logic.
|
// that logic.
|
//
|
//
|
(* ram_style = "distributed" *)
|
(* ram_style = "distributed" *)
|
`ifdef OPT_NO_USERMODE
|
reg [31:0] regset [0:(OPT_NO_USERMODE)? 15:31];
|
reg [31:0] regset [0:15];
|
|
`else
|
|
reg [31:0] regset [0:31];
|
|
`endif
|
|
|
|
// Condition codes
|
// Condition codes
|
// (BUS, TRAP,ILL,BREAKEN,STEP,GIE,SLEEP ), V, N, C, Z
|
// (BUS, TRAP,ILL,BREAKEN,STEP,GIE,SLEEP ), V, N, C, Z
|
reg [3:0] flags, iflags;
|
reg [3:0] flags, iflags;
|
wire [14:0] w_uflags, w_iflags;
|
wire [14:0] w_uflags, w_iflags;
|
reg break_en, step, sleep, r_halted;
|
reg break_en, step, sleep, r_halted;
|
wire break_pending, trap, gie, ubreak;
|
wire break_pending, trap, gie, ubreak, pending_interrupt;
|
wire w_clear_icache, ill_err_u;
|
wire w_clear_icache, ill_err_u;
|
reg ill_err_i;
|
reg ill_err_i;
|
reg ibus_err_flag;
|
reg ibus_err_flag;
|
wire ubus_err_flag;
|
wire ubus_err_flag;
|
wire idiv_err_flag, udiv_err_flag;
|
wire idiv_err_flag, udiv_err_flag;
|
wire ifpu_err_flag, ufpu_err_flag;
|
wire ifpu_err_flag, ufpu_err_flag;
|
wire ihalt_phase, uhalt_phase;
|
wire ihalt_phase, uhalt_phase;
|
|
|
// The master chip enable
|
// The master chip enable
|
wire master_ce;
|
wire master_ce, master_stall;
|
|
|
//
|
//
|
//
|
//
|
// PIPELINE STAGE #1 :: Prefetch
|
// PIPELINE STAGE #1 :: Prefetch
|
// Variable declarations
|
// Variable declarations
|
//
|
//
|
|
//{{{
|
reg [(AW+1):0] pf_pc;
|
reg [(AW+1):0] pf_pc;
|
|
wire [(AW+1):0] pf_request_address, pf_instruction_pc;
|
reg new_pc;
|
reg new_pc;
|
wire clear_pipeline;
|
wire clear_pipeline;
|
assign clear_pipeline = new_pc;
|
|
|
|
wire dcd_stalled;
|
reg dcd_stalled;
|
wire pf_cyc, pf_stb, pf_we, pf_busy, pf_ack, pf_stall, pf_err;
|
wire pf_cyc, pf_stb, pf_we, pf_ack, pf_stall, pf_err;
|
wire [(AW-1):0] pf_addr;
|
wire [(AW-1):0] pf_addr;
|
wire [31:0] pf_data;
|
wire [31:0] pf_data;
|
wire [31:0] pf_instruction;
|
wire [31:0] pf_instruction;
|
wire [(AW-1):0] pf_instruction_pc;
|
|
wire pf_valid, pf_gie, pf_illegal;
|
wire pf_valid, pf_gie, pf_illegal;
|
|
wire pf_stalled;
|
|
wire pf_new_pc;
|
|
`ifdef FORMAL
|
|
wire [31:0] f_dcd_insn_word;
|
|
wire f_dcd_insn_gie;
|
|
reg [31:0] f_op_insn_word;
|
|
reg [31:0] f_alu_insn_word;
|
|
`endif
|
|
|
|
assign clear_pipeline = new_pc;
|
|
//}}}
|
|
|
//
|
//
|
//
|
//
|
// PIPELINE STAGE #2 :: Instruction Decode
|
// PIPELINE STAGE #2 :: Instruction Decode
|
// Variable declarations
|
// Variable declarations
|
//
|
//
|
//
|
//
|
|
//{{{
|
reg op_valid /* verilator public_flat */,
|
reg op_valid /* verilator public_flat */,
|
op_valid_mem, op_valid_alu;
|
op_valid_mem, op_valid_alu;
|
reg op_valid_div, op_valid_fpu;
|
reg op_valid_div, op_valid_fpu;
|
wire op_stall, dcd_ce, dcd_phase;
|
wire op_stall, dcd_ce, dcd_phase;
|
wire [3:0] dcd_opn;
|
wire [3:0] dcd_opn;
|
wire [4:0] dcd_A, dcd_B, dcd_R;
|
wire [4:0] dcd_A, dcd_B, dcd_R, dcd_preA, dcd_preB;
|
wire dcd_Acc, dcd_Bcc, dcd_Apc, dcd_Bpc, dcd_Rcc, dcd_Rpc;
|
wire dcd_Acc, dcd_Bcc, dcd_Apc, dcd_Bpc, dcd_Rcc, dcd_Rpc;
|
wire [3:0] dcd_F;
|
wire [3:0] dcd_F;
|
wire dcd_wR, dcd_rA, dcd_rB,
|
wire dcd_wR, dcd_rA, dcd_rB,
|
dcd_ALU, dcd_M, dcd_DIV, dcd_FP,
|
dcd_ALU, dcd_M, dcd_DIV, dcd_FP,
|
dcd_wF, dcd_gie, dcd_break, dcd_lock,
|
dcd_wF, dcd_gie, dcd_break, dcd_lock,
|
dcd_pipe, dcd_ljmp;
|
dcd_pipe, dcd_ljmp;
|
wire dcd_valid;
|
wire dcd_valid;
|
wire [AW:0] dcd_pc /* verilator public_flat */;
|
wire [AW+1:0] dcd_pc /* verilator public_flat */;
|
wire [31:0] dcd_I;
|
wire [31:0] dcd_I;
|
wire dcd_zI; // true if dcd_I == 0
|
wire dcd_zI; // true if dcd_I == 0
|
wire dcd_A_stall, dcd_B_stall, dcd_F_stall;
|
wire dcd_A_stall, dcd_B_stall, dcd_F_stall;
|
|
|
wire dcd_illegal;
|
wire dcd_illegal;
|
wire dcd_early_branch;
|
wire dcd_early_branch, dcd_early_branch_stb;
|
wire [(AW-1):0] dcd_branch_pc;
|
wire [(AW+1):0] dcd_branch_pc;
|
|
|
wire dcd_sim;
|
wire dcd_sim;
|
wire [22:0] dcd_sim_immv;
|
wire [22:0] dcd_sim_immv;
|
|
wire prelock_stall;
|
|
wire cc_invalid_for_dcd;
|
|
wire pending_sreg_write;
|
|
//}}}
|
|
|
|
|
//
|
//
|
//
|
//
|
// PIPELINE STAGE #3 :: Read Operands
|
// PIPELINE STAGE #3 :: Read Operands
|
// Variable declarations
|
// Variable declarations
|
//
|
//
|
//
|
//
|
//
|
//
|
|
//{{{
|
// Now, let's read our operands
|
// Now, let's read our operands
|
reg [4:0] alu_reg;
|
reg [4:0] alu_reg;
|
wire [3:0] op_opn;
|
wire [3:0] op_opn;
|
wire [4:0] op_R;
|
reg [4:0] op_R;
|
|
reg op_Rcc;
|
|
reg [4:0] op_Aid, op_Bid;
|
|
reg op_rA, op_rB;
|
reg [31:0] r_op_Av, r_op_Bv;
|
reg [31:0] r_op_Av, r_op_Bv;
|
reg [(AW-1):0] op_pc;
|
reg [(AW+1):0] op_pc;
|
wire [31:0] w_op_Av, w_op_Bv;
|
wire [31:0] w_op_Av, w_op_Bv, op_Av, op_Bv;
|
wire [31:0] op_A_nowait, op_B_nowait, op_Av, op_Bv;
|
reg [31:0] w_pcB_v, w_pcA_v;
|
|
reg [31:0] w_op_BnI;
|
reg op_wR, op_wF;
|
reg op_wR, op_wF;
|
wire op_gie, op_Rcc;
|
wire op_gie;
|
wire [14:0] op_Fl;
|
wire [3:0] op_Fl;
|
reg [6:0] r_op_F;
|
reg [6:0] r_op_F;
|
wire [7:0] op_F;
|
wire [7:0] op_F;
|
wire op_ce, op_phase, op_pipe, op_change_data_ce;
|
wire op_ce, op_phase, op_pipe;
|
|
reg r_op_break;
|
|
reg [3:0] r_op_opn;
|
|
wire w_op_valid;
|
|
wire [8:0] w_cpu_info;
|
// Some pipeline control wires
|
// Some pipeline control wires
|
reg op_illegal;
|
reg op_illegal;
|
wire op_break;
|
wire op_break;
|
wire op_lock;
|
wire op_lock;
|
|
|
`ifdef VERILATOR
|
`ifdef VERILATOR
|
reg op_sim /* verilator public_flat */;
|
reg op_sim /* verilator public_flat */;
|
reg [22:0] op_sim_immv /* verilator public_flat */;
|
reg [22:0] op_sim_immv /* verilator public_flat */;
|
|
`else
|
|
wire op_sim = 1'b0;
|
`endif
|
`endif
|
|
//}}}
|
|
|
|
|
//
|
//
|
//
|
//
|
// PIPELINE STAGE #4 :: ALU / Memory
|
// PIPELINE STAGE #4 :: ALU / Memory
|
// Variable declarations
|
// Variable declarations
|
//
|
//
|
//
|
//
|
wire [(AW-1):0] alu_pc;
|
//{{{
|
|
wire [(AW+1):0] alu_pc;
|
reg r_alu_pc_valid, mem_pc_valid;
|
reg r_alu_pc_valid, mem_pc_valid;
|
wire alu_pc_valid;
|
wire alu_pc_valid;
|
wire alu_phase;
|
wire alu_phase;
|
wire alu_ce /* verilator public_flat */, alu_stall;
|
wire alu_ce /* verilator public_flat */, alu_stall;
|
wire [31:0] alu_result;
|
wire [31:0] alu_result;
|
| Line 324... |
Line 393... |
wire set_cond;
|
wire set_cond;
|
reg alu_wR, alu_wF;
|
reg alu_wR, alu_wF;
|
wire alu_gie, alu_illegal;
|
wire alu_gie, alu_illegal;
|
|
|
|
|
|
|
wire mem_ce, mem_stalled;
|
wire mem_ce, mem_stalled;
|
wire mem_pipe_stalled;
|
wire mem_pipe_stalled;
|
wire mem_valid, mem_ack, mem_stall, mem_err, bus_err,
|
wire mem_valid, mem_ack, mem_stall, mem_err, bus_err,
|
mem_cyc_gbl, mem_cyc_lcl, mem_stb_gbl, mem_stb_lcl, mem_we;
|
mem_cyc_gbl, mem_cyc_lcl, mem_stb_gbl, mem_stb_lcl, mem_we;
|
wire [4:0] mem_wreg;
|
wire [4:0] mem_wreg;
|
| Line 340... |
Line 408... |
|
|
wire div_ce, div_error, div_busy, div_valid;
|
wire div_ce, div_error, div_busy, div_valid;
|
wire [31:0] div_result;
|
wire [31:0] div_result;
|
wire [3:0] div_flags;
|
wire [3:0] div_flags;
|
|
|
assign div_ce = (master_ce)&&(!clear_pipeline)&&(op_valid_div)
|
|
&&(!mem_rdbusy)&&(!div_busy)&&(!fpu_busy)
|
|
&&(set_cond);
|
|
|
|
wire fpu_ce, fpu_error, fpu_busy, fpu_valid;
|
wire fpu_ce, fpu_error, fpu_busy, fpu_valid;
|
wire [31:0] fpu_result;
|
wire [31:0] fpu_result;
|
wire [3:0] fpu_flags;
|
wire [3:0] fpu_flags;
|
|
reg adf_ce_unconditional;
|
|
|
assign fpu_ce = (master_ce)&&(!clear_pipeline)&&(op_valid_fpu)
|
wire bus_lock;
|
&&(!mem_rdbusy)&&(!div_busy)&&(!fpu_busy)
|
|
&&(set_cond);
|
reg dbgv, dbg_clear_pipe;
|
|
reg [31:0] dbg_val;
|
|
|
|
assign div_ce = (op_valid_div)&&(adf_ce_unconditional)&&(set_cond);
|
|
assign fpu_ce = (IMPLEMENT_FPU)&&(op_valid_fpu)&&(adf_ce_unconditional)&&(set_cond);
|
|
|
wire adf_ce_unconditional;
|
//}}}
|
|
|
//
|
//
|
//
|
//
|
// PIPELINE STAGE #5 :: Write-back
|
// PIPELINE STAGE #5 :: Write-back
|
// Variable declarations
|
// Variable declarations
|
//
|
//
|
|
//{{{
|
wire wr_reg_ce, wr_flags_ce, wr_write_pc, wr_write_cc,
|
wire wr_reg_ce, wr_flags_ce, wr_write_pc, wr_write_cc,
|
wr_write_scc, wr_write_ucc;
|
wr_write_scc, wr_write_ucc;
|
wire [4:0] wr_reg_id;
|
wire [4:0] wr_reg_id;
|
wire [31:0] wr_gpreg_vl, wr_spreg_vl;
|
wire [31:0] wr_gpreg_vl, wr_spreg_vl;
|
wire w_switch_to_interrupt, w_release_from_interrupt;
|
wire w_switch_to_interrupt, w_release_from_interrupt;
|
reg [(AW+1):0] ipc;
|
reg [(AW+1):0] ipc;
|
wire [(AW+1):0] upc;
|
wire [(AW+1):0] upc;
|
|
reg last_write_to_cc;
|
|
wire cc_write_hold;
|
|
reg r_clear_icache;
|
|
//}}}
|
|
|
|
`ifdef FORMAL
|
|
wire [F_LGDEPTH-1:0]
|
|
f_gbl_arb_nreqs, f_gbl_arb_nacks, f_gbl_arb_outstanding,
|
|
f_lcl_arb_nreqs, f_lcl_arb_nacks, f_lcl_arb_outstanding,
|
|
f_gbl_mem_nreqs, f_gbl_mem_nacks, f_gbl_mem_outstanding,
|
|
f_lcl_mem_nreqs, f_lcl_mem_nacks, f_lcl_mem_outstanding,
|
|
f_gbl_pf_nreqs, f_gbl_pf_nacks, f_gbl_pf_outstanding,
|
|
f_lcl_pf_nreqs, f_lcl_pf_nacks, f_lcl_pf_outstanding,
|
|
f_mem_nreqs, f_mem_nacks, f_mem_outstanding;
|
|
reg f_pf_nreqs, f_pf_nacks, f_pf_outstanding;
|
|
wire f_mem_pc;
|
|
`endif
|
|
|
|
|
//
|
//
|
// MASTER: clock enable.
|
// MASTER: clock enable.
