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//////////////////////////////////////////////////////////////////////
////                                                              ////
////  OR1200's Exception logic                                    ////
////                                                              ////
////  This file is part of the OpenRISC 1200 project              ////
////  http://www.opencores.org/cores/or1k/                        ////
////                                                              ////
////  Description                                                 ////
////  Handles all OR1K exceptions inside CPU block.               ////
////                                                              ////
////  To Do:                                                      ////
////   - make it smaller and faster                               ////
////                                                              ////
////  Author(s):                                                  ////
////      - Damjan Lampret, lampret@opencores.org                 ////
////                                                              ////
//////////////////////////////////////////////////////////////////////
////                                                              ////
//// Copyright (C) 2000 Authors and OPENCORES.ORG                 ////
////                                                              ////
//// This source file may be used and distributed without         ////
//// restriction provided that this copyright statement is not    ////
//// removed from the file and that any derivative work contains  ////
//// the original copyright notice and the associated disclaimer. ////
////                                                              ////
//// This source file is free software; you can redistribute it   ////
//// and/or modify it under the terms of the GNU Lesser General   ////
//// Public License as published by the Free Software Foundation; ////
//// either version 2.1 of the License, or (at your option) any   ////
//// later version.                                               ////
////                                                              ////
//// This source is distributed in the hope that it will be       ////
//// useful, but WITHOUT ANY WARRANTY; without even the implied   ////
//// warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR      ////
//// PURPOSE.  See the GNU Lesser General Public License for more ////
//// details.                                                     ////
////                                                              ////
//// You should have received a copy of the GNU Lesser General    ////
//// Public License along with this source; if not, download it   ////
//// from http://www.opencores.org/lgpl.shtml                     ////
////                                                              ////
//////////////////////////////////////////////////////////////////////
//
// CVS Revision History
//
// $Log: not supported by cvs2svn $
// Revision 1.12  2002/08/22 02:16:45  lampret
// Fixed IMMU bug.
//
// Revision 1.11  2002/08/18 19:54:28  lampret
// Added store buffer.
//
// Revision 1.10  2002/07/14 22:17:17  lampret
// Added simple trace buffer [only for Xilinx Virtex target]. Fixed instruction fetch abort when new exception is recognized.
//
// Revision 1.9  2002/02/11 04:33:17  lampret
// Speed optimizations (removed duplicate _cyc_ and _stb_). Fixed D/IMMU cache-inhibit attr.
//
// Revision 1.8  2002/01/28 01:16:00  lampret
// Changed 'void' nop-ops instead of insn[0] to use insn[16]. Debug unit stalls the tick timer. Prepared new flag generation for add and and insns. Blocked DC/IC while they are turned off. Fixed I/D MMU SPRs layout except WAYs. TODO: smart IC invalidate, l.j 2 and TLB ways.
//
// Revision 1.7  2002/01/23 07:52:36  lampret
// Changed default reset values for SR and ESR to match or1ksim's. Fixed flop model in or1200_dpram_32x32 when OR1200_XILINX_RAM32X1D is defined.
//
// Revision 1.6  2002/01/18 14:21:43  lampret
// Fixed 'the NPC single-step fix'.
//
// Revision 1.5  2002/01/18 07:56:00  lampret
// No more low/high priority interrupts (PICPR removed). Added tick timer exception. Added exception prefix (SR[EPH]). Fixed single-step bug whenreading NPC.
//
// Revision 1.4  2002/01/14 21:11:50  lampret
// Changed alignment exception EPCR. Not tested yet.
//
// Revision 1.3  2002/01/14 19:09:57  lampret
// Fixed order of syscall and range exceptions.
//
// Revision 1.2  2002/01/14 06:18:22  lampret
// Fixed mem2reg bug in FAST implementation. Updated debug unit to work with new genpc/if.
//
// Revision 1.1  2002/01/03 08:16:15  lampret
// New prefixes for RTL files, prefixed module names. Updated cache controllers and MMUs.
//
// Revision 1.15  2001/11/27 23:13:11  lampret
// Fixed except_stop width and fixed EX PC for 1400444f no-ops.
//
// Revision 1.14  2001/11/23 08:38:51  lampret
// Changed DSR/DRR behavior and exception detection.
//
// Revision 1.13  2001/11/20 18:46:15  simons
// Break point bug fixed
//
// Revision 1.12  2001/11/18 09:58:28  lampret
// Fixed some l.trap typos.
//
// Revision 1.11  2001/11/18 08:36:28  lampret
// For GDB changed single stepping and disabled trap exception.
//
// Revision 1.10  2001/11/13 10:02:21  lampret
// Added 'setpc'. Renamed some signals (except_flushpipe into flushpipe etc)
//
// Revision 1.9  2001/11/10 03:43:57  lampret
// Fixed exceptions.
//
// Revision 1.8  2001/10/21 17:57:16  lampret
// Removed params from generic_XX.v. Added translate_off/on in sprs.v and id.v. Removed spr_addr from dc.v and ic.v. Fixed CR+LF.
//
// Revision 1.7  2001/10/14 13:12:09  lampret
// MP3 version.
//
// Revision 1.1.1.1  2001/10/06 10:18:36  igorm
// no message
//
// Revision 1.2  2001/08/09 13:39:33  lampret
// Major clean-up.
//
// Revision 1.1  2001/07/20 00:46:03  lampret
// Development version of RTL. Libraries are missing.
//
//
 
// synopsys translate_off
`include "timescale.v"
// synopsys translate_on
`include "or1200_defines.v"
 
`define OR1200_EXCEPTFSM_WIDTH 3
`define OR1200_EXCEPTFSM_IDLE   `OR1200_EXCEPTFSM_WIDTH'd0
`define OR1200_EXCEPTFSM_FLU1   `OR1200_EXCEPTFSM_WIDTH'd1
`define OR1200_EXCEPTFSM_FLU2   `OR1200_EXCEPTFSM_WIDTH'd2
`define OR1200_EXCEPTFSM_FLU3   `OR1200_EXCEPTFSM_WIDTH'd3
`define OR1200_EXCEPTFSM_FLU4   `OR1200_EXCEPTFSM_WIDTH'd4
`define OR1200_EXCEPTFSM_FLU5   `OR1200_EXCEPTFSM_WIDTH'd5
 
//
// Exception recognition and sequencing
//
 
module or1200_except(
        // Clock and reset
        clk, rst,
 
        // Internal i/f
        sig_ibuserr, sig_dbuserr, sig_illegal, sig_align, sig_range, sig_dtlbmiss, sig_dmmufault,
        sig_int, sig_syscall, sig_trap, sig_itlbmiss, sig_immufault, sig_tick,
        branch_taken, genpc_freeze, id_freeze, ex_freeze, wb_freeze, if_stall,
        if_pc, lr_sav, flushpipe, extend_flush, except_type, except_start,
        except_started, except_stop, ex_void,
        spr_dat_ppc, spr_dat_npc, datain, du_dsr, epcr_we, eear_we, esr_we, pc_we, epcr, eear,
        esr, sr_we, to_sr, sr, lsu_addr, abort_ex, icpu_ack_i, icpu_err_i, dcpu_ack_i, dcpu_err_i
);
 
