// Transform $le into $ge by swapping A and B
$ge #(.A_SIGNED(B_SIGNED), .B_SIGNED(A_SIGNED), .A_WIDTH(B_WIDTH), .B_WIDTH(A_WIDTH), .Y_WIDTH(Y_WIDTH)) _TECHMAP_REPLACE_ (.A(B), .B(A), .Y(Y));
end
- else if (A_WIDTH != B_WIDTH) begin
+ else begin
// Perform sign extension on A and B
localparam WIDTH = A_WIDTH > B_WIDTH ? A_WIDTH : B_WIDTH;
wire [WIDTH-1:0] AA = {{(WIDTH-A_WIDTH){A_SIGNED ? A[A_WIDTH-1] : 1'b0}}, A};
wire [WIDTH-1:0] BB = {{(WIDTH-B_WIDTH){B_SIGNED ? B[B_WIDTH-1] : 1'b0}}, B};
- if (_TECHMAP_CELLTYPE_ == "$gt")
- $gt #(.A_SIGNED(A_SIGNED), .B_SIGNED(B_SIGNED), .A_WIDTH(WIDTH), .B_WIDTH(WIDTH), .Y_WIDTH(Y_WIDTH)) _TECHMAP_REPLACE_ (.A(AA), .B(BB), .Y(Y));
- else if (_TECHMAP_CELLTYPE_ == "$ge")
- $ge #(.A_SIGNED(A_SIGNED), .B_SIGNED(B_SIGNED), .A_WIDTH(WIDTH), .B_WIDTH(WIDTH), .Y_WIDTH(Y_WIDTH)) _TECHMAP_REPLACE_ (.A(AA), .B(BB), .Y(Y));
- else
- wire _TECHMAP_FAIL_ = 1;
- end
- else begin
- localparam cmp_width = `LUT_WIDTH/2;
- localparam lcu_width = (A_WIDTH+cmp_width-1)/cmp_width;
- wire [lcu_width-1:0] P, G, CO;
- genvar i, j;
- for (i = 0; i < A_WIDTH; i=i+cmp_width) begin
- wire [cmp_width-1:0] PP, GG;
- for (j = cmp_width-1; j >= 0 && i+j < A_WIDTH; j = j-1) begin
- // Bit-wise equality (xnor) of sign-extended A and B
- assign PP[j] = A[i+j] ^~ B[i+j];
- if (i+j == A_WIDTH-1 && A_SIGNED && B_SIGNED)
- assign GG[j] = ~A[i+j] & B[i+j];
- else if (j == cmp_width-1)
- assign GG[j] = A[i+j] & ~B[i+j];
- else
- // 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[j] = &PP[cmp_width-1:j+1] & (A[i+j] & ~B[i+j]);
- end
- // Propagate only if all bit pairs are equal
- // (inconclusive evidence to say A >= B)
- assign P[i/cmp_width] = &PP;
- // Generate if any bit pairs call for it
- assign G[i/cmp_width] = |GG;
- end
// For $ge operation, start with the assumption that A and B are
// equal (propagating this equality if A and B turn out to be so)
if (_TECHMAP_CELLTYPE_ == "$ge")
- wire CI = 1'b1;
+ localparam CI = 1'b1;
else
- wire CI = 1'b0;
- $lcu #(.WIDTH(lcu_width)) lcu (.P(P), .G(G), .CI(CI), .CO(CO));
- assign Y = CO[lcu_width-1];
+ localparam CI = 1'b0;
+ $__CMP2LCU #(.AB_WIDTH(WIDTH), .AB_SIGNED(A_SIGNED && B_SIGNED), .LCU_WIDTH(0), .BUDGET(`LUT_WIDTH), .CI(CI))
+ _TECHMAP_REPLACE_ (.A(AA), .B(BB), .P(), .G(), .PP(1'b1), .GG(1'b0), .Y(Y));
+ end
+endgenerate
+endmodule
+
+module $__CMP2LCU (A, B, P, G, PP, GG, Y);
+
+parameter AB_WIDTH = 0;
+parameter AB_SIGNED = 0;
+parameter LCU_WIDTH = 0;
+parameter BUDGET = 0;
+parameter CI = 0;
+
+input [AB_WIDTH-1:0] A;
+input [AB_WIDTH-1:0] B;
+input [LCU_WIDTH-1:0] P;
+input [LCU_WIDTH-1:0] G;
+input PP;
+input GG;
+output Y;
+
+parameter [AB_WIDTH-1:0] _TECHMAP_CONSTMSK_A_ = 0;
+parameter [AB_WIDTH-1:0] _TECHMAP_CONSTMSK_B_ = 0;
+
+generate
+ if (AB_WIDTH == 0) begin
+ if (BUDGET < `LUT_WIDTH)
+ $__CMP2LCU #(.AB_WIDTH(AB_WIDTH), .AB_SIGNED(AB_SIGNED), .LCU_WIDTH(LCU_WIDTH+1), .BUDGET(`LUT_WIDTH), .CI(CI))
+ _TECHMAP_REPLACE_ (.A(A), .B(B), .P({P, PP}), .G({G, GG}), .PP(1'b1), .GG(1'b0), .Y(Y));
+ else begin
+ wire [LCU_WIDTH-1:0] CO;
+ $lcu #(.WIDTH(LCU_WIDTH)) _TECHMAP_REPLACE_ (.P(P), .G(G), .CI(CI), .CO(CO));
+ assign Y = CO[LCU_WIDTH-1];
+ end
+ end
+ else begin
+ if (BUDGET < 2)
+ $__CMP2LCU #(.AB_WIDTH(AB_WIDTH), .AB_SIGNED(AB_SIGNED), .LCU_WIDTH(LCU_WIDTH+1), .BUDGET(`LUT_WIDTH), .CI(CI))
+ _TECHMAP_REPLACE_ (.A(A), .B(B), .P({P, PP}), .G({G, GG}), .PP(1'b1), .GG(1'b0), .Y(Y));
+ else begin
+ wire PPP, GGG;
+ // Bit-wise equality (xnor) of A and B
+ assign PPP = A[AB_WIDTH-1] ^~ B[AB_WIDTH-1];
+ if (AB_SIGNED)
+ assign GGG = ~A[AB_WIDTH-1] & B[AB_WIDTH-1];
+ else if (BUDGET == `LUT_WIDTH)
+ assign GGG = A[AB_WIDTH-1] & ~B[AB_WIDTH-1];
+ else
+ // 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 GGG = PP & (A[AB_WIDTH-1] & ~B[AB_WIDTH-1]);
+ $__CMP2LCU #(.AB_WIDTH(AB_WIDTH-1), .AB_SIGNED(1'b0), .LCU_WIDTH(LCU_WIDTH), .BUDGET(BUDGET-2), .CI(CI))
+ _TECHMAP_REPLACE_ (.A(A[AB_WIDTH-2:0]), .B(B[AB_WIDTH-2:0]), .P(P), .G(G),
+ // Propagate only if all bit pairs are equal
+ // (inconclusive evidence to say A >= B)
+ .PP(PP & PPP),
+ // Generate if any bit pairs call for it
+ .GG(GG | GGG),
+ .Y(Y));
+ end
end
endgenerate
endmodule