|
//
|
//
|
assign master_ce = ((!i_halt)||(alu_phase))&&(!o_break)&&(!sleep);
|
assign master_ce = ((!i_halt)||(alu_phase))
|
|
&&(!cc_write_hold)&&(!o_break)&&(!sleep);
|
|
|
|
|
//
|
//
|
// PIPELINE STAGE #1 :: Prefetch
|
// PIPELINE STAGE #1 :: Prefetch
|
// Calculate stall conditions
|
// Calculate stall conditions
|
| Line 386... |
Line 473... |
|
|
//
|
//
|
// PIPELINE STAGE #2 :: Instruction Decode
|
// PIPELINE STAGE #2 :: Instruction Decode
|
// Calculate stall conditions
|
// Calculate stall conditions
|
|
|
`ifdef OPT_PIPELINED
|
always @(*)
|
assign dcd_stalled = (dcd_valid)&&(op_stall);
|
if (OPT_PIPELINED)
|
`else // Not pipelined -- either double or single fetch
|
dcd_stalled = (dcd_valid)&&(op_stall);
|
assign dcd_stalled = (dcd_valid)&&(op_stall);
|
else
|
`endif
|
dcd_stalled = (!master_ce)||(ill_err_i)||(dcd_valid)||(op_valid)
|
|
||(ibus_err_flag)||(idiv_err_flag)
|
|
||(alu_busy)||(div_busy)||(fpu_busy)||(mem_busy);
|
//
|
//
|
// PIPELINE STAGE #3 :: Read Operands
|
// PIPELINE STAGE #3 :: Read Operands
|
// Calculate stall conditions
|
// Calculate stall conditions
|
wire prelock_stall;
|
//{{{
|
`ifdef OPT_PIPELINED
|
generate if (OPT_PIPELINED)
|
reg cc_invalid_for_dcd;
|
begin : GEN_OP_STALL
|
|
reg r_cc_invalid_for_dcd;
|
|
always @(posedge i_clk)
|
|
r_cc_invalid_for_dcd <=
|
|
(set_cond)&&(op_valid)
|
|
&&((op_wF)||((op_wR)&&(op_R[4:0] == { op_gie, `CPU_CC_REG })))
|
|
||((r_cc_invalid_for_dcd)
|
|
&&((alu_busy)||(mem_rdbusy)||(div_busy)||(fpu_busy)));
|
|
|
|
assign cc_invalid_for_dcd = r_cc_invalid_for_dcd;
|
|
|
|
reg r_pending_sreg_write;
|
|
initial r_pending_sreg_write = 1'b0;
|
always @(posedge i_clk)
|
always @(posedge i_clk)
|
cc_invalid_for_dcd <= (wr_flags_ce)
|
if (clear_pipeline)
|
||(wr_reg_ce)&&(wr_reg_id[3:0] == `CPU_CC_REG)
|
r_pending_sreg_write <= 1'b0;
|
||(op_valid)&&((op_wF)||((op_wR)&&(op_R[3:0] == `CPU_CC_REG)))
|
else if (((adf_ce_unconditional)||(mem_ce))
|
||((alu_wF)||((alu_wR)&&(alu_reg[3:0] == `CPU_CC_REG)))
|
&&(set_cond)&&(!op_illegal)
|
||(mem_busy)||(div_busy)||(fpu_busy);
|
&&(op_wR)
|
|
&&(op_R[3:1] == 3'h7)
|
assign op_stall = (op_valid)&&( // Only stall if we're loaded w/validins
|
&&(op_R[4:0] != { gie, 4'hf }))
|
// Stall if we're stopped, and not allowed to execute
|
r_pending_sreg_write <= 1'b1;
|
// an instruction
|
else if ((!mem_rdbusy)&&(!alu_busy))
|
// (!master_ce) // Already captured in alu_stall
|
r_pending_sreg_write <= 1'b0;
|
//
|
|
// Stall if going into the ALU and the ALU is stalled
|
assign pending_sreg_write = r_pending_sreg_write;
|
// i.e. if the memory is busy, or we are single
|
|
// stepping. This also includes our stalls for
|
assign op_stall = (op_valid)&&(
|
// op_break and op_lock, so we don't need to
|
//{{{
|
// include those as well here.
|
// Only stall if we're loaded w/validins and the
|
// This also includes whether or not the divide or
|
// next stage is accepting our instruction
|
// floating point units are busy.
|
(!adf_ce_unconditional)&&(!mem_ce)
|
(alu_stall)
|
|
||(((op_valid_div)||(op_valid_fpu))
|
|
&&(!adf_ce_unconditional))
|
|
//
|
|
// Stall if we are going into memory with an operation
|
|
// that cannot be pipelined, and the memory is
|
|
// already busy
|
|
||(mem_stalled) // &&(op_valid_mem) part of mem_stalled
|
|
||(op_Rcc)
|
|
)
|
)
|
||(dcd_valid)&&(
|
||(dcd_valid)&&(
|
// Stall if we need to wait for an operand A
|
// Stall if we need to wait for an operand A
|
// to be ready to read
|
// to be ready to read
|
(dcd_A_stall)
|
(dcd_A_stall)
|
| Line 439... |
Line 531... |
||(dcd_B_stall)
|
||(dcd_B_stall)
|
// Or if we need to wait on flags to work on the
|
// Or if we need to wait on flags to work on the
|
// CC register
|
// CC register
|
||(dcd_F_stall)
|
||(dcd_F_stall)
|
);
|
);
|
|
//}}}
|
assign op_ce = ((dcd_valid)||(dcd_illegal)||(dcd_early_branch))&&(!op_stall);
|
assign op_ce = ((dcd_valid)||(dcd_illegal)||(dcd_early_branch))&&(!op_stall);
|
|
|
`else
|
end else begin // !OPT_PIPELINED
|
assign op_stall = (alu_busy)||(div_busy)||(fpu_busy)||(wr_reg_ce)
|
|
||(mem_busy)||(op_valid)||(!master_ce)||(wr_flags_ce);
|
assign op_stall = 1'b0; // (o_break)||(pending_interrupt);
|
assign op_ce = ((dcd_valid)||(dcd_illegal)||(dcd_early_branch))&&(!op_stall);
|
assign op_ce = ((dcd_valid)||(dcd_early_branch))&&(!op_stall);
|
`endif
|
assign pending_sreg_write = 1'b0;
|
|
assign cc_invalid_for_dcd = 1'b0;
|
|
|
|
// Verilator lint_off UNUSED
|
|
wire [1:0] pipe_unused;
|
|
assign pipe_unused = { cc_invalid_for_dcd,
|
|
pending_sreg_write };
|
|
// Verilator lint_on UNUSED
|
|
end endgenerate
|
|
|
// BUT ... op_ce is too complex for many of the data operations. So
|
// BUT ... op_ce is too complex for many of the data operations. So
|
// let's make their circuit enable code simpler. In particular, if
|
// let's make their circuit enable code simpler. In particular, if
|
// op_ doesn't need to be preserved, we can change it all we want
|
// op_ doesn't need to be preserved, we can change it all we want
|
// ... right? The clear_pipeline code, for example, really only needs
|
// ... right? The clear_pipeline code, for example, really only needs
|
// to determine whether op_valid is true.
|
// to determine whether op_valid is true.
|
assign op_change_data_ce = (!op_stall);
|
// assign op_change_data_ce = (!op_stall);
|
|
//}}}
|
|
|
//
|
//
|
// PIPELINE STAGE #4 :: ALU / Memory
|
// PIPELINE STAGE #4 :: ALU / Memory
|
// Calculate stall conditions
|
// Calculate stall conditions
|
//
|
//
|
|
//{{{
|
// 1. Basic stall is if the previous stage is valid and the next is
|
// 1. Basic stall is if the previous stage is valid and the next is
|
// busy.
|
// busy.
|
// 2. Also stall if the prior stage is valid and the master clock enable
|
// 2. Also stall if the prior stage is valid and the master clock enable
|
// is de-selected
|
// is de-selected
|
// 3. Stall if someone on the other end is writing the CC register,
|
// 3. Stall if someone on the other end is writing the CC register,
|
// since we don't know if it'll put us to sleep or not.
|
// since we don't know if it'll put us to sleep or not.
|
// 4. Last case: Stall if we would otherwise move a break instruction
|
// 4. Last case: Stall if we would otherwise move a break instruction
|
// through the ALU. Break instructions are not allowed through
|
// through the ALU. Break instructions are not allowed through
|
// the ALU.
|
// the ALU.
|
`ifdef OPT_PIPELINED
|
generate if (OPT_PIPELINED)
|
assign alu_stall = (((!master_ce)||(mem_rdbusy)||(alu_busy))&&(op_valid_alu)) //Case 1&2
|
begin : GEN_ALU_STALL
|
||(prelock_stall)
|
assign alu_stall = (((master_stall)||(mem_rdbusy))&&(op_valid_alu)) //Case 1&2
|
||((op_valid)&&(op_break))
|
||(wr_reg_ce)&&(wr_write_cc);
|
||(wr_reg_ce)&&(wr_write_cc)
|
// assign // alu_ce = (master_ce)&&(op_valid_alu)&&(!alu_stall)
|
||(div_busy)||(fpu_busy);
|
// &&(!clear_pipeline)&&(!op_illegal)
|
assign alu_ce = (master_ce)&&(op_valid_alu)&&(!alu_stall)
|
// &&(!pending_sreg_write)
|
&&(!clear_pipeline);
|
// &&(!alu_sreg_stall);
|
`else
|
assign alu_ce = (adf_ce_unconditional)&&(op_valid_alu);
|
assign alu_stall = (op_valid_alu)&&((!master_ce)||(op_break));
|
|
assign alu_ce = (master_ce)&&(op_valid_alu)&&(!alu_stall)&&(!clear_pipeline);
|
// Verilator lint_off unused
|
`endif
|
wire unused_alu_stall = alu_stall;
|
|
// Verilator lint_on unused
|
|
end else begin
|
|
|
|
assign alu_stall = (master_stall);
|
|
//assign alu_ce = (master_ce)&&(op_valid_alu)
|
|
// &&(!clear_pipeline)
|
|
// &&(!alu_stall);
|
|
assign alu_ce = (adf_ce_unconditional)&&(op_valid_alu);
|
|
|
|
// Verilator lint_off unused
|
|
wire unused_alu_stall = alu_stall;
|
|
// Verilator lint_on unused
|
|
end endgenerate
|
//
|
//
|
|
|
//
|
//
|
// Note: if you change the conditions for mem_ce, you must also change
|
// Note: if you change the conditions for mem_ce, you must also change
|
// alu_pc_valid.
|
// alu_pc_valid.
|
//
|
//
|
assign mem_ce = (master_ce)&&(op_valid_mem)&&(!mem_stalled)
|
assign mem_ce = (master_ce)&&(op_valid_mem)&&(!mem_stalled)
|
&&(!clear_pipeline);
|
&&(!clear_pipeline);
|
|
|
`ifdef OPT_PIPELINED_BUS_ACCESS
|
generate if (OPT_PIPELINED_BUS_ACCESS)
|
assign mem_stalled = (!master_ce)||(alu_busy)||((op_valid_mem)&&(
|
begin
|
|
|
|
assign mem_stalled = (master_stall)||((op_valid_mem)&&(
|
(mem_pipe_stalled)
|
(mem_pipe_stalled)
|
||(prelock_stall)
|
||(bus_err)||(div_error)
|
||((!op_pipe)&&(mem_busy))
|
||((!op_pipe)&&(mem_busy))
|
||(div_busy)
|
|
||(fpu_busy)
|
|
// Stall waiting for flags to be valid
|
// Stall waiting for flags to be valid
|
// Or waiting for a write to the PC register
|
// Or waiting for a write to the PC register
|
// Or CC register, since that can change the
|
// Or CC register, since that can change the
|
// PC as well
|
// PC as well
|
||((wr_reg_ce)&&(wr_reg_id[4] == op_gie)
|
||((wr_reg_ce)
|
&&((wr_write_pc)||(wr_write_cc)))));
|
&&((wr_write_pc)||(wr_write_cc)))));
|
`else
|
end else if (OPT_PIPELINED)
|
`ifdef OPT_PIPELINED
|
begin
|
assign mem_stalled = (mem_busy)||((op_valid_mem)&&(
|
assign mem_stalled = (master_stall)||((op_valid_mem)&&(
|
(!master_ce)
|
(bus_err)||(div_error)||(mem_busy)
|
// Stall waiting for flags to be valid
|
// Stall waiting for flags to be valid
|
// Or waiting for a write to the PC register
|
// Or waiting for a write to the PC register
|
// Or CC register, since that can change the
|
// Or CC register, since that can change the
|
// PC as well
|
// PC as well
|
||((wr_reg_ce)&&(wr_reg_id[4] == op_gie)&&((wr_write_pc)||(wr_write_cc)))));
|
||((wr_reg_ce)
|
`else
|
&&((wr_write_pc)||(wr_write_cc)))));
|
assign mem_stalled = (op_valid_mem)&&(!master_ce);
|
end else begin
|
`endif
|
|
`endif
|
assign mem_stalled = (master_stall);
|
|
|
|
end endgenerate
|
|
//}}}
|
|
|
|
assign master_stall = (!master_ce)||(!op_valid)||(ill_err_i)
|
|
||(ibus_err_flag)||(idiv_err_flag)
|
|
||(pending_interrupt)&&(!alu_phase)
|
|
||(alu_busy)||(div_busy)||(fpu_busy)||(op_break)
|
|
||((OPT_PIPELINED)&&(
|
|
((OPT_LOCK)&&(prelock_stall))
|
|
||((mem_busy)&&(op_illegal))
|
|
||((mem_busy)&&(op_valid_div))
|
|
||(alu_illegal)||(o_break)));
|
|
|
|
|
// ALU, DIV, or FPU CE ... equivalent to the OR of all three of these
|
// ALU, DIV, or FPU CE ... equivalent to the OR of all three of these
|
assign adf_ce_unconditional = (master_ce)&&(!clear_pipeline)&&(op_valid)
|
always @(*)
|
&&(!op_valid_mem)&&(!mem_rdbusy)
|
if (OPT_PIPELINED)
|
&&((!op_valid_alu)||(!alu_stall))&&(!op_break)
|
adf_ce_unconditional =
|
&&(!div_busy)&&(!fpu_busy)&&(!clear_pipeline);
|
(!master_stall)&&(!op_valid_mem)&&(!mem_rdbusy)
|
|
&&((!mem_busy)||(!op_wR)||(op_R[4:1] != { gie, 3'h7}));
|
|
else
|
|
adf_ce_unconditional = (!master_stall)&&(op_valid)&&(!op_valid_mem);
|
|
|
//
|
//
|
//
|
//
|
// PIPELINE STAGE #1 :: Prefetch
|
// PIPELINE STAGE #1 :: Prefetch
|
//
|
//
|
//
|
//
|
wire pf_stalled;
|
//{{{
|
assign pf_stalled = (dcd_stalled)||(dcd_phase);
|
assign pf_stalled = (dcd_stalled)||(dcd_phase);
|
|
|
wire pf_new_pc;
|
assign pf_new_pc = (new_pc)||((dcd_early_branch_stb)&&(!clear_pipeline));
|
assign pf_new_pc = (new_pc)||((dcd_early_branch)&&(!clear_pipeline));
|
|
|
|
wire [(AW-1):0] pf_request_address;
|
assign pf_request_address = ((dcd_early_branch_stb)&&(!clear_pipeline))
|
assign pf_request_address = ((dcd_early_branch)&&(!clear_pipeline))
|
? dcd_branch_pc:pf_pc;
|
? dcd_branch_pc:pf_pc[(AW+1):2];
|
|
assign pf_gie = gie;
|
assign pf_gie = gie;
|
|
`ifdef FORMAL
|
|
abs_prefetch #(ADDRESS_WIDTH)
|
|
//{{{
|
|
pf(i_clk, (i_reset), pf_new_pc, w_clear_icache,
|
|
(!pf_stalled),