//
// I/O
//
input                           clk;
input                           rst;
input                           sig_ibuserr;
input                           sig_dbuserr;
input                           sig_illegal;
input                           sig_align;
input                           sig_range;
input                           sig_dtlbmiss;
input                           sig_dmmufault;
input                           sig_int;
input                           sig_syscall;
input                           sig_trap;
input                           sig_itlbmiss;
input                           sig_immufault;
input                           sig_tick;
input                           branch_taken;
input                           genpc_freeze;
input                           id_freeze;
input                           ex_freeze;
input                           wb_freeze;
input                           if_stall;
input   [31:0]                   if_pc;
output  [31:2]                  lr_sav;
input   [31:0]                   datain;
input   [`OR1200_DU_DSR_WIDTH-1:0]     du_dsr;
input                           epcr_we;
input                           eear_we;
input                           esr_we;
input                           pc_we;
output  [31:0]                   epcr;
output  [31:0]                   eear;
output  [`OR1200_SR_WIDTH-1:0]   esr;
input   [`OR1200_SR_WIDTH-1:0]   to_sr;
input                           sr_we;
input   [`OR1200_SR_WIDTH-1:0]   sr;
input   [31:0]                   lsu_addr;
output                          flushpipe;
output                          extend_flush;
output  [`OR1200_EXCEPT_WIDTH-1:0]       except_type;
output                          except_start;
output                          except_started;
output  [12:0]                   except_stop;
input                           ex_void;
output  [31:0]                   spr_dat_ppc;
output  [31:0]                   spr_dat_npc;
output                          abort_ex;
input                           icpu_ack_i;
input                           icpu_err_i;
input                           dcpu_ack_i;
input                           dcpu_err_i;
 
//
// Internal regs and wires
//
reg     [`OR1200_EXCEPT_WIDTH-1:0]       except_type;
reg     [31:0]                   id_pc;
reg     [31:0]                   ex_pc;
reg     [31:0]                   wb_pc;
reg     [31:0]                   epcr;
reg     [31:0]                   eear;
reg     [`OR1200_SR_WIDTH-1:0]           esr;
reg     [2:0]                    id_exceptflags;
reg     [2:0]                    ex_exceptflags;
reg     [`OR1200_EXCEPTFSM_WIDTH-1:0]    state;
reg                             extend_flush;
reg                             extend_flush_last;
reg                             ex_dslot;
reg                             delayed1_ex_dslot;
reg                             delayed2_ex_dslot;
wire                            except_started;
wire    [12:0]                   except_trig;
wire                            except_flushpipe;
reg     [2:0]                    delayed_iee;
reg     [2:0]                    delayed_tee;
wire                            int_pending;
wire                            tick_pending;
 
//
// Simple combinatorial logic
//
assign except_started = extend_flush & except_start;
assign lr_sav = ex_pc[31:2];
assign spr_dat_ppc = wb_pc;
assign spr_dat_npc = ex_void ? id_pc : ex_pc;
assign except_start = (except_type != `OR1200_EXCEPT_NONE) & extend_flush;
assign int_pending = sig_int & sr[`OR1200_SR_IEE] & delayed_iee[2] & ~ex_freeze & ~branch_taken & ~ex_dslot;
assign tick_pending = sig_tick & sr[`OR1200_SR_TEE] & ~ex_freeze & ~branch_taken & ~ex_dslot;
assign abort_ex = sig_dbuserr | sig_dmmufault | sig_dtlbmiss | sig_align | sig_illegal;         // Abort write into RF by load & other instructions
 
//
// Order defines exception detection priority
//
assign except_trig = {
                        tick_pending            & ~du_dsr[`OR1200_DU_DSR_TTE],
                        int_pending             & ~du_dsr[`OR1200_DU_DSR_IE],
                        ex_exceptflags[1]       & ~du_dsr[`OR1200_DU_DSR_IME],
                        ex_exceptflags[0]        & ~du_dsr[`OR1200_DU_DSR_IPFE],
                        ex_exceptflags[2]       & ~du_dsr[`OR1200_DU_DSR_BUSEE],
                        sig_illegal             & ~du_dsr[`OR1200_DU_DSR_IIE],
                        sig_align               & ~du_dsr[`OR1200_DU_DSR_AE],
                        sig_dtlbmiss            & ~du_dsr[`OR1200_DU_DSR_DME],
                        sig_dmmufault           & ~du_dsr[`OR1200_DU_DSR_DPFE],
                        sig_dbuserr             & ~du_dsr[`OR1200_DU_DSR_BUSEE],
                        sig_range               & ~du_dsr[`OR1200_DU_DSR_RE],
                        sig_trap                & ~du_dsr[`OR1200_DU_DSR_TE] & ~ex_freeze,
                        sig_syscall             & ~du_dsr[`OR1200_DU_DSR_SCE] & ~ex_freeze
                };
assign except_stop = {
                        tick_pending            & du_dsr[`OR1200_DU_DSR_TTE],
                        int_pending             & du_dsr[`OR1200_DU_DSR_IE],
                        ex_exceptflags[1]       & du_dsr[`OR1200_DU_DSR_IME],
                        ex_exceptflags[0]        & du_dsr[`OR1200_DU_DSR_IPFE],
                        ex_exceptflags[2]       & du_dsr[`OR1200_DU_DSR_BUSEE],
                        sig_illegal             & du_dsr[`OR1200_DU_DSR_IIE],
                        sig_align               & du_dsr[`OR1200_DU_DSR_AE],
                        sig_dtlbmiss            & du_dsr[`OR1200_DU_DSR_DME],
                        sig_dmmufault           & du_dsr[`OR1200_DU_DSR_DPFE],
                        sig_dbuserr             & du_dsr[`OR1200_DU_DSR_BUSEE],
                        sig_range               & du_dsr[`OR1200_DU_DSR_RE],
                        sig_trap                & du_dsr[`OR1200_DU_DSR_TE] & ~ex_freeze,
                        sig_syscall             & du_dsr[`OR1200_DU_DSR_SCE] & ~ex_freeze
                };
 
//
// PC and Exception flags pipelines
//
always @(posedge clk or posedge rst) begin
        if (rst) begin
                id_pc <= #1 32'd0;
                id_exceptflags <= #1 3'b000;
        end
        else if (flushpipe) begin
                id_pc <= #1 32'h0000_0000;
                id_exceptflags <= #1 3'b000;
        end
        else if (!id_freeze) begin
                id_pc <= #1 if_pc;
                id_exceptflags <= #1 { sig_ibuserr, sig_itlbmiss, sig_immufault };
        end
end
 
