Subversion Repositories m32632

// +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

//

// This file is part of the M32632 project

// http://opencores.org/project,m32632

//

// Filename: REGISTERS.v

// Version:  1.0

// Date:     30 May 2015

//

// Copyright (C) 2015 Udo Moeller

// 

// 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 

// 

// +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

//

//      Modules contained in this file:

//      1. CONFIG_REGS  Configuration and Debug Registers

//      2. FP_STAT_REG  Floating Point Status Register

//      3. REGISTER             General Purpose Registers

//

// ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

// ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

//

//      1. CONFIG_REGS  Configuration and Debug Registers

//

// ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

module CONFIG_REGS ( BCLK, BRESET, WREN, LD_OUT, OPCODE, SRC1, WRADR, PC_ARCHI, USER, PCMATCH, DBG_HIT, READ,

                                         CFG, MCR, PTB_WR, PTB_SEL, IVAR, CINV, Y_INIT, DSR, DBG_TRAPS, DBG_IN );

        input                   BCLK,BRESET;

        input                   WREN,LD_OUT;

        input    [7:0]   OPCODE;

        input   [31:0]   SRC1;

        input    [5:0]   WRADR;

        input   [31:0]   PC_ARCHI;

        input                   USER;

        input                   PCMATCH;

        input                   DBG_HIT;

        input                   READ;

        output  [12:0]   CFG;

        output   [3:0]   MCR;

        output                  PTB_WR;

        output                  PTB_SEL;

        output   [1:0]   IVAR;

        output   [3:0]   CINV;

        output                  Y_INIT;

        output   [3:0]   DSR;

        output   [2:0]   DBG_TRAPS;

        output  [40:2]  DBG_IN;

        reg              [3:0]   MCR;

        reg             [12:0]   CFG;

        reg              [1:0]   old_cfg;

        reg                             PTB_WR,PTB_SEL;

        reg                             ivarreg;

        reg              [1:0]   ci_all,ci_line;

        reg                             check_y;

        wire                    ld_cfg,ld_mcr,do_cinv;

        wire                    init_ic,init_dc;

        wire                    op_ok;

        assign op_ok = (OPCODE == 8'h6A);       // Special Opcode - for security reason

        assign ld_cfg  = op_ok & (WRADR == 6'h1C)          & WREN;

        assign ld_mcr  = op_ok & (WRADR == 6'd9)           & WREN;

        assign do_cinv = op_ok & (WRADR[5:4] == 2'b11) & WREN;

        // PF is not implemented

        always @(posedge BCLK or negedge BRESET)

                if (!BRESET) CFG <= 13'h0;

                        else if (ld_cfg) CFG <= SRC1[12:0];

        always @(posedge BCLK or negedge BRESET)

                if (!BRESET) MCR <= 4'h0;

                        else if (ld_mcr) MCR <= SRC1[3:0];

        always @(posedge BCLK) ivarreg <= op_ok & (WRADR[5:1] == 5'd7) & WREN;  // IVAR0/1 = Reg. Nr. 14/15

        assign IVAR = {ivarreg,PTB_SEL};

        always @(posedge BCLK) PTB_WR  <= op_ok & (WRADR[5:1] == 5'd6) & WREN;  // PTB0/1 = Reg. Nr. 12/13

        always @(posedge BCLK) PTB_SEL <= WRADR[0];

        // The Cache content will be invalid if the Enable-Bit is set to 0

        always @(posedge BCLK) old_cfg <= {CFG[11],CFG[9]};

        // Cache Invalidate : the Flags are coming out of the Short-field which is otherwise used for Register selection

        always @(posedge BCLK) ci_all  <= do_cinv &  WRADR[2] ? WRADR[1:0] : 2'b0;       // clear all

        always @(posedge BCLK) ci_line <= do_cinv & ~WRADR[2] ? WRADR[1:0] : 2'b0;       // clear cache line

        assign init_ic = old_cfg[1] & (~CFG[11] | ci_all[1]);

        assign init_dc = old_cfg[0] & (~CFG[9]  | ci_all[0]);

        assign CINV = {init_ic,ci_line[1],init_dc,ci_line[0]};

        // Y_INIT is neccessary if nothing has changed and therefore no DC/IC_INIT is generated

        always @(posedge BCLK) check_y <= ld_cfg | do_cinv;

        assign Y_INIT = check_y & ~init_ic & ~init_dc;  // goes to register "old_init"

