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decode optimization

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This commit is contained in:
Blaise Tine
2021-06-28 05:06:30 -07:00
parent f84c8a0b5d
commit 6ae2f5199d
8 changed files with 132 additions and 165 deletions
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262
hw/rtl/VX_decode.v
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@@ -2,9 +2,17 @@
`include "VX_print_instr.vh"
`ifdef EXT_F_ENABLE
`define USED_REGS(f,r) used_regs[{f,r}] = 1
`define SET_REG(d,f,s) \
d = {f, s}
`define USED_REG(d,f,s) \
`SET_REG(d,f,s); \
used_regs[{f, s}] = 1
`else
`define USED_REGS(f,r) used_regs[r] = 1
`define SET_REG(d,f,s) \
d = s
`define USED_REG(d,f,s) \
`SET_REG(d,f,s); \
used_regs[s] = 1
`endif
module VX_decode #(
@@ -28,10 +36,9 @@ module VX_decode #(
reg [`EX_BITS-1:0] ex_type;
reg [`OP_BITS-1:0] op_type;
reg [`MOD_BITS-1:0] op_mod;
reg [4:0] rd_r, rs1_r, rs2_r, rs3_r;
reg [`NR_BITS-1:0] rd_r, rs1_r, rs2_r, rs3_r;
reg [31:0] imm;
reg use_rd, use_PC, use_imm;
reg rd_fp, rs1_fp, rs2_fp;
reg is_join, is_wstall;
reg [`NUM_REGS-1:0] used_regs;
@@ -56,20 +63,17 @@ module VX_decode #(
ex_type = 0;
op_type = 'x;
op_mod = 'x;
rd_r = 'x;
rs1_r = 'x;
rs2_r = 'x;
rs3_r = 'x;
imm = 'x;
use_imm = 'x;
use_PC = 'x;
use_rd = 0;
use_PC = 0;
use_imm = 0;
rd_fp = 0;
rs1_fp = 0;
rs2_fp = 0;
is_join = 0;
is_wstall = 0;
used_regs = 0;
rd_r = rd;
rs1_r = rs1;
rs2_r = rs2;
rs3_r = rs3;
used_regs = 0;
case (opcode)
`INST_I: begin
@@ -86,11 +90,12 @@ module VX_decode #(
default:;
endcase
op_mod = 0;
imm = {{20{alu_imm[11]}}, alu_imm};
use_rd = 1;
use_imm = 1;
`USED_REGS (1'b0, rd);
`USED_REGS (1'b0, rs1);
use_PC = 0;
imm = {{20{alu_imm[11]}}, alu_imm};
`USED_REG (rd_r, 1'b0, rd);
`USED_REG (rs1_r, 1'b0, rs1);
end
`INST_R: begin
ex_type = `EX_ALU;
@@ -123,54 +128,57 @@ module VX_decode #(
default:;
endcase
op_mod = 0;
end
use_rd = 1;
`USED_REGS (1'b0, rd);
`USED_REGS (1'b0, rs1);
`USED_REGS (1'b0, rs2);
end
use_rd = 1;
use_imm = 0;
use_PC = 0;
`USED_REG (rd_r, 1'b0, rd);
`USED_REG (rs1_r, 1'b0, rs1);
`USED_REG (rs2_r, 1'b0, rs2);
end
`INST_LUI: begin
ex_type = `EX_ALU;
op_type = `OP_BITS'(`ALU_LUI);
op_mod = 0;
rs1_r = 0;
imm = {upper_imm, 12'(0)};
use_rd = 1;
use_imm = 1;
`USED_REGS (1'b0, rd);
`USED_REGS (1'b0, 5'b0);
use_imm = 1;
use_PC = 0;
imm = {upper_imm, 12'(0)};
`USED_REG (rd_r, 1'b0, rd);
`USED_REG (rs1_r, 1'b0, 5'b0);
end
`INST_AUIPC: begin
ex_type = `EX_ALU;
op_type = `OP_BITS'(`ALU_AUIPC);