//
// delayed_iee
//
// SR[IEE] should not enable interrupts right away
// when it is restored with l.rfe. Instead delayed_iee
// together with SR[IEE] enables interrupts once
// pipeline is again ready.
//
always @(posedge rst or posedge clk)
        if (rst)
                delayed_iee <= #1 3'b000;
        else if (!sr[`OR1200_SR_IEE])
                delayed_iee <= #1 3'b000;
        else
                delayed_iee <= #1 {delayed_iee[1:0], 1'b1};
 
//
// delayed_tee
//
// SR[TEE] should not enable tick exceptions right away
// when it is restored with l.rfe. Instead delayed_tee
// together with SR[TEE] enables tick exceptions once
// pipeline is again ready.
//
always @(posedge rst or posedge clk)
        if (rst)
                delayed_tee <= #1 3'b000;
        else if (!sr[`OR1200_SR_TEE])
                delayed_tee <= #1 3'b000;
        else
                delayed_tee <= #1 {delayed_tee[1:0], 1'b1};
 
//
// PC and Exception flags pipelines
//
always @(posedge clk or posedge rst) begin
        if (rst) begin
                ex_dslot <= #1 1'b0;
                ex_pc <= #1 32'd0;
                ex_exceptflags <= #1 3'b000;
                delayed1_ex_dslot <= #1 1'b0;
                delayed2_ex_dslot <= #1 1'b0;
        end
        else if (flushpipe) begin
                ex_dslot <= #1 1'b0;
                ex_pc <= #1 32'h0000_0000;
                ex_exceptflags <= #1 3'b000;
                delayed1_ex_dslot <= #1 1'b0;
                delayed2_ex_dslot <= #1 1'b0;
        end
        else if (!ex_freeze & id_freeze) begin
                ex_dslot <= #1 1'b0;
                ex_pc <= #1 id_pc;
                ex_exceptflags <= #1 3'b000;
                delayed1_ex_dslot <= #1 ex_dslot;
                delayed2_ex_dslot <= #1 delayed1_ex_dslot;
        end
        else if (!ex_freeze) begin
                ex_dslot <= #1 branch_taken;
                ex_pc <= #1 id_pc;
                ex_exceptflags <= #1 id_exceptflags;
                delayed1_ex_dslot <= #1 ex_dslot;
                delayed2_ex_dslot <= #1 delayed1_ex_dslot;
        end
end
 
//
// PC and Exception flags pipelines
//
always @(posedge clk or posedge rst) begin
        if (rst) begin
                wb_pc <= #1 32'd0;
        end
        else if (!wb_freeze) begin
                wb_pc <= #1 ex_pc;
        end
end
 
//
// Flush pipeline
//
assign flushpipe = except_flushpipe | pc_we | extend_flush;
 
//
// We have started execution of exception handler:
//  1. Asserted for 3 clock cycles
//  2. Don't execute any instruction that is still in pipeline and is not part of exception handler
//
assign except_flushpipe = |except_trig & !state;
 