        // +++++++++++++  DEBUG Unit  +++++++++++++++

        reg              [3:0]   DSR;

        reg             [12:0]   dcr;

        reg             [31:0]   bpc;

        reg             [31:2]  car;

        wire                    op_dbg,ld_dcr,ld_bpc,ld_dsr,ld_car;

        wire                    enable;

        assign op_dbg = (OPCODE == 8'h76);

        assign ld_dcr = op_dbg & (WRADR == 6'h11) & WREN;

        assign ld_bpc = op_dbg & (WRADR == 6'h12) & WREN;

        assign ld_dsr = op_dbg & (WRADR == 6'h13) & WREN;

        assign ld_car = op_dbg & (WRADR == 6'h14) & WREN;

        assign enable = dcr[12] & (USER ? dcr[10] : dcr[11]);   // DEN & (USER ? UD : SD)

        always @(posedge BCLK or negedge BRESET)

                if (!BRESET) dcr <= 13'd0;

                        else if (ld_dcr) dcr <= {SRC1[23:19],SRC1[7:0]};

        always @(posedge BCLK) if (ld_bpc) bpc <= SRC1;

        always @(posedge BCLK) if (ld_car) car <= SRC1[31:2];

        //                                      DEN               SD        DEN       UD       CAE      CRD      CAE      CWR    VNP/CBE  CAR

        assign DBG_IN = {(dcr[12] & dcr[11]),(dcr[12] & dcr[10]),(dcr[7] & dcr[6]),(dcr[7] & dcr[5]),dcr[4:0],car};

        always @(posedge BCLK or negedge BRESET)

                if (!BRESET) DSR <= 4'd0;

                  else

                        if (ld_dsr) DSR <= SRC1[31:28];

                          else

                                begin

                                  DSR[3] <= DBG_HIT ? READ : DSR[3];

                                  DSR[2] <= DSR[2] | PCMATCH;

                                  DSR[1] <= DSR[1];

                                  DSR[0] <= DSR[0] | DBG_HIT;

                                end

        assign DBG_TRAPS[0] = enable & dcr[9] & (PC_ARCHI == bpc);       // dcr[9]=PCE

        assign DBG_TRAPS[1] = DBG_HIT;  // Compare Adress Hit

        assign DBG_TRAPS[2] = dcr[8];   // TR, Trap enable

endmodule

// ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

//

//      2. FP_STAT_REG  Floating Point Status Register

//

// ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

module FP_STAT_REG ( BCLK, BRESET, LFSR, UP_SP, UP_DP, TT_SP, TT_DP, WREN, WRADR, DIN, FSR, TWREN, FPU_TRAP, SAVE_PC);

        input                   BCLK;

        input                   BRESET;

        input                   LFSR;   // Load by LFSR opcode

        input                   UP_SP,UP_DP;    // update if calculation operation

        input    [4:0]   TT_SP,TT_DP;

        input                   WREN;   // for RMB and LFSR

        input    [5:4]  WRADR;

        input   [16:0]   DIN;    // Data for LFSR opcode

        output  [31:0]   FSR;

        output                  TWREN;

        output  reg             FPU_TRAP;

        output                  SAVE_PC;

        reg              [4:3]  trap_d;

        reg                             update_d;

        reg                             set_rm_d;

        reg             [10:0]   set_bits;

        reg              [4:0]   flags;

        reg                             rm_bit;

        wire                    load_fsr;

        wire                    update,update_i;

        wire     [4:0]   trap;

        wire                    uflag,iflag,rmflag;

        assign load_fsr = LFSR & WREN;

        assign trap = UP_SP ? TT_SP : TT_DP;

        // This signal suppresses write into registers if FPU Trap, timing critical signal !

        assign TWREN = ~((UP_SP & (TT_SP[2:0] != 3'b0)) | (UP_DP & (TT_DP[2:0] != 3'b0)));

        always @(posedge BCLK or negedge BRESET)

                if (!BRESET) FPU_TRAP <= 1'b0;

                  else FPU_TRAP <= ~FPU_TRAP & ~TWREN;  // one pulse of one cycle informs the Opcode Decoder

        assign update_i = (UP_SP | UP_DP) & ~FPU_TRAP;  // unfortunately one FPU opcode may follow !

        always @(posedge BCLK) update_d <= update_i;

        always @(posedge BCLK) trap_d   <= trap[4:3];

        always @(posedge BCLK) set_rm_d <= WREN & (WRADR == 2'b10);

        assign update = update_d & ~FPU_TRAP;