op_mod = 0;
imm = {upper_imm, 12'(0)};
use_rd = 1;
use_PC = 1;
use_imm = 1;
`USED_REGS (1'b0, rd);
use_PC = 1;
imm = {upper_imm, 12'(0)};
`USED_REG (rd_r, 1'b0, rd);
end
`INST_JAL: begin
ex_type = `EX_ALU;
op_type = `OP_BITS'(`BR_JAL);
op_mod = 1;
imm = {{11{jal_imm[20]}}, jal_imm};
use_rd = 1;
use_PC = 1;
use_imm = 1;
use_PC = 1;
is_wstall = 1;
`USED_REGS (1'b0, rd);
imm = {{11{jal_imm[20]}}, jal_imm};
`USED_REG (rd_r, 1'b0, rd);
end
`INST_JALR: begin
ex_type = `EX_ALU;
op_type = `OP_BITS'(`BR_JALR);
op_mod = 1;
imm = {{20{jalr_imm[11]}}, jalr_imm};
use_rd = 1;
use_imm = 1;
use_PC = 0;
is_wstall = 1;
`USED_REGS (1'b0, rd);
`USED_REGS (1'b0, rs1);
imm = {{20{jalr_imm[11]}}, jalr_imm};
`USED_REG (rd_r, 1'b0, rd);
`USED_REG (rs1_r, 1'b0, rs1);
end
`INST_B: begin
ex_type = `EX_ALU;
@@ -184,12 +192,12 @@ module VX_decode #(
default:;
endcase
op_mod = 1;
imm = {{20{instr[31]}}, instr[7], instr[30:25], instr[11:8], 1'b0};
use_PC = 1;
use_imm = 1;
use_PC = 1;
is_wstall = 1;
`USED_REGS (1'b0, rs1);
`USED_REGS (1'b0, rs2);
imm = {{20{instr[31]}}, instr[7], instr[30:25], instr[11:8], 1'b0};
`USED_REG (rs1_r, 1'b0, rs1);
`USED_REG (rs2_r, 1'b0, rs2);
end
`INST_SYS : begin
if (func3 == 0) begin
@@ -203,26 +211,28 @@ module VX_decode #(
default:;
endcase
op_mod = 1;
imm = 32'd4;
use_rd = 1;
use_PC = 1;
use_imm = 1;
`USED_REGS (1'b0, rd);
use_PC = 1;
imm = 32'd4;
`USED_REG (rd_r, 1'b0, rd);
end else begin
ex_type = `EX_CSR;
case (func3[1:0])
2'h0: op_type = `OP_BITS'(`CSR_RW);
2'h1: op_type = `OP_BITS'(`CSR_RW);
2'h2: op_type = `OP_BITS'(`CSR_RS);
2'h3: op_type = `OP_BITS'(`CSR_RC);
default:;
endcase
imm = 32'(u_12);
use_rd = 1;
use_imm = func3[2];
`USED_REGS (1'b0, rd);
if (!func3[2])
`USED_REGS (1'b0, rs1);
use_imm = func3[2];
imm = 32'(u_12); // addr
`USED_REG (rd_r, 1'b0, rd);
if (func3[2]) begin
`SET_REG(rs1_r, 1'b0, rs1); // imm
end else begin
`USED_REG (rs1_r, 1'b0, rs1);
end
end
end
`ifdef EXT_F_ENABLE
@@ -231,13 +241,10 @@ module VX_decode #(
`INST_L: begin
ex_type = `EX_LSU;
op_type = `OP_BITS'({1'b0, func3});
use_rd = 1;
imm = {{20{u_12[11]}}, u_12};
use_rd = 1;
`USED_REGS (1'b0, rs1);
`USED_REGS ((opcode == `INST_FL), rd);
`ifdef EXT_F_ENABLE
rd_fp = (opcode == `INST_FL);
`endif
`USED_REG (rd_r, (opcode == `INST_FL), rd);
`USED_REG (rs1_r, 1'b0, rs1);
end
`ifdef EXT_F_ENABLE
`INST_FS,
@@ -246,11 +253,8 @@ module VX_decode #(
ex_type = `EX_LSU;
op_type = `OP_BITS'({1'b1, func3});
imm = {{20{func7[6]}}, func7, rd};
`USED_REGS (1'b0, rs1);