|
|
pf_request_address,
|
|
pf_instruction, pf_instruction_pc,
|
|
pf_valid,
|
|
pf_cyc, pf_stb, pf_we, pf_addr, pf_data,
|
|
pf_ack, pf_stall, pf_err, i_wb_data,
|
|
pf_illegal);
|
|
always @(*)
|
|
begin
|
|
f_pf_nreqs = 0;
|
|
f_pf_nacks = 0;
|
|
f_pf_outstanding = 0;
|
|
end
|
|
//}}}
|
|
`else
|
`ifdef OPT_SINGLE_FETCH
|
`ifdef OPT_SINGLE_FETCH
|
prefetch #(ADDRESS_WIDTH)
|
prefetch #(ADDRESS_WIDTH)
|
pf(i_clk, (i_rst), pf_new_pc, w_clear_icache,
|
//{{{
|
|
pf(i_clk, (i_reset), pf_new_pc, w_clear_icache,
|
(!pf_stalled),
|
(!pf_stalled),
|
pf_request_address,
|
pf_request_address,
|
pf_instruction, pf_instruction_pc,
|
pf_instruction, pf_instruction_pc,
|
pf_valid, pf_illegal,
|
pf_valid, pf_illegal,
|
pf_cyc, pf_stb, pf_we, pf_addr, pf_data,
|
pf_cyc, pf_stb, pf_we, pf_addr, pf_data,
|
pf_ack, pf_stall, pf_err, i_wb_data);
|
pf_ack, pf_stall, pf_err, i_wb_data);
|
|
//}}}
|
`else
|
`else
|
`ifdef OPT_DOUBLE_FETCH
|
`ifdef OPT_DOUBLE_FETCH
|
|
|
wire [1:0] pf_dbg;
|
|
dblfetch #(ADDRESS_WIDTH)
|
dblfetch #(ADDRESS_WIDTH)
|
pf(i_clk, i_rst, pf_new_pc,
|
//{{{
|
w_clear_icache,
|
pf(i_clk, i_reset, pf_new_pc, w_clear_icache,
|
(!pf_stalled),
|
(!pf_stalled),
|
pf_request_address,
|
pf_request_address,
|
pf_instruction, pf_instruction_pc,
|
pf_instruction, pf_instruction_pc,
|
pf_valid,
|
pf_valid,
|
pf_cyc, pf_stb, pf_we, pf_addr, pf_data,
|
pf_cyc, pf_stb, pf_we, pf_addr, pf_data,
|
pf_ack, pf_stall, pf_err, i_wb_data,
|
pf_ack, pf_stall, pf_err, i_wb_data,
|
pf_illegal);
|
pf_illegal);
|
|
//}}}
|
|
|
`else // Not single fetch and not double fetch
|
`else // Not single fetch and not double fetch
|
|
|
`ifdef OPT_TRADITIONAL_PFCACHE
|
`ifdef OPT_TRADITIONAL_PFCACHE
|
pfcache #(LGICACHE, ADDRESS_WIDTH)
|
pfcache #(LGICACHE, ADDRESS_WIDTH)
|
pf(i_clk, i_rst, pf_new_pc, w_clear_icache,
|
//{{{
|
|
pf(i_clk, i_reset, pf_new_pc, w_clear_icache,
|
// dcd_pc,
|
// dcd_pc,
|
(!pf_stalled),
|
(!pf_stalled),
|
pf_request_address,
|
pf_request_address,
|
pf_instruction, pf_instruction_pc, pf_valid,
|
pf_instruction, pf_instruction_pc, pf_valid,
|
pf_cyc, pf_stb, pf_we, pf_addr, pf_data,
|
pf_cyc, pf_stb, pf_we, pf_addr, pf_data,
|
pf_ack, pf_stall, pf_err, i_wb_data,
|
pf_ack, pf_stall, pf_err, i_wb_data,
|
pf_illegal);
|
pf_illegal);
|
|
//}}}
|
`else
|
`else
|
pipefetch #(RESET_BUS_ADDRESS, LGICACHE, ADDRESS_WIDTH)
|
pipefetch #({RESET_BUS_ADDRESS, 2'b00}, LGICACHE, ADDRESS_WIDTH)
|
pf(i_clk, i_rst, pf_new_pc,
|
//{{{
|
|
pf(i_clk, i_reset, pf_new_pc,
|
w_clear_icache, (!pf_stalled),
|
w_clear_icache, (!pf_stalled),
|
(new_pc)?pf_pc[(AW+1):2]:dcd_branch_pc,
|
(new_pc)?pf_pc:dcd_branch_pc,
|
pf_instruction, pf_instruction_pc, pf_valid,
|
pf_instruction, pf_instruction_pc, pf_valid,
|
pf_cyc, pf_stb, pf_we, pf_addr, pf_data,
|
pf_cyc, pf_stb, pf_we, pf_addr, pf_data,
|
pf_ack, pf_stall, pf_err, i_wb_data,
|
pf_ack, pf_stall, pf_err, i_wb_data,
|
(mem_cyc_lcl)||(mem_cyc_gbl),
|
(mem_cyc_lcl)||(mem_cyc_gbl),
|
pf_illegal);
|
pf_illegal);
|
|
//}}}
|
`endif // OPT_TRADITIONAL_CACHE
|
`endif // OPT_TRADITIONAL_CACHE
|
`endif // OPT_DOUBLE_FETCH
|
`endif // OPT_DOUBLE_FETCH
|
`endif // OPT_SINGLE_FETCH
|
`endif // OPT_SINGLE_FETCH
|
|
`endif // FORMAL
|
|
//}}}
|
|
|
assign dcd_ce = (!dcd_valid)||(!dcd_stalled);
|
//
|
idecode #(AW, IMPLEMENT_MPY, EARLY_BRANCHING, IMPLEMENT_DIVIDE,
|
//
|
IMPLEMENT_FPU)
|
// PIPELINE STAGE #2 :: Instruction Decode
|
|
//
|
|
//
|
|
//{{{
|
|
assign dcd_ce =((OPT_PIPELINED)&&(!dcd_valid))||(!dcd_stalled);
|
|
idecode #(.ADDRESS_WIDTH(AW),
|
|
.OPT_MPY((IMPLEMENT_MPY!=0)? 1'b1:1'b0),
|
|
.OPT_PIPELINED(OPT_PIPELINED),
|
|
.OPT_EARLY_BRANCHING(EARLY_BRANCHING),
|
|
.OPT_DIVIDE(IMPLEMENT_DIVIDE),
|
|
.OPT_FPU(IMPLEMENT_FPU),
|
|
.OPT_LOCK(OPT_LOCK),
|
|
.OPT_OPIPE(OPT_PIPELINED_BUS_ACCESS),
|
|
.OPT_NO_USERMODE(OPT_NO_USERMODE),
|
|
`ifdef VERILATOR
|
|
.OPT_SIM(1'b1),
|
|
`else
|
|
.OPT_SIM(1'b0),
|
|
`endif
|
|
.OPT_CIS(OPT_CIS))
|
instruction_decoder(i_clk,
|
instruction_decoder(i_clk,
|
(clear_pipeline)||(w_clear_icache),
|
(i_reset)||(clear_pipeline)||(w_clear_icache),
|
dcd_ce,
|
dcd_ce,
|
dcd_stalled, pf_instruction, pf_gie,
|
dcd_stalled, pf_instruction, pf_gie,
|
pf_instruction_pc, pf_valid, pf_illegal,
|
pf_instruction_pc, pf_valid, pf_illegal,
|
dcd_valid, dcd_phase,
|
dcd_valid, dcd_phase,
|
dcd_illegal, dcd_pc, dcd_gie,
|
dcd_illegal, dcd_pc,
|
{ dcd_Rcc, dcd_Rpc, dcd_R },
|
{ dcd_Rcc, dcd_Rpc, dcd_R },
|
{ dcd_Acc, dcd_Apc, dcd_A },
|
{ dcd_Acc, dcd_Apc, dcd_A },
|
{ dcd_Bcc, dcd_Bpc, dcd_B },
|
{ dcd_Bcc, dcd_Bpc, dcd_B },
|
|
dcd_preA, dcd_preB,
|
dcd_I, dcd_zI, dcd_F, dcd_wF, dcd_opn,
|
dcd_I, dcd_zI, dcd_F, dcd_wF, dcd_opn,
|
dcd_ALU, dcd_M, dcd_DIV, dcd_FP, dcd_break, dcd_lock,
|
dcd_ALU, dcd_M, dcd_DIV, dcd_FP, dcd_break, dcd_lock,
|
dcd_wR,dcd_rA, dcd_rB,
|
dcd_wR,dcd_rA, dcd_rB,
|
dcd_early_branch,
|
dcd_early_branch, dcd_early_branch_stb,
|
dcd_branch_pc, dcd_ljmp,
|
dcd_branch_pc, dcd_ljmp,
|
dcd_pipe,
|
dcd_pipe,
|
dcd_sim, dcd_sim_immv);
|
dcd_sim, dcd_sim_immv
|
|
`ifdef FORMAL
|
|
, f_dcd_insn_word, f_dcd_insn_gie
|
|
`endif
|
|
);
|
|
assign dcd_gie = pf_gie;
|
|
//}}}
|
|
|
`ifdef OPT_PIPELINED_BUS_ACCESS
|
//
|
|
//
|
|
// PIPELINE STAGE #3 :: Read Operands (Registers)
|
|
//
|
|
//
|
|
//{{{
|
|
generate if (OPT_PIPELINED_BUS_ACCESS)
|
|
begin : GEN_OP_PIPE
|
reg r_op_pipe;
|
reg r_op_pipe;
|
|
|
initial r_op_pipe = 1'b0;
|
initial r_op_pipe = 1'b0;
|
// To be a pipeable operation, there must be
|
// To be a pipeable operation, there must be
|
// two valid adjacent instructions
|
// two valid adjacent instructions
|
// Both must be memory instructions
|
// Both must be memory instructions
|
// Both must be writes, or both must be reads
|
// Both must be writes, or both must be reads
|
// Both operations must be to the same identical address,
|
// Both operations must be to the same identical address,
|
// or at least a single (one) increment above that address
|
// or at least a single (one) increment above that
|
|
// address
|
//
|
//
|
// However ... we need to know this before this clock, hence this is
|
// However ... we need to know this before this clock, hence
|
// calculated in the instruction decoder.
|
// this is calculated in the instruction decoder.
|
always @(posedge i_clk)
|
always @(posedge i_clk)
|
if (clear_pipeline)
|
if ((clear_pipeline)||(i_halt))
|
r_op_pipe <= 1'b0;
|
r_op_pipe <= 1'b0;
|
else if (op_ce)
|
else if (op_ce)
|
r_op_pipe <= dcd_pipe;
|
r_op_pipe <= (dcd_pipe)&&(op_valid_mem);
|
|
else if ((wr_reg_ce)&&(wr_reg_id == op_Bid[4:0]))
|
|
r_op_pipe <= 1'b0;
|
else if (mem_ce) // Clear us any time an op_ is clocked in
|
else if (mem_ce) // Clear us any time an op_ is clocked in
|
r_op_pipe <= 1'b0;
|
r_op_pipe <= 1'b0;
|
|
|
assign op_pipe = r_op_pipe;
|
assign op_pipe = r_op_pipe;
|
`else
|
end else begin
|
|
|
assign op_pipe = 1'b0;
|
assign op_pipe = 1'b0;
|
`endif
|
|
|
|
//
|
end endgenerate
|
//
|
|
// PIPELINE STAGE #3 :: Read Operands (Registers)
|
// `define NO_DISTRIBUTED_RAM
|
//
|
`ifdef NO_DISTRIBUTED_RAM
|
//
|
reg [31:0] pre_rewrite_value, pre_op_Av, pre_op_Bv;
|
`ifdef OPT_NO_USERMODE
|
reg pre_rewrite_flag_A, pre_rewrite_flag_B;
|
|
|
|
always @(posedge i_clk)
|
|
if (dcd_ce)
|
|
begin
|
|
pre_rewrite_flag_A <= (wr_reg_ce)&&(dcd_preA == wr_reg_id);
|
|
pre_rewrite_flag_B <= (wr_reg_ce)&&(dcd_preB == wr_reg_id);
|
|
pre_rewrite_value <= wr_gpreg_vl;
|
|
end
|
|
|
|
generate if (OPT_NO_USERMODE)
|
|
begin
|
|
always @(posedge i_clk)
|
|
if (dcd_ce)
|
|
begin
|
|
pre_op_Av <= regset[dcd_preA[3:0]];
|
|
pre_op_Bv <= regset[dcd_preB[3:0]];
|
|
end
|
|
end else begin
|
|
|
|
always @(posedge i_clk)
|
|
if (dcd_ce)
|
|
begin
|
|
pre_op_Av <= regset[dcd_preA];
|
|
pre_op_Bv <= regset[dcd_preB];
|
|
end
|
|
|
|
end endgenerate
|
|
|
|
assign w_op_Av = (pre_rewrite_flag_A) ? pre_rewrite_value : pre_op_Av;
|
|
assign w_op_Bv = (pre_rewrite_flag_B) ? pre_rewrite_value : pre_op_Bv;
|
|
`else
|
|
generate if (OPT_NO_USERMODE)
|
|
begin
|
assign w_op_Av = regset[dcd_A[3:0]];
|
assign w_op_Av = regset[dcd_A[3:0]];
|
assign w_op_Bv = regset[dcd_B[3:0]];
|
assign w_op_Bv = regset[dcd_B[3:0]];
|
`else
|
end else begin
|
|
|
assign w_op_Av = regset[dcd_A];
|
assign w_op_Av = regset[dcd_A];
|
assign w_op_Bv = regset[dcd_B];
|
assign w_op_Bv = regset[dcd_B];
|
|
|
|
end endgenerate
|
|
|
|
// verilator lint_off UNUSED
|
|
wire [9:0] unused_prereg_addrs;
|
|
assign unused_prereg_addrs = { dcd_preA, dcd_preB };
|
|
// verilator lint_on UNUSED
|
`endif
|
`endif
|
|
|
wire [8:0] w_cpu_info;
|
|
assign w_cpu_info = {
|
assign w_cpu_info = {
|
|
//{{{
|
1'b1,
|
1'b1,
|
(IMPLEMENT_MPY >0)? 1'b1:1'b0,
|
(IMPLEMENT_MPY >0)? 1'b1:1'b0,
|
(IMPLEMENT_DIVIDE >0)? 1'b1:1'b0,
|
(IMPLEMENT_DIVIDE >0)? 1'b1:1'b0,
|
(IMPLEMENT_FPU >0)? 1'b1:1'b0,
|
(IMPLEMENT_FPU >0)? 1'b1:1'b0,
|
`ifdef OPT_PIPELINED
|
OPT_PIPELINED,
|
1'b1,
|
|
`else
|
|
1'b0,
|
|
`endif
|
|
`ifdef OPT_TRADITIONAL_CACHE
|
`ifdef OPT_TRADITIONAL_CACHE
|
1'b1,
|
1'b1,
|
`else
|
`else
|
1'b0,
|
1'b0,
|
`endif
|
`endif
|
`ifdef OPT_EARLY_BRANCHING
|
(EARLY_BRANCHING > 0)? 1'b1:1'b0,
|
1'b1,
|
OPT_PIPELINED_BUS_ACCESS,
|
`else
|
OPT_CIS
|
1'b0,
|
|
`endif
|
|
`ifdef OPT_PIPELINED_BUS_ACCESS
|
|
1'b1,
|
|
`else
|
|
1'b0,
|
|
`endif
|
|
`ifdef OPT_CIS
|
|
1'b1
|
|
`else
|
|
1'b0
|
|
`endif
|
|
};
|
};
|
|
//}}}
|
|
|
|
always @(*)
|
|
if ((OPT_NO_USERMODE)||(dcd_A[4] == dcd_gie))
|
|
w_pcA_v[(AW+1):0] = { dcd_pc[AW+1:2], 2'b00 };
|
|
else
|
|
w_pcA_v[(AW+1):0] = { upc[(AW+1):2], uhalt_phase, 1'b0 };
|
|
|
wire [31:0] w_pcA_v;
|
|
assign w_pcA_v[(AW+1):0] = { (dcd_A[4] == dcd_gie)
|
|
? { dcd_pc[AW:1], 2'b00 }
|
|
: { upc[(AW+1):2], uhalt_phase, 1'b0 } };
|
|
generate
|
generate
|
if (AW < 30)
|
if (AW < 30)
|
assign w_pcA_v[31:(AW+2)] = 0;
|
always @(*)
|
|
w_pcA_v[31:(AW+2)] = 0;
|
endgenerate
|
endgenerate
|
|
|
`ifdef OPT_PIPELINED
|
generate if (OPT_PIPELINED)
|
reg [4:0] op_Aid, op_Bid;
|
begin : OPV
|
reg op_rA, op_rB;
|
initial op_R = 0;
|
|
initial op_Aid = 0;
|
|
initial op_Bid = 0;
|
|
initial op_rA = 0;
|
|
initial op_rB = 0;
|
|
initial op_Rcc = 0;
|
always @(posedge i_clk)
|
always @(posedge i_clk)
|
if (op_ce)
|
if (op_ce)
|
begin
|
begin
|
|
op_R <= dcd_R;
|
op_Aid <= dcd_A;
|
op_Aid <= dcd_A;
|
op_Bid <= dcd_B;
|
op_Bid <= dcd_B;
|
op_rA <= dcd_rA;
|
op_rA <= (dcd_rA)&&(!dcd_early_branch)&&(!dcd_illegal);
|
op_rB <= dcd_rB;
|
op_rB <= (dcd_rB)&&(!dcd_early_branch)&&(!dcd_illegal);
|
|
op_Rcc <= (dcd_Rcc)&&(dcd_wR)&&(dcd_R[4]==dcd_gie);
|
end
|
end
|
`endif
|
|
|
end else begin
|
|
|
|
always @(*)
|
|
begin
|
|
op_R = dcd_R;
|
|
op_Aid = dcd_A;
|
|
op_Bid = dcd_B;
|
|
op_rA = dcd_rA;
|
|
op_rB = dcd_rB;
|
|
op_Rcc = (dcd_Rcc)&&(dcd_wR)&&(dcd_R[4]==dcd_gie);
|
|
end
|
|
|
|
end endgenerate
|
|
|
|
|
always @(posedge i_clk)
|
always @(posedge i_clk)
|
if (op_ce)
|
if ((!OPT_PIPELINED)||(op_ce))
|
begin
|
begin
|
`ifdef OPT_PIPELINED
|
if ((OPT_PIPELINED)&&(wr_reg_ce)&&(wr_reg_id == dcd_A))
|
if ((wr_reg_ce)&&(wr_reg_id == dcd_A))
|
|
r_op_Av <= wr_gpreg_vl;
|
r_op_Av <= wr_gpreg_vl;
|
else
|
else if (dcd_Apc)
|
`endif
|
|
if (dcd_Apc)
|
|
r_op_Av <= w_pcA_v;
|
r_op_Av <= w_pcA_v;
|
else if (dcd_Acc)
|
else if (dcd_Acc)
|
r_op_Av <= { w_cpu_info, w_op_Av[22:16], 1'b0, (dcd_A[4])?w_uflags:w_iflags };
|
r_op_Av <= { w_cpu_info, w_op_Av[22:16], 1'b0, (dcd_A[4])?w_uflags:w_iflags };
|
else
|
else
|
r_op_Av <= w_op_Av;
|
r_op_Av <= w_op_Av;
|
`ifdef OPT_PIPELINED
|
end else if (OPT_PIPELINED)
|
end else
|
|
begin
|
begin
|
if ((wr_reg_ce)&&(wr_reg_id == op_Aid)&&(op_rA))
|
if ((wr_reg_ce)&&(wr_reg_id == op_Aid)&&(op_rA))
|
r_op_Av <= wr_gpreg_vl;
|
r_op_Av <= wr_gpreg_vl;
