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improved decoder checking atomic and RW and MW and privileged instructions

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David Harris 2023-07-02 00:02:03 -07:00
parent 07cf1dd9da
commit 110dd42cfb
1 changed files with 27 additions and 15 deletions
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42
src/ieu/controller.sv
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@ -83,7 +83,7 @@ module controller import cvw::*; #(parameter cvw_t P) (
logic [6:0] OpD; // Opcode in Decode stage
logic [2:0] Funct3D; // Funct3 field in Decode stage
logic [6:0] Funct7D; // Funct7 field in Decode stage
logic [4:0] Rs1D, Rs2D; // Rs1/2 source register in Decode stage
logic [4:0] Rs1D, Rs2D, RdD; // Rs1/2 source register / dest reg in Decode stage
`define CTRLW 23
@ -127,19 +127,22 @@ module controller import cvw::*; #(parameter cvw_t P) (
logic IFunctD, RFunctD, MFunctD; // Detect I, R, and M-type RV32IM/Rv64IM instructions
logic LFunctD, SFunctD, BFunctD; // Detect load, store, branch instructions
logic FLSFunctD; // Detect floating-point loads and stores
logic JFunctD; // detect jalr instruction
logic JRFunctD; // detect jalr instruction
logic FenceFunctD; // Detect fence instruction
logic AFunctD, AMOFunctD; // Detect atomic instructions
logic RWFunctD, MWFunctD; // detect RW/MW instructions
logic PFunctD, CSRFunctD; // detect privileged / CSR instruction
logic FenceM; // Fence.I or sfence.VMA instruction in memory stage
logic [2:0] ALUSelectD; // ALU Output selection mux control
logic IWValidFunct3D; // Detects if Funct3 is valid for IW instructions
// Extract fields
assign OpD = InstrD[6:0];
assign OpD = InstrD[6:0];
assign Funct3D = InstrD[14:12];
assign Funct7D = InstrD[31:25];
assign Rs1D = InstrD[19:15];
assign Rs2D = InstrD[24:20];
assign Rs1D = InstrD[19:15];
assign Rs2D = InstrD[24:20];
assign RdD = InstrD[11:7];
// Funct 7 checking
// Be rigorous about detecting illegal instructions if CSRs or bit manipulation is supported
@ -163,7 +166,7 @@ module controller import cvw::*; #(parameter cvw_t P) (
assign FLSFunctD = (Funct3D == 3'b010 & P.F_SUPPORTED) | (Funct3D == 3'b011 & P.D_SUPPORTED) |
(Funct3D == 3'b100 & P.Q_SUPPORTED) | (Funct3D == 3'b001 & P.ZFH_SUPPORTED);
assign FenceFunctD = (Funct3D == 3'b000) | (P.ZIFENCEI_SUPPORTED & Funct3D == 3'b001);
assign AFunctD = (Funct3D == 3'b010);
assign AFunctD = (Funct3D == 3'b010) | (P.XLEN == 64 & Funct3D == 3'b011);
assign AMOFunctD = (InstrD[31:27] == 5'b00001) |
(InstrD[31:27] == 5'b00000) |
(InstrD[31:27] == 5'b00100) |
@ -173,10 +176,15 @@ module controller import cvw::*; #(parameter cvw_t P) (
(InstrD[31:27] == 5'b10100) |
(InstrD[31:27] == 5'b11000) |
(InstrD[31:27] == 5'b11100);
assign RWFunctD = ((Funct3D == 3'b000 | Funct3D == 3'b001 | Funct3D == 3'b101) & Funct7ZeroD |
(Funct3D == 3'b000 | Funct3D == 3'b101) & Funct7b5D) & (P.XLEN == 64);
assign MWFunctD = MFunctD & (P.XLEN == 64) & ~(Funct3D == 3'b001 | Funct3D == 3'b010 | Funct3D == 3'b011);
assign SFunctD = Funct3D == 3'b000 | Funct3D == 3'b001 | Funct3D == 3'b010 |
((P.XLEN == 64) & (Funct3D == 3'b011));
assign BFunctD = (Funct3D[2:1] != 2'b01); // legal branches
assign JFunctD = (Funct3D == 3'b000);
assign BFunctD = Funct3D[2:1] != 2'b01; // legal branches
assign JRFunctD = Funct3D == 3'b000;
assign PFunctD = Funct3D == 3'b000 & Rs1D == 5'b0 & RdD == 5'b0;
assign CSRFunctD = Funct3D[1:0] != 2'b00;
assign IWValidFunct3D = Funct3D == 3'b000 | Funct3D == 3'b001 | Funct3D == 3'b101;
end else begin:legalcheck2
assign IFunctD = 1; // Don't bother to separate out shift decoding
@ -187,9 +195,13 @@ module controller import cvw::*; #(parameter cvw_t P) (
assign FenceFunctD = 1; // don't bother to check fields for fences
assign AFunctD = 1; // don't bother to check fields for atomics
assign AMOFunctD = 1; // don't bother to check Funct7 for AMO operations
assign RWFunctD = 1; // don't bother to check fields for RW instructions
assign MWFunctD = 1; // don't bother to check fields for MW instructions
assign SFunctD = 1; // don't bother to check Funct3 for stores
assign BFunctD = 1; // don't bother to check Funct3 for branches
assign JFunctD = 1; // don't bother to check Funct3 for jumps
assign JRFunctD = 1; // don't bother to check Funct3 for jalrs
assign PFunctD = 1; // don't bother to check fields for privileged instructions
assign CSRFunctD = 1; // don't bother to check Funct3 for CSR operations
assign IWValidFunct3D = 1;
end
@ -231,19 +243,19 @@ module controller import cvw::*; #(parameter cvw_t P) (
else if (MFunctD)
ControlsD = `CTRLW'b1_000_00_00_011_0_0_0_0_0_0_0_0_1_00_0; // Multiply/divide
7'b0110111: ControlsD = `CTRLW'b1_100_01_00_000_0_0_0_1_0_0_0_0_0_00_0; // lui
7'b0111011: if (RFunctD & (P.XLEN == 64))
7'b0111011: if (RWFunctD)
ControlsD = `CTRLW'b1_000_00_00_000_0_1_0_0_1_0_0_0_0_00_0; // R-type W instructions for RV64i
else if (MFunctD & (P.XLEN == 64))
else if (MWFunctD)
ControlsD = `CTRLW'b1_000_00_00_011_0_0_0_0_1_0_0_0_1_00_0; // W-type Multiply/Divide
7'b1100011: if (BFunctD)
ControlsD = `CTRLW'b0_010_11_00_000_1_0_0_0_0_0_0_0_0_00_0; // branches
7'b1100111: if (JFunctD)
7'b1100111: if (JRFunctD)
ControlsD = `CTRLW'b1_000_01_00_000_0_0_1_1_0_0_0_0_0_00_0; // jalr
7'b1101111: ControlsD = `CTRLW'b1_011_11_00_000_0_0_1_1_0_0_0_0_0_00_0; // jal
7'b1110011: if (P.ZICSR_SUPPORTED) begin
if (Funct3D == 3'b000)
ControlsD = `CTRLW'b0_000_00_00_000_0_0_0_0_0_0_1_0_0_00_0; // privileged; decoded further in priveleged modules
else
if (PFunctD)
ControlsD = `CTRLW'b0_000_00_00_000_0_0_0_0_0_0_1_0_0_00_0; // privileged; decoded further in privdec modules
else if (CSRFunctD)
ControlsD = `CTRLW'b1_000_00_00_010_0_0_0_0_0_1_0_0_0_00_0; // csrs
end
endcase