`USED_REGS ((opcode == `INST_FS), rs2);
`ifdef EXT_F_ENABLE
rs2_fp = (opcode == `INST_FS);
`endif
`USED_REG (rs1_r, 1'b0, rs1);
`USED_REG (rs2_r, (opcode == `INST_FS), rs2);
end
`ifdef EXT_F_ENABLE
`INST_FMADD,
@@ -261,80 +265,61 @@ module VX_decode #(
op_type = `OP_BITS'(opcode[3:0]);
op_mod = func3;
use_rd = 1;
rd_fp = 1;
rs1_fp = 1;
rs2_fp = 1;
`USED_REGS (1'b1, rd);
`USED_REGS (1'b1, rs1);
`USED_REGS (1'b1, rs2);
`USED_REGS (1'b1, rs3);
`USED_REG (rd_r, 1'b1, rd);
`USED_REG (rs1_r, 1'b1, rs1);
`USED_REG (rs2_r, 1'b1, rs2);
`USED_REG (rs3_r, 1'b1, rs3);
end
`INST_FCI: begin
ex_type = `EX_FPU;
op_mod = func3;
use_rd = 1;
op_mod = func3;
use_rd = 1;
case (func7)
7'h00, // FADD
7'h04, // FSUB
7'h08, // FMUL
7'h0C: // FDIV
begin
7'h00, // FADD
7'h04, // FSUB
7'h08, // FMUL
7'h0C: begin // FDIV
op_type = `OP_BITS'(func7[3:0]);
rd_fp = 1;
rs1_fp = 1;
rs2_fp = 1;
`USED_REGS (1'b1, rd);
`USED_REGS (1'b1, rs1);
`USED_REGS (1'b1, rs2);
`USED_REG (rd_r, 1'b1, rd);
`USED_REG (rs1_r, 1'b1, rs1);
`USED_REG (rs2_r, 1'b1, rs2);
end
7'h2C: begin
op_type = `OP_BITS'(`FPU_SQRT);
rd_fp = 1;
rs1_fp = 1;
`USED_REGS (1'b1, rd);
`USED_REGS (1'b1, rs1);
`USED_REG (rd_r, 1'b1, rd);
`USED_REG (rs1_r, 1'b1, rs1);
end
7'h50: begin
op_type = `OP_BITS'(`FPU_CMP);
rs1_fp = 1;
rs2_fp = 1;
`USED_REGS (1'b0, rd);
`USED_REGS (1'b1, rs1);
`USED_REGS (1'b1, rs2);
`USED_REG (rd_r, 1'b0, rd);
`USED_REG (rs1_r, 1'b1, rs1);
`USED_REG (rs2_r, 1'b1, rs2);
end
7'h60: begin
op_type = (instr[20]) ? `OP_BITS'(`FPU_CVTWUS) : `OP_BITS'(`FPU_CVTWS);
rs1_fp = 1;
`USED_REGS (1'b0, rd);
`USED_REGS (1'b1, rs1);
`USED_REG (rd_r, 1'b0, rd);
`USED_REG (rs1_r, 1'b1, rs1);
end
7'h68: begin
op_type = (instr[20]) ? `OP_BITS'(`FPU_CVTSWU) : `OP_BITS'(`FPU_CVTSW);
rd_fp = 1;
`USED_REGS (1'b1, rd);
`USED_REGS (1'b0, rs1);
`USED_REG (rd_r, 1'b1, rd);
`USED_REG (rs1_r, 1'b0, rs1);
end
7'h10: begin
// FSGNJ=0, FSGNJN=1, FSGNJX=2
op_type = `OP_BITS'(`FPU_MISC);
op_mod = {1'b0, func3[1:0]};
rd_fp = 1;
rs1_fp = 1;
rs2_fp = 1;
`USED_REGS (1'b1, rd);
`USED_REGS (1'b1, rs1);
`USED_REGS (1'b1, rs2);
`USED_REG (rd_r, 1'b1, rd);
`USED_REG (rs1_r, 1'b1, rs1);
`USED_REG (rs2_r, 1'b1, rs2);
end
7'h14: begin
// FMIN=3, FMAX=4
op_type = `OP_BITS'(`FPU_MISC);
op_mod = func3[0] ? 4 : 3;
rd_fp = 1;
rs1_fp = 1;
rs2_fp = 1;
`USED_REGS (1'b1, rd);
`USED_REGS (1'b1, rs1);
`USED_REGS (1'b1, rs2);
`USED_REG (rd_r, 1'b1, rd);
`USED_REG (rs1_r, 1'b1, rs1);
`USED_REG (rs2_r, 1'b1, rs2);
end
7'h70: begin
if (func3[0]) begin