|
`endif
|
|
end
|
end
|
|
|
wire [31:0] w_op_BnI, w_pcB_v;
|
always @(*)
|
assign w_pcB_v[(AW+1):0] = { (dcd_B[4] == dcd_gie)
|
if ((OPT_NO_USERMODE)||(dcd_B[4] == dcd_gie))
|
? { dcd_pc[AW:1], 2'b00 }
|
w_pcB_v[(AW+1):0] = { dcd_pc[AW+1:2], 2'b00 };
|
: { upc[(AW+1):2], uhalt_phase, 1'b0 } };
|
else
|
|
w_pcB_v[(AW+1):0] = { upc[(AW+1):2], uhalt_phase, 1'b0 };
|
generate
|
generate
|
if (AW < 30)
|
if (AW < 30)
|
assign w_pcB_v[31:(AW+2)] = 0;
|
always @(*)
|
|
w_pcB_v[31:(AW+2)] = 0;
|
endgenerate
|
endgenerate
|
|
|
assign w_op_BnI = (!dcd_rB) ? 32'h00
|
always @(*)
|
`ifdef OPT_PIPELINED
|
if (!dcd_rB)
|
: ((wr_reg_ce)&&(wr_reg_id == dcd_B)) ? wr_gpreg_vl
|
w_op_BnI = 0;
|
`endif
|
else if ((OPT_PIPELINED)&&(wr_reg_ce)&&(wr_reg_id == dcd_B))
|
: ((dcd_Bcc) ? { w_cpu_info, w_op_Bv[22:16], // w_op_B[31:14],
|
w_op_BnI = wr_gpreg_vl;
|
1'b0, (dcd_B[4])?w_uflags:w_iflags}
|
else if (dcd_Bcc)
|
: w_op_Bv);
|
w_op_BnI = { w_cpu_info, w_op_Bv[22:16], 1'b0,
|
|
(dcd_B[4]) ? w_uflags : w_iflags };
|
|
else
|
|
w_op_BnI = w_op_Bv;
|
|
|
always @(posedge i_clk)
|
always @(posedge i_clk)
|
`ifdef OPT_PIPELINED
|
if ((!OPT_PIPELINED)||(op_ce))
|
if ((op_ce)&&(dcd_Bpc)&&(dcd_rB))
|
begin
|
r_op_Bv <= w_pcB_v + { dcd_I[29:0], 2'b00 };
|
|
else if (op_ce)
|
|
r_op_Bv <= w_op_BnI + dcd_I;
|
|
else if ((wr_reg_ce)&&(op_Bid == wr_reg_id)&&(op_rB))
|
|
r_op_Bv <= wr_gpreg_vl;
|
|
`else
|
|
if ((dcd_Bpc)&&(dcd_rB))
|
if ((dcd_Bpc)&&(dcd_rB))
|
r_op_Bv <= w_pcB_v + { dcd_I[29:0], 2'b00 };
|
r_op_Bv <= w_pcB_v + { dcd_I[29:0], 2'b00 };
|
else
|
else
|
r_op_Bv <= w_op_BnI + dcd_I;
|
r_op_Bv <= w_op_BnI + dcd_I;
|
`endif
|
end else if ((OPT_PIPELINED)&&(op_rB)
|
|
&&(wr_reg_ce)&&(op_Bid == wr_reg_id))
|
|
r_op_Bv <= wr_gpreg_vl;
|
|
|
// The logic here has become more complex than it should be, no thanks
|
// The logic here has become more complex than it should be, no thanks
|
// to Xilinx's Vivado trying to help. The conditions are supposed to
|
// to Xilinx's Vivado trying to help. The conditions are supposed to
|
// be two sets of four bits: the top bits specify what bits matter, the
|
// be two sets of four bits: the top bits specify what bits matter, the
|
// bottom specify what those top bits must equal. However, two of
|
// bottom specify what those top bits must equal. However, two of
|
| Line 765... |
Line 1005... |
// conditions checking those bits. Therefore, Vivado complains that
|
// conditions checking those bits. Therefore, Vivado complains that
|
// these two bits are redundant. Hence the convoluted expression
|
// these two bits are redundant. Hence the convoluted expression
|
// below, arriving at what we finally want in the (now wire net)
|
// below, arriving at what we finally want in the (now wire net)
|
// op_F.
|
// op_F.
|
always @(posedge i_clk)
|
always @(posedge i_clk)
|
if (op_ce) // Cannot do op_change_data_ce here since op_F depends
|
if ((!OPT_PIPELINED)||(op_ce))
|
|
// Cannot do op_change_data_ce here since op_F depends
|
// upon being either correct for a valid op, or correct
|
// upon being either correct for a valid op, or correct
|
// for the last valid op
|
// for the last valid op
|
begin // Set the flag condition codes, bit order is [3:0]=VNCZ
|
begin // Set the flag condition codes, bit order is [3:0]=VNCZ
|
case(dcd_F[2:0])
|
case(dcd_F[2:0])
|
3'h0: r_op_F <= 7'h00; // Always
|
3'h0: r_op_F <= 7'h00; // Always
|
| Line 782... |
Line 1023... |
3'h7: r_op_F <= 7'h20; // NC
|
3'h7: r_op_F <= 7'h20; // NC
|
endcase
|
endcase
|
end // Bit order is { (flags_not_used), VNCZ mask, VNCZ value }
|
end // Bit order is { (flags_not_used), VNCZ mask, VNCZ value }
|
assign op_F = { r_op_F[3], r_op_F[6:0] };
|
assign op_F = { r_op_F[3], r_op_F[6:0] };
|
|
|
wire w_op_valid;
|
assign w_op_valid = (!clear_pipeline)&&(dcd_valid)
|
assign w_op_valid = (!clear_pipeline)&&(dcd_valid)&&(!dcd_ljmp)&&(!dcd_early_branch);
|
&&(!dcd_ljmp)&&(!dcd_early_branch);
|
|
|
initial op_valid = 1'b0;
|
initial op_valid = 1'b0;
|
initial op_valid_alu = 1'b0;
|
initial op_valid_alu = 1'b0;
|
initial op_valid_mem = 1'b0;
|
initial op_valid_mem = 1'b0;
|
initial op_valid_div = 1'b0;
|
initial op_valid_div = 1'b0;
|
initial op_valid_fpu = 1'b0;
|
initial op_valid_fpu = 1'b0;
|
always @(posedge i_clk)
|
always @(posedge i_clk)
|
if (clear_pipeline)
|
if ((i_reset)||(clear_pipeline))
|
begin
|
begin
|
op_valid <= 1'b0;
|
op_valid <= 1'b0;
|
op_valid_alu <= 1'b0;
|
op_valid_alu <= 1'b0;
|
op_valid_mem <= 1'b0;
|
op_valid_mem <= 1'b0;
|
op_valid_div <= 1'b0;
|
op_valid_div <= 1'b0;
|
| Line 807... |
Line 1049... |
// have in our queue. This instruction must then
|
// have in our queue. This instruction must then
|
// move forward, and get a stall cycle inserted.
|
// move forward, and get a stall cycle inserted.
|
// Hence, the test on dcd_stalled here. If we must
|
// Hence, the test on dcd_stalled here. If we must
|
// wait until our operands are valid, then we aren't
|
// wait until our operands are valid, then we aren't
|
// valid yet until then.
|
// valid yet until then.
|
op_valid<= (w_op_valid)||(dcd_illegal)&&(dcd_valid)||(dcd_early_branch);
|
if (OPT_PIPELINED || !op_valid)
|
op_valid_alu <= (w_op_valid)&&((dcd_ALU)||(dcd_illegal)
|
begin
|
||(dcd_early_branch));
|
op_valid <= (w_op_valid)||(dcd_early_branch);
|
op_valid_mem <= (dcd_M)&&(!dcd_illegal)&&(w_op_valid);
|
op_valid_alu <= (w_op_valid)&&((dcd_ALU)||(dcd_illegal));
|
op_valid_div <= (dcd_DIV)&&(!dcd_illegal)&&(w_op_valid);
|
op_valid_mem <= (dcd_M)&&(!dcd_illegal)
|
op_valid_fpu <= (dcd_FP)&&(!dcd_illegal)&&(w_op_valid);
|
&&(w_op_valid);
|
|
op_valid_div <= (IMPLEMENT_DIVIDE)&&(dcd_DIV)&&(!dcd_illegal)&&(w_op_valid);
|
|
op_valid_fpu <= (IMPLEMENT_FPU)&&(dcd_FP)&&(!dcd_illegal)&&(w_op_valid);
|
|
end else if ((adf_ce_unconditional)||(mem_ce))
|
|
begin
|
|
op_valid <= 1'b0;
|
|
op_valid_alu <= 1'b0;
|
|
op_valid_mem <= 1'b0;
|
|
op_valid_div <= 1'b0;
|
|
op_valid_fpu <= 1'b0;
|
|
end
|
end else if ((adf_ce_unconditional)||(mem_ce))
|
end else if ((adf_ce_unconditional)||(mem_ce))
|
begin
|
begin
|
op_valid <= 1'b0;
|
op_valid <= 1'b0;
|
op_valid_alu <= 1'b0;
|
op_valid_alu <= 1'b0;
|
op_valid_mem <= 1'b0;
|
op_valid_mem <= 1'b0;
|
| Line 831... |
Line 1083... |
// break to repeat and continue upon return. To get out of this
|
// break to repeat and continue upon return. To get out of this
|
// condition, replace the break instruction with what it is supposed
|
// condition, replace the break instruction with what it is supposed
|
// to be, step through it, and then replace it back. In this fashion,
|
// to be, step through it, and then replace it back. In this fashion,
|
// a debugger can step through code.
|
// a debugger can step through code.
|
// assign w_op_break = (dcd_break)&&(r_dcd_I[15:0] == 16'h0001);
|
// assign w_op_break = (dcd_break)&&(r_dcd_I[15:0] == 16'h0001);
|
reg r_op_break;
|
|
|
|
initial r_op_break = 1'b0;
|
initial r_op_break = 1'b0;
|
always @(posedge i_clk)
|
always @(posedge i_clk)
|
if ((i_rst)||(clear_pipeline)) r_op_break <= 1'b0;
|
if (clear_pipeline)
|
else if (op_ce)
|
|
r_op_break <= (dcd_break);
|
|
else if (!op_valid)
|
|
r_op_break <= 1'b0;
|
r_op_break <= 1'b0;
|
|
else if ((OPT_PIPELINED)&&(op_ce))
|
|
r_op_break <= (dcd_valid)&&(dcd_break)&&(!dcd_illegal);
|
|
else if ((!OPT_PIPELINED)&&(dcd_valid))
|
|
r_op_break <= (dcd_break)&&(!dcd_illegal);
|
assign op_break = r_op_break;
|
assign op_break = r_op_break;
|
|
|
`ifdef OPT_PIPELINED
|
generate if ((!OPT_PIPELINED)||(!OPT_LOCK))
|
generate
|
|
if (IMPLEMENT_LOCK != 0)
|
|
begin
|
begin
|
|
|
|
assign op_lock = 1'b0;
|
|
|
|
// Verilator lint_off UNUSED
|
|
wire dcd_lock_unused;
|
|
assign dcd_lock_unused = dcd_lock;
|
|
// Verilator lint_on UNUSED
|
|
|
|
end else // if (IMPLEMENT_LOCK != 0)
|
|
begin : OPLOCK
|
reg r_op_lock;
|
reg r_op_lock;
|
|
|
initial r_op_lock = 1'b0;
|
initial r_op_lock = 1'b0;
|
always @(posedge i_clk)
|
always @(posedge i_clk)
|
if (clear_pipeline)
|
if (clear_pipeline)
|
r_op_lock <= 1'b0;
|
r_op_lock <= 1'b0;
|
else if (op_ce)
|
else if (op_ce)
|
r_op_lock <= (dcd_valid)&&(dcd_lock)&&(!clear_pipeline);
|
r_op_lock <= (dcd_valid)&&(dcd_lock)
|
|
&&(!dcd_illegal);
|
assign op_lock = r_op_lock;
|
assign op_lock = r_op_lock;
|
|
|
end else begin
|
|
assign op_lock = 1'b0;
|
|
end endgenerate
|
end endgenerate
|
|
|
`else
|
|
assign op_lock = 1'b0;
|
|
`endif
|
|
|
|
`ifdef OPT_ILLEGAL_INSTRUCTION
|
|
initial op_illegal = 1'b0;
|
initial op_illegal = 1'b0;
|
always @(posedge i_clk)
|
always @(posedge i_clk)
|
if (clear_pipeline)
|
if ((i_reset)||(clear_pipeline))
|
op_illegal <= 1'b0;
|
|
else if(op_ce)
|
|
`ifdef OPT_PIPELINED
|
|
op_illegal <= (dcd_valid)&&((dcd_illegal)||((dcd_lock)&&(IMPLEMENT_LOCK == 0)));
|
|
`else
|
|
op_illegal <= (dcd_valid)&&((dcd_illegal)||(dcd_lock));
|
|
`endif
|
|
else if(alu_ce)
|
|
op_illegal <= 1'b0;
|
op_illegal <= 1'b0;
|
`endif
|
else if (OPT_PIPELINED)
|
|
begin
|
// No generate on EARLY_BRANCHING here, since if EARLY_BRANCHING is not
|
|
// set, dcd_early_branch will simply be a wire connected to zero and
|
|
// this logic should just optimize.
|
|
`ifdef OPT_PIPELINED
|
|
always @(posedge i_clk)
|
|
if (op_ce)
|
if (op_ce)
|
|
op_illegal <= (dcd_valid)&&(!dcd_ljmp)
|
|
&&(!dcd_early_branch)&&(dcd_illegal);
|
|
end else if (!OPT_PIPELINED)
|
begin
|
begin
|
op_wF <= (dcd_wF)&&((!dcd_Rcc)||(!dcd_wR))
|
if (dcd_valid)
|
&&(!dcd_early_branch)&&(!dcd_illegal);
|
op_illegal <= (!dcd_ljmp)&&(!dcd_early_branch)&&(dcd_illegal);
|
op_wR <= (dcd_wR)&&(!dcd_early_branch)&&(!dcd_illegal);
|
|
end
|
end
|
`else
|
|
always @(posedge i_clk)
|
always @(posedge i_clk)
|
begin
|
if ((!OPT_PIPELINED)||(op_ce))
|
op_wF <= (dcd_wF)&&((!dcd_Rcc)||(!dcd_wR))
|
op_wF <= (dcd_wF)&&((!dcd_Rcc)||(!dcd_wR))
|
&&(!dcd_early_branch)&&(!dcd_illegal);
|
&&(!dcd_early_branch);
|
op_wR <= (dcd_wR)&&(!dcd_early_branch)&&(!dcd_illegal);
|
|
end
|
generate if ((OPT_PIPELINED)||(EARLY_BRANCHING))
|
`endif
|
begin
|
|
|
|
always @(posedge i_clk)
|
|
if (op_ce)
|
|
op_wR <= (dcd_wR)&&(!dcd_early_branch);
|
|
|
|
end else begin
|
|
|
|
always @(*)
|
|
op_wR = (dcd_wR);
|
|
|
|
end endgenerate
|
|
|
`ifdef VERILATOR
|
`ifdef VERILATOR
|
`ifdef SINGLE_FETCH
|
`ifdef SINGLE_FETCH
|
always @(*)
|
always @(*)
|
begin
|
begin
|
op_sim = dcd_sim;
|
op_sim = dcd_sim;
|
op_sim_immv = dcd_sim_immv;
|
op_sim_immv = dcd_sim_immv;
|
end
|
end
|
`else
|
`else
|
always @(posedge i_clk)
|
always @(posedge i_clk)
|
if (op_change_data_ce)
|
if (op_ce)
|
begin
|
begin
|
op_sim <= dcd_sim;
|
op_sim <= dcd_sim;
|
op_sim_immv <= dcd_sim_immv;
|
op_sim_immv <= dcd_sim_immv;
|
end
|
end
|
`endif
|
`endif
|
`endif
|
`endif
|
|
|
reg [3:0] r_op_opn;
|
|
reg [4:0] r_op_R;
|
|
reg r_op_Rcc;
|
|
reg r_op_gie;
|
|
|
|
initial r_op_gie = 1'b0;
|
generate if ((OPT_PIPELINED)||(EARLY_BRANCHING))
|
|
begin : SET_OP_PC
|
|
|
|
initial op_pc[0] = 1'b0;
|
always @(posedge i_clk)
|
always @(posedge i_clk)
|
if (op_change_data_ce)
|
if (op_ce)
|
|
op_pc <= (dcd_early_branch)?dcd_branch_pc:dcd_pc;
|
|
|
|
end else begin : SET_OP_PC
|
|
|
|
always @(*)
|
|
op_pc = dcd_pc;
|
|
|
|
end endgenerate
|
|
|
|
generate if (!OPT_PIPELINED)
|
|
begin
|
|
always @(*)
|
|
r_op_opn = dcd_opn;
|
|
|
|
end else begin
|
|
|
|
always @(posedge i_clk)
|
|
if (op_ce)
|
begin
|
begin
|
// Which ALU operation? Early branches are
|
// Which ALU operation? Early branches are
|
// unimplemented moves
|
// unimplemented moves
|
r_op_opn <= (dcd_early_branch) ? 4'hf : dcd_opn;
|
r_op_opn <= ((dcd_early_branch)||(dcd_illegal))
|
|
? `CPU_MOV_OP : dcd_opn;
|
// opM <= dcd_M; // Is this a memory operation?
