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lsu supports quad enabled subwordreads

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This commit is contained in:
Kevin Kim 2024-03-05 17:07:39 -08:00
parent d1a1345e4d
commit 9d73e5bd0d
2 changed files with 28 additions and 82 deletions
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2
src/lsu/lsu.sv
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@ -417,7 +417,7 @@ module lsu import cvw::*; #(parameter cvw_t P) (
// Subword Accesses
/////////////////////////////////////////////////////////////////////////////////////////////
subwordread #(P.LLEN) subwordread(.ReadDataWordMuxM(LittleEndianReadDataWordM), .PAdrM(PAdrM[2:0]), .BigEndianM,
subwordread #(P) subwordread(.ReadDataWordMuxM(LittleEndianReadDataWordM), .PAdrM(PAdrM[3:0]), .BigEndianM,
.FpLoadStoreM, .Funct3M(LSUFunct3M), .ReadDataM);
subwordwrite #(P.LLEN) subwordwrite(.LSUFunct3M, .IMAFWriteDataM, .LittleEndianWriteDataM);

108
src/lsu/subwordread.sv
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@ -28,98 +28,44 @@
// and limitations under the License.
////////////////////////////////////////////////////////////////////////////////////////////////
module subwordread #(parameter LLEN)
(
input logic [LLEN-1:0] ReadDataWordMuxM,
input logic [2:0] PAdrM,
module subwordread import cvw::*; #(parameter cvw_t P) (
input logic [P.LLEN-1:0] ReadDataWordMuxM,
input logic [3:0] PAdrM,
input logic [2:0] Funct3M,
input logic FpLoadStoreM,
input logic BigEndianM,
output logic [LLEN-1:0] ReadDataM
output logic [P.LLEN-1:0] ReadDataM
);
localparam ADRBITS = $clog2(P.LLEN)-3;
logic [7:0] ByteM;
logic [15:0] HalfwordM;
logic [2:0] PAdrSwap;
logic [31:0] WordM;
logic [63:0] DblWordM;
logic [ADRBITS-1:0] PAdrSwap;
// Funct3M[2] is the unsigned bit. mask upper bits.
// Funct3M[1:0] is the size of the memory access.
assign PAdrSwap = PAdrM ^ {3{BigEndianM}};
if (P.BIGENDIAN_SUPPORTED) assign PAdrSwap = PAdrM[ADRBITS-1:0] ^ {ADRBITS{BigEndianM}};
else assign PAdrSwap = PAdrM[ADRBITS-1:0];
assign ByteM = ReadDataWordMuxM[PAdrSwap*8 +: 8];
assign HalfwordM = ReadDataWordMuxM[PAdrSwap[ADRBITS-1:1]*16 +: 16];
if (P.LLEN >= 64) assign WordM = ReadDataWordMuxM[PAdrSwap[ADRBITS-1:2] * 32 +: 32];
else assign WordM = ReadDataWordMuxM;
if (LLEN == 64) begin:swrmux
// ByteMe mux
always_comb
case(PAdrSwap[2:0])
3'b000: ByteM = ReadDataWordMuxM[7:0];
3'b001: ByteM = ReadDataWordMuxM[15:8];
3'b010: ByteM = ReadDataWordMuxM[23:16];
3'b011: ByteM = ReadDataWordMuxM[31:24];
3'b100: ByteM = ReadDataWordMuxM[39:32];
3'b101: ByteM = ReadDataWordMuxM[47:40];
3'b110: ByteM = ReadDataWordMuxM[55:48];
3'b111: ByteM = ReadDataWordMuxM[63:56];
endcase
// halfword mux
always_comb
case(PAdrSwap[2:1])
2'b00: HalfwordM = ReadDataWordMuxM[15:0];
2'b01: HalfwordM = ReadDataWordMuxM[31:16];
