lm32_decoder.v

changeset 24
c336e674a37e
parent 23
252df75c8f67
child 25
7422134cbfea
     1.1 diff -r 252df75c8f67 -r c336e674a37e lm32_decoder.v
     1.2 --- a/lm32_decoder.v	Sun Mar 06 21:17:31 2011 +0000
     1.3 +++ /dev/null	Thu Jan 01 00:00:00 1970 +0000
     1.4 @@ -1,583 +0,0 @@
     1.5 -// =============================================================================
     1.6 -//                           COPYRIGHT NOTICE
     1.7 -// Copyright 2006 (c) Lattice Semiconductor Corporation
     1.8 -// ALL RIGHTS RESERVED
     1.9 -// This confidential and proprietary software may be used only as authorised by
    1.10 -// a licensing agreement from Lattice Semiconductor Corporation.
    1.11 -// The entire notice above must be reproduced on all authorized copies and
    1.12 -// copies may only be made to the extent permitted by a licensing agreement from
    1.13 -// Lattice Semiconductor Corporation.
    1.14 -//
    1.15 -// Lattice Semiconductor Corporation        TEL : 1-800-Lattice (USA and Canada)
    1.16 -// 5555 NE Moore Court                            408-826-6000 (other locations)
    1.17 -// Hillsboro, OR 97124                     web  : http://www.latticesemi.com/
    1.18 -// U.S.A                                   email: techsupport@latticesemi.com
    1.19 -// =============================================================================/
    1.20 -//                         FILE DETAILS
    1.21 -// Project          : LatticeMico32
    1.22 -// File             : lm32_decoder.v
    1.23 -// Title            : Instruction decoder
    1.24 -// Dependencies     : lm32_include.v
    1.25 -// Version          : 6.1.17
    1.26 -//                  : Initial Release
    1.27 -// Version          : 7.0SP2, 3.0
    1.28 -//                  : No Change
    1.29 -// Version          : 3.1
    1.30 -//                  : Support for static branch prediction. Information about
    1.31 -//                  : branch type is generated and passed on to the predictor.
    1.32 -// Version          : 3.2
    1.33 -//                  : No change
    1.34 -// Version          : 3.3
    1.35 -//                  : Renamed port names that conflict with keywords reserved
    1.36 -//                  : in System-Verilog.
    1.37 -// =============================================================================
    1.38 -
    1.39 -`include "lm32_include.v"
    1.40 -
    1.41 -// Index of opcode field in an instruction
    1.42 -`define LM32_OPCODE_RNG         31:26
    1.43 -`define LM32_OP_RNG             30:26
    1.44 -
    1.45 -// Opcodes - Some are only listed as 5 bits as their MSB is a don't care
    1.46 -`define LM32_OPCODE_ADD         5'b01101
    1.47 -`define LM32_OPCODE_AND         5'b01000
    1.48 -`define LM32_OPCODE_ANDHI       6'b011000
    1.49 -`define LM32_OPCODE_B           6'b110000
    1.50 -`define LM32_OPCODE_BI          6'b111000
    1.51 -`define LM32_OPCODE_BE          6'b010001
    1.52 -`define LM32_OPCODE_BG          6'b010010
    1.53 -`define LM32_OPCODE_BGE         6'b010011
    1.54 -`define LM32_OPCODE_BGEU        6'b010100
    1.55 -`define LM32_OPCODE_BGU         6'b010101
