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//////////////////////////////////////////////////////////////////////

////                                                              ////

////  OR1200's CPU                                                ////

////                                                              ////

////  This file is part of the OpenRISC 1200 project              ////

////  http://www.opencores.org/project,or1k                       ////

////                                                              ////

////  Description                                                 ////

////  Instantiation of internal CPU blocks. IFETCH, SPRS, FRZ,    ////

////  ALU, EXCEPT, ID, WBMUX, OPERANDMUX, RF etc.                 ////

////                                                              ////

////  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                     ////

////                                                              ////

//////////////////////////////////////////////////////////////////////

//

// $Log: or1200_cpu.v,v $

// Revision 2.0  2010/06/30 11:00:00  ORSoC

// Major update: 

// Structure reordered and bugs fixed. 

// synopsys translate_off

`include "timescale.v"

// synopsys translate_on

`include "or1200_defines.v"

module or1200_cpu(

        // Clk & Rst

        clk, rst,

        // Insn interface

        ic_en,

        icpu_adr_o, icpu_cycstb_o, icpu_sel_o, icpu_tag_o,

        icpu_dat_i, icpu_ack_i, icpu_rty_i, icpu_err_i, icpu_adr_i, icpu_tag_i,

        immu_en,

        // Debug unit

        id_void, id_insn, ex_void,

        ex_insn, ex_freeze, wb_insn, wb_freeze, id_pc, ex_pc, wb_pc, branch_op,

        spr_dat_npc, rf_dataw, ex_flushpipe,

        du_stall, du_addr, du_dat_du, du_read, du_write, du_except_stop,

        du_except_trig, du_dsr, du_dmr1, du_hwbkpt, du_hwbkpt_ls_r, du_dat_cpu,

        du_lsu_store_dat, du_lsu_load_dat,

        abort_mvspr, abort_ex,

        // Data interface

        dc_en,

        dcpu_adr_o, dcpu_cycstb_o, dcpu_we_o, dcpu_sel_o, dcpu_tag_o,

        dcpu_dat_o, dcpu_dat_i, dcpu_ack_i, dcpu_rty_i, dcpu_err_i, dcpu_tag_i,

        sb_en, dmmu_en, dc_no_writethrough,

        // SR Interface

        boot_adr_sel_i,

        // Interrupt & tick exceptions

        sig_int, sig_tick,

        // SPR interface

        supv, spr_addr, spr_dat_cpu, spr_dat_pic, spr_dat_tt, spr_dat_pm,

        spr_dat_dmmu, spr_dat_immu, spr_dat_du, spr_cs, spr_we, mtspr_dc_done

);

parameter dw = `OR1200_OPERAND_WIDTH;

parameter aw = `OR1200_REGFILE_ADDR_WIDTH;

//

// I/O ports

//

//

// Clk & Rst

//

input                           clk;

input                           rst;

//

// Insn (IC) interface

//

output                          ic_en;

output  [31:0]                   icpu_adr_o;

output                          icpu_cycstb_o;

output  [3:0]                    icpu_sel_o;

output  [3:0]                    icpu_tag_o;

input   [31:0]                   icpu_dat_i;

input                           icpu_ack_i;

input                           icpu_rty_i;

input                           icpu_err_i;

input   [31:0]                   icpu_adr_i;

input   [3:0]                    icpu_tag_i;

//

// Insn (IMMU) interface

//

output                          immu_en;

//

// Debug interface

//

output                          id_void;

output  [31:0]                   id_insn;

output                          ex_void;

output  [31:0]                   ex_insn;

output                          ex_freeze;

output  [31:0]                   wb_insn;

output                          wb_freeze;

output  [31:0]                   id_pc;

output  [31:0]                   ex_pc;

output  [31:0]                   wb_pc;

output                          ex_flushpipe;

output  [`OR1200_BRANCHOP_WIDTH-1:0]     branch_op;

input                           du_stall;

input   [dw-1:0]         du_addr;

input   [dw-1:0]         du_dat_du;

input                           du_read;

input                           du_write;

input   [`OR1200_DU_DSR_WIDTH-1:0]       du_dsr;

input   [24:0]                   du_dmr1;

input                           du_hwbkpt;

input                           du_hwbkpt_ls_r;

output  [13:0]                   du_except_trig;

output  [13:0]                   du_except_stop;

output  [dw-1:0]         du_dat_cpu;

output  [dw-1:0]         rf_dataw;

output  [dw-1:0]         du_lsu_store_dat;

output  [dw-1:0]         du_lsu_load_dat;