//
// Exception FSM that sequences execution of exception handler
//
// except_type signals which exception handler we start fetching in:
//  1. Asserted in next clock cycle after exception is recognized
//
always @(posedge clk or posedge rst) begin
        if (rst) begin
                state <= #1 `OR1200_EXCEPTFSM_IDLE;
                except_type <= #1 `OR1200_EXCEPT_NONE;
                extend_flush <= #1 1'b0;
                epcr <= #1 32'b0;
                eear <= #1 32'b0;
                esr <= #1 {1'b1, {`OR1200_SR_WIDTH-2{1'b0}}, 1'b1};
                extend_flush_last <= #1 1'b0;
        end
        else begin
                case (state)    // synopsys full_case parallel_case
                        `OR1200_EXCEPTFSM_IDLE:
                                if (except_flushpipe) begin
                                        state <= #1 `OR1200_EXCEPTFSM_FLU1;
                                        extend_flush <= #1 1'b1;
                                        esr <= #1 sr_we ? to_sr : sr;
                                        casex (except_trig)
                                                13'b1_xxxx_xxxx_xxxx: begin
                                                        except_type <= #1 `OR1200_EXCEPT_TICK;
                                                        epcr <= #1 ex_dslot ? wb_pc : delayed1_ex_dslot ? id_pc : delayed2_ex_dslot ? id_pc : id_pc;
                                                end
                                                13'b0_1xxx_xxxx_xxxx: begin
                                                        except_type <= #1 `OR1200_EXCEPT_INT;
                                                        epcr <= #1 ex_dslot ? wb_pc : delayed1_ex_dslot ? id_pc : delayed2_ex_dslot ? id_pc : id_pc;
                                                end
                                                13'b0_01xx_xxxx_xxxx: begin
                                                        except_type <= #1 `OR1200_EXCEPT_ITLBMISS;
//
// itlb miss exception and active ex_dslot caused wb_pc to put into eear instead of +4 address of ex_pc (or id_pc since it was equal to ex_pc?)
//                                                      eear <= #1 ex_dslot ? wb_pc : delayed1_ex_dslot ? id_pc : delayed2_ex_dslot ? id_pc : id_pc;
//      mmu-icdc-O2 ex_pc only OK when no ex_dslot      eear <= #1 ex_dslot ? ex_pc : delayed1_ex_dslot ? id_pc : delayed2_ex_dslot ? id_pc : id_pc;
//      mmu-icdc-O2 ex_pc only OK when no ex_dslot      epcr <= #1 ex_dslot ? wb_pc : delayed1_ex_dslot ? id_pc : delayed2_ex_dslot ? id_pc : id_pc;
                                                        eear <= #1 ex_dslot ? ex_pc : ex_pc;
                                                        epcr <= #1 ex_dslot ? wb_pc : ex_pc;
//                                                      eear <= #1 ex_dslot ? ex_pc : delayed1_ex_dslot ? id_pc : delayed2_ex_dslot ? id_pc : id_pc;
//                                                      epcr <= #1 ex_dslot ? wb_pc : delayed1_ex_dslot ? id_pc : delayed2_ex_dslot ? id_pc : id_pc;
                                                end
                                                13'b0_001x_xxxx_xxxx: begin
                                                        except_type <= #1 `OR1200_EXCEPT_IPF;
//
// ipf exception and active ex_dslot caused wb_pc to put into eear instead of +4 address of ex_pc (or id_pc since it was equal to ex_pc?)
//                                                      eear <= #1 ex_dslot ? wb_pc : delayed1_ex_dslot ? id_pc : delayed2_ex_dslot ? id_pc : id_pc;
                                                        eear <= #1 ex_dslot ? ex_pc : delayed1_ex_dslot ? id_pc : delayed2_ex_dslot ? id_pc : id_pc;
                                                        epcr <= #1 ex_dslot ? wb_pc : delayed1_ex_dslot ? id_pc : delayed2_ex_dslot ? id_pc : id_pc;
                                                end
                                                13'b0_0001_xxxx_xxxx: begin
                                                        except_type <= #1 `OR1200_EXCEPT_BUSERR;
                                                        eear <= #1 ex_dslot ? wb_pc : ex_pc;
                                                        epcr <= #1 ex_dslot ? wb_pc : ex_pc;
                                                end
                                                13'b0_0000_1xxx_xxxx: begin
                                                        except_type <= #1 `OR1200_EXCEPT_ILLEGAL;
                                                        eear <= #1 ex_pc;
                                                        epcr <= #1 ex_dslot ? wb_pc : ex_pc;
                                                end
                                                13'b0_0000_01xx_xxxx: begin
                                                        except_type <= #1 `OR1200_EXCEPT_ALIGN;
                                                        eear <= #1 lsu_addr;
                                                        epcr <= #1 ex_dslot ? wb_pc : ex_pc;
                                                end
                                                13'b0_0000_001x_xxxx: begin
                                                        except_type <= #1 `OR1200_EXCEPT_DTLBMISS;
                                                        eear <= #1 lsu_addr;
                                                        epcr <= #1 ex_dslot ? wb_pc : ex_pc;
                                                end
                                                13'b0_0000_0001_xxxx: begin
                                                        except_type <= #1 `OR1200_EXCEPT_DPF;
                                                        eear <= #1 lsu_addr;
                                                        epcr <= #1 ex_dslot ? wb_pc : ex_pc;
                                                end
                                                13'b0_0000_0000_1xxx: begin     // Data Bus Error
                                                        except_type <= #1 `OR1200_EXCEPT_BUSERR;
                                                        eear <= #1 lsu_addr;
                                                        epcr <= #1 ex_dslot ? wb_pc : ex_pc;
                                                end
                                                13'b0_0000_0000_01xx: begin
                                                        except_type <= #1 `OR1200_EXCEPT_RANGE;
                                                        epcr <= #1 ex_dslot ? wb_pc : delayed1_ex_dslot ? id_pc : delayed2_ex_dslot ? id_pc : id_pc;
                                                end
                                                13'b0_0000_0000_001x: begin
                                                        except_type <= #1 `OR1200_EXCEPT_TRAP;
                                                        epcr <= #1 ex_dslot ? wb_pc : ex_pc;
                                                end
                                                13'b0_0000_0000_0001: begin
                                                        except_type <= #1 `OR1200_EXCEPT_SYSCALL;
                                                        epcr <= #1 ex_dslot ? wb_pc : delayed1_ex_dslot ? id_pc : delayed2_ex_dslot ? id_pc : id_pc;
                                                end
                                                default:
                                                        except_type <= #1 `OR1200_EXCEPT_NONE;
                                        endcase
                                end
                                else if (pc_we) begin
                                        state <= #1 `OR1200_EXCEPTFSM_FLU1;
                                        extend_flush <= #1 1'b1;
                                end
                                else begin
                                        if (epcr_we)
                                                epcr <= #1 datain;
                                        if (eear_we)
                                                eear <= #1 datain;
                                        if (esr_we)
                                                esr <= #1 {1'b1, datain[`OR1200_SR_WIDTH-2:0]};
                                end
                        `OR1200_EXCEPTFSM_FLU1:
                                if (icpu_ack_i | icpu_err_i | genpc_freeze)
                                        state <= #1 `OR1200_EXCEPTFSM_FLU2;
                        `OR1200_EXCEPTFSM_FLU2:
                                if (except_type == `OR1200_EXCEPT_TRAP) begin
                                        state <= #1 `OR1200_EXCEPTFSM_IDLE;
                                        extend_flush <= #1 1'b0;
                                        extend_flush_last <= #1 1'b0;
                                        except_type <= #1 `OR1200_EXCEPT_NONE;
                                end
                                else
                                        state <= #1 `OR1200_EXCEPTFSM_FLU3;
                        `OR1200_EXCEPTFSM_FLU3:
                                        begin
                                                state <= #1 `OR1200_EXCEPTFSM_FLU4;
                                        end
                        `OR1200_EXCEPTFSM_FLU4: begin
                                        state <= #1 `OR1200_EXCEPTFSM_FLU5;
                                        extend_flush <= #1 1'b0;
                                        extend_flush_last <= #1 1'b0; // damjan
                                end
                        `OR1200_EXCEPTFSM_FLU5: begin
                                if (!if_stall && !id_freeze) begin
                                        state <= #1 `OR1200_EXCEPTFSM_IDLE;
                                        except_type <= #1 `OR1200_EXCEPT_NONE;
                                        extend_flush_last <= #1 1'b0;
                                end
                        end
                endcase
        end
end
 