    1.56 -`define LM32_OPCODE_BNE         6'b010111
    1.57 -`define LM32_OPCODE_CALL        6'b110110
    1.58 -`define LM32_OPCODE_CALLI       6'b111110
    1.59 -`define LM32_OPCODE_CMPE        5'b11001
    1.60 -`define LM32_OPCODE_CMPG        5'b11010
    1.61 -`define LM32_OPCODE_CMPGE       5'b11011
    1.62 -`define LM32_OPCODE_CMPGEU      5'b11100
    1.63 -`define LM32_OPCODE_CMPGU       5'b11101
    1.64 -`define LM32_OPCODE_CMPNE       5'b11111
    1.65 -`define LM32_OPCODE_DIVU        6'b100011
    1.66 -`define LM32_OPCODE_LB          6'b000100
    1.67 -`define LM32_OPCODE_LBU         6'b010000
    1.68 -`define LM32_OPCODE_LH          6'b000111
    1.69 -`define LM32_OPCODE_LHU         6'b001011
    1.70 -`define LM32_OPCODE_LW          6'b001010
    1.71 -`define LM32_OPCODE_MODU        6'b110001
    1.72 -`define LM32_OPCODE_MUL         5'b00010
    1.73 -`define LM32_OPCODE_NOR         5'b00001
    1.74 -`define LM32_OPCODE_OR          5'b01110
    1.75 -`define LM32_OPCODE_ORHI        6'b011110
    1.76 -`define LM32_OPCODE_RAISE       6'b101011
    1.77 -`define LM32_OPCODE_RCSR        6'b100100
    1.78 -`define LM32_OPCODE_SB          6'b001100
    1.79 -`define LM32_OPCODE_SEXTB       6'b101100
    1.80 -`define LM32_OPCODE_SEXTH       6'b110111
    1.81 -`define LM32_OPCODE_SH          6'b000011
    1.82 -`define LM32_OPCODE_SL          5'b01111
    1.83 -`define LM32_OPCODE_SR          5'b00101
    1.84 -`define LM32_OPCODE_SRU         5'b00000
    1.85 -`define LM32_OPCODE_SUB         6'b110010
    1.86 -`define LM32_OPCODE_SW          6'b010110
    1.87 -`define LM32_OPCODE_USER        6'b110011
    1.88 -`define LM32_OPCODE_WCSR        6'b110100
    1.89 -`define LM32_OPCODE_XNOR        5'b01001
    1.90 -`define LM32_OPCODE_XOR         5'b00110
    1.91 -
    1.92 -/////////////////////////////////////////////////////
    1.93 -// Module interface
    1.94 -/////////////////////////////////////////////////////
    1.95 -
    1.96 -module lm32_decoder (
    1.97 -    // ----- Inputs -------
    1.98 -    instruction,
    1.99 -    // ----- Outputs -------
   1.100 -    d_result_sel_0,
   1.101 -    d_result_sel_1,        
   1.102 -    x_result_sel_csr,
   1.103 -`ifdef LM32_MC_ARITHMETIC_ENABLED
   1.104 -    x_result_sel_mc_arith,
   1.105 -`endif    
   1.106 -`ifdef LM32_NO_BARREL_SHIFT    
   1.107 -    x_result_sel_shift,
   1.108 -`endif
   1.109 -`ifdef CFG_SIGN_EXTEND_ENABLED
   1.110 -    x_result_sel_sext,
   1.111 -`endif    
   1.112 -    x_result_sel_logic,
   1.113 -`ifdef CFG_USER_ENABLED
   1.114 -    x_result_sel_user,
   1.115 -`endif
   1.116 -    x_result_sel_add,
   1.117 -    m_result_sel_compare,
   1.118 -`ifdef CFG_PL_BARREL_SHIFT_ENABLED
   1.119 -    m_result_sel_shift,  
   1.120 -`endif    
   1.121 -    w_result_sel_load,
   1.122 -`ifdef CFG_PL_MULTIPLY_ENABLED
   1.123 -    w_result_sel_mul,
   1.124 -`endif
   1.125 -    x_bypass_enable,
   1.126 -    m_bypass_enable,
   1.127 -    read_enable_0,
   1.128 -    read_idx_0,
   1.129 -    read_enable_1,
   1.130 -    read_idx_1,
   1.131 -    write_enable,
   1.132 -    write_idx,