//

// Data (DC) interface

//

output  [31:0]                   dcpu_adr_o;

output                          dcpu_cycstb_o;

output                          dcpu_we_o;

output  [3:0]                    dcpu_sel_o;

output  [3:0]                    dcpu_tag_o;

output  [31:0]                   dcpu_dat_o;

input   [31:0]                   dcpu_dat_i;

input                           dcpu_ack_i;

input                           dcpu_rty_i;

input                           dcpu_err_i;

input   [3:0]                    dcpu_tag_i;

output                          dc_en;

output                          dc_no_writethrough;

//

// Data (DMMU) interface

//

output                          sb_en;

output                          dmmu_en;

output                          abort_ex;

output                          abort_mvspr;

//

// SR Interface 

//

input                           boot_adr_sel_i;

//

// SPR interface

//

output                          supv;

input   [dw-1:0]         spr_dat_pic;

input   [dw-1:0]         spr_dat_tt;

input   [dw-1:0]         spr_dat_pm;

input   [dw-1:0]         spr_dat_dmmu;

input   [dw-1:0]         spr_dat_immu;

input   [dw-1:0]         spr_dat_du;

output  [dw-1:0]         spr_addr;

output  [dw-1:0]         spr_dat_cpu;

output  [dw-1:0]         spr_dat_npc;

output  [31:0]                   spr_cs;

output                          spr_we;

input                           mtspr_dc_done;

//

// Interrupt exceptions

//

input                           sig_int;

input                           sig_tick;

//

// Internal wires

//

wire    [31:0]                   if_insn;

wire                            saving_if_insn;

wire    [31:0]                   if_pc;

wire    [aw-1:0]         rf_addrw;

wire    [aw-1:0]                 rf_addra;

wire    [aw-1:0]                 rf_addrb;

wire                            rf_rda;

wire                            rf_rdb;

wire    [dw-1:0]         id_simm;

wire    [dw-1:2]                id_branch_addrtarget;

wire    [dw-1:2]                ex_branch_addrtarget;

wire    [`OR1200_ALUOP_WIDTH-1:0]        alu_op;

wire    [`OR1200_ALUOP2_WIDTH-1:0]       alu_op2;

wire    [`OR1200_COMPOP_WIDTH-1:0]       comp_op;

wire    [`OR1200_BRANCHOP_WIDTH-1:0]     pre_branch_op;

wire    [`OR1200_BRANCHOP_WIDTH-1:0]     branch_op;

wire    [`OR1200_LSUOP_WIDTH-1:0]        id_lsu_op;

wire                            genpc_freeze;

wire                            if_freeze;

wire                            id_freeze;

wire                            ex_freeze;

wire                            wb_freeze;

wire    [`OR1200_SEL_WIDTH-1:0]  sel_a;

wire    [`OR1200_SEL_WIDTH-1:0]  sel_b;

wire    [`OR1200_RFWBOP_WIDTH-1:0]       rfwb_op;

wire    [`OR1200_FPUOP_WIDTH-1:0]       fpu_op;

wire    [dw-1:0]         rf_dataw;

wire    [dw-1:0]         rf_dataa;

wire    [dw-1:0]         rf_datab;

wire    [dw-1:0]         muxed_a;

wire    [dw-1:0]         muxed_b;

wire    [dw-1:0]         wb_forw;

wire                            wbforw_valid;

wire    [dw-1:0]         operand_a;

wire    [dw-1:0]         operand_b;

wire    [dw-1:0]         alu_dataout;

wire    [dw-1:0]         lsu_dataout;

wire    [dw-1:0]         sprs_dataout;

wire    [dw-1:0]         fpu_dataout;

wire                            fpu_done;

wire    [31:0]                   ex_simm;

wire    [`OR1200_MULTICYCLE_WIDTH-1:0]   multicycle;

wire    [`OR1200_WAIT_ON_WIDTH-1:0]      wait_on;

wire    [`OR1200_EXCEPT_WIDTH-1:0]       except_type;

wire    [4:0]                    cust5_op;

