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Remerge shifter

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This commit is contained in:
David Harris 2023-03-24 15:53:19 -07:00
commit 11379c6dee
1 changed files with 11 additions and 44 deletions
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src/ieu/shifter.sv
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@ -44,68 +44,37 @@ module shifter (
if (`ZBB_SUPPORTED) begin: rotfunnel32 //rv32 shifter with rotates
always_comb // funnel mux
case({Right, Rotate})
<<<<<<< HEAD
2'b00: Z = {A[31:0], 31'b0};
2'b01: Z = {A[31:0], A[31:1]};
2'b10: Z = {{31{Sign}}, A[31:0]};
2'b11: Z = {A[30:0], A};
endcase
assign TruncAmt = Amt; // shift amount
end else begin // rv64 with rotates
=======
2'b00: z = {A[31:0], 31'b0};
2'b01: z = {A[31:0], A[31:1]};
2'b10: z = {{31{Sign}}, A[31:0]};
2'b11: z = {A[30:0], A[31:0]};
2'b11: Z = {A[30:0], A[31:0]};
endcase
end else begin: norotfunnel32 //rv32 shifter without rotates
always_comb // funnel mux
if (Right) z = {{31{Sign}}, A[31:0]};
else z = {A[31:0], 31'b0};
if (Right) Z = {{31{Sign}}, A[31:0]};
else Z = {A[31:0], 31'b0};
end
assign amttrunc = Amt; // shift amount
assign TruncAmt = Amt; // shift amount
end else begin // rv64
logic [`XLEN-1:0] A64;
mux3 #(64) extendmux({{32{1'b0}}, A[31:0]}, {{32{A[31]}}, A[31:0]}, A, {~W64, SubArith}, A64); // bottom 32 bits are always A[31:0], so effectively a 32-bit upper mux
if (`ZBB_SUPPORTED) begin: rotfunnel64 // rv64 shifter with rotates
>>>>>>> 46e08410112c38dc213a034105f96f6979e1680a
// shifter rotate source select mux
logic [`XLEN-1:0] RotA; // rotate source
mux2 #(`XLEN) rotmux(A, {A[31:0], A[31:0]}, W64, RotA); // W64 rotatons
always_comb // funnel mux
case ({Right, Rotate})
<<<<<<< HEAD
2'b00: Z = {A[63:0],{63'b0}};
2'b01: Z = {RotA, RotA[63:1]};
2'b10: Z = {{63{Sign}}, A[63:0]};
2'b11: Z = {RotA[62:0], RotA};
endcase
assign TruncAmt = W64 ? {1'b0, Amt[4:0]} : Amt; // 32- or 64-bit shift
end
end else begin: norotfunnel
if (`XLEN==32) begin:shifter // RV32
always_comb // funnel mux
if (Right) Z = {{31{Sign}}, A[31:0]};
else Z = {A[31:0], 31'b0};
assign TruncAmt = Amt; // shift amount
end else begin:shifter // RV64
always_comb // funnel mux
if (Right) Z = {{63{Sign}}, A[63:0]};
else Z = {A[63:0], {63'b0}};
assign TruncAmt = W64 ? {1'b0, Amt[4:0]} : Amt; // 32- or 64-bit shift
=======
2'b00: z = {A64[63:0],{63'b0}};
2'b01: z = {RotA[63:0], RotA[63:1]};
2'b10: z = {{63{Sign}}, A64[63:0]};
2'b11: z = {RotA[62:0], RotA[63:0]};
2'b00: Z = {A64[63:0],{63'b0}};
2'b01: Z = {RotA[63:0], RotA[63:1]};
2'b10: Z = {{63{Sign}}, A64[63:0]};
2'b11: Z = {RotA[62:0], RotA[63:0]};
endcase
end else begin: norotfunnel64 // rv64 shifter without rotates
always_comb // funnel mux
if (Right) z = {{63{Sign}}, A64[63:0]};
else z = {A64[63:0], {63'b0}};
>>>>>>> 46e08410112c38dc213a034105f96f6979e1680a
if (Right) Z = {{63{Sign}}, A64[63:0]};
else Z = {A64[63:0], {63'b0}};
end
assign amttrunc = W64 ? {1'b0, Amt[4:0]} : Amt; // 32- or 64-bit shift
assign TruncAmt = W64 ? {1'b0, Amt[4:0]} : Amt; // 32- or 64-bit shift
end
// Opposite offset for right shifts
@ -115,5 +84,3 @@ module shifter (
assign ZShift = Z >> Offset;
assign Y = ZShift[`XLEN-1:0];
endmodule