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techmap: fix shiftx2mux decomposition

This commit is contained in:
Eddie Hung 2020-02-07 11:02:48 -08:00
parent e6bb7b0782
commit affae35847
1 changed files with 6 additions and 8 deletions
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14
techlibs/common/techmap.v
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@ -149,16 +149,14 @@ module _90_shift_shiftx (A, B, Y);
_TECHMAP_CONSTVAL_B_[CLOG2_Y_WIDTH-1:0] == {CLOG2_Y_WIDTH{1'b0}}) begin
// Halve the size of $shift/$shiftx by $mux-ing A according to
// the LSB of B, after discarding the zeroed bits
localparam len = 2**(B_WIDTH-1);
localparam Y_WIDTH2 = 2**CLOG2_Y_WIDTH;
wire [len-1:0] T, F, AA;
wire [(A_WIDTH+Y_WIDTH2*2):0] Apad = {{Y_WIDTH2*2{extbit}}, A};
localparam entries = (A_WIDTH+Y_WIDTH-1)/Y_WIDTH2;
localparam len = Y_WIDTH2 * ((entries+1)/2);
wire [len-1:0] AA;
wire [(A_WIDTH+Y_WIDTH2+Y_WIDTH-1)-1:0] Apad = {{(Y_WIDTH2+Y_WIDTH-1){extbit}}, A};
genvar i;
for (i = 0; i < A_WIDTH; i=i+Y_WIDTH2*2) begin
assign F[i/2 +: Y_WIDTH2] = A[i +: Y_WIDTH2];
assign T[i/2 +: Y_WIDTH2] = Apad[i+Y_WIDTH2 +: Y_WIDTH2];
assign AA[i/2 +: Y_WIDTH2] = B[CLOG2_Y_WIDTH] ? T[i/2 +: Y_WIDTH2] : F[i/2 +: Y_WIDTH2];
end
for (i = 0; i < A_WIDTH; i=i+Y_WIDTH2*2)
assign AA[i/2 +: Y_WIDTH2] = B[CLOG2_Y_WIDTH] ? Apad[i+Y_WIDTH2 +: Y_WIDTH2] : Apad[i +: Y_WIDTH2];
wire [B_WIDTH-2:0] BB = {B[B_WIDTH-1:CLOG2_Y_WIDTH+1], {CLOG2_Y_WIDTH{1'b0}}};
if (_TECHMAP_CELLTYPE_ == "$shift")
$shift #(.A_SIGNED(A_SIGNED), .B_SIGNED(B_SIGNED), .A_WIDTH(len), .B_WIDTH(B_WIDTH-1), .Y_WIDTH(Y_WIDTH)) _TECHMAP_REPLACE_ (.A(AA), .B(BB), .Y(Y));