wire    [5:0]                    cust5_limm;

wire                            if_flushpipe;

wire                            id_flushpipe;

wire                            ex_flushpipe;

wire                            wb_flushpipe;

wire                            extend_flush;

wire                            ex_branch_taken;

wire                            flag;

wire                            flagforw;

wire                            flag_we;

wire                            flagforw_alu;

wire                            flag_we_alu;

wire                            flagforw_fpu;

wire                            flag_we_fpu;

wire                            carry;

wire                            cyforw;

wire                            cy_we_alu;

wire                            ovforw;

wire                            ov_we_alu;

wire                            ovforw_mult_mac;

wire                            ov_we_mult_mac;

wire                            cy_we_rf;

wire                            lsu_stall;

wire                            epcr_we;

wire                            eear_we;

wire                            esr_we;

wire                            pc_we;

wire    [31:0]                   epcr;

wire    [31:0]                   eear;

wire    [`OR1200_SR_WIDTH-1:0]   esr;

wire    [`OR1200_FPCSR_WIDTH-1:0]       fpcsr;

wire                            fpcsr_we;

wire                            sr_we;

wire    [`OR1200_SR_WIDTH-1:0]   to_sr;

wire    [`OR1200_SR_WIDTH-1:0]   sr;

wire                            dsx;

wire                            except_flushpipe;

wire                            except_start;

wire                            except_started;

wire                            fpu_except_started;

wire    [31:0]                   wb_insn;

wire                            sig_syscall;

wire                            sig_trap;

wire                            sig_range;

wire                            sig_fp;

wire    [31:0]                   spr_dat_cfgr;

wire    [31:0]                   spr_dat_rf;

wire    [31:0]                  spr_dat_npc;

wire    [31:0]                   spr_dat_ppc;

wire    [31:0]                   spr_dat_mac;

wire [31:0]                      spr_dat_fpu;

wire                            mtspr_done;

wire                            force_dslot_fetch;

wire                            no_more_dslot;

wire                            ex_void;

wire                            ex_spr_read;

wire                            ex_spr_write;

wire                            if_stall;

wire                            id_macrc_op;

wire                            ex_macrc_op;

wire    [`OR1200_MACOP_WIDTH-1:0] id_mac_op;

wire    [`OR1200_MACOP_WIDTH-1:0] mac_op;

wire    [31:0]                   mult_mac_result;

wire                            mult_mac_stall;

wire    [13:0]                   except_trig;

wire    [13:0]                   except_stop;

wire                            genpc_refetch;

wire                            rfe;

wire                            lsu_unstall;

wire                            except_align;

wire                            except_dtlbmiss;

wire                            except_dmmufault;

wire                            except_illegal;

wire                            except_itlbmiss;

wire                            except_immufault;

wire                            except_ibuserr;

wire                            except_dbuserr;

wire                            abort_ex;

wire                            abort_mvspr;

//

// Send exceptions to Debug Unit

//

assign du_except_trig = except_trig;

assign du_except_stop = except_stop;

assign du_lsu_store_dat = operand_b;

assign du_lsu_load_dat  = lsu_dataout;

//

// Data cache enable

//

`ifdef OR1200_NO_DC

assign dc_en = 1'b0;

`else

   assign dc_en = sr[`OR1200_SR_DCE];

`endif

//

// Instruction cache enable

//

`ifdef OR1200_NO_IC

assign ic_en = 1'b0;

`else

assign ic_en = sr[`OR1200_SR_ICE];

`endif

//

// SB enable

//

`ifdef OR1200_SB_IMPLEMENTED

//assign sb_en = sr[`OR1200_SR_SBE]; // SBE not defined  -- jb

`else

assign sb_en = 1'b0;

`endif

//

// DMMU enable

//

`ifdef OR1200_NO_DMMU

assign dmmu_en = 1'b0;

`else

assign dmmu_en = sr[`OR1200_SR_DME];

`endif

//

// IMMU enable

//

`ifdef OR1200_NO_IMMU

assign immu_en = 1'b0;

`else

assign immu_en = sr[`OR1200_SR_IME] & ~except_started;

`endif

//

// SUPV bit

//

assign supv = sr[`OR1200_SR_SM];