|
// opM <= dcd_M; // Is this a memory operation?
|
// What register will these results be written into?
|
// What register will these results be written into?
|
r_op_R <= dcd_R;
|
|
r_op_Rcc <= (dcd_Rcc)&&(dcd_wR)&&(dcd_R[4]==dcd_gie);
|
|
// User level (1), vs supervisor (0)/interrupts disabled
|
|
r_op_gie <= dcd_gie;
|
|
|
|
//
|
|
op_pc <= (dcd_early_branch)?dcd_branch_pc:dcd_pc[AW:1];
|
|
end
|
end
|
|
|
|
end endgenerate
|
|
|
assign op_opn = r_op_opn;
|
assign op_opn = r_op_opn;
|
assign op_R = r_op_R;
|
assign op_gie = gie;
|
assign op_gie = r_op_gie;
|
|
assign op_Rcc = r_op_Rcc;
|
|
|
|
assign op_Fl = (op_gie)?(w_uflags):(w_iflags);
|
assign op_Fl = (op_gie)?(w_uflags[3:0]):(w_iflags[3:0]);
|
|
|
|
generate if (OPT_CIS)
|
|
begin : OPT_CIS_OP_PHASE
|
|
|
`ifdef OPT_CIS
|
|
reg r_op_phase;
|
reg r_op_phase;
|
|
|
initial r_op_phase = 1'b0;
|
initial r_op_phase = 1'b0;
|
always @(posedge i_clk)
|
always @(posedge i_clk)
|
if (clear_pipeline)
|
if ((i_reset)||(clear_pipeline))
|
r_op_phase <= 1'b0;
|
r_op_phase <= 1'b0;
|
else if (op_change_data_ce)
|
else if (op_ce)
|
r_op_phase <= (dcd_phase)&&((!dcd_wR)||(!dcd_Rpc));
|
r_op_phase <= (dcd_phase)&&((!dcd_wR)||(!dcd_Rpc));
|
assign op_phase = r_op_phase;
|
assign op_phase = r_op_phase;
|
`else
|
end else begin : OPT_NOCIS_OP_PHASE
|
assign op_phase = 1'b0;
|
assign op_phase = 1'b0;
|
`endif
|
|
|
// verilator lint_off UNUSED
|
|
wire OPT_CIS_dcdRpc;
|
|
assign OPT_CIS_dcdRpc = dcd_Rpc;
|
|
// verilator lint_on UNUSED
|
|
end endgenerate
|
|
|
// This is tricky. First, the PC and Flags registers aren't kept in
|
// This is tricky. First, the PC and Flags registers aren't kept in
|
// register set but in special registers of their own. So step one
|
// register set but in special registers of their own. So step one
|
// is to select the right register. Step to is to replace that
|
// is to select the right register. Step to is to replace that
|
// register with the results of an ALU or memory operation, if such
|
// register with the results of an ALU or memory operation, if such
|
| Line 970... |
Line 1244... |
// The alternative approach would be to define some sort of
|
// The alternative approach would be to define some sort of
|
// op_stall wire, which would stall any upstream stage.
|
// op_stall wire, which would stall any upstream stage.
|
// We'll create a flag here to start our coordination. Once we
|
// We'll create a flag here to start our coordination. Once we
|
// define this flag to something other than just plain zero, then
|
// define this flag to something other than just plain zero, then
|
// the stalls will already be in place.
|
// the stalls will already be in place.
|
`ifdef OPT_PIPELINED
|
generate if (OPT_PIPELINED)
|
assign op_Av = ((wr_reg_ce)&&(wr_reg_id == op_Aid)) // &&(op_rA))
|
begin
|
|
|
|
assign op_Av = ((wr_reg_ce)&&(wr_reg_id == op_Aid))
|
? wr_gpreg_vl : r_op_Av;
|
? wr_gpreg_vl : r_op_Av;
|
`else
|
|
|
end else begin
|
|
|
assign op_Av = r_op_Av;
|
assign op_Av = r_op_Av;
|
`endif
|
|
|
|
`ifdef OPT_PIPELINED
|
end endgenerate
|
|
|
// Stall if we have decoded an instruction that will read register A
|
// Stall if we have decoded an instruction that will read register A
|
// AND ... something that may write a register is running
|
// AND ... something that may write a register is running
|
// AND (series of conditions here ...)
|
// AND (series of conditions here ...)
|
// The operation might set flags, and we wish to read the
|
// The operation might set flags, and we wish to read the
|
// CC register
|
// CC register
|
// OR ... (No other conditions)
|
// OR ... (No other conditions)
|
|
generate if (OPT_PIPELINED)
|
|
begin
|
|
|
assign dcd_A_stall = (dcd_rA) // &&(dcd_valid) is checked for elsewhere
|
assign dcd_A_stall = (dcd_rA) // &&(dcd_valid) is checked for elsewhere
|
&&((op_valid)||(mem_rdbusy)
|
&&((op_valid)||(mem_rdbusy)
|
||(div_busy)||(fpu_busy))
|
||(div_busy)||(fpu_busy))
|
&&(((op_wF)||(cc_invalid_for_dcd))&&(dcd_Acc))
|
&&(((op_wF)||(cc_invalid_for_dcd))&&(dcd_Acc))
|
||((dcd_rA)&&(dcd_Acc)&&(cc_invalid_for_dcd));
|
||((dcd_rA)&&(dcd_Acc)&&(cc_invalid_for_dcd));
|
`else
|
end else begin
|
|
|
// There are no pipeline hazards, if we aren't pipelined
|
// There are no pipeline hazards, if we aren't pipelined
|
assign dcd_A_stall = 1'b0;
|
assign dcd_A_stall = 1'b0;
|
`endif
|
|
|
|
`ifdef OPT_PIPELINED
|
end endgenerate
|
assign op_Bv = ((wr_reg_ce)&&(wr_reg_id == op_Bid)&&(op_rB))
|
|
|
assign op_Bv = ((OPT_PIPELINED)&&(wr_reg_ce)
|
|
&&(wr_reg_id == op_Bid)&&(op_rB))
|
? wr_gpreg_vl: r_op_Bv;
|
? wr_gpreg_vl: r_op_Bv;
|
`else
|
|
assign op_Bv = r_op_Bv;
|
|
`endif
|
|
|
|
`ifdef OPT_PIPELINED
|
generate if (OPT_PIPELINED)
|
|
begin
|
// Stall if we have decoded an instruction that will read register B
|
// Stall if we have decoded an instruction that will read register B
|
// AND ... something that may write a (unknown) register is running
|
// AND ... something that may write a (unknown) register is running
|
// AND (series of conditions here ...)
|
// AND (series of conditions here ...)
|
// The operation might set flags, and we wish to read the
|
// The operation might set flags, and we wish to read the
|
// CC register
|
// CC register
|
// OR the operation might set register B, and we still need
|
// OR the operation might set register B, and we still need
|
// a clock to add the offset to it
|
// a clock to add the offset to it
|
assign dcd_B_stall = (dcd_rB) // &&(dcd_valid) is checked for elsewhere
|
assign dcd_B_stall = (dcd_rB) // &&(dcd_valid) is checked for elsewhere
|
|
//{{{
|
// If the op stage isn't valid, yet something
|
// If the op stage isn't valid, yet something
|
// is running, then it must have been valid.
|
// is running, then it must have been valid.
|
// We'll use the last values from that stage
|
// We'll use the last values from that stage
|
// (op_wR, op_wF, op_R) in our logic below.
|
// (op_wR, op_wF, op_R) in our logic below.
|
&&((op_valid)||(mem_rdbusy)
|
&&((op_valid)||(mem_rdbusy)
|
| Line 1037... |
Line 1319... |
// is clear, so we're okay then.
|
// is clear, so we're okay then.
|
//
|
//
|
((!dcd_zI)&&(
|
((!dcd_zI)&&(
|
((op_R == dcd_B)&&(op_wR))
|
((op_R == dcd_B)&&(op_wR))
|
||((mem_rdbusy)&&(!dcd_pipe))
|
||((mem_rdbusy)&&(!dcd_pipe))
|
|
||(((alu_busy)||(div_busy))&&(alu_reg == dcd_B))
|
|
||((wr_reg_ce)&&(wr_reg_id[3:1] == 3'h7))
|
))
|
))
|
// Stall following any instruction that will
|
// Stall following any instruction that will
|
// set the flags, if we're going to need the
|
// set the flags, if we're going to need the
|
// flags (CC) register for op_B.
|
// flags (CC) register for op_B.
|
||(((op_wF)||(cc_invalid_for_dcd))&&(dcd_Bcc))
|
||(((op_wF)||(cc_invalid_for_dcd))&&(dcd_Bcc))
|
// Stall on any ongoing memory operation that
|
// Stall on any ongoing memory operation that
|
// will write to op_B -- captured above
|
// will write to op_B -- captured above
|
// ||((mem_busy)&&(!mem_we)&&(mem_last_reg==dcd_B)&&(!dcd_zI))
|
// ||((mem_busy)&&(!mem_we)&&(mem_last_reg==dcd_B)&&(!dcd_zI))
|
)
|
)
|
||((dcd_rB)&&(dcd_Bcc)&&(cc_invalid_for_dcd));
|
||((dcd_rB)&&(dcd_Bcc)&&(cc_invalid_for_dcd));
|
|
//}}}
|
assign dcd_F_stall = ((!dcd_F[3])
|
assign dcd_F_stall = ((!dcd_F[3])
|
||((dcd_rA)&&(dcd_Acc))
|
//{{{
|
||((dcd_rB)&&(dcd_Bcc)))
|
||((dcd_rA)&&(dcd_A[3:1]==3'h7)
|
&&(op_valid)&&(op_Rcc);
|
&&(dcd_A[4:0] != { gie, 4'hf}))
|
|
||((dcd_rB)&&(dcd_B[3:1]==3'h7))
|
|
&&(dcd_B[4:0] != { gie, 4'hf}))
|
|
&&(((op_valid)&&(op_wR)
|
|
&&(op_R[3:1]==3'h7)
|
|
&&(op_R[4:0]!={gie, 4'hf}))
|
|
||(pending_sreg_write));
|
// &&(dcd_valid) is checked for elsewhere
|
// &&(dcd_valid) is checked for elsewhere
|
`else
|
//}}}
|
|
end else begin
|
// No stalls without pipelining, 'cause how can you have a pipeline
|
// No stalls without pipelining, 'cause how can you have a pipeline
|
// hazard without the pipeline?
|
// hazard without the pipeline?
