From: Clifford Wolf Date: Thu, 6 Mar 2014 10:54:22 +0000 (+0100) Subject: Improved techmap of shift with wide B inputs X-Git-Tag: yosys-0.3.0~89 X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=d7f29bb23f9bb2c74e02bc1221bcf27efc7ee4dc;p=yosys.git Improved techmap of shift with wide B inputs --- diff --git a/techlibs/common/stdcells.v b/techlibs/common/stdcells.v index fdee26b6f..a51dcb944 100644 --- a/techlibs/common/stdcells.v +++ b/techlibs/common/stdcells.v @@ -165,6 +165,7 @@ parameter B_WIDTH = 1; parameter Y_WIDTH = 1; parameter WIDTH = Y_WIDTH; +localparam BB_WIDTH = $clog2(WIDTH) + 1 < B_WIDTH ? $clog2(WIDTH) + 1 : B_WIDTH; input [A_WIDTH-1:0] A; input [B_WIDTH-1:0] B; @@ -181,11 +182,16 @@ generate .A(A), .Y(chain[WIDTH-1:0]) ); - assign Y = chain[WIDTH*(B_WIDTH+1)-1 : WIDTH*B_WIDTH]; - for (i = 0; i < B_WIDTH; i = i + 1) begin:V + assign Y = chain[WIDTH*(BB_WIDTH+1)-1 : WIDTH*BB_WIDTH]; + for (i = 0; i < BB_WIDTH; i = i + 1) begin:V wire [WIDTH-1:0] unshifted, shifted, result; assign unshifted = chain[WIDTH*i + WIDTH-1 : WIDTH*i]; assign chain[WIDTH*(i+1) + WIDTH-1 : WIDTH*(i+1)] = result; + wire BBIT; + if (i == BB_WIDTH-1 && BB_WIDTH < B_WIDTH) + assign BBIT = |B[B_WIDTH-1:BB_WIDTH-1]; + else + assign BBIT = B[i]; \$__shift #( .WIDTH(WIDTH), .SHIFT(0 - (2 ** (i > 30 ? 30 : i))) @@ -200,7 +206,7 @@ generate .A(unshifted), .B(shifted), .Y(result), - .S(B[i]) + .S(BBIT) ); end endgenerate @@ -218,6 +224,7 @@ parameter B_WIDTH = 1; parameter Y_WIDTH = 1; localparam WIDTH = A_WIDTH > Y_WIDTH ? A_WIDTH : Y_WIDTH; +localparam BB_WIDTH = $clog2(WIDTH) + 1 < B_WIDTH ? $clog2(WIDTH) + 1 : B_WIDTH; input [A_WIDTH-1:0] A; input [B_WIDTH-1:0] B; @@ -225,7 +232,7 @@ output [Y_WIDTH-1:0] Y; genvar i; generate - wire [WIDTH*(B_WIDTH+1)-1:0] chain; + wire [WIDTH*(BB_WIDTH+1)-1:0] chain; \$pos #( .A_SIGNED(A_SIGNED), .A_WIDTH(A_WIDTH), @@ -234,11 +241,16 @@ generate .A(A), .Y(chain[WIDTH-1:0]) ); - assign Y = chain[WIDTH*(B_WIDTH+1)-1 : WIDTH*B_WIDTH]; - for (i = 0; i < B_WIDTH; i = i + 1) begin:V + assign Y = chain[WIDTH*(BB_WIDTH+1)-1 : WIDTH*BB_WIDTH]; + for (i = 0; i < BB_WIDTH; i = i + 1) begin:V wire [WIDTH-1:0] unshifted, shifted, result; assign unshifted = chain[WIDTH*i + WIDTH-1 : WIDTH*i]; assign chain[WIDTH*(i+1) + WIDTH-1 : WIDTH*(i+1)] = result; + wire BBIT; + if (i == BB_WIDTH-1 && BB_WIDTH < B_WIDTH) + assign BBIT = |B[B_WIDTH-1:BB_WIDTH-1]; + else + assign BBIT = B[i]; \$__shift #( .WIDTH(WIDTH), .SHIFT(2 ** (i > 30 ? 