//

// FLAG write enable

//

assign flagforw = (flag_we_alu & flagforw_alu) | (flagforw_fpu & flag_we_fpu);

assign flag_we = (flag_we_alu | flag_we_fpu) & ~abort_mvspr;

//

// Flag for any MTSPR instructions, that must block execution, to indicate done

//

assign mtspr_done = mtspr_dc_done;

//

// Range exception

//

assign sig_range = sr[`OR1200_SR_OV];

//

// Instantiation of instruction fetch block

//

or1200_genpc or1200_genpc(

        .clk(clk),

        .rst(rst),

        .icpu_adr_o(icpu_adr_o),

        .icpu_cycstb_o(icpu_cycstb_o),

        .icpu_sel_o(icpu_sel_o),

        .icpu_tag_o(icpu_tag_o),

        .icpu_rty_i(icpu_rty_i),

        .icpu_adr_i(icpu_adr_i),

        .pre_branch_op(pre_branch_op),

        .branch_op(branch_op),

        .except_type(except_type),

        .except_start(except_start),

        .except_prefix(sr[`OR1200_SR_EPH]),

        .id_branch_addrtarget(id_branch_addrtarget),

        .ex_branch_addrtarget(ex_branch_addrtarget),

        .muxed_b(muxed_b),

        .operand_b(operand_b),

        .flag(flag),

        .flagforw(flagforw),

        .ex_branch_taken(ex_branch_taken),

        .epcr(epcr),

        .spr_dat_i(spr_dat_cpu),

        .spr_pc_we(pc_we),

        .genpc_refetch(genpc_refetch),

        .genpc_freeze(genpc_freeze),

        .no_more_dslot(no_more_dslot)

);

//

// Instantiation of instruction fetch block

//

or1200_if or1200_if(

        .clk(clk),

        .rst(rst),

        .icpu_dat_i(icpu_dat_i),

        .icpu_ack_i(icpu_ack_i),

        .icpu_err_i(icpu_err_i),

        .icpu_adr_i(icpu_adr_i),

        .icpu_tag_i(icpu_tag_i),

        .if_freeze(if_freeze),

        .if_insn(if_insn),

        .if_pc(if_pc),

        .saving_if_insn(saving_if_insn),

        .if_flushpipe(if_flushpipe),

        .if_stall(if_stall),

        .no_more_dslot(no_more_dslot),

        .genpc_refetch(genpc_refetch),

        .rfe(rfe),

        .except_itlbmiss(except_itlbmiss),

        .except_immufault(except_immufault),

        .except_ibuserr(except_ibuserr)

);