endmodule

Line No.	Rev	Author	Line
1	504	lampret	`//////////////////////////////////////////////////////////////////////`
2			`//// ////`
3			`//// OR1200's Exception logic ////`
4			`//// ////`
5			`//// This file is part of the OpenRISC 1200 project ////`
6			`//// http://www.opencores.org/cores/or1k/ ////`
7			`//// ////`
8			`//// Description ////`
9			`//// Handles all OR1K exceptions inside CPU block. ////`
10			`//// ////`
11			`//// To Do: ////`
12			`//// - make it smaller and faster ////`
13			`//// ////`
14			`//// Author(s): ////`
15			`//// - Damjan Lampret, lampret@opencores.org ////`
16			`//// ////`
17			`//////////////////////////////////////////////////////////////////////`
18			`//// ////`
19			`//// Copyright (C) 2000 Authors and OPENCORES.ORG ////`
20			`//// ////`
21			`//// This source file may be used and distributed without ////`
22			`//// restriction provided that this copyright statement is not ////`
23			`//// removed from the file and that any derivative work contains ////`
24			`//// the original copyright notice and the associated disclaimer. ////`
25			`//// ////`
26			`//// This source file is free software; you can redistribute it ////`
27			`//// and/or modify it under the terms of the GNU Lesser General ////`
28			`//// Public License as published by the Free Software Foundation; ////`
29			`//// either version 2.1 of the License, or (at your option) any ////`
30			`//// later version. ////`
31			`//// ////`
32			`//// This source is distributed in the hope that it will be ////`
33			`//// useful, but WITHOUT ANY WARRANTY; without even the implied ////`
34			`//// warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR ////`
35			`//// PURPOSE. See the GNU Lesser General Public License for more ////`
36			`//// details. ////`
37			`//// ////`
38			`//// You should have received a copy of the GNU Lesser General ////`
39			`//// Public License along with this source; if not, download it ////`
40			`//// from http://www.opencores.org/lgpl.shtml ////`
41			`//// ////`
42			`//////////////////////////////////////////////////////////////////////`
43			`//`
44			`// CVS Revision History`
45			`//`
46			`// $Log: not supported by cvs2svn $`
47	1011	lampret	`// Revision 1.12 2002/08/22 02:16:45 lampret`
48			`// Fixed IMMU bug.`
49			`//`
50	993	lampret	`// Revision 1.11 2002/08/18 19:54:28 lampret`
51			`// Added store buffer.`
52			`//`
53	977	lampret	`// Revision 1.10 2002/07/14 22:17:17 lampret`
54			`// Added simple trace buffer [only for Xilinx Virtex target]. Fixed instruction fetch abort when new exception is recognized.`
55			`//`
56	895	lampret	`// Revision 1.9 2002/02/11 04:33:17 lampret`
57			`// Speed optimizations (removed duplicate _cyc_ and _stb_). Fixed D/IMMU cache-inhibit attr.`
58			`//`
59	660	lampret	`// Revision 1.8 2002/01/28 01:16:00 lampret`
60			`// Changed 'void' nop-ops instead of insn[0] to use insn[16]. Debug unit stalls the tick timer. Prepared new flag generation for add and and insns. Blocked DC/IC while they are turned off. Fixed I/D MMU SPRs layout except WAYs. TODO: smart IC invalidate, l.j 2 and TLB ways.`
61			`//`
62	617	lampret	`// Revision 1.7 2002/01/23 07:52:36 lampret`
63			`// Changed default reset values for SR and ESR to match or1ksim's. Fixed flop model in or1200_dpram_32x32 when OR1200_XILINX_RAM32X1D is defined.`
64			`//`
65	610	lampret	`// Revision 1.6 2002/01/18 14:21:43 lampret`
66			`// Fixed 'the NPC single-step fix'.`
67			`//`
68	595	lampret	`// Revision 1.5 2002/01/18 07:56:00 lampret`
69			`// No more low/high priority interrupts (PICPR removed). Added tick timer exception. Added exception prefix (SR[EPH]). Fixed single-step bug whenreading NPC.`
70			`//`
71	589	lampret	`// Revision 1.4 2002/01/14 21:11:50 lampret`
72			`// Changed alignment exception EPCR. Not tested yet.`
73			`//`
74	571	lampret	`// Revision 1.3 2002/01/14 19:09:57 lampret`
75			`// Fixed order of syscall and range exceptions.`
76			`//`
77	570	lampret	`// Revision 1.2 2002/01/14 06:18:22 lampret`
78			`// Fixed mem2reg bug in FAST implementation. Updated debug unit to work with new genpc/if.`
79			`//`
80	562	lampret	`// Revision 1.1 2002/01/03 08:16:15 lampret`
81			`// New prefixes for RTL files, prefixed module names. Updated cache controllers and MMUs.`
82			`//`
83	504	lampret	`// Revision 1.15 2001/11/27 23:13:11 lampret`
84			`// Fixed except_stop width and fixed EX PC for 1400444f no-ops.`
85			`//`
86			`// Revision 1.14 2001/11/23 08:38:51 lampret`
87			`// Changed DSR/DRR behavior and exception detection.`
88			`//`
89			`// Revision 1.13 2001/11/20 18:46:15 simons`
90			`// Break point bug fixed`
91			`//`
92			`// Revision 1.12 2001/11/18 09:58:28 lampret`
93			`// Fixed some l.trap typos.`
94			`//`
95			`// Revision 1.11 2001/11/18 08:36:28 lampret`
96			`// For GDB changed single stepping and disabled trap exception.`
97			`//`
98			`// Revision 1.10 2001/11/13 10:02:21 lampret`
99			`// Added 'setpc'. Renamed some signals (except_flushpipe into flushpipe etc)`
100			`//`
101			`// Revision 1.9 2001/11/10 03:43:57 lampret`
102			`// Fixed exceptions.`
103			`//`
104			`// Revision 1.8 2001/10/21 17:57:16 lampret`