|
assign dcd_B_stall = 1'b0;
|
assign dcd_B_stall = 1'b0;
|
assign dcd_F_stall = 1'b0;
|
assign dcd_F_stall = 1'b0;
|
`endif
|
end endgenerate
|
|
|
|
//}}}
|
//
|
//
|
//
|
//
|
// PIPELINE STAGE #4 :: Apply Instruction
|
// PIPELINE STAGE #4 :: Apply Instruction
|
//
|
//
|
//
|
//
|
cpuops #(IMPLEMENT_MPY) doalu(i_clk, (clear_pipeline),
|
// ALU
|
|
cpuops #(IMPLEMENT_MPY) doalu(i_clk, ((i_reset)||(clear_pipeline)),
|
|
//{{{
|
alu_ce, op_opn, op_Av, op_Bv,
|
alu_ce, op_opn, op_Av, op_Bv,
|
alu_result, alu_flags, alu_valid, alu_busy);
|
alu_result, alu_flags, alu_valid, alu_busy);
|
|
//}}}
|
|
|
generate
|
// Divide
|
if (IMPLEMENT_DIVIDE != 0)
|
//{{{
|
begin
|
generate if (IMPLEMENT_DIVIDE != 0)
|
div thedivide(i_clk, (clear_pipeline), div_ce, op_opn[0],
|
begin : DIVIDE
|
|
`ifdef FORMAL
|
|
`define DIVIDE_MODULE abs_div
|
|
`else
|
|
`define DIVIDE_MODULE div
|
|
`endif
|
|
`DIVIDE_MODULE thedivide(i_clk, ((i_reset)||(clear_pipeline)),
|
|
div_ce, op_opn[0],
|
op_Av, op_Bv, div_busy, div_valid, div_error, div_result,
|
op_Av, op_Bv, div_busy, div_valid, div_error, div_result,
|
div_flags);
|
div_flags);
|
|
|
end else begin
|
end else begin
|
|
|
assign div_error = 1'b0; // Can't be high unless div_valid
|
assign div_error = 1'b0; // Can't be high unless div_valid
|
assign div_busy = 1'b0;
|
assign div_busy = 1'b0;
|
assign div_valid = 1'b0;
|
assign div_valid = 1'b0;
|
assign div_result= 32'h00;
|
assign div_result= 32'h00;
|
assign div_flags = 4'h0;
|
assign div_flags = 4'h0;
|
|
|
|
// Make verilator happy here
|
|
// verilator lint_off UNUSED
|
|
wire unused_divide;
|
|
assign unused_divide = div_ce;
|
|
// verilator lint_on UNUSED
|
end endgenerate
|
end endgenerate
|
|
//}}}
|
|
|
generate
|
// (Non-existent) FPU
|
if (IMPLEMENT_FPU != 0)
|
//{{{
|
begin
|
generate if (IMPLEMENT_FPU != 0)
|
|
begin : FPU
|
//
|
//
|
// sfpu thefpu(i_clk, i_rst, fpu_ce,
|
// sfpu thefpu(i_clk, i_reset, fpu_ce, op_opn[2:0],
|
// op_Av, op_Bv, fpu_busy, fpu_valid, fpu_err, fpu_result,
|
// op_Av, op_Bv, fpu_busy, fpu_valid, fpu_err, fpu_result,
|
// fpu_flags);
|
// fpu_flags);
|
//
|
//
|
assign fpu_error = 1'b0; // Must only be true if fpu_valid
|
assign fpu_error = 1'b0; // Must only be true if fpu_valid
|
assign fpu_busy = 1'b0;
|
assign fpu_busy = 1'b0;
|
| Line 1101... |
Line 1415... |
assign fpu_busy = 1'b0;
|
assign fpu_busy = 1'b0;
|
assign fpu_valid = 1'b0;
|
assign fpu_valid = 1'b0;
|
assign fpu_result= 32'h00;
|
assign fpu_result= 32'h00;
|
assign fpu_flags = 4'h0;
|
assign fpu_flags = 4'h0;
|
end endgenerate
|
end endgenerate
|
|
//}}}
|
|
|
|
|
assign set_cond = ((op_F[7:4]&op_Fl[3:0])==op_F[3:0]);
|
assign set_cond = ((op_F[7:4]&op_Fl[3:0])==op_F[3:0]);
|
initial alu_wF = 1'b0;
|
initial alu_wF = 1'b0;
|
initial alu_wR = 1'b0;
|
initial alu_wR = 1'b0;
|
|
generate if (OPT_PIPELINED)
|
|
begin
|
always @(posedge i_clk)
|
always @(posedge i_clk)
|
if (i_rst)
|
if (i_reset)
|
begin
|
begin
|
alu_wR <= 1'b0;
|
alu_wR <= 1'b0;
|
alu_wF <= 1'b0;
|
alu_wF <= 1'b0;
|
end else if (alu_ce)
|
end else if (alu_ce)
|
begin
|
begin
|
// alu_reg <= op_R;
|
// alu_reg <= op_R;
|
alu_wR <= (op_wR)&&(set_cond);
|
alu_wR <= (op_wR)&&(set_cond)&&(!op_illegal);
|
alu_wF <= (op_wF)&&(set_cond);
|
alu_wF <= (op_wF)&&(set_cond)&&(!op_illegal);
|
end else if (!alu_busy) begin
|
end else if (!alu_busy) begin
|
// These are strobe signals, so clear them if not
|
// These are strobe signals, so clear them if not
|
// set for any particular clock
|
// set for any particular clock
|
alu_wR <= (i_halt)&&(i_dbg_we);
|
alu_wR <= (r_halted)&&(i_dbg_we);
|
alu_wF <= 1'b0;
|
alu_wF <= 1'b0;
|
end
|
end
|
|
end else begin
|
|
|
|
always @(posedge i_clk)
|
|
alu_wR <= (op_wR)&&(set_cond)&&(!op_illegal);
|
|
always @(posedge i_clk)
|
|
alu_wF <= (op_wF)&&(set_cond)&&(!op_illegal);
|
|
|
|
end endgenerate
|
|
|
|
generate if (OPT_CIS)
|
|
begin : GEN_ALU_PHASE
|
|
|
`ifdef OPT_CIS
|
|
reg r_alu_phase;
|
reg r_alu_phase;
|
initial r_alu_phase = 1'b0;
|
initial r_alu_phase = 1'b0;
|
always @(posedge i_clk)
|
always @(posedge i_clk)
|
if (i_rst)
|
if ((i_reset)||(clear_pipeline))
|
r_alu_phase <= 1'b0;
|
r_alu_phase <= 1'b0;
|
else if ((adf_ce_unconditional)||(mem_ce))
|
else if (((adf_ce_unconditional)||(mem_ce))&&(op_valid))
|
r_alu_phase <= op_phase;
|
r_alu_phase <= op_phase;
|
|
else if ((adf_ce_unconditional)||(mem_ce))
|
|
r_alu_phase <= 1'b0;
|
assign alu_phase = r_alu_phase;
|
assign alu_phase = r_alu_phase;
|
`else
|
end else begin
|
|
|
assign alu_phase = 1'b0;
|
assign alu_phase = 1'b0;
|
`endif
|
end endgenerate
|
|
|
|
generate if (OPT_PIPELINED)
|
|
begin
|
|
|
`ifdef OPT_PIPELINED
|
|
always @(posedge i_clk)
|
always @(posedge i_clk)
|
if (adf_ce_unconditional)
|
if (adf_ce_unconditional)
|
alu_reg <= op_R;
|
alu_reg <= op_R;
|
else if ((i_halt)&&(i_dbg_we))
|
else if ((r_halted)&&(i_dbg_we))
|
alu_reg <= i_dbg_reg;
|
alu_reg <= i_dbg_reg;
|
`else
|
|
|
end else begin
|
|
|
always @(posedge i_clk)
|
always @(posedge i_clk)
|
if ((i_halt)&&(i_dbg_we))
|
if ((r_halted)&&(i_dbg_we))
|
alu_reg <= i_dbg_reg;
|
alu_reg <= i_dbg_reg;
|
else
|
else
|
alu_reg <= op_R;
|
alu_reg <= op_R;
|
`endif
|
end endgenerate
|
|
|
//
|
//
|
// DEBUG Register write access starts here
|
// DEBUG Register write access starts here
|
//
|
//
|
reg dbgv;
|
//{{{
|
initial dbgv = 1'b0;
|
initial dbgv = 1'b0;
|
always @(posedge i_clk)
|
always @(posedge i_clk)
|
dbgv <= (!i_rst)&&(i_halt)&&(i_dbg_we)&&(r_halted);
|
if (i_reset)
|
reg [31:0] dbg_val;
|
dbgv <= 0;
|
|
else
|
|
dbgv <= (i_dbg_we)&&(r_halted);
|
|
|
always @(posedge i_clk)
|
always @(posedge i_clk)
|
dbg_val <= i_dbg_data;
|
dbg_val <= i_dbg_data;
|
`ifdef OPT_NO_USERMODE
|
|
assign alu_gie = 1'b0;
|
|
`else
|
|
`ifdef OPT_PIPELINED
|
|
reg r_alu_gie;
|
|
|
|
always @(posedge i_clk)
|
always @(posedge i_clk)
|
if ((adf_ce_unconditional)||(mem_ce))
|
if ((i_reset)||(clear_pipeline))
|
r_alu_gie <= op_gie;
|
dbg_clear_pipe <= 0;
|
assign alu_gie = r_alu_gie;
|
else if ((i_dbg_we)&&(r_halted))
|
`else
|
begin
|
assign alu_gie = op_gie;
|
if (!OPT_PIPELINED)
|
`endif
|
dbg_clear_pipe <= 1'b1;
|
`endif
|
else if ((i_dbg_reg == op_Bid)&&(op_rB))
|
|
dbg_clear_pipe <= 1'b1;
|
|
else if (i_dbg_reg[3:1] == 3'h7)
|
|
dbg_clear_pipe <= 1'b1;
|
|
else
|
|
dbg_clear_pipe <= 1'b0;
|
|
end else if ((!OPT_PIPELINED)&&(i_clear_pf_cache))
|
|
dbg_clear_pipe <= 1'b1;
|
|
else
|
|
dbg_clear_pipe <= 1'b0;
|
|
|
`ifdef OPT_PIPELINED
|
assign alu_gie = gie;
|
reg [(AW-1):0] r_alu_pc;
|
//}}}
|
always @(posedge i_clk)
|
|
if ((adf_ce_unconditional)
|
generate if (OPT_PIPELINED)
|
||((master_ce)&&(op_valid_mem)&&(!clear_pipeline)
|
begin : GEN_ALU_PC
|
&&(!mem_stalled)))
|
reg [(AW+1):0] r_alu_pc;
|
|
initial r_alu_pc = 0;
|
|
always @(posedge i_clk)
|
|
if (i_reset)
|
|
r_alu_pc <= 0;
|
|
else if ((adf_ce_unconditional)
|
|
||((master_ce)&&(op_valid_mem)
|
|
&&(!clear_pipeline)&&(!mem_stalled)))
|
r_alu_pc <= op_pc;
|
r_alu_pc <= op_pc;
|
assign alu_pc = r_alu_pc;
|
assign alu_pc = r_alu_pc;
|
`else
|
|
|
end else begin
|
|
|
assign alu_pc = op_pc;
|
assign alu_pc = op_pc;
|
`endif
|
|
|
|
|
end endgenerate
|
|
|
|
generate if (OPT_PIPELINED)
|
|
begin : SET_ALU_ILLEGAL
|
reg r_alu_illegal;
|
reg r_alu_illegal;
|
|
|
initial r_alu_illegal = 0;
|
initial r_alu_illegal = 0;
|
always @(posedge i_clk)
|
always @(posedge i_clk)
|
if (clear_pipeline)
|
if (clear_pipeline)
|
r_alu_illegal <= 1'b0;
|
r_alu_illegal <= 1'b0;
|
else if (alu_ce)
|
else if (adf_ce_unconditional)
|
r_alu_illegal <= op_illegal;
|
r_alu_illegal <= op_illegal;
|
else
|
else
|
r_alu_illegal <= 1'b0;
|
r_alu_illegal <= 1'b0;
|
|
|
assign alu_illegal = (r_alu_illegal);
|
assign alu_illegal = (r_alu_illegal);
|
|
end else begin : SET_ALU_ILLEGAL
|
|
assign alu_illegal = op_illegal;
|
|
end endgenerate
|
|
|
initial r_alu_pc_valid = 1'b0;
|
initial r_alu_pc_valid = 1'b0;
|
initial mem_pc_valid = 1'b0;
|
initial mem_pc_valid = 1'b0;
|
always @(posedge i_clk)
|
always @(posedge i_clk)
|
if (clear_pipeline)
|
if (clear_pipeline)
|
| Line 1209... |
Line 1566... |
r_alu_pc_valid <= 1'b1;
|
r_alu_pc_valid <= 1'b1;
|
else if (((!alu_busy)&&(!div_busy)&&(!fpu_busy))||(clear_pipeline))
|
else if (((!alu_busy)&&(!div_busy)&&(!fpu_busy))||(clear_pipeline))
|
r_alu_pc_valid <= 1'b0;
|
r_alu_pc_valid <= 1'b0;
|
assign alu_pc_valid = (r_alu_pc_valid)&&((!alu_busy)&&(!div_busy)&&(!fpu_busy));
|
assign alu_pc_valid = (r_alu_pc_valid)&&((!alu_busy)&&(!div_busy)&&(!fpu_busy));
|
always @(posedge i_clk)
|
always @(posedge i_clk)
|
if (i_rst)
|
if (i_reset)
|
mem_pc_valid <= 1'b0;
|
mem_pc_valid <= 1'b0;
|
else
|
else
|
mem_pc_valid <= (mem_ce);
|
mem_pc_valid <= (mem_ce);
|
|
|
wire bus_lock;
|
// Bus lock logic
|
`ifdef OPT_PIPELINED
|
//{{{
|
generate
|
generate
|
if (IMPLEMENT_LOCK != 0)
|
if ((OPT_PIPELINED)&&(!OPT_LOCK))
|
begin
|
begin : BUSLOCK
|
reg r_prelock_stall;
|
reg r_prelock_stall;
|
|
|
initial r_prelock_stall = 1'b0;
|
initial r_prelock_stall = 1'b0;
|
always @(posedge i_clk)
|
always @(posedge i_clk)
|
if (clear_pipeline)
|
if (clear_pipeline)
|
| Line 1233... |
Line 1590... |
r_prelock_stall <= 1'b0;
|
r_prelock_stall <= 1'b0;
|
|
|
assign prelock_stall = r_prelock_stall;
|
assign prelock_stall = r_prelock_stall;
|
|
|
reg r_prelock_primed;
|
reg r_prelock_primed;
|
|
initial r_prelock_primed = 1'b0;
|
always @(posedge i_clk)
|
always @(posedge i_clk)
|
if (clear_pipeline)
|
if (clear_pipeline)
|
r_prelock_primed <= 1'b0;
|
r_prelock_primed <= 1'b0;
|
else if (r_prelock_stall)
|
else if (r_prelock_stall)
|
r_prelock_primed <= 1'b1;
|
r_prelock_primed <= 1'b1;
|
| Line 1258... |
Line 1616... |
assign bus_lock = |r_bus_lock;
|
assign bus_lock = |r_bus_lock;
|
end else begin
|
end else begin
|
assign prelock_stall = 1'b0;
|
assign prelock_stall = 1'b0;
|
assign bus_lock = 1'b0;
|
assign bus_lock = 1'b0;
|
end endgenerate
|
end endgenerate
|
`else
|
//}}}
|
assign bus_lock = 1'b0;
|
|
`endif
|
|
|
|
`ifdef OPT_PIPELINED_BUS_ACCESS
|
// Memory interface
|
pipemem #(AW,IMPLEMENT_LOCK) domem(i_clk, i_rst,(mem_ce)&&(set_cond), bus_lock,
|
//{{{
|
|
generate if (OPT_DCACHE)
|
|
begin : MEM_DCACHE
|
|
|
|
dcache #(.LGCACHELEN(OPT_LGDCACHE), .ADDRESS_WIDTH(AW),
|
|
.LGNLINES(OPT_LGDCACHE-3), .OPT_LOCAL_BUS(WITH_LOCAL_BUS),
|
|
.OPT_PIPE(OPT_MEMPIPE),
|
|
.OPT_LOCK(OPT_LOCK)
|
|
`ifdef FORMAL
|
|
, .OPT_FIFO_DEPTH(2)
|
|
, .F_LGDEPTH(F_LGDEPTH)
|
|
`endif
|
|
) docache(i_clk, i_reset,
|
|
///{{{
|
|
(mem_ce)&&(set_cond), bus_lock,
|
(op_opn[2:0]), op_Bv, op_Av, op_R,
|
(op_opn[2:0]), op_Bv, op_Av, op_R,
|
mem_busy, mem_pipe_stalled,
|
mem_busy, mem_pipe_stalled,
|
mem_valid, bus_err, mem_wreg, mem_result,
|
mem_valid, bus_err, mem_wreg, mem_result,
|
mem_cyc_gbl, mem_cyc_lcl,
|
mem_cyc_gbl, mem_cyc_lcl,
|
mem_stb_gbl, mem_stb_lcl,
|
mem_stb_gbl, mem_stb_lcl,
|
mem_we, mem_addr, mem_data, mem_sel,
|
mem_we, mem_addr, mem_data, mem_sel,
|
mem_ack, mem_stall, mem_err, i_wb_data);
|
mem_ack, mem_stall, mem_err, i_wb_data
|
|
`ifdef FORMAL
|
|
, f_mem_nreqs, f_mem_nacks, f_mem_outstanding, f_mem_pc
|
|
`endif
|
|
// , o_dcache_debug
|
|
);
|
|
///}}}
|
|
end else begin : NO_CACHE
|
|
if (OPT_PIPELINED_BUS_ACCESS)
|
|
begin : MEM
|
|
|
|
pipemem #(.ADDRESS_WIDTH(AW),
|
|
.IMPLEMENT_LOCK(OPT_LOCK),
|
|
.WITH_LOCAL_BUS(WITH_LOCAL_BUS)
|
|
`ifdef FORMAL
|
|
, .OPT_MAXDEPTH(4'h3),
|
|
.F_LGDEPTH(F_LGDEPTH)
|
|
`endif
|
|
) domem(i_clk,i_reset,
|
|
///{{{
|
|
(mem_ce)&&(set_cond), bus_lock,
|
|
(op_opn[2:0]), op_Bv, op_Av, op_R,
|
|
mem_busy, mem_pipe_stalled,
|
|
mem_valid, bus_err, mem_wreg, mem_result,
|
|
mem_cyc_gbl, mem_cyc_lcl,
|
|
mem_stb_gbl, mem_stb_lcl,
|
|
mem_we, mem_addr, mem_data, mem_sel,
|
|
mem_ack, mem_stall, mem_err, i_wb_data
|
|
`ifdef FORMAL
|
|
, f_mem_nreqs, f_mem_nacks, f_mem_outstanding, f_mem_pc
|
|
`endif
|
|
);
|
|
//}}}
|
|
end else begin : MEM
|
|
|
`else // PIPELINED_BUS_ACCESS
|
memops #(.ADDRESS_WIDTH(AW),
|
memops #(AW,IMPLEMENT_LOCK,WITH_LOCAL_BUS) domem(i_clk, i_rst,
|
.IMPLEMENT_LOCK(OPT_LOCK),
|
|
.WITH_LOCAL_BUS(WITH_LOCAL_BUS)
|
|
`ifdef FORMAL
|
|
, .F_LGDEPTH(F_LGDEPTH)
|
|
`endif // F_LGDEPTH
|
|
) domem(i_clk,i_reset,
|
|
//{{{
|
(mem_ce)&&(set_cond), bus_lock,
|
(mem_ce)&&(set_cond), bus_lock,
|
(op_opn[2:0]), op_Bv, op_Av, op_R,
|
(op_opn[2:0]), op_Bv, op_Av, op_R,
|
mem_busy,
|
mem_busy,
|
mem_valid, bus_err, mem_wreg, mem_result,
|
mem_valid, bus_err, mem_wreg, mem_result,
|
mem_cyc_gbl, mem_cyc_lcl,
|
mem_cyc_gbl, mem_cyc_lcl,
|
mem_stb_gbl, mem_stb_lcl,
|
mem_stb_gbl, mem_stb_lcl,
|
mem_we, mem_addr, mem_data, mem_sel,
|
mem_we, mem_addr, mem_data, mem_sel,
|
mem_ack, mem_stall, mem_err, i_wb_data);
|
mem_ack, mem_stall, mem_err, i_wb_data
|
|
`ifdef FORMAL
|
|
, f_mem_nreqs, f_mem_nacks, f_mem_outstanding
|
|
`endif
|
|
);
|
|
`ifdef FORMAL
|
|
assign f_mem_pc = 1'b0;
|
|
`endif
|
|
//}}}
|
assign mem_pipe_stalled = 1'b0;
|
assign mem_pipe_stalled = 1'b0;
|
`endif // PIPELINED_BUS_ACCESS
|
end end endgenerate
|
assign mem_rdbusy = ((mem_busy)&&(!mem_we));
|
|
|
assign mem_rdbusy = (mem_busy)&&((!OPT_PIPELINED)||(!mem_we));
|
|
|
// Either the prefetch or the instruction gets the memory bus, but
|
// Either the prefetch or the instruction gets the memory bus, but
|
// never both.