@@ -344,17 +329,16 @@ module VX_decode #(
// FMV.X.W=5
op_type = `OP_BITS'(`FPU_MISC);
op_mod = 5;
end
rs1_fp = 1;
`USED_REGS (1'b0, rd);
`USED_REGS (1'b1, rs1);
end
`USED_REG (rd_r, 1'b0, rd);
`USED_REG (rs1_r, 1'b1, rs1);
end
7'h78: begin
// FMV.W.X=6
op_type = `OP_BITS'(`FPU_MISC);
op_mod = 6;
rd_fp = 1;
`USED_REGS (1'b1, rd);
op_mod = 6;
`USED_REG (rd_r, 1'b1, rd);
`USED_REG (rs1_r, 1'b0, rs1);
end
default:;
endcase
@@ -366,17 +350,17 @@ module VX_decode #(
3'h0: begin
op_type = `OP_BITS'(`GPU_TMC);
is_wstall = 1;
`USED_REGS (1'b0, rs1);
`USED_REG (rs1_r, 1'b0, rs1);
end
3'h1: begin
op_type = `OP_BITS'(`GPU_WSPAWN);
`USED_REGS (1'b0, rs1);
`USED_REGS (1'b0, rs2);
`USED_REG (rs1_r, 1'b0, rs1);
`USED_REG (rs2_r, 1'b0, rs2);
end
3'h2: begin
op_type = `OP_BITS'(`GPU_SPLIT);
is_wstall = 1;
`USED_REGS (1'b0, rs1);
`USED_REG (rs1_r, 1'b0, rs1);
end
3'h3: begin
op_type = `OP_BITS'(`GPU_JOIN);
@@ -385,8 +369,8 @@ module VX_decode #(
3'h4: begin
op_type = `OP_BITS'(`GPU_BAR);
is_wstall = 1;
`USED_REGS (1'b0, rs1);
`USED_REGS (1'b0, rs2);
`USED_REG (rs1_r, 1'b0, rs1);
`USED_REG (rs2_r, 1'b0, rs2);
end
default:;
endcase
@@ -396,32 +380,20 @@ module VX_decode #(
end
// disable write to integer register r0
wire wb = use_rd && (rd_fp || (rd_r != 0));
assign decode_if.valid = ifetch_rsp_if.valid;
assign decode_if.wid = ifetch_rsp_if.wid;
assign decode_if.tmask = ifetch_rsp_if.tmask;
assign decode_if.PC = ifetch_rsp_if.PC;
assign decode_if.ex_type = ex_type;
assign decode_if.op_type = op_type;
assign decode_if.op_mod = op_mod;
assign decode_if.wb = wb;
`ifdef EXT_F_ENABLE
assign decode_if.rd = {rd_fp, rd_r};
assign decode_if.rs1 = {rs1_fp, rs1_r};
assign decode_if.rs2 = {rs2_fp, rs2_r};
assign decode_if.rs3 = {1'b1, rs3_r};
`else
`UNUSED_VAR (rd_fp)
`UNUSED_VAR (rs1_fp)
`UNUSED_VAR (rs2_fp)
assign decode_if.rd = rd_r;
assign decode_if.rs1 = rs1_r;
assign decode_if.rs2 = rs2_r;
assign decode_if.rs3 = rs3_r;
`endif
wire wb = use_rd && (| rd_r);
assign decode_if.valid = ifetch_rsp_if.valid;
assign decode_if.wid = ifetch_rsp_if.wid;
assign decode_if.tmask = ifetch_rsp_if.tmask;
assign decode_if.PC = ifetch_rsp_if.PC;
assign decode_if.ex_type = ex_type;
assign decode_if.op_type = op_type;
assign decode_if.op_mod = op_mod;
assign decode_if.wb = wb;
assign decode_if.rd = rd_r;
assign decode_if.rs1 = rs1_r;
assign decode_if.rs2 = rs2_r;
assign decode_if.rs3 = rs3_r;
assign decode_if.imm = imm;
assign decode_if.use_PC = use_PC;
assign decode_if.use_imm = use_imm;