//

// Instantiation of instruction decode/control logic

//

or1200_ctrl or1200_ctrl(

        .clk(clk),

        .rst(rst),

        .id_freeze(id_freeze),

        .ex_freeze(ex_freeze),

        .wb_freeze(wb_freeze),

        .if_flushpipe(if_flushpipe),

        .id_flushpipe(id_flushpipe),

        .ex_flushpipe(ex_flushpipe),

        .wb_flushpipe(wb_flushpipe),

        .extend_flush(extend_flush),

        .except_flushpipe(except_flushpipe),

        .abort_mvspr(abort_mvspr),

        .if_insn(if_insn),

        .id_insn(id_insn),

        .ex_insn(ex_insn),

        .id_branch_op(pre_branch_op),

        .ex_branch_op(branch_op),

        .ex_branch_taken(ex_branch_taken),

        .rf_addra(rf_addra),

        .rf_addrb(rf_addrb),

        .rf_rda(rf_rda),

        .rf_rdb(rf_rdb),

        .alu_op(alu_op),

        .alu_op2(alu_op2),

        .mac_op(mac_op),

        .comp_op(comp_op),

        .rf_addrw(rf_addrw),

        .rfwb_op(rfwb_op),

        .fpu_op(fpu_op),

        .pc_we(pc_we),

        .wb_insn(wb_insn),

        .id_simm(id_simm),

        .id_branch_addrtarget(id_branch_addrtarget),

        .ex_branch_addrtarget(ex_branch_addrtarget),

        .ex_simm(ex_simm),

        .sel_a(sel_a),

        .sel_b(sel_b),

        .id_lsu_op(id_lsu_op),

        .cust5_op(cust5_op),

        .cust5_limm(cust5_limm),

        .id_pc(id_pc),

        .ex_pc(ex_pc),

        .multicycle(multicycle),

        .wait_on(wait_on),

        .wbforw_valid(wbforw_valid),

        .sig_syscall(sig_syscall),

        .sig_trap(sig_trap),

        .force_dslot_fetch(force_dslot_fetch),

        .no_more_dslot(no_more_dslot),

        .id_void(id_void),

        .ex_void(ex_void),

        .ex_spr_read(ex_spr_read),

        .ex_spr_write(ex_spr_write),

        .id_mac_op(id_mac_op),

        .id_macrc_op(id_macrc_op),

        .ex_macrc_op(ex_macrc_op),

        .rfe(rfe),

        .du_hwbkpt(du_hwbkpt),

        .except_illegal(except_illegal),

        .dc_no_writethrough(dc_no_writethrough)

);

//

// Instantiation of register file

//

or1200_rf or1200_rf(

        .clk(clk),

        .rst(rst),

        .cy_we_i(cy_we_alu),

        .cy_we_o(cy_we_rf),

        .supv(sr[`OR1200_SR_SM]),

        .wb_freeze(wb_freeze),

        .addrw(rf_addrw),

        .dataw(rf_dataw),

        .id_freeze(id_freeze),

        .we(rfwb_op[0]),

        .flushpipe(wb_flushpipe),

        .addra(rf_addra),

        .rda(rf_rda),

        .dataa(rf_dataa),

        .addrb(rf_addrb),

        .rdb(rf_rdb),

        .datab(rf_datab),

        .spr_cs(spr_cs[`OR1200_SPR_GROUP_SYS]),

        .spr_write(spr_we),

        .spr_addr(spr_addr),

        .spr_dat_i(spr_dat_cpu),

        .spr_dat_o(spr_dat_rf),

        .du_read(du_read)

);

//

// Instantiation of operand muxes

//

or1200_operandmuxes or1200_operandmuxes(

        .clk(clk),

        .rst(rst),

        .id_freeze(id_freeze),

        .ex_freeze(ex_freeze),

        .rf_dataa(rf_dataa),

        .rf_datab(rf_datab),

        .ex_forw(rf_dataw),

        .wb_forw(wb_forw),

        .simm(id_simm),

        .sel_a(sel_a),

        .sel_b(sel_b),

        .operand_a(operand_a),

        .operand_b(operand_b),

        .muxed_a(muxed_a),

        .muxed_b(muxed_b)

);

//

// Instantiation of CPU's ALU

//

or1200_alu or1200_alu(

        .a(operand_a),

        .b(operand_b),

        .mult_mac_result(mult_mac_result),

        .macrc_op(ex_macrc_op),

        .alu_op(alu_op),

        .alu_op2(alu_op2),

        .comp_op(comp_op),

        .cust5_op(cust5_op),

        .cust5_limm(cust5_limm),

        .result(alu_dataout),

        .flagforw(flagforw_alu),

        .flag_we(flag_we_alu),

        .cyforw(cyforw),

        .cy_we(cy_we_alu),

        .ovforw(ovforw),

        .ov_we(ov_we_alu),

        .flag(flag),

        .carry(carry)

);

//

// FPU's exception is being dealt with

//    

assign fpu_except_started = except_started && (except_type == `OR1200_EXCEPT_FLOAT);

//

// Instantiation of FPU

//

or1200_fpu or1200_fpu(

        .clk(clk),

        .rst(rst),

        .ex_freeze(ex_freeze),

        .a(operand_a),

        .b(operand_b),

        .fpu_op(fpu_op),

        .result(fpu_dataout),

        .done(fpu_done),

        .flagforw(flagforw_fpu),

        .flag_we(flag_we_fpu),

        .sig_fp(sig_fp),

        .except_started(fpu_except_started),

        .fpcsr_we(fpcsr_we),

        .fpcsr(fpcsr),

        .spr_cs(spr_cs[`OR1200_SPR_GROUP_FPU]),

        .spr_write(spr_we),

        .spr_addr(spr_addr),

        .spr_dat_i(spr_dat_cpu),

        .spr_dat_o(spr_dat_fpu)

);

//

// Instantiation of CPU's multiply unit

//

or1200_mult_mac or1200_mult_mac(

        .clk(clk),

        .rst(rst),

        .ex_freeze(ex_freeze),