2'b10: HalfwordM = ReadDataWordMuxM[47:32];
2'b11: HalfwordM = ReadDataWordMuxM[63:48];
endcase
logic [31:0] WordM;
always_comb
case(PAdrSwap[2])
1'b0: WordM = ReadDataWordMuxM[31:0];
1'b1: WordM = ReadDataWordMuxM[63:32];
endcase
if (P.LLEN >= 64) assign DblWordM = ReadDataWordMuxM[PAdrSwap[ADRBITS-1] * 64 +: 64];
logic [63:0] DblWordM;
assign DblWordM = ReadDataWordMuxM[63:0];
// sign extension/ NaN boxing
always_comb
// sign extension/ NaN boxing
always_comb
case(Funct3M)
3'b000: ReadDataM = {{LLEN-8{ByteM[7]}}, ByteM}; // lb
3'b001: ReadDataM = {{LLEN-16{HalfwordM[15]|FpLoadStoreM}}, HalfwordM[15:0]}; // lh/flh
3'b010: ReadDataM = {{LLEN-32{WordM[31]|FpLoadStoreM}}, WordM[31:0]}; // lw/flw
3'b011: ReadDataM = {{LLEN-64{DblWordM[63]|FpLoadStoreM}}, DblWordM[63:0]}; // ld/fld
3'b100: ReadDataM = {{LLEN-8{1'b0}}, ByteM[7:0]}; // lbu
//3'b100: ReadDataM = FpLoadStoreM ? ReadDataWordMuxM : {{LLEN-8{1'b0}}, ByteM[7:0]}; // lbu/flq - only needed when LLEN=128
3'b101: ReadDataM = {{LLEN-16{1'b0}}, HalfwordM[15:0]}; // lhu
3'b110: ReadDataM = {{LLEN-32{1'b0}}, WordM[31:0]}; // lwu
default: ReadDataM = ReadDataWordMuxM; // Shouldn't happen
3'b000: ReadDataM = {{(P.LLEN-8){ByteM[7]}}, ByteM}; // lb
3'b001: ReadDataM = {{P.LLEN-16{HalfwordM[15]|FpLoadStoreM}}, HalfwordM[15:0]}; // lh/flh
3'b010: ReadDataM = {{P.LLEN-32{WordM[31]|FpLoadStoreM}}, WordM[31:0]}; // lw/flw
3'b011: if (P.LLEN >= 64) ReadDataM = {{P.LLEN-64{DblWordM[63]|FpLoadStoreM}}, DblWordM[63:0]}; // ld/fld
else ReadDataM = ReadDataWordMuxM;
3'b100: if (P.LLEN == 128) ReadDataM = FpLoadStoreM ? ReadDataWordMuxM : {{P.LLEN-8{1'b0}}, ByteM[7:0]}; // lbu/flq
else ReadDataM = {{P.LLEN-8{1'b0}}, ByteM[7:0]}; // lbu
3'b101: ReadDataM = {{P.LLEN-16{1'b0}}, HalfwordM[15:0]}; // lhu
3'b110: ReadDataM = {{P.LLEN-32{1'b0}}, WordM[31:0]}; // lwu
default: ReadDataM = ReadDataWordMuxM; // Shouldn't happen
endcase
end else begin:swrmux // 32-bit
// byte mux
always_comb
case(PAdrSwap[1:0])
2'b00: ByteM = ReadDataWordMuxM[7:0];
2'b01: ByteM = ReadDataWordMuxM[15:8];
2'b10: ByteM = ReadDataWordMuxM[23:16];
2'b11: ByteM = ReadDataWordMuxM[31:24];
endcase
// halfword mux
always_comb
case(PAdrSwap[1])
1'b0: HalfwordM = ReadDataWordMuxM[15:0];
1'b1: HalfwordM = ReadDataWordMuxM[31:16];
endcase
// sign extension
always_comb
case(Funct3M)
3'b000: ReadDataM = {{LLEN-8{ByteM[7]}}, ByteM}; // lb
3'b001: ReadDataM = {{LLEN-16{HalfwordM[15]|FpLoadStoreM}}, HalfwordM[15:0]}; // lh/flh
3'b010: ReadDataM = {{LLEN-32{ReadDataWordMuxM[31]|FpLoadStoreM}}, ReadDataWordMuxM[31:0]}; // lw/flw
3'b011: ReadDataM = ReadDataWordMuxM; // fld
3'b100: ReadDataM = {{LLEN-8{1'b0}}, ByteM[7:0]}; // lbu
3'b101: ReadDataM = {{LLEN-16{1'b0}}, HalfwordM[15:0]}; // lhu
default: ReadDataM = ReadDataWordMuxM; // Shouldn't happen
endcase
end
endmodule