   1.133 -    immediate,
   1.134 -    branch_offset,
   1.135 -    load,
   1.136 -    store,
   1.137 -    size,
   1.138 -    sign_extend,
   1.139 -    adder_op,
   1.140 -    logic_op,
   1.141 -`ifdef CFG_PL_BARREL_SHIFT_ENABLED
   1.142 -    direction,
   1.143 -`endif
   1.144 -`ifdef CFG_MC_BARREL_SHIFT_ENABLED
   1.145 -    shift_left,
   1.146 -    shift_right,
   1.147 -`endif
   1.148 -`ifdef CFG_MC_MULTIPLY_ENABLED
   1.149 -    multiply,
   1.150 -`endif
   1.151 -`ifdef CFG_MC_DIVIDE_ENABLED
   1.152 -    divide,
   1.153 -    modulus,
   1.154 -`endif
   1.155 -    branch,
   1.156 -    branch_reg,
   1.157 -    condition,
   1.158 -    bi_conditional,
   1.159 -    bi_unconditional,
   1.160 -`ifdef CFG_DEBUG_ENABLED
   1.161 -    break_opcode,
   1.162 -`endif
   1.163 -    scall,
   1.164 -    eret,
   1.165 -`ifdef CFG_DEBUG_ENABLED
   1.166 -    bret,
   1.167 -`endif
   1.168 -`ifdef CFG_USER_ENABLED
   1.169 -    user_opcode,
   1.170 -`endif
   1.171 -    csr_write_enable
   1.172 -    );
   1.173 -
   1.174 -/////////////////////////////////////////////////////
   1.175 -// Inputs
   1.176 -/////////////////////////////////////////////////////
   1.177 -
   1.178 -input [`LM32_INSTRUCTION_RNG] instruction;       // Instruction to decode
   1.179 -
   1.180 -/////////////////////////////////////////////////////
   1.181 -// Outputs
   1.182 -/////////////////////////////////////////////////////
   1.183 -
   1.184 -output [`LM32_D_RESULT_SEL_0_RNG] d_result_sel_0;
   1.185 -reg    [`LM32_D_RESULT_SEL_0_RNG] d_result_sel_0;
   1.186 -output [`LM32_D_RESULT_SEL_1_RNG] d_result_sel_1;
   1.187 -reg    [`LM32_D_RESULT_SEL_1_RNG] d_result_sel_1;
   1.188 -output x_result_sel_csr;
   1.189 -reg    x_result_sel_csr;
   1.190 -`ifdef LM32_MC_ARITHMETIC_ENABLED
   1.191 -output x_result_sel_mc_arith;
   1.192 -reg    x_result_sel_mc_arith;
   1.193 -`endif
   1.194 -`ifdef LM32_NO_BARREL_SHIFT    
   1.195 -output x_result_sel_shift;
   1.196 -reg    x_result_sel_shift;
   1.197 -`endif
   1.198 -`ifdef CFG_SIGN_EXTEND_ENABLED
   1.199 -output x_result_sel_sext;
   1.200 -reg    x_result_sel_sext;
   1.201 -`endif
   1.202 -output x_result_sel_logic;
   1.203 -reg    x_result_sel_logic;
   1.204 -`ifdef CFG_USER_ENABLED
   1.205 -output x_result_sel_user;
   1.206 -reg    x_result_sel_user;
   1.207 -`endif
   1.208 -output x_result_sel_add;
   1.209 -reg    x_result_sel_add;
   1.210 -output m_result_sel_compare;
   1.211 -reg    m_result_sel_compare;
   1.212 -`ifdef CFG_PL_BARREL_SHIFT_ENABLED
   1.213 -output m_result_sel_shift;
   1.214 -reg    m_result_sel_shift;
   1.215 -`endif
   1.216 -output w_result_sel_load;
   1.217 -reg    w_result_sel_load;
   1.218 -`ifdef CFG_PL_MULTIPLY_ENABLED
   1.219 -output w_result_sel_mul;
   1.220 -reg    w_result_sel_mul;
   1.221 -`endif
   1.222 -output x_bypass_enable;
   1.223 -wire   x_bypass_enable;
   1.224 -output m_bypass_enable;
   1.225 -wire   m_bypass_enable;
   1.226 -output read_enable_0;
   1.227 -wire   read_enable_0;
   1.228 -output [`LM32_REG_IDX_RNG] read_idx_0;
   1.229 -wire   [`LM32_REG_IDX_RNG] read_idx_0;
   1.230 -output read_enable_1;