105			`// Removed params from generic_XX.v. Added translate_off/on in sprs.v and id.v. Removed spr_addr from dc.v and ic.v. Fixed CR+LF.`
106			`//`
107			`// Revision 1.7 2001/10/14 13:12:09 lampret`
108			`// MP3 version.`
109			`//`
110			`// Revision 1.1.1.1 2001/10/06 10:18:36 igorm`
111			`// no message`
112			`//`
113			`// Revision 1.2 2001/08/09 13:39:33 lampret`
114			`// Major clean-up.`
115			`//`
116			`// Revision 1.1 2001/07/20 00:46:03 lampret`
117			`// Development version of RTL. Libraries are missing.`
118			`//`
119			`//`
120
121			`// synopsys translate_off`
122			`include "timescale.v"
123			`// synopsys translate_on`
124			`include "or1200_defines.v"
125
126			`define OR1200_EXCEPTFSM_WIDTH 3
127			`define OR1200_EXCEPTFSM_IDLE `OR1200_EXCEPTFSM_WIDTH'd0
128			`define OR1200_EXCEPTFSM_FLU1 `OR1200_EXCEPTFSM_WIDTH'd1
129			`define OR1200_EXCEPTFSM_FLU2 `OR1200_EXCEPTFSM_WIDTH'd2
130			`define OR1200_EXCEPTFSM_FLU3 `OR1200_EXCEPTFSM_WIDTH'd3
131			`define OR1200_EXCEPTFSM_FLU4 `OR1200_EXCEPTFSM_WIDTH'd4
132			`define OR1200_EXCEPTFSM_FLU5 `OR1200_EXCEPTFSM_WIDTH'd5
133
134			`//`
135			`// Exception recognition and sequencing`
136			`//`
137
138			`module or1200_except(`
139			`// Clock and reset`
140			`clk, rst,`
141
142			`// Internal i/f`
143			`sig_ibuserr, sig_dbuserr, sig_illegal, sig_align, sig_range, sig_dtlbmiss, sig_dmmufault,`
144	589	lampret	`sig_int, sig_syscall, sig_trap, sig_itlbmiss, sig_immufault, sig_tick,`
145	895	lampret	`branch_taken, genpc_freeze, id_freeze, ex_freeze, wb_freeze, if_stall,`
146	504	lampret	`if_pc, lr_sav, flushpipe, extend_flush, except_type, except_start,`
147	595	lampret	`except_started, except_stop, ex_void,`
148	589	lampret	`spr_dat_ppc, spr_dat_npc, datain, du_dsr, epcr_we, eear_we, esr_we, pc_we, epcr, eear,`
149	1011	lampret	`esr, sr_we, to_sr, sr, lsu_addr, abort_ex, icpu_ack_i, icpu_err_i, dcpu_ack_i, dcpu_err_i`
150	504	lampret	`);`
151
152			`//`
153			`// I/O`
154			`//`
155			`input clk;`
156			`input rst;`
157			`input sig_ibuserr;`
158			`input sig_dbuserr;`
159			`input sig_illegal;`
160			`input sig_align;`
161			`input sig_range;`
162			`input sig_dtlbmiss;`
163			`input sig_dmmufault;`
164	589	lampret	`input sig_int;`
165	504	lampret	`input sig_syscall;`
166			`input sig_trap;`
167			`input sig_itlbmiss;`
168			`input sig_immufault;`
169	589	lampret	`input sig_tick;`
170	504	lampret	`input branch_taken;`
171	895	lampret	`input genpc_freeze;`
172	504	lampret	`input id_freeze;`
173			`input ex_freeze;`
174			`input wb_freeze;`
175			`input if_stall;`
176			`input [31:0] if_pc;`
177			`output [31:2] lr_sav;`
178			`input [31:0] datain;`
179			input [`OR1200_DU_DSR_WIDTH-1:0] du_dsr;
180			`input epcr_we;`
181			`input eear_we;`
182			`input esr_we;`
183			`input pc_we;`
184			`output [31:0] epcr;`
185			`output [31:0] eear;`
186	1011	lampret	output [`OR1200_SR_WIDTH-1:0] esr;
187			input [`OR1200_SR_WIDTH-1:0] to_sr;
188			`input sr_we;`
189			input [`OR1200_SR_WIDTH-1:0] sr;
190	504	lampret	`input [31:0] lsu_addr;`
191			`output flushpipe;`
192			`output extend_flush;`
193			output [`OR1200_EXCEPT_WIDTH-1:0] except_type;
194			`output except_start;`
195			`output except_started;`
196			`output [12:0] except_stop;`
197	595	lampret	`input ex_void;`
198	589	lampret	`output [31:0] spr_dat_ppc;`
199			`output [31:0] spr_dat_npc;`
200	617	lampret	`output abort_ex;`
201	895	lampret	`input icpu_ack_i;`
202			`input icpu_err_i;`
203			`input dcpu_ack_i;`
204			`input dcpu_err_i;`
205	504	lampret
206			`//`
207			`// Internal regs and wires`
208			`//`
209			reg [`OR1200_EXCEPT_WIDTH-1:0] except_type;
210			`reg [31:0] id_pc;`
211			`reg [31:0] ex_pc;`
212			`reg [31:0] wb_pc;`
213			`reg [31:0] epcr;`
214			`reg [31:0] eear;`
215			reg [`OR1200_SR_WIDTH-1:0] esr;
216	589	lampret	`reg [2:0] id_exceptflags;`
217			`reg [2:0] ex_exceptflags;`
218	504	lampret	reg [`OR1200_EXCEPTFSM_WIDTH-1:0] state;
219			`reg extend_flush;`
220			`reg extend_flush_last;`
221			`reg ex_dslot;`
222			`reg delayed1_ex_dslot;`
223			`reg delayed2_ex_dslot;`
224			`wire except_started;`
225			`wire [12:0] except_trig;`
226			`wire except_flushpipe;`
227	589	lampret	`reg [2:0] delayed_iee;`
228			`reg [2:0] delayed_tee;`
229			`wire int_pending;`
230			`wire tick_pending;`
231	504	lampret
232			`//`
233			`// Simple combinatorial logic`
234			`//`
235			`assign except_started = extend_flush & except_start;`
236			`assign lr_sav = ex_pc[31:2];`
237	589	lampret	`assign spr_dat_ppc = wb_pc;`
238	595	lampret	`assign spr_dat_npc = ex_void ? id_pc : ex_pc;`
239	562	lampret	assign except_start = (except_type != `OR1200_EXCEPT_NONE) & extend_flush;
240	589	lampret	assign int_pending = sig_int & sr[`OR1200_SR_IEE] & delayed_iee[2] & ~ex_freeze & ~branch_taken & ~ex_dslot;
241	610	lampret	assign tick_pending = sig_tick & sr[`OR1200_SR_TEE] & ~ex_freeze & ~branch_taken & ~ex_dslot;
242	617	lampret	`assign abort_ex = sig_dbuserr \| sig_dmmufault \| sig_dtlbmiss \| sig_align \| sig_illegal; // Abort write into RF by load & other instructions`
243	504	lampret
244			`//`
245			`// Order defines exception detection priority`
246			`//`
247			`assign except_trig = {`
248	617	lampret	tick_pending & ~du_dsr[`OR1200_DU_DSR_TTE],