|
// never both.
|
wbdblpriarb #(32,AW) pformem(i_clk, i_rst,
|
wbdblpriarb #(.DW(32),.AW(AW)
|
|
`ifdef FORMAL
|
|
,.F_LGDEPTH(F_LGDEPTH), .F_MAX_STALL(2), .F_MAX_ACK_DELAY(2)
|
|
`endif // FORMAL
|
|
) pformem(i_clk, i_reset,
|
|
//{{{
|
// Memory access to the arbiter, priority position
|
// Memory access to the arbiter, priority position
|
mem_cyc_gbl, mem_cyc_lcl, mem_stb_gbl, mem_stb_lcl,
|
mem_cyc_gbl, mem_cyc_lcl, mem_stb_gbl, mem_stb_lcl,
|
mem_we, mem_addr, mem_data, mem_sel,
|
mem_we, mem_addr, mem_data, mem_sel,
|
mem_ack, mem_stall, mem_err,
|
mem_ack, mem_stall, mem_err,
|
// Prefetch access to the arbiter
|
// Prefetch access to the arbiter
|
| Line 1308... |
Line 1731... |
pf_cyc,1'b0,pf_stb, 1'b0, pf_we, pf_addr, mem_data, mem_sel,
|
pf_cyc,1'b0,pf_stb, 1'b0, pf_we, pf_addr, mem_data, mem_sel,
|
pf_ack, pf_stall, pf_err,
|
pf_ack, pf_stall, pf_err,
|
// Common wires, in and out, of the arbiter
|
// Common wires, in and out, of the arbiter
|
o_wb_gbl_cyc, o_wb_lcl_cyc, o_wb_gbl_stb, o_wb_lcl_stb,
|
o_wb_gbl_cyc, o_wb_lcl_cyc, o_wb_gbl_stb, o_wb_lcl_stb,
|
o_wb_we, o_wb_addr, o_wb_data, o_wb_sel,
|
o_wb_we, o_wb_addr, o_wb_data, o_wb_sel,
|
i_wb_ack, i_wb_stall, i_wb_err);
|
i_wb_ack, i_wb_stall, i_wb_err
|
|
`ifdef FORMAL
|
|
,f_gbl_arb_nreqs, f_gbl_arb_nacks, f_gbl_arb_outstanding,
|
|
f_lcl_arb_nreqs, f_lcl_arb_nacks, f_lcl_arb_outstanding,
|
|
f_gbl_mem_nreqs, f_gbl_mem_nacks, f_gbl_mem_outstanding,
|
|
f_lcl_mem_nreqs, f_lcl_mem_nacks, f_lcl_mem_outstanding,
|
|
f_gbl_pf_nreqs, f_gbl_pf_nacks, f_gbl_pf_outstanding,
|
|
f_lcl_pf_nreqs, f_lcl_pf_nacks, f_lcl_pf_outstanding
|
|
`endif
|
|
);
|
|
//}}}
|
|
//}}}
|
|
|
|
|
//
|
//
|
//
|
//
|
//
|
//
|
| Line 1322... |
Line 1755... |
//
|
//
|
//
|
//
|
//
|
//
|
// PIPELINE STAGE #5 :: Write-back results
|
// PIPELINE STAGE #5 :: Write-back results
|
//
|
//
|
|
//{{{
|
//
|
//
|
// This stage is not allowed to stall. If results are ready to be
|
// This stage is not allowed to stall. If results are ready to be
|
// written back, they are written back at all cost. Sleepy CPU's
|
// written back, they are written back at all cost. Sleepy CPU's
|
// won't prevent write back, nor debug modes, halting the CPU, nor
|
// won't prevent write back, nor debug modes, halting the CPU, nor
|
// anything else. Indeed, the (master_ce) bit is only as relevant
|
// anything else. Indeed, the (master_ce) bit is only as relevant
|
| Line 1339... |
Line 1773... |
// Further, alu_wR includes (set_cond), so we don't need to
|
// Further, alu_wR includes (set_cond), so we don't need to
|
// check for that here either.
|
// check for that here either.
|
assign wr_reg_ce = (dbgv)||(mem_valid)
|
assign wr_reg_ce = (dbgv)||(mem_valid)
|
||((!clear_pipeline)&&(!alu_illegal)
|
||((!clear_pipeline)&&(!alu_illegal)
|
&&(((alu_wR)&&(alu_valid))
|
&&(((alu_wR)&&(alu_valid))
|
||(div_valid)||(fpu_valid)));
|
||((div_valid)&&(!div_error))
|
|
||((fpu_valid)&&(!fpu_error))));
|
// Which register shall be written?
|
// Which register shall be written?
|
// COULD SIMPLIFY THIS: by adding three bits to these registers,
|
// COULD SIMPLIFY THIS: by adding three bits to these registers,
|
// One or PC, one for CC, and one for GIE match
|
// One or PC, one for CC, and one for GIE match
|
// Note that the alu_reg is the register to write on a divide or
|
// Note that the alu_reg is the register to write on a divide or
|
// FPU operation.
|
// FPU operation.
|
`ifdef OPT_NO_USERMODE
|
generate if (OPT_NO_USERMODE)
|
assign wr_reg_id[3:0] = (alu_wR|div_valid|fpu_valid)
|
begin
|
? alu_reg[3:0]:mem_wreg[3:0];
|
assign wr_reg_id[3:0] = (mem_valid)
|
|
? mem_wreg[3:0] : alu_reg[3:0];
|
|
|
assign wr_reg_id[4] = 1'b0;
|
assign wr_reg_id[4] = 1'b0;
|
`else
|
end else begin
|
assign wr_reg_id = (alu_wR|div_valid|fpu_valid)?alu_reg:mem_wreg;
|
assign wr_reg_id = (mem_valid) ? mem_wreg : alu_reg;
|
`endif
|
end endgenerate
|
|
|
// Are we writing to the CC register?
|
// Are we writing to the CC register?
|
assign wr_write_cc = (wr_reg_id[3:0] == `CPU_CC_REG);
|
assign wr_write_cc = (wr_reg_id[3:0] == `CPU_CC_REG);
|
assign wr_write_scc = (wr_reg_id[4:0] == {1'b0, `CPU_CC_REG});
|
assign wr_write_scc = (wr_reg_id[4:0] == {1'b0, `CPU_CC_REG});
|
assign wr_write_ucc = (wr_reg_id[4:0] == {1'b1, `CPU_CC_REG});
|
assign wr_write_ucc = (wr_reg_id[4:0] == {1'b1, `CPU_CC_REG});
|
| Line 1367... |
Line 1804... |
:((div_valid|fpu_valid))
|
:((div_valid|fpu_valid))
|
? ((div_valid) ? div_result:fpu_result)
|
? ((div_valid) ? div_result:fpu_result)
|
:((dbgv) ? dbg_val : alu_result));
|
:((dbgv) ? dbg_val : alu_result));
|
assign wr_spreg_vl = ((mem_valid) ? mem_result
|
assign wr_spreg_vl = ((mem_valid) ? mem_result
|
:((dbgv) ? dbg_val : alu_result));
|
:((dbgv) ? dbg_val : alu_result));
|
|
|
|
generate if (OPT_NO_USERMODE)
|
|
begin : SET_REGISTERS
|
|
|
|
always @(posedge i_clk)
|
|
if (wr_reg_ce)
|
|
regset[{1'b0,wr_reg_id[3:0]}] <= wr_gpreg_vl;
|
|
|
|
end else begin : SET_REGISTERS
|
|
|
always @(posedge i_clk)
|
always @(posedge i_clk)
|
if (wr_reg_ce)
|
if (wr_reg_ce)
|
`ifdef OPT_NO_USERMODE
|
|
regset[wr_reg_id[3:0]] <= wr_gpreg_vl;
|
|
`else
|
|
regset[wr_reg_id] <= wr_gpreg_vl;
|
regset[wr_reg_id] <= wr_gpreg_vl;
|
`endif
|
|
|
end endgenerate
|
|
|
|
|
//
|
//
|
// Write back to the condition codes/flags register ...
|
// Write back to the condition codes/flags register ...
|
// When shall we write to our flags register? alu_wF already
|
// When shall we write to our flags register? alu_wF already
|
// includes the set condition ...
|
// includes the set condition ...
|
assign wr_flags_ce = ((alu_wF)||(div_valid)||(fpu_valid))&&(!clear_pipeline)&&(!alu_illegal);
|
assign wr_flags_ce = (alu_wF)&&((alu_valid)
|
|
||(div_valid)||(fpu_valid))
|
|
&&(!clear_pipeline)&&(!alu_illegal);
|
assign w_uflags = { 1'b0, uhalt_phase, ufpu_err_flag,
|
assign w_uflags = { 1'b0, uhalt_phase, ufpu_err_flag,
|
udiv_err_flag, ubus_err_flag, trap, ill_err_u,
|
udiv_err_flag, ubus_err_flag, trap, ill_err_u,
|
ubreak, step, 1'b1, sleep,
|
ubreak, step, 1'b1, sleep,
|
((wr_flags_ce)&&(alu_gie))?alu_flags:flags };
|
((wr_flags_ce)&&(alu_gie))?alu_flags:flags };
|
assign w_iflags = { 1'b0, ihalt_phase, ifpu_err_flag,
|
assign w_iflags = { 1'b0, ihalt_phase, ifpu_err_flag,
|
| Line 1424... |
Line 1872... |
// Upon a CPU halt, any break condition will be reset. The
|
// Upon a CPU halt, any break condition will be reset. The
|
// external debugger will then need to deal with whatever
|
// external debugger will then need to deal with whatever
|
// condition has taken place.
|
// condition has taken place.
|
initial break_en = 1'b0;
|
initial break_en = 1'b0;
|
always @(posedge i_clk)
|
always @(posedge i_clk)
|
if ((i_rst)||(i_halt))
|
if ((i_reset)||(i_halt))
|
break_en <= 1'b0;
|
break_en <= 1'b0;
|
else if ((wr_reg_ce)&&(wr_write_scc))
|
else if ((wr_reg_ce)&&(wr_write_scc))
|
break_en <= wr_spreg_vl[`CPU_BREAK_BIT];
|
break_en <= wr_spreg_vl[`CPU_BREAK_BIT];
|
|
|
`ifdef OPT_PIPELINED
|
generate if (OPT_PIPELINED)
|
|
begin : GEN_PENDING_BREAK
|
reg r_break_pending;
|
reg r_break_pending;
|
|
|
initial r_break_pending = 1'b0;
|
initial r_break_pending = 1'b0;
|
always @(posedge i_clk)
|
always @(posedge i_clk)
|
if ((clear_pipeline)||(!op_valid))
|
if ((clear_pipeline)||(!op_valid))
|
r_break_pending <= 1'b0;
|
r_break_pending <= 1'b0;
|
else if (op_break)
|
else if ((op_break)&&(!r_break_pending))
|
r_break_pending <= (!alu_busy)&&(!div_busy)&&(!fpu_busy)&&(!mem_busy)&&(!wr_reg_ce);
|
r_break_pending <= (!alu_busy)&&(!div_busy)
|
else
|
&&(!fpu_busy)&&(!mem_busy)
|
r_break_pending <= 1'b0;
|
&&(!wr_reg_ce);
|
|
// else
|
|
// r_break_pending <= 1'b0;
|
assign break_pending = r_break_pending;
|
assign break_pending = r_break_pending;
|
`else
|
end else begin
|
|
|
assign break_pending = op_break;
|
assign break_pending = op_break;
|
`endif
|
end endgenerate
|
|
|
|
|
assign o_break = ((break_en)||(!op_gie))&&(break_pending)
|
assign o_break = ((break_en)||(!op_gie))&&(break_pending)
|
&&(!clear_pipeline)
|
&&(!clear_pipeline)
|
|
||(ill_err_i)
|
||((!alu_gie)&&(bus_err))
|
||((!alu_gie)&&(bus_err))
|
||((!alu_gie)&&(div_error))
|
||((!alu_gie)&&(div_error))
|
||((!alu_gie)&&(fpu_error))
|
||((!alu_gie)&&(fpu_error))
|
||((!alu_gie)&&(alu_illegal)&&(!clear_pipeline));
|
||((!alu_gie)&&(alu_illegal)&&(!clear_pipeline));
|
|
|
| Line 1460... |
Line 1913... |
// interrupt mode causes the processor to halt until a reset. This is
|
// interrupt mode causes the processor to halt until a reset. This is
|
// a panic/fault halt. The trick is that you cannot be allowed to
|
// a panic/fault halt. The trick is that you cannot be allowed to
|
// set the sleep bit and switch to supervisor mode in the same
|
// set the sleep bit and switch to supervisor mode in the same
|
// instruction: users are not allowed to halt the CPU.
|
// instruction: users are not allowed to halt the CPU.
|
initial sleep = 1'b0;
|
initial sleep = 1'b0;
|
`ifdef OPT_NO_USERMODE
|
generate if (OPT_NO_USERMODE)
|
|
begin : GEN_NO_USERMODE_SLEEP
|
reg r_sleep_is_halt;
|
reg r_sleep_is_halt;
|
initial r_sleep_is_halt = 1'b0;
|
initial r_sleep_is_halt = 1'b0;
|
always @(posedge i_clk)
|
always @(posedge i_clk)
|
if (i_rst)
|
if (i_reset)
|
r_sleep_is_halt <= 1'b0;
|
r_sleep_is_halt <= 1'b0;
|
else if ((wr_reg_ce)&&(wr_write_cc)
|
else if ((wr_reg_ce)&&(wr_write_cc)
|
&&(wr_spreg_vl[`CPU_SLEEP_BIT])
|
&&(wr_spreg_vl[`CPU_SLEEP_BIT])
|
&&(!wr_spreg_vl[`CPU_GIE_BIT]))
|
&&(!wr_spreg_vl[`CPU_GIE_BIT]))
|
r_sleep_is_halt <= 1'b1;
|
r_sleep_is_halt <= 1'b1;
|
|
|
// Trying to switch to user mode, either via a WAIT or an RTU
|
// Trying to switch to user mode, either via a WAIT or an RTU
|
// instruction will cause the CPU to sleep until an interrupt, in
|
// instruction will cause the CPU to sleep until an interrupt, in
|
// the NO-USERMODE build.
|
// the NO-USERMODE build.
|
always @(posedge i_clk)
|
always @(posedge i_clk)
|
if ((i_rst)||((i_interrupt)&&(!r_sleep_is_halt)))
|
if ((i_reset)||((i_interrupt)&&(!r_sleep_is_halt)))
|
sleep <= 1'b0;
|
sleep <= 1'b0;
|
else if ((wr_reg_ce)&&(wr_write_cc)
|
else if ((wr_reg_ce)&&(wr_write_cc)
|
&&(wr_spreg_vl[`CPU_GIE_BIT]))
|
&&(wr_spreg_vl[`CPU_GIE_BIT]))
|
sleep <= 1'b1;
|
sleep <= 1'b1;
|
`else
|
end else begin : GEN_SLEEP
|
|
|
always @(posedge i_clk)
|
always @(posedge i_clk)
|
if ((i_rst)||(w_switch_to_interrupt))
|
if ((i_reset)||(w_switch_to_interrupt))
|
sleep <= 1'b0;
|
sleep <= 1'b0;
|
else if ((wr_reg_ce)&&(wr_write_cc)&&(!alu_gie))
|
else if ((wr_reg_ce)&&(wr_write_cc)&&(!alu_gie))
|
// In supervisor mode, we have no protections. The
|
// In supervisor mode, we have no protections.
|
// supervisor can set the sleep bit however he wants.
|
// The supervisor can set the sleep bit however
|
// Well ... not quite. Switching to user mode and
|
// he wants. Well ... not quite. Switching to
|
// sleep mode shouold only be possible if the interrupt
|
// user mode and sleep mode shouold only be
|
// flag isn't set.
|
// possible if the interrupt flag isn't set.