   1.231 -wire   read_enable_1;
   1.232 -output [`LM32_REG_IDX_RNG] read_idx_1;
   1.233 -wire   [`LM32_REG_IDX_RNG] read_idx_1;
   1.234 -output write_enable;
   1.235 -wire   write_enable;
   1.236 -output [`LM32_REG_IDX_RNG] write_idx;
   1.237 -wire   [`LM32_REG_IDX_RNG] write_idx;
   1.238 -output [`LM32_WORD_RNG] immediate;
   1.239 -wire   [`LM32_WORD_RNG] immediate;
   1.240 -output [`LM32_PC_RNG] branch_offset;
   1.241 -wire   [`LM32_PC_RNG] branch_offset;
   1.242 -output load;
   1.243 -wire   load;
   1.244 -output store;
   1.245 -wire   store;
   1.246 -output [`LM32_SIZE_RNG] size;
   1.247 -wire   [`LM32_SIZE_RNG] size;
   1.248 -output sign_extend;
   1.249 -wire   sign_extend;
   1.250 -output adder_op;
   1.251 -wire   adder_op;
   1.252 -output [`LM32_LOGIC_OP_RNG] logic_op;
   1.253 -wire   [`LM32_LOGIC_OP_RNG] logic_op;
   1.254 -`ifdef CFG_PL_BARREL_SHIFT_ENABLED
   1.255 -output direction;
   1.256 -wire   direction;
   1.257 -`endif
   1.258 -`ifdef CFG_MC_BARREL_SHIFT_ENABLED
   1.259 -output shift_left;
   1.260 -wire   shift_left;
   1.261 -output shift_right;
   1.262 -wire   shift_right;
   1.263 -`endif
   1.264 -`ifdef CFG_MC_MULTIPLY_ENABLED
   1.265 -output multiply;
   1.266 -wire   multiply;
   1.267 -`endif
   1.268 -`ifdef CFG_MC_DIVIDE_ENABLED
   1.269 -output divide;
   1.270 -wire   divide;
   1.271 -output modulus;
   1.272 -wire   modulus;
   1.273 -`endif
   1.274 -output branch;
   1.275 -wire   branch;
   1.276 -output branch_reg;
   1.277 -wire   branch_reg;
   1.278 -output [`LM32_CONDITION_RNG] condition;
   1.279 -wire   [`LM32_CONDITION_RNG] condition;
   1.280 -output bi_conditional;
   1.281 -wire bi_conditional;
   1.282 -output bi_unconditional;
   1.283 -wire bi_unconditional;
   1.284 -`ifdef CFG_DEBUG_ENABLED
   1.285 -output break_opcode;
   1.286 -wire   break_opcode;
   1.287 -`endif
   1.288 -output scall;
   1.289 -wire   scall;
   1.290 -output eret;
   1.291 -wire   eret;
   1.292 -`ifdef CFG_DEBUG_ENABLED
   1.293 -output bret;
   1.294 -wire   bret;
   1.295 -`endif
   1.296 -`ifdef CFG_USER_ENABLED
   1.297 -output [`LM32_USER_OPCODE_RNG] user_opcode;
   1.298 -wire   [`LM32_USER_OPCODE_RNG] user_opcode;
   1.299 -`endif
   1.300 -output csr_write_enable;
   1.301 -wire   csr_write_enable;
   1.302 -
   1.303 -/////////////////////////////////////////////////////
   1.304 -// Internal nets and registers 
   1.305 -/////////////////////////////////////////////////////
   1.306 -
   1.307 -wire [`LM32_WORD_RNG] extended_immediate;       // Zero or sign extended immediate
   1.308 -wire [`LM32_WORD_RNG] high_immediate;           // Immediate as high 16 bits
   1.309 -wire [`LM32_WORD_RNG] call_immediate;           // Call immediate
   1.310 -wire [`LM32_WORD_RNG] branch_immediate;         // Conditional branch immediate
   1.311 -wire sign_extend_immediate;                     // Whether the immediate should be sign extended (`TRUE) or zero extended (`FALSE)
   1.312 -wire select_high_immediate;                     // Whether to select the high immediate  
   1.313 -wire select_call_immediate;                     // Whether to select the call immediate 