        // The Flags are set and stay "1" 

        assign iflag  = (update & trap_d[4]) | flags[4];        // Inexact Result

        assign uflag  = (update & trap_d[3]) | flags[3];        // Underflow

        assign rmflag = (set_rm_d & ~FPU_TRAP) | rm_bit;        // Register Modify

        always @(posedge BCLK or negedge BRESET)

                if (!BRESET) flags[4:3] <= 2'b0;        // Inexact = Bit6, Underflow = Bit4

                  else

                  begin

                        if (load_fsr) flags[4:3] <= {DIN[6],DIN[4]};

                          else

                                if (update) flags[4:3] <= {iflag,uflag};

                  end

        always @(posedge BCLK or negedge BRESET)

                if (!BRESET) flags[2:0] <= 3'b0; // TT Field = Bit2-0

                  else

                  begin

                        if (load_fsr) flags[2:0] <= DIN[2:0];

                          else

                                if (update_i) flags[2:0] <= trap[2:0];

                  end

        always @(posedge BCLK or negedge BRESET)

                if (!BRESET) rm_bit <= 1'b0;    // Register Modify Bit

                  else

                  begin

                        if (load_fsr) rm_bit <= DIN[16];

                          else

                                if (set_rm_d & ~FPU_TRAP) rm_bit <= 1'b1;       // in case of TRAP there is no writing to Register

                  end

        always @(posedge BCLK or negedge BRESET)

                if (!BRESET) set_bits <= 11'b0; // all other Bits

                  else

                        if (load_fsr) set_bits <= {DIN[15:7],DIN[5],DIN[3]};

        assign FSR = {15'h0,rmflag,set_bits[10:2],iflag,set_bits[1],uflag,set_bits[0],flags[2:0]};

        assign SAVE_PC = (UP_SP | UP_DP) & ~FPU_TRAP;   // Store the correct PC for FPU Trap

endmodule

// ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

//

//      3. REGISTER             General Purpose Registers

//

// ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

module REGISTER( BCLK, ENWR, DOWR, BYDIN, DIN, RADR, WADR, WMASKE, DOUT, SELI );

input                   BCLK;

input                   DOWR,ENWR;

input   [31:0]   BYDIN,DIN;

input    [7:0]   RADR;

input    [5:0]   WADR;

input    [1:0]   WMASKE;

output  [31:0]   DOUT;

output reg              SELI;

reg              [2:0]   MX;

wire     [3:0]   BE;

wire                    eq_rw;

// +++++++++++++++++++ Memories ++++++++++++++++++++

reg              [7:0]   REGFILE_D [0:63];

reg              [7:0]   REGFILE_C [0:63];

reg              [7:0]   REGFILE_B [0:63];

reg              [7:0]   REGFILE_A [0:63];

reg             [31:0]   RF;

assign  BE = {WMASKE[1],WMASKE[1],(WMASKE[1] | WMASKE[0]),1'b1};

assign  eq_rw = ENWR & (RADR[5:0] == WADR);

always @(posedge BCLK) if (RADR[7]) MX[2:0] <= BE[2:0] & {{3{eq_rw}}};

always @(posedge BCLK) if (RADR[7]) SELI <= RADR[6];

assign DOUT[31:16] = MX[2] ? BYDIN[31:16] : RF[31:16];

assign DOUT[15:8]  = MX[1] ? BYDIN[15:8]  : RF[15:8];

assign DOUT[7:0]   = MX[0] ? BYDIN[7:0]   : RF[7:0];

// ++++++++++++++++ Register File 64 * 32 Bits ++++++++++++

always @(posedge BCLK)

        if (RADR[7])

                begin

                        RF[31:24] <= REGFILE_D[RADR[5:0]];

                        RF[23:16] <= REGFILE_C[RADR[5:0]];

                        RF[15:8]  <= REGFILE_B[RADR[5:0]];

                        RF[7:0]   <= REGFILE_A[RADR[5:0]];

                end

always @(posedge BCLK)

        if (DOWR)

                begin

                        if (BE[3]) REGFILE_D[WADR] <= DIN[31:24];

                        if (BE[2]) REGFILE_C[WADR] <= DIN[23:16];

                        if (BE[1]) REGFILE_B[WADR] <= DIN[15:8];

                        if (BE[0]) REGFILE_A[WADR] <= DIN[7:0];

                end

endmodule