249	589	lampret	int_pending & ~du_dsr[`OR1200_DU_DSR_IE],
250			ex_exceptflags[1] & ~du_dsr[`OR1200_DU_DSR_IME],
251			ex_exceptflags[0] & ~du_dsr[`OR1200_DU_DSR_IPFE],
252			ex_exceptflags[2] & ~du_dsr[`OR1200_DU_DSR_BUSEE],
253	504	lampret	sig_illegal & ~du_dsr[`OR1200_DU_DSR_IIE],
254			sig_align & ~du_dsr[`OR1200_DU_DSR_AE],
255			sig_dtlbmiss & ~du_dsr[`OR1200_DU_DSR_DME],
256			sig_dmmufault & ~du_dsr[`OR1200_DU_DSR_DPFE],
257			sig_dbuserr & ~du_dsr[`OR1200_DU_DSR_BUSEE],
258	570	lampret	sig_range & ~du_dsr[`OR1200_DU_DSR_RE],
259	562	lampret	sig_trap & ~du_dsr[`OR1200_DU_DSR_TE] & ~ex_freeze,
260	570	lampret	sig_syscall & ~du_dsr[`OR1200_DU_DSR_SCE] & ~ex_freeze
261	504	lampret	`};`
262			`assign except_stop = {`
263	617	lampret	tick_pending & du_dsr[`OR1200_DU_DSR_TTE],
264	589	lampret	int_pending & du_dsr[`OR1200_DU_DSR_IE],
265			ex_exceptflags[1] & du_dsr[`OR1200_DU_DSR_IME],
266			ex_exceptflags[0] & du_dsr[`OR1200_DU_DSR_IPFE],
267			ex_exceptflags[2] & du_dsr[`OR1200_DU_DSR_BUSEE],
268	504	lampret	sig_illegal & du_dsr[`OR1200_DU_DSR_IIE],
269			sig_align & du_dsr[`OR1200_DU_DSR_AE],
270			sig_dtlbmiss & du_dsr[`OR1200_DU_DSR_DME],
271			sig_dmmufault & du_dsr[`OR1200_DU_DSR_DPFE],
272			sig_dbuserr & du_dsr[`OR1200_DU_DSR_BUSEE],
273	570	lampret	sig_range & du_dsr[`OR1200_DU_DSR_RE],
274	562	lampret	sig_trap & du_dsr[`OR1200_DU_DSR_TE] & ~ex_freeze,
275	570	lampret	sig_syscall & du_dsr[`OR1200_DU_DSR_SCE] & ~ex_freeze
276	504	lampret	`};`
277
278			`//`
279			`// PC and Exception flags pipelines`
280			`//`
281			`always @(posedge clk or posedge rst) begin`
282			`if (rst) begin`
283			`id_pc <= #1 32'd0;`
284	589	lampret	`id_exceptflags <= #1 3'b000;`
285	504	lampret	`end`
286	562	lampret	`else if (flushpipe) begin`
287			`id_pc <= #1 32'h0000_0000;`
288	589	lampret	`id_exceptflags <= #1 3'b000;`
289	562	lampret	`end`
290	504	lampret	`else if (!id_freeze) begin`
291			`id_pc <= #1 if_pc;`
292	589	lampret	`id_exceptflags <= #1 { sig_ibuserr, sig_itlbmiss, sig_immufault };`
293	504	lampret	`end`
294			`end`
295
296			`//`
297	589	lampret	`// delayed_iee`
298	504	lampret	`//`
299	589	lampret	`// SR[IEE] should not enable interrupts right away`
300			`// when it is restored with l.rfe. Instead delayed_iee`
301			`// together with SR[IEE] enables interrupts once`
302	504	lampret	`// pipeline is again ready.`
303			`//`
304			`always @(posedge rst or posedge clk)`
305			`if (rst)`
306	589	lampret	`delayed_iee <= #1 3'b000;`
307			else if (!sr[`OR1200_SR_IEE])
308			`delayed_iee <= #1 3'b000;`
309	504	lampret	`else`
310	589	lampret	`delayed_iee <= #1 {delayed_iee[1:0], 1'b1};`
311	504	lampret
312			`//`
313	589	lampret	`// delayed_tee`
314			`//`
315			`// SR[TEE] should not enable tick exceptions right away`
316			`// when it is restored with l.rfe. Instead delayed_tee`
317			`// together with SR[TEE] enables tick exceptions once`
318			`// pipeline is again ready.`
319			`//`
320			`always @(posedge rst or posedge clk)`
321			`if (rst)`
322			`delayed_tee <= #1 3'b000;`
323			else if (!sr[`OR1200_SR_TEE])
324			`delayed_tee <= #1 3'b000;`
325			`else`
326			`delayed_tee <= #1 {delayed_tee[1:0], 1'b1};`
327
328			`//`
329	504	lampret	`// PC and Exception flags pipelines`
330			`//`
331			`always @(posedge clk or posedge rst) begin`
332			`if (rst) begin`
333			`ex_dslot <= #1 1'b0;`
334			`ex_pc <= #1 32'd0;`
335	589	lampret	`ex_exceptflags <= #1 3'b000;`
336	504	lampret	`delayed1_ex_dslot <= #1 1'b0;`
337			`delayed2_ex_dslot <= #1 1'b0;`
338			`end`
339	562	lampret	`else if (flushpipe) begin`
340			`ex_dslot <= #1 1'b0;`
341			`ex_pc <= #1 32'h0000_0000;`
342	589	lampret	`ex_exceptflags <= #1 3'b000;`
343	562	lampret	`delayed1_ex_dslot <= #1 1'b0;`
344			`delayed2_ex_dslot <= #1 1'b0;`
345			`end`
346	504	lampret	`else if (!ex_freeze & id_freeze) begin`
347			`ex_dslot <= #1 1'b0;`
348			`ex_pc <= #1 id_pc;`
349	589	lampret	`ex_exceptflags <= #1 3'b000;`
350	504	lampret	`delayed1_ex_dslot <= #1 ex_dslot;`
351			`delayed2_ex_dslot <= #1 delayed1_ex_dslot;`
352			`end`
353			`else if (!ex_freeze) begin`
354			`ex_dslot <= #1 branch_taken;`
355			`ex_pc <= #1 id_pc;`
356			`ex_exceptflags <= #1 id_exceptflags;`
357			`delayed1_ex_dslot <= #1 ex_dslot;`
358			`delayed2_ex_dslot <= #1 delayed1_ex_dslot;`
359			`end`
360			`end`
361
362			`//`
363			`// PC and Exception flags pipelines`
364			`//`
365			`always @(posedge clk or posedge rst) begin`
366			`if (rst) begin`
367			`wb_pc <= #1 32'd0;`
368			`end`
369			`else if (!wb_freeze) begin`
370			`wb_pc <= #1 ex_pc;`
371			`end`
372			`end`
373
374			`//`
375			`// Flush pipeline`
376			`//`
377	562	lampret	`assign flushpipe = except_flushpipe \| pc_we \| extend_flush;`
378	504	lampret
379			`//`
380			`// We have started execution of exception handler:`
381			`// 1. Asserted for 3 clock cycles`
382			`// 2. Don't execute any instruction that is still in pipeline and is not part of exception handler`
383			`//`
384	562	lampret	`assign except_flushpipe = \|except_trig & !state;`
385	504	lampret
386			`//`
387			`// Exception FSM that sequences execution of exception handler`
388			`//`
389			`// except_type signals which exception handler we start fetching in:`