   1.314 -
   1.315 -/////////////////////////////////////////////////////
   1.316 -// Functions
   1.317 -/////////////////////////////////////////////////////
   1.318 -
   1.319 -`include "lm32_functions.v"
   1.320 -
   1.321 -/////////////////////////////////////////////////////
   1.322 -// Combinational logic
   1.323 -/////////////////////////////////////////////////////
   1.324 -
   1.325 -// Determine opcode
   1.326 -assign op_add    = instruction[`LM32_OP_RNG] == `LM32_OPCODE_ADD;
   1.327 -assign op_and    = instruction[`LM32_OP_RNG] == `LM32_OPCODE_AND;
   1.328 -assign op_andhi  = instruction[`LM32_OPCODE_RNG] == `LM32_OPCODE_ANDHI;
   1.329 -assign op_b      = instruction[`LM32_OPCODE_RNG] == `LM32_OPCODE_B;
   1.330 -assign op_bi     = instruction[`LM32_OPCODE_RNG] == `LM32_OPCODE_BI;
   1.331 -assign op_be     = instruction[`LM32_OPCODE_RNG] == `LM32_OPCODE_BE;
   1.332 -assign op_bg     = instruction[`LM32_OPCODE_RNG] == `LM32_OPCODE_BG;
   1.333 -assign op_bge    = instruction[`LM32_OPCODE_RNG] == `LM32_OPCODE_BGE;
   1.334 -assign op_bgeu   = instruction[`LM32_OPCODE_RNG] == `LM32_OPCODE_BGEU;
   1.335 -assign op_bgu    = instruction[`LM32_OPCODE_RNG] == `LM32_OPCODE_BGU;
   1.336 -assign op_bne    = instruction[`LM32_OPCODE_RNG] == `LM32_OPCODE_BNE;
   1.337 -assign op_call   = instruction[`LM32_OPCODE_RNG] == `LM32_OPCODE_CALL;
   1.338 -assign op_calli  = instruction[`LM32_OPCODE_RNG] == `LM32_OPCODE_CALLI;
   1.339 -assign op_cmpe   = instruction[`LM32_OP_RNG] == `LM32_OPCODE_CMPE;
   1.340 -assign op_cmpg   = instruction[`LM32_OP_RNG] == `LM32_OPCODE_CMPG;
   1.341 -assign op_cmpge  = instruction[`LM32_OP_RNG] == `LM32_OPCODE_CMPGE;
   1.342 -assign op_cmpgeu = instruction[`LM32_OP_RNG] == `LM32_OPCODE_CMPGEU;
   1.343 -assign op_cmpgu  = instruction[`LM32_OP_RNG] == `LM32_OPCODE_CMPGU;
   1.344 -assign op_cmpne  = instruction[`LM32_OP_RNG] == `LM32_OPCODE_CMPNE;
   1.345 -`ifdef CFG_MC_DIVIDE_ENABLED
   1.346 -assign op_divu   = instruction[`LM32_OPCODE_RNG] == `LM32_OPCODE_DIVU;
   1.347 -`endif
   1.348 -assign op_lb     = instruction[`LM32_OPCODE_RNG] == `LM32_OPCODE_LB;
   1.349 -assign op_lbu    = instruction[`LM32_OPCODE_RNG] == `LM32_OPCODE_LBU;
   1.350 -assign op_lh     = instruction[`LM32_OPCODE_RNG] == `LM32_OPCODE_LH;
   1.351 -assign op_lhu    = instruction[`LM32_OPCODE_RNG] == `LM32_OPCODE_LHU;
   1.352 -assign op_lw     = instruction[`LM32_OPCODE_RNG] == `LM32_OPCODE_LW;
   1.353 -`ifdef CFG_MC_DIVIDE_ENABLED
   1.354 -assign op_modu   = instruction[`LM32_OPCODE_RNG] == `LM32_OPCODE_MODU;
   1.355 -`endif
   1.356 -`ifdef LM32_MULTIPLY_ENABLED
   1.357 -assign op_mul    = instruction[`LM32_OP_RNG] == `LM32_OPCODE_MUL;
   1.358 -`endif
   1.359 -assign op_nor    = instruction[`LM32_OP_RNG] == `LM32_OPCODE_NOR;
   1.360 -assign op_or     = instruction[`LM32_OP_RNG] == `LM32_OPCODE_OR;
   1.361 -assign op_orhi   = instruction[`LM32_OPCODE_RNG] == `LM32_OPCODE_ORHI;
   1.362 -assign op_raise  = instruction[`LM32_OPCODE_RNG] == `LM32_OPCODE_RAISE;
   1.363 -assign op_rcsr   = instruction[`LM32_OPCODE_RNG] == `LM32_OPCODE_RCSR;