|
// Thus: if (i_interrupt)&&(wr_spreg_vl[GIE])
|
// Thus: if (i_interrupt)
|
|
// &&(wr_spreg_vl[GIE])
|
// don't set the sleep bit
|
// don't set the sleep bit
|
// otherwise however it would o.w. be set
|
// otherwise however it would o.w. be set
|
sleep <= (wr_spreg_vl[`CPU_SLEEP_BIT])
|
sleep <= (wr_spreg_vl[`CPU_SLEEP_BIT])
|
&&((!i_interrupt)||(!wr_spreg_vl[`CPU_GIE_BIT]));
|
&&((!i_interrupt)
|
else if ((wr_reg_ce)&&(wr_write_cc)&&(wr_spreg_vl[`CPU_GIE_BIT]))
|
||(!wr_spreg_vl[`CPU_GIE_BIT]));
|
// In user mode, however, you can only set the sleep
|
else if ((wr_reg_ce)&&(wr_write_cc)
|
// mode while remaining in user mode. You can't switch
|
&&(wr_spreg_vl[`CPU_GIE_BIT]))
|
// to sleep mode *and* supervisor mode at the same
|
// In user mode, however, you can only set the
|
// time, lest you halt the CPU.
|
// sleep mode while remaining in user mode.
|
|
// You can't switch to sleep mode *and*
|
|
// supervisor mode at the same time, lest you
|
|
// halt the CPU.
|
sleep <= wr_spreg_vl[`CPU_SLEEP_BIT];
|
sleep <= wr_spreg_vl[`CPU_SLEEP_BIT];
|
`endif
|
end endgenerate
|
|
|
always @(posedge i_clk)
|
always @(posedge i_clk)
|
if (i_rst)
|
if (i_reset)
|
step <= 1'b0;
|
step <= 1'b0;
|
else if ((wr_reg_ce)&&(!alu_gie)&&(wr_write_ucc))
|
else if ((wr_reg_ce)&&(!alu_gie)&&(wr_write_ucc))
|
step <= wr_spreg_vl[`CPU_STEP_BIT];
|
step <= wr_spreg_vl[`CPU_STEP_BIT];
|
|
|
// The GIE register. Only interrupts can disable the interrupt register
|
// The GIE register. Only interrupts can disable the interrupt register
|
`ifdef OPT_NO_USERMODE
|
generate if (OPT_NO_USERMODE)
|
|
begin
|
|
|
assign w_switch_to_interrupt = 1'b0;
|
assign w_switch_to_interrupt = 1'b0;
|
assign w_release_from_interrupt = 1'b0;
|
assign w_release_from_interrupt = 1'b0;
|
`else
|
|
|
end else begin : GEN_PENDING_INTERRUPT
|
|
reg r_pending_interrupt;
|
|
|
|
always @(posedge i_clk)
|
|
if (i_reset)
|
|
r_pending_interrupt <= 1'b0;
|
|
else if ((clear_pipeline)||(w_switch_to_interrupt)||(!gie))
|
|
r_pending_interrupt <= 1'b0;
|
|
else if (i_interrupt)
|
|
r_pending_interrupt <= 1'b1;
|
|
else if (adf_ce_unconditional)
|
|
begin
|
|
if ((op_illegal)||(step)||(break_pending))
|
|
r_pending_interrupt <= 1'b1;
|
|
end else if (break_pending)
|
|
r_pending_interrupt <= 1'b1;
|
|
else if ((mem_ce)&&(step))
|
|
r_pending_interrupt <= 1'b1;
|
|
|
|
assign pending_interrupt = r_pending_interrupt;
|
|
|
|
|
assign w_switch_to_interrupt = (gie)&&(
|
assign w_switch_to_interrupt = (gie)&&(
|
// On interrupt (obviously)
|
// On interrupt (obviously)
|
((i_interrupt)&&(!alu_phase)&&(!bus_lock))
|
((pending_interrupt)
|
// If we are stepping the CPU
|
&&(!alu_phase)&&(!bus_lock)&&(!mem_busy))
|
||(((alu_pc_valid)||(mem_pc_valid))&&(step)&&(!alu_phase)&&(!bus_lock))
|
//
|
// If we encounter a break instruction, if the break
|
|
// enable isn't set.
|
|
||((master_ce)&&(break_pending)&&(!break_en))
|
|
// On an illegal instruction
|
|
||((alu_illegal)&&(!clear_pipeline))
|
|
// On division by zero. If the divide isn't
|
// On division by zero. If the divide isn't
|
// implemented, div_valid and div_error will be short
|
// implemented, div_valid and div_error will be short
|
// circuited and that logic will be bypassed
|
// circuited and that logic will be bypassed
|
||(div_error)
|
||(div_error)
|
|
//
|
// Same thing on a floating point error. Note that
|
// Same thing on a floating point error. Note that
|
// fpu_error must *never* be set unless fpu_valid is
|
// fpu_error must *never* be set unless fpu_valid is
|
// also set as well, else this will fail.
|
// also set as well, else this will fail.
|
||(fpu_error)
|
||(fpu_error)
|
//
|
//
|
|
//
|
||(bus_err)
|
||(bus_err)
|
|
//
|
// If we write to the CC register
|
// If we write to the CC register
|
||((wr_reg_ce)&&(!wr_spreg_vl[`CPU_GIE_BIT])
|
||((wr_reg_ce)&&(!wr_spreg_vl[`CPU_GIE_BIT])
|
&&(wr_reg_id[4])&&(wr_write_cc))
|
&&(wr_reg_id[4])&&(wr_write_cc))
|
);
|
);
|
assign w_release_from_interrupt = (!gie)&&(!i_interrupt)
|
assign w_release_from_interrupt = (!gie)&&(!i_interrupt)
|
// Then if we write the sCC register
|
// Then if we write the sCC register
|
&&(((wr_reg_ce)&&(wr_spreg_vl[`CPU_GIE_BIT])
|
&&(((wr_reg_ce)&&(wr_spreg_vl[`CPU_GIE_BIT])
|
&&(wr_write_scc))
|
&&(wr_write_scc))
|
);
|
);
|
`endif
|
end endgenerate
|
|
|
`ifdef OPT_NO_USERMODE
|
generate if (OPT_NO_USERMODE)
|
|
begin
|
assign gie = 1'b0;
|
assign gie = 1'b0;
|
`else
|
end else begin : SET_GIE
|
|
|
reg r_gie;
|
reg r_gie;
|
|
|
initial r_gie = 1'b0;
|
initial r_gie = 1'b0;
|
always @(posedge i_clk)
|
always @(posedge i_clk)
|
if (i_rst)
|
if (i_reset)
|
r_gie <= 1'b0;
|
r_gie <= 1'b0;
|
else if (w_switch_to_interrupt)
|
else if (w_switch_to_interrupt)
|
r_gie <= 1'b0;
|
r_gie <= 1'b0;
|
else if (w_release_from_interrupt)
|
else if (w_release_from_interrupt)
|
r_gie <= 1'b1;
|
r_gie <= 1'b1;
|
assign gie = r_gie;
|
assign gie = r_gie;
|
`endif
|
end endgenerate
|
|
|
|
generate if (OPT_NO_USERMODE)
|
|
begin
|
|
|
`ifdef OPT_NO_USERMODE
|
|
assign trap = 1'b0;
|
assign trap = 1'b0;
|
assign ubreak = 1'b0;
|
assign ubreak = 1'b0;
|
`else
|
|
|
end else begin : SET_TRAP_N_UBREAK
|
|
|
reg r_trap;
|
reg r_trap;
|
|
|
initial r_trap = 1'b0;
|
initial r_trap = 1'b0;
|
always @(posedge i_clk)
|
always @(posedge i_clk)
|
if ((i_rst)||(w_release_from_interrupt))
|
if ((i_reset)||(w_release_from_interrupt))
|
r_trap <= 1'b0;
|
r_trap <= 1'b0;
|
else if ((alu_gie)&&(wr_reg_ce)&&(!wr_spreg_vl[`CPU_GIE_BIT])
|
else if ((alu_gie)&&(wr_reg_ce)&&(!wr_spreg_vl[`CPU_GIE_BIT])
|
&&(wr_write_ucc)) // &&(wr_reg_id[4]) implied
|
&&(wr_write_ucc)) // &&(wr_reg_id[4]) implied
|
r_trap <= 1'b1;
|
r_trap <= 1'b1;
|
else if ((wr_reg_ce)&&(wr_write_ucc)&&(!alu_gie))
|
else if ((wr_reg_ce)&&(wr_write_ucc)&&(!alu_gie))
|
| Line 1581... |
Line 2068... |
|
|
reg r_ubreak;
|
reg r_ubreak;
|
|
|
initial r_ubreak = 1'b0;
|
initial r_ubreak = 1'b0;
|
always @(posedge i_clk)
|
always @(posedge i_clk)
|
if ((i_rst)||(w_release_from_interrupt))
|
if ((i_reset)||(w_release_from_interrupt))
|
r_ubreak <= 1'b0;
|
r_ubreak <= 1'b0;
|
else if ((op_gie)&&(break_pending)&&(w_switch_to_interrupt))
|
else if ((op_gie)&&(break_pending)&&(w_switch_to_interrupt))
|
r_ubreak <= 1'b1;
|
r_ubreak <= 1'b1;
|
else if (((!alu_gie)||(dbgv))&&(wr_reg_ce)&&(wr_write_ucc))
|
else if (((!alu_gie)||(dbgv))&&(wr_reg_ce)&&(wr_write_ucc))
|
r_ubreak <= (ubreak)&&(wr_spreg_vl[`CPU_BREAK_BIT]);
|
r_ubreak <= (ubreak)&&(wr_spreg_vl[`CPU_BREAK_BIT]);
|
|
|
assign trap = r_trap;
|
assign trap = r_trap;
|
assign ubreak = r_ubreak;
|
assign ubreak = r_ubreak;
|
`endif
|
|
|
end endgenerate
|
|
|
|
|
`ifdef OPT_ILLEGAL_INSTRUCTION
|
|
initial ill_err_i = 1'b0;
|
initial ill_err_i = 1'b0;
|
always @(posedge i_clk)
|
always @(posedge i_clk)
|
if (i_rst)
|
if (i_reset)
|
ill_err_i <= 1'b0;
|
ill_err_i <= 1'b0;
|
// Only the debug interface can clear this bit
|
// Only the debug interface can clear this bit
|
else if ((dbgv)&&(wr_write_scc))
|
else if ((dbgv)&&(wr_write_scc))
|
ill_err_i <= (ill_err_i)&&(wr_spreg_vl[`CPU_ILL_BIT]);
|
ill_err_i <= (ill_err_i)&&(wr_spreg_vl[`CPU_ILL_BIT]);
|
else if ((alu_illegal)&&(!alu_gie)&&(!clear_pipeline))
|
else if ((alu_illegal)&&(!alu_gie)&&(!clear_pipeline))
|
ill_err_i <= 1'b1;
|
ill_err_i <= 1'b1;
|
|
|
`ifdef OPT_NO_USERMODE
|
generate if (OPT_NO_USERMODE)
|
|
begin
|
|
|
assign ill_err_u = 1'b0;
|
assign ill_err_u = 1'b0;
|
`else
|
|
|
end else begin : SET_USER_ILLEGAL_INSN
|
|
|
reg r_ill_err_u;
|
reg r_ill_err_u;
|
|
|
initial r_ill_err_u = 1'b0;
|
initial r_ill_err_u = 1'b0;
|
always @(posedge i_clk)
|
always @(posedge i_clk)
|
// The bit is automatically cleared on release from interrupt
|
// The bit is automatically cleared on release from interrupt
|
// or reset
|
// or reset
|
if ((i_rst)||(w_release_from_interrupt))
|
if ((i_reset)||(w_release_from_interrupt))
|
r_ill_err_u <= 1'b0;
|
r_ill_err_u <= 1'b0;
|
// If the supervisor (or debugger) writes to this register,
|
// If the supervisor (or debugger) writes to this
|
// clearing the bit, then clear it
|
// register, clearing the bit, then clear it
|
else if (((!alu_gie)||(dbgv))&&(wr_reg_ce)&&(wr_write_ucc))
|
else if (((!alu_gie)||(dbgv))&&(wr_reg_ce)&&(wr_write_ucc))
|
r_ill_err_u <=((ill_err_u)&&(wr_spreg_vl[`CPU_ILL_BIT]));
|
r_ill_err_u <=((ill_err_u)&&(wr_spreg_vl[`CPU_ILL_BIT]));
|
else if ((alu_illegal)&&(alu_gie)&&(!clear_pipeline))
|
else if ((alu_illegal)&&(alu_gie)&&(!clear_pipeline))
|
r_ill_err_u <= 1'b1;
|
r_ill_err_u <= 1'b1;
|
|
|
assign ill_err_u = r_ill_err_u;
|
assign ill_err_u = r_ill_err_u;
|
`endif
|
|
`else
|
end endgenerate
|
assign ill_err_u = 1'b0;
|
|
assign ill_err_i = 1'b0;
|
|
`endif
|
|
// Supervisor/interrupt bus error flag -- this will crash the CPU if
|
// Supervisor/interrupt bus error flag -- this will crash the CPU if
|
// ever set.
|
// ever set.
|
initial ibus_err_flag = 1'b0;
|
initial ibus_err_flag = 1'b0;
|
always @(posedge i_clk)
|
always @(posedge i_clk)
|
if (i_rst)
|
if (i_reset)
|
ibus_err_flag <= 1'b0;
|
ibus_err_flag <= 1'b0;
|
else if ((dbgv)&&(wr_write_scc))
|
else if ((dbgv)&&(wr_write_scc))
|
ibus_err_flag <= (ibus_err_flag)&&(wr_spreg_vl[`CPU_BUSERR_BIT]);
|
ibus_err_flag <= (ibus_err_flag)&&(wr_spreg_vl[`CPU_BUSERR_BIT]);
|
else if ((bus_err)&&(!alu_gie))
|
else if ((bus_err)&&(!alu_gie))
|
ibus_err_flag <= 1'b1;
|
ibus_err_flag <= 1'b1;
|
// User bus error flag -- if ever set, it will cause an interrupt to
|
// User bus error flag -- if ever set, it will cause an interrupt to
|
// supervisor mode.
|
// supervisor mode.
|
`ifdef OPT_NO_USERMODE
|
generate if (OPT_NO_USERMODE)
|
|
begin
|
|
|
assign ubus_err_flag = 1'b0;
|
assign ubus_err_flag = 1'b0;
|
`else
|
|
|
end else begin : SET_USER_BUSERR
|
|
|
reg r_ubus_err_flag;
|
reg r_ubus_err_flag;
|
|
|
initial r_ubus_err_flag = 1'b0;
|
initial r_ubus_err_flag = 1'b0;
|
always @(posedge i_clk)
|
always @(posedge i_clk)
|
if ((i_rst)||(w_release_from_interrupt))
|
if ((i_reset)||(w_release_from_interrupt))
|
r_ubus_err_flag <= 1'b0;
|
r_ubus_err_flag <= 1'b0;
|
else if (((!alu_gie)||(dbgv))&&(wr_reg_ce)&&(wr_write_ucc))
|
else if (((!alu_gie)||(dbgv))&&(wr_reg_ce)&&(wr_write_ucc))
|
r_ubus_err_flag <= (ubus_err_flag)&&(wr_spreg_vl[`CPU_BUSERR_BIT]);
|
r_ubus_err_flag <= (ubus_err_flag)&&(wr_spreg_vl[`CPU_BUSERR_BIT]);
|
else if ((bus_err)&&(alu_gie))
|
else if ((bus_err)&&(alu_gie))
|
r_ubus_err_flag <= 1'b1;
|
r_ubus_err_flag <= 1'b1;
|
|
|
assign ubus_err_flag = r_ubus_err_flag;
|
assign ubus_err_flag = r_ubus_err_flag;
|
`endif
|
end endgenerate
|
|
|
generate
|
generate if (IMPLEMENT_DIVIDE != 0)
|
if (IMPLEMENT_DIVIDE != 0)
|
begin : DIVERR
|
begin
|
|
reg r_idiv_err_flag, r_udiv_err_flag;
|
reg r_idiv_err_flag, r_udiv_err_flag;
|
|
|
// Supervisor/interrupt divide (by zero) error flag -- this will
|
// Supervisor/interrupt divide (by zero) error flag -- this will
|
// crash the CPU if ever set. This bit is thus available for us
|
// crash the CPU if ever set. This bit is thus available for us
|
// to be able to tell if/why the CPU crashed.
|
// to be able to tell if/why the CPU crashed.
|