30 : i)) @@ -253,7 +265,7 @@ generate .A(unshifted), .B(shifted), .Y(result), - .S(B[i]) + .S(BBIT) ); end endgenerate @@ -271,6 +283,7 @@ parameter B_WIDTH = 1; parameter Y_WIDTH = 1; localparam WIDTH = Y_WIDTH; +localparam BB_WIDTH = $clog2(WIDTH) + 1 < B_WIDTH ? $clog2(WIDTH) + 1 : B_WIDTH; input [A_WIDTH-1:0] A; input [B_WIDTH-1:0] B; @@ -292,6 +305,11 @@ generate wire [WIDTH-1:0] unshifted, shifted, result; assign unshifted = chain[WIDTH*i + WIDTH-1 : WIDTH*i]; assign chain[WIDTH*(i+1) + WIDTH-1 : WIDTH*(i+1)] = result; + wire BBIT; + if (i == BB_WIDTH-1 && BB_WIDTH < B_WIDTH) + assign BBIT = |B[B_WIDTH-1:BB_WIDTH-1]; + else + assign BBIT = B[i]; \$__shift #( .WIDTH(WIDTH), .SHIFT(0 - (2 ** (i > 30 ? 30 : i))) @@ -306,7 +324,7 @@ generate .A(unshifted), .B(shifted), .Y(result), - .S(B[i]) + .S(BBIT) ); end endgenerate @@ -324,6 +342,7 @@ parameter B_WIDTH = 1; parameter Y_WIDTH = 1; localparam WIDTH = A_WIDTH > Y_WIDTH ? A_WIDTH : Y_WIDTH; +localparam BB_WIDTH = $clog2(WIDTH) + 1 < B_WIDTH ? $clog2(WIDTH) + 1 : B_WIDTH; input [A_WIDTH-1:0] A; input [B_WIDTH-1:0] B; @@ -331,7 +350,7 @@ output [Y_WIDTH-1:0] Y; genvar i; generate - wire [WIDTH*(B_WIDTH+1)-1:0] chain; + wire [WIDTH*(BB_WIDTH+1)-1:0] chain; \$pos #( .A_SIGNED(A_SIGNED), .A_WIDTH(A_WIDTH), @@ -342,18 +361,23 @@ generate ); for (i = 0; i < Y_WIDTH; i = i + 1) begin:Y if (i < WIDTH) begin - assign Y[i] = chain[WIDTH*B_WIDTH + i]; + assign Y[i] = chain[WIDTH*BB_WIDTH + i]; end else if (A_SIGNED) begin - assign Y[i] = chain[WIDTH*B_WIDTH + WIDTH-1]; + assign Y[i] = chain[WIDTH*BB_WIDTH + WIDTH-1]; end else begin assign Y[i] = 0; end end - for (i = 0; i < B_WIDTH; i = i + 1) begin:V + for (i = 0; i < BB_WIDTH; i = i + 1) begin:V wire [WIDTH-1:0] unshifted, shifted, result; assign unshifted = chain[WIDTH*i + WIDTH-1 : WIDTH*i]; assign chain[WIDTH*(i+1) + WIDTH-1 : WIDTH*(i+1)] = result; + wire BBIT; + if (i == BB_WIDTH-1 && BB_WIDTH < B_WIDTH) + assign BBIT = |B[B_WIDTH-1:BB_WIDTH-1]; + else + assign BBIT = B[i]; \$__shift #( .WIDTH(WIDTH), .SHIFT(2 ** (i > 30 ? 30 : i)) @@ -368,7 +392,7 @@ generate .A(unshifted), .B(shifted), .Y(result), - .S(B[i]) + .S(BBIT) ); end endgenerate