   1.364 -assign op_sb     = instruction[`LM32_OPCODE_RNG] == `LM32_OPCODE_SB;
   1.365 -`ifdef CFG_SIGN_EXTEND_ENABLED
   1.366 -assign op_sextb  = instruction[`LM32_OPCODE_RNG] == `LM32_OPCODE_SEXTB;
   1.367 -assign op_sexth  = instruction[`LM32_OPCODE_RNG] == `LM32_OPCODE_SEXTH;
   1.368 -`endif
   1.369 -assign op_sh     = instruction[`LM32_OPCODE_RNG] == `LM32_OPCODE_SH;
   1.370 -`ifdef LM32_BARREL_SHIFT_ENABLED
   1.371 -assign op_sl     = instruction[`LM32_OP_RNG] == `LM32_OPCODE_SL;      
   1.372 -`endif
   1.373 -assign op_sr     = instruction[`LM32_OP_RNG] == `LM32_OPCODE_SR;
   1.374 -assign op_sru    = instruction[`LM32_OP_RNG] == `LM32_OPCODE_SRU;
   1.375 -assign op_sub    = instruction[`LM32_OPCODE_RNG] == `LM32_OPCODE_SUB;
   1.376 -assign op_sw     = instruction[`LM32_OPCODE_RNG] == `LM32_OPCODE_SW;
   1.377 -assign op_user   = instruction[`LM32_OPCODE_RNG] == `LM32_OPCODE_USER;
   1.378 -assign op_wcsr   = instruction[`LM32_OPCODE_RNG] == `LM32_OPCODE_WCSR;
   1.379 -assign op_xnor   = instruction[`LM32_OP_RNG] == `LM32_OPCODE_XNOR;
   1.380 -assign op_xor    = instruction[`LM32_OP_RNG] == `LM32_OPCODE_XOR;
   1.381 -
   1.382 -// Group opcodes by function
   1.383 -assign arith = op_add | op_sub;
   1.384 -assign logical = op_and | op_andhi | op_nor | op_or | op_orhi | op_xor | op_xnor;
   1.385 -assign cmp = op_cmpe | op_cmpg | op_cmpge | op_cmpgeu | op_cmpgu | op_cmpne;
   1.386 -assign bi_conditional = op_be | op_bg | op_bge | op_bgeu  | op_bgu | op_bne;
   1.387 -assign bi_unconditional = op_bi;
   1.388 -assign bra = op_b | bi_unconditional | bi_conditional;
   1.389 -assign call = op_call | op_calli;
   1.390 -`ifdef LM32_BARREL_SHIFT_ENABLED
   1.391 -assign shift = op_sl | op_sr | op_sru;
   1.392 -`endif
   1.393 -`ifdef LM32_NO_BARREL_SHIFT
   1.394 -assign shift = op_sr | op_sru;
   1.395 -`endif
   1.396 -`ifdef CFG_MC_BARREL_SHIFT_ENABLED
   1.397 -assign shift_left = op_sl;
   1.398 -assign shift_right = op_sr | op_sru;
   1.399 -`endif
   1.400 -`ifdef CFG_SIGN_EXTEND_ENABLED
   1.401 -assign sext = op_sextb | op_sexth;
   1.402 -`endif
   1.403 -`ifdef LM32_MULTIPLY_ENABLED
   1.404 -assign multiply = op_mul;
   1.405 -`endif
   1.406 -`ifdef CFG_MC_DIVIDE_ENABLED
   1.407 -assign divide = op_divu; 
   1.408 -assign modulus = op_modu;
   1.409 -`endif
   1.410 -assign load = op_lb | op_lbu | op_lh | op_lhu | op_lw;
   1.411 -assign store = op_sb | op_sh | op_sw;
   1.412 -
   1.413 -// Select pipeline multiplexor controls
   1.414 -always @(*)
   1.415 -begin
   1.416 -    // D stage
   1.417 -    if (call) 
   1.418 -        d_result_sel_0 = `LM32_D_RESULT_SEL_0_NEXT_PC;
   1.419 -    else 
   1.420 -        d_result_sel_0 = `LM32_D_RESULT_SEL_0_REG_0;
   1.421 -    if (call) 
   1.422 -        d_result_sel_1 = `LM32_D_RESULT_SEL_1_ZERO;         
   1.423 -    else if ((instruction[31] == 1'b0) && !bra) 
   1.424 -        d_result_sel_1 = `LM32_D_RESULT_SEL_1_IMMEDIATE;
   1.425 -    else
   1.426 -        d_result_sel_1 = `LM32_D_RESULT_SEL_1_REG_1; 
   1.427 -    // X stage
   1.428 -    x_result_sel_csr = `FALSE;
   1.429 -`ifdef LM32_MC_ARITHMETIC_ENABLED
   1.430 -    x_result_sel_mc_arith = `FALSE;
