output [Y_WIDTH-1:0] Y;
parameter _TECHMAP_CELLTYPE_ = "";
-localparam gt_width = `LUT_WIDTH/2;
+localparam cmp_width = `LUT_WIDTH/2;
generate
- if (_TECHMAP_CELLTYPE_ == "" || (A_WIDTH <= gt_width || B_WIDTH <= gt_width))
+ if (_TECHMAP_CELLTYPE_ == "" || (A_WIDTH <= cmp_width || B_WIDTH <= cmp_width))
wire _TECHMAP_FAIL_ = 1;
else if (_TECHMAP_CELLTYPE_ == "$lt") begin
// Transform $lt into $gt by swapping A and B
- $gt #(.A_SIGNED(B_SIGNED), .B_SIGNED(A_SIGNED), .A_WIDTH(B_WIDTH), .B_WIDTH(A_WIDTH), .Y_WIDTH(Y_WIDTH)) _TECHMAP_REPLACE_ (.A(B), .B(A), .Y(Y));
+ $gt #(.A_SIGNED(B_SIGNED), .B_SIGNED(A_SIGNED), .A_WIDTH(B_WIDTH), .B_WIDTH(A_WIDTH), .Y_WIDTH(Y_WIDTH)) _TECHMAP_REPLACE_ (.A(B), .B(A), .Y(Y));
end
else if (_TECHMAP_CELLTYPE_ == "$le") begin
// Transform $le into $ge by swapping A and B
- $ge #(.A_SIGNED(B_SIGNED), .B_SIGNED(A_SIGNED), .A_WIDTH(B_WIDTH), .B_WIDTH(A_WIDTH), .Y_WIDTH(Y_WIDTH)) _TECHMAP_REPLACE_ (.A(B), .B(A), .Y(Y));
+ $ge #(.A_SIGNED(B_SIGNED), .B_SIGNED(A_SIGNED), .A_WIDTH(B_WIDTH), .B_WIDTH(A_WIDTH), .Y_WIDTH(Y_WIDTH)) _TECHMAP_REPLACE_ (.A(B), .B(A), .Y(Y));
end
else begin
// Perform sign extension on A and B
wire [WIDTH-1:0] BB = {{(WIDTH-B_WIDTH){B_SIGNED ? B[B_WIDTH-1] : 1'b0}}, B};
// Compute width of $lcu/carry-chain cell
- localparam lcu_width = (WIDTH+gt_width-1)/gt_width;
+ localparam lcu_width = (WIDTH+cmp_width-1)/cmp_width;
wire [lcu_width-1:0] P, G, CO;
genvar i, j;
integer j;
- for (i = 0; i < WIDTH; i=i+gt_width) begin
- wire [gt_width-1:0] PP, GG;
- if (i < WIDTH-gt_width) begin
+ for (i = 0; i < WIDTH; i=i+cmp_width) begin
+ wire [cmp_width-1:0] PP, GG;
+ if (i < WIDTH-cmp_width) begin
// Bit-wise equality (xnor) of sign-extended A and B
- assign PP = AA[i +: gt_width] ^~ BB[i +: gt_width];
+ assign PP = AA[i +: cmp_width] ^~ BB[i +: cmp_width];
// Priority "encoder" that checks A[i] == 1'b1 && B[i] == 1'b0
// from MSB down, deferring to less significant bits if the
// MSBs are equal
- assign GG[gt_width-1] = AA[i+gt_width-1] & ~BB[i+gt_width-1];
- for (j = gt_width-2; j >= 0; j=j-1)
- assign GG[j] = &PP[gt_width-1:j+1] & (AA[i+j] & ~BB[i+j]);
+ assign GG[cmp_width-1] = AA[i+cmp_width-1] & ~BB[i+cmp_width-1];
+ for (j = cmp_width-2; j >= 0; j=j-1)
+ assign GG[j] = &PP[cmp_width-1:j+1] & (AA[i+j] & ~BB[i+j]);
// Propagate only if all bits are equal
// (inconclusive evidence to say A >= B)
- assign P[i/gt_width] = &PP;
+ assign P[i/cmp_width] = &PP;
// Generate if any pairs call for it
- assign G[i/gt_width] = |GG;
+ assign G[i/cmp_width] = |GG;
end
else begin
assign PP = AA[WIDTH-1:i] ^~ BB[WIDTH-1:i];
assign GG[WIDTH-i-1] = AA[WIDTH-1] & ~BB[WIDTH-1];
for (j = WIDTH-i-2; j >= 0; j=j-1)
assign GG[j] = &PP[WIDTH-i-1:j+1] & (AA[i+j] & ~BB[i+j]);
- assign P[i/gt_width] = &PP[WIDTH-i-1:0];
- assign G[i/gt_width] = |GG[WIDTH-i-1:0];
+ assign P[i/cmp_width] = &PP[WIDTH-i-1:0];
+ assign G[i/cmp_width] = |GG[WIDTH-i-1:0];
end
end
// For $ge operation, start with the assumption that A and B are