390			`// 1. Asserted in next clock cycle after exception is recognized`
391			`//`
392			`always @(posedge clk or posedge rst) begin`
393			`if (rst) begin`
394			state <= #1 `OR1200_EXCEPTFSM_IDLE;
395			except_type <= #1 `OR1200_EXCEPT_NONE;
396			`extend_flush <= #1 1'b0;`
397			`epcr <= #1 32'b0;`
398			`eear <= #1 32'b0;`
399	660	lampret	esr <= #1 {1'b1, {`OR1200_SR_WIDTH-2{1'b0}}, 1'b1};
400	504	lampret	`extend_flush_last <= #1 1'b0;`
401			`end`
402			`else begin`
403			`case (state) // synopsys full_case parallel_case`
404			`OR1200_EXCEPTFSM_IDLE:
405			`if (except_flushpipe) begin`
406			state <= #1 `OR1200_EXCEPTFSM_FLU1;
407			`extend_flush <= #1 1'b1;`
408	1011	lampret	`esr <= #1 sr_we ? to_sr : sr;`
409	504	lampret	`casex (except_trig)`
410			`13'b1_xxxx_xxxx_xxxx: begin`
411	617	lampret	except_type <= #1 `OR1200_EXCEPT_TICK;
412	504	lampret	`epcr <= #1 ex_dslot ? wb_pc : delayed1_ex_dslot ? id_pc : delayed2_ex_dslot ? id_pc : id_pc;`
413			`end`
414			`13'b0_1xxx_xxxx_xxxx: begin`
415	617	lampret	except_type <= #1 `OR1200_EXCEPT_INT;
416	504	lampret	`epcr <= #1 ex_dslot ? wb_pc : delayed1_ex_dslot ? id_pc : delayed2_ex_dslot ? id_pc : id_pc;`
417			`end`
418			`13'b0_01xx_xxxx_xxxx: begin`
419	617	lampret	except_type <= #1 `OR1200_EXCEPT_ITLBMISS;
420	977	lampret	`//`
421			`// itlb miss exception and active ex_dslot caused wb_pc to put into eear instead of +4 address of ex_pc (or id_pc since it was equal to ex_pc?)`
422			`// eear <= #1 ex_dslot ? wb_pc : delayed1_ex_dslot ? id_pc : delayed2_ex_dslot ? id_pc : id_pc;`
423	993	lampret	`// mmu-icdc-O2 ex_pc only OK when no ex_dslot eear <= #1 ex_dslot ? ex_pc : delayed1_ex_dslot ? id_pc : delayed2_ex_dslot ? id_pc : id_pc;`
424			`// mmu-icdc-O2 ex_pc only OK when no ex_dslot epcr <= #1 ex_dslot ? wb_pc : delayed1_ex_dslot ? id_pc : delayed2_ex_dslot ? id_pc : id_pc;`
425			`eear <= #1 ex_dslot ? ex_pc : ex_pc;`
426			`epcr <= #1 ex_dslot ? wb_pc : ex_pc;`
427			`// eear <= #1 ex_dslot ? ex_pc : delayed1_ex_dslot ? id_pc : delayed2_ex_dslot ? id_pc : id_pc;`
428			`// epcr <= #1 ex_dslot ? wb_pc : delayed1_ex_dslot ? id_pc : delayed2_ex_dslot ? id_pc : id_pc;`
429	504	lampret	`end`
430			`13'b0_001x_xxxx_xxxx: begin`
431	617	lampret	except_type <= #1 `OR1200_EXCEPT_IPF;
432	977	lampret	`//`
433			`// ipf exception and active ex_dslot caused wb_pc to put into eear instead of +4 address of ex_pc (or id_pc since it was equal to ex_pc?)`
434			`// eear <= #1 ex_dslot ? wb_pc : delayed1_ex_dslot ? id_pc : delayed2_ex_dslot ? id_pc : id_pc;`
435			`eear <= #1 ex_dslot ? ex_pc : delayed1_ex_dslot ? id_pc : delayed2_ex_dslot ? id_pc : id_pc;`
436	504	lampret	`epcr <= #1 ex_dslot ? wb_pc : delayed1_ex_dslot ? id_pc : delayed2_ex_dslot ? id_pc : id_pc;`
437			`end`
438			`13'b0_0001_xxxx_xxxx: begin`
439	617	lampret	except_type <= #1 `OR1200_EXCEPT_BUSERR;
440			`eear <= #1 ex_dslot ? wb_pc : ex_pc;`
441			`epcr <= #1 ex_dslot ? wb_pc : ex_pc;`
442			`end`
443			`13'b0_0000_1xxx_xxxx: begin`
444	504	lampret	except_type <= #1 `OR1200_EXCEPT_ILLEGAL;
445	610	lampret	`eear <= #1 ex_pc;`
446			`epcr <= #1 ex_dslot ? wb_pc : ex_pc;`
447	504	lampret	`end`
448	617	lampret	`13'b0_0000_01xx_xxxx: begin`
449	504	lampret	except_type <= #1 `OR1200_EXCEPT_ALIGN;
450			`eear <= #1 lsu_addr;`
451	571	lampret	`epcr <= #1 ex_dslot ? wb_pc : ex_pc;`
452	504	lampret	`end`
453	617	lampret	`13'b0_0000_001x_xxxx: begin`
454	504	lampret	except_type <= #1 `OR1200_EXCEPT_DTLBMISS;
455			`eear <= #1 lsu_addr;`
456			`epcr <= #1 ex_dslot ? wb_pc : ex_pc;`
457			`end`
458	617	lampret	`13'b0_0000_0001_xxxx: begin`
459	504	lampret	except_type <= #1 `OR1200_EXCEPT_DPF;
460			`eear <= #1 lsu_addr;`
461			`epcr <= #1 ex_dslot ? wb_pc : ex_pc;`
462			`end`
463	617	lampret	`13'b0_0000_0000_1xxx: begin // Data Bus Error`
464	504	lampret	except_type <= #1 `OR1200_EXCEPT_BUSERR;
465			`eear <= #1 lsu_addr;`
466	562	lampret	`epcr <= #1 ex_dslot ? wb_pc : ex_pc;`
467	504	lampret	`end`
468			`13'b0_0000_0000_01xx: begin`
469			except_type <= #1 `OR1200_EXCEPT_RANGE;
470			`epcr <= #1 ex_dslot ? wb_pc : delayed1_ex_dslot ? id_pc : delayed2_ex_dslot ? id_pc : id_pc;`
471			`end`
472			`13'b0_0000_0000_001x: begin`
473			except_type <= #1 `OR1200_EXCEPT_TRAP;
474	610	lampret	`epcr <= #1 ex_dslot ? wb_pc : ex_pc;`
475	504	lampret	`end`
476			`13'b0_0000_0000_0001: begin`
477			except_type <= #1 `OR1200_EXCEPT_SYSCALL;
478			`epcr <= #1 ex_dslot ? wb_pc : delayed1_ex_dslot ? id_pc : delayed2_ex_dslot ? id_pc : id_pc;`
479			`end`
480			`default:`
481			except_type <= #1 `OR1200_EXCEPT_NONE;
482			`endcase`
483			`end`
484			`else if (pc_we) begin`
485			state <= #1 `OR1200_EXCEPTFSM_FLU1;
486			`extend_flush <= #1 1'b1;`
487			`end`
488			`else begin`
489			`if (epcr_we)`
490			`epcr <= #1 datain;`
491			`if (eear_we)`
492			`eear <= #1 datain;`
493			`if (esr_we)`
494	589	lampret	esr <= #1 {1'b1, datain[`OR1200_SR_WIDTH-2:0]};
495	504	lampret	`end`
496			`OR1200_EXCEPTFSM_FLU1:
497	895	lampret	`if (icpu_ack_i \| icpu_err_i \| genpc_freeze)`
498	504	lampret	state <= #1 `OR1200_EXCEPTFSM_FLU2;
499			`OR1200_EXCEPTFSM_FLU2:
500			if (except_type == `OR1200_EXCEPT_TRAP) begin

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