   1.431 -`endif
   1.432 -`ifdef LM32_NO_BARREL_SHIFT
   1.433 -    x_result_sel_shift = `FALSE;
   1.434 -`endif
   1.435 -`ifdef CFG_SIGN_EXTEND_ENABLED
   1.436 -    x_result_sel_sext = `FALSE;
   1.437 -`endif
   1.438 -    x_result_sel_logic = `FALSE;
   1.439 -`ifdef CFG_USER_ENABLED        
   1.440 -    x_result_sel_user = `FALSE;
   1.441 -`endif
   1.442 -    x_result_sel_add = `FALSE;
   1.443 -    if (op_rcsr)
   1.444 -        x_result_sel_csr = `TRUE;
   1.445 -`ifdef LM32_MC_ARITHMETIC_ENABLED    
   1.446 -`ifdef CFG_MC_BARREL_SHIFT_ENABLED
   1.447 -    else if (shift_left | shift_right) 
   1.448 -        x_result_sel_mc_arith = `TRUE;
   1.449 -`endif
   1.450 -`ifdef CFG_MC_DIVIDE_ENABLED
   1.451 -    else if (divide | modulus)
   1.452 -        x_result_sel_mc_arith = `TRUE;        
   1.453 -`endif
   1.454 -`ifdef CFG_MC_MULTIPLY_ENABLED
   1.455 -    else if (multiply)
   1.456 -        x_result_sel_mc_arith = `TRUE;            
   1.457 -`endif
   1.458 -`endif
   1.459 -`ifdef LM32_NO_BARREL_SHIFT
   1.460 -    else if (shift)
   1.461 -        x_result_sel_shift = `TRUE;        
   1.462 -`endif
   1.463 -`ifdef CFG_SIGN_EXTEND_ENABLED
   1.464 -    else if (sext)
   1.465 -        x_result_sel_sext = `TRUE;
   1.466 -`endif        
   1.467 -    else if (logical) 
   1.468 -        x_result_sel_logic = `TRUE;
   1.469 -`ifdef CFG_USER_ENABLED        
   1.470 -    else if (op_user)
   1.471 -        x_result_sel_user = `TRUE;
   1.472 -`endif
   1.473 -    else 
   1.474 -        x_result_sel_add = `TRUE;        
   1.475 -    
   1.476 -    // M stage
   1.477 -
   1.478 -    m_result_sel_compare = cmp;
   1.479 -`ifdef CFG_PL_BARREL_SHIFT_ENABLED
   1.480 -    m_result_sel_shift = shift;
   1.481 -`endif
   1.482 -
   1.483 -    // W stage
   1.484 -    w_result_sel_load = load;
   1.485 -`ifdef CFG_PL_MULTIPLY_ENABLED
   1.486 -    w_result_sel_mul = op_mul; 
   1.487 -`endif
   1.488 -end
   1.489 -
   1.490 -// Set if result is valid at end of X stage
   1.491 -assign x_bypass_enable =  arith 
   1.492 -                        | logical
   1.493 -`ifdef CFG_MC_BARREL_SHIFT_ENABLED
   1.494 -                        | shift_left
   1.495 -                        | shift_right
   1.496 -`endif                        
   1.497 -`ifdef CFG_MC_MULTIPLY_ENABLED
   1.498 -                        | multiply
   1.499 -`endif
   1.500 -`ifdef CFG_MC_DIVIDE_ENABLED
   1.501 -                        | divide
   1.502 -                        | modulus
   1.503 -`endif
   1.504 -`ifdef LM32_NO_BARREL_SHIFT
   1.505 -                        | shift
   1.506 -`endif                  
   1.507 -`ifdef CFG_SIGN_EXTEND_ENABLED
   1.508 -                        | sext 
   1.509 -`endif                        
   1.510 -`ifdef CFG_USER_ENABLED
   1.511 -                        | op_user
   1.512 -`endif
   1.513 -                        | op_rcsr
   1.514 -                        ;
   1.515 -// Set if result is valid at end of M stage                        
   1.516 -assign m_bypass_enable = x_bypass_enable 
   1.517 -`ifdef CFG_PL_BARREL_SHIFT_ENABLED
   1.518 -                        | shift
