Simplified byte write enable logic.

This commit is contained in:
Ross Thompson 2022-03-10 18:13:35 -06:00
parent 396c97fc36
commit d0cf41dbe4
3 changed files with 11 additions and 37 deletions

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@ -106,7 +106,7 @@ module ram #(parameter BASE=0, RANGE = 65535) (
end // initial begin
end // if (FPGA)
swbytemask swbytemask(.HSIZED, .HADDRD(A), .ByteMask(ByteMaskM));
swbytemask swbytemask(.HSIZED, .HADDRD(A[2:0]), .ByteMask(ByteMaskM));
assign initTrans = HREADY & HSELRam & (HTRANS != 2'b00);

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@ -31,34 +31,20 @@
`include "wally-config.vh"
module subwordwrite (
input logic [2:0] HADDRD,
input logic [3:0] HSIZED,
input logic [`XLEN-1:0] HWDATAIN,
output logic [`XLEN-1:0] HWDATA,
input logic [2:0] HADDRD,
input logic [3:0] HSIZED,
input logic [`XLEN-1:0] HWDATAIN,
output logic [`XLEN-1:0] HWDATA,
output logic [`XLEN/8-1:0] ByteWEN
);
);
logic [`XLEN-1:0] WriteDataSubwordDuplicated;
logic [`XLEN-1:0] WriteDataSubwordDuplicated;
logic [(`XLEN/8)-1:0] ByteMaskM;
swbytemask swbytemask(.HSIZED, .HADDRD, .ByteMask(ByteMaskM));
assign ByteWEN = ByteMaskM;
if (`XLEN == 64) begin:sww
logic [7:0] ByteMaskM;
// Compute write mask
assign ByteWEN = ByteMaskM;
always_comb
case(HSIZED[1:0])
2'b00: begin ByteMaskM = 8'b00000000; ByteMaskM[HADDRD[2:0]] = 1; end // sb
2'b01: case (HADDRD[2:1])
2'b00: ByteMaskM = 8'b00000011;
2'b01: ByteMaskM = 8'b00001100;
2'b10: ByteMaskM = 8'b00110000;
2'b11: ByteMaskM = 8'b11000000;
endcase
2'b10: if (HADDRD[2]) ByteMaskM = 8'b11110000;
else ByteMaskM = 8'b00001111;
2'b11: ByteMaskM = 8'b11111111;
endcase
// Handle subword writes
always_comb
case(HSIZED[1:0])
@ -81,18 +67,6 @@ module subwordwrite (
end
end else begin:sww // 32-bit
logic [3:0] ByteMaskM;
// Compute write mask
assign ByteWEN = ByteMaskM;
always_comb
case(HSIZED[1:0])
2'b00: begin ByteMaskM = 4'b0000; ByteMaskM[HADDRD[1:0]] = 1; end // sb
2'b01: if (HADDRD[1]) ByteMaskM = 4'b1100;
else ByteMaskM = 4'b0011;
2'b10: ByteMaskM = 4'b1111;
default: ByteMaskM = 4'b111; // shouldn't happen
endcase
// Handle subword writes
always_comb
case(HSIZED[1:0])

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@ -32,7 +32,7 @@
module swbytemask (
input logic [3:0] HSIZED,
input logic [31:0] HADDRD,
input logic [2:0] HADDRD,
output logic [`XLEN/8-1:0] ByteMask);