   1.519 -`endif
   1.520 -                        | cmp
   1.521 -                        ;
   1.522 -// Register file read port 0                        
   1.523 -assign read_enable_0 = ~(op_bi | op_calli);
   1.524 -assign read_idx_0 = instruction[25:21];
   1.525 -// Register file read port 1 
   1.526 -assign read_enable_1 = ~(op_bi | op_calli | load);
   1.527 -assign read_idx_1 = instruction[20:16];
   1.528 -// Register file write port
   1.529 -assign write_enable = ~(bra | op_raise | store | op_wcsr);
   1.530 -assign write_idx = call
   1.531 -                    ? 5'd29
   1.532 -                    : instruction[31] == 1'b0 
   1.533 -                        ? instruction[20:16] 
   1.534 -                        : instruction[15:11];
   1.535 -                        
   1.536 -// Size of load/stores                        
   1.537 -assign size = instruction[27:26];
   1.538 -// Whether to sign or zero extend
   1.539 -assign sign_extend = instruction[28];                      
   1.540 -// Set adder_op to 1 to perform a subtraction
   1.541 -assign adder_op = op_sub | op_cmpe | op_cmpg | op_cmpge | op_cmpgeu | op_cmpgu | op_cmpne | bra;
   1.542 -// Logic operation (and, or, etc)
   1.543 -assign logic_op = instruction[29:26];
   1.544 -`ifdef CFG_PL_BARREL_SHIFT_ENABLED
   1.545 -// Shift direction
   1.546 -assign direction = instruction[29];
   1.547 -`endif
   1.548 -// Control flow microcodes
   1.549 -assign branch = bra | call;
   1.550 -assign branch_reg = op_call | op_b;
   1.551 -assign condition = instruction[28:26];      
   1.552 -`ifdef CFG_DEBUG_ENABLED
   1.553 -assign break_opcode = op_raise & ~instruction[2];
   1.554 -`endif
   1.555 -assign scall = op_raise & instruction[2];
   1.556 -assign eret = op_b & (instruction[25:21] == 5'd30);
   1.557 -`ifdef CFG_DEBUG_ENABLED
   1.558 -assign bret = op_b & (instruction[25:21] == 5'd31);
   1.559 -`endif
   1.560 -`ifdef CFG_USER_ENABLED
   1.561 -// Extract user opcode
   1.562 -assign user_opcode = instruction[10:0];
   1.563 -`endif
   1.564 -// CSR read/write
   1.565 -assign csr_write_enable = op_wcsr;
   1.566 -
   1.567 -// Extract immediate from instruction
   1.568 -
   1.569 -assign sign_extend_immediate = ~(op_and | op_cmpgeu | op_cmpgu | op_nor | op_or | op_xnor | op_xor);
   1.570 -assign select_high_immediate = op_andhi | op_orhi;
   1.571 -assign select_call_immediate = instruction[31];
   1.572 -
   1.573 -assign high_immediate = {instruction[15:0], 16'h0000};
   1.574 -assign extended_immediate = {{16{sign_extend_immediate & instruction[15]}}, instruction[15:0]};
   1.575 -assign call_immediate = {{6{instruction[25]}}, instruction[25:0]};
   1.576 -assign branch_immediate = {{16{instruction[15]}}, instruction[15:0]};
   1.577 -
   1.578 -assign immediate = select_high_immediate == `TRUE 
   1.579 -                        ? high_immediate 
   1.580 -                        : extended_immediate;
   1.581 -   
   1.582 -assign branch_offset = select_call_immediate == `TRUE   
   1.583 -                        ? call_immediate
   1.584 -                        : branch_immediate;
   1.585 -    
   1.586 -endmodule 
   1.587 -