From 16b0ccf04ca83d76f9bd182e125dd75fa838753a Mon Sep 17 00:00:00 2001 From: David Shah Date: Thu, 18 Jul 2019 11:33:37 +0100 Subject: [PATCH] mul2dsp: Lower partial products always have unsigned inputs Signed-off-by: David Shah --- techlibs/common/mul2dsp.v | 72 ++++++++++++++++++++++----------------- 1 file changed, 41 insertions(+), 31 deletions(-) diff --git a/techlibs/common/mul2dsp.v b/techlibs/common/mul2dsp.v index 7344bc5fe..31469ddeb 100644 --- a/techlibs/common/mul2dsp.v +++ b/techlibs/common/mul2dsp.v @@ -92,20 +92,25 @@ module \$__mul_gen (A, B, Y); genvar i; generate if (A_WIDTH > `DSP_A_MAXWIDTH) begin - localparam n_floored = A_WIDTH/`DSP_A_MAXWIDTH; - localparam n = n_floored + (n_floored*`DSP_A_MAXWIDTH < A_WIDTH ? 1 : 0); +`ifdef DSP_A_SIGNEDONLY + localparam sign_headroom = 1; +`else + localparam sign_headroom = 0; +`endif + localparam n_floored = A_WIDTH/(`DSP_A_MAXWIDTH - sign_headroom); + localparam n = n_floored + (n_floored*(`DSP_A_MAXWIDTH - sign_headroom) < A_WIDTH ? 1 : 0); wire [`DSP_A_MAXWIDTH+B_WIDTH-1:0] partial [n-1:1]; wire [Y_WIDTH-1:0] partial_sum [n-2:0]; localparam int_yw = `MIN(Y_WIDTH, B_WIDTH+`DSP_A_MAXWIDTH); \$__mul_gen #( - .A_SIGNED(A_SIGNED), + .A_SIGNED(0), .B_SIGNED(B_SIGNED), .A_WIDTH(`DSP_A_MAXWIDTH), .B_WIDTH(B_WIDTH), .Y_WIDTH(int_yw) ) mul_slice_first ( - .A(A[`DSP_A_MAXWIDTH-1:0]), + .A({{sign_headroom{1'b0}}, A[`DSP_A_MAXWIDTH-sign_headroom-1:0]}), .B(B), .Y(partial_sum[0][int_yw-1:0]) ); @@ -114,73 +119,78 @@ module \$__mul_gen (A, B, Y); for (i = 1; i < n-1; i=i+1) begin:slice \$__mul_gen #( - .A_SIGNED(A_SIGNED), + .A_SIGNED(0), .B_SIGNED(B_SIGNED), .A_WIDTH(`DSP_A_MAXWIDTH), .B_WIDTH(B_WIDTH), .Y_WIDTH(int_yw) ) mul_slice ( - .A(A[(i+1)*`DSP_A_MAXWIDTH-1:i*`DSP_A_MAXWIDTH]), + .A({{sign_headroom{1'b0}}, A[(i+1)*(`DSP_A_MAXWIDTH-sign_headroom)-1:i*(`DSP_A_MAXWIDTH-sign_headroom)]}), .B(B), .Y(partial[i][int_yw-1:0]) ); //assign partial_sum[i] = (partial[i] << i*`DSP_A_MAXWIDTH) + partial_sum[i-1]; assign partial_sum[i] = { partial[i][int_yw-1:0] - + partial_sum[i-1][Y_WIDTH-1:(i*`DSP_A_MAXWIDTH)], - partial_sum[i-1][(i*`DSP_A_MAXWIDTH)-1:0] + + partial_sum[i-1][Y_WIDTH-1:(i*(`DSP_A_MAXWIDTH-sign_headroom))], + partial_sum[i-1][(i*(`DSP_A_MAXWIDTH-sign_headroom))-1:0] }; end \$__mul_gen #( .A_SIGNED(A_SIGNED), .B_SIGNED(B_SIGNED), - .A_WIDTH(A_WIDTH-(n-1)*`DSP_A_MAXWIDTH), + .A_WIDTH(A_WIDTH-(n-1)*(`DSP_A_MAXWIDTH-sign_headroom)), .B_WIDTH(B_WIDTH), - .Y_WIDTH(`MIN(Y_WIDTH, A_WIDTH-(n-1)*`DSP_A_MAXWIDTH+B_WIDTH)), + .Y_WIDTH(`MIN(Y_WIDTH, A_WIDTH-(n-1)*(`DSP_A_MAXWIDTH-sign_headroom)+B_WIDTH)), ) mul_slice_last ( - .A(A[A_WIDTH-1:(n-1)*`DSP_A_MAXWIDTH]), + .A(A[A_WIDTH-1:(n-1)*(`DSP_A_MAXWIDTH-sign_headroom)]), .B(B), - .Y(partial[n-1][`MIN(Y_WIDTH, A_WIDTH-(n-1)*`DSP_A_MAXWIDTH+B_WIDTH)-1:0]) + .Y(partial[n-1][`MIN(Y_WIDTH, A_WIDTH-(n-1)*(`DSP_A_MAXWIDTH-sign_headroom)+B_WIDTH)-1:0]) ); //assign Y = (partial[n-1] << (n-1)*`DSP_A_MAXWIDTH) + partial_sum[n-2]; assign Y = { - partial[n-1][`MIN(Y_WIDTH, A_WIDTH-(n-1)*`DSP_A_MAXWIDTH+B_WIDTH):0] - + partial_sum[n-2][Y_WIDTH-1:((n-1)*`DSP_A_MAXWIDTH)], - partial_sum[n-2][((n-1)*`DSP_A_MAXWIDTH)-1:0] + partial[n-1][`MIN(Y_WIDTH, A_WIDTH-(n-1)*(`DSP_A_MAXWIDTH-sign_headroom)+B_WIDTH):0] + + partial_sum[n-2][Y_WIDTH-1:((n-1)*(`DSP_A_MAXWIDTH-sign_headroom))], + partial_sum[n-2][((n-1)*(`DSP_A_MAXWIDTH-sign_headroom))-1:0] }; end else if (B_WIDTH > `DSP_B_MAXWIDTH) begin - localparam n_floored = B_WIDTH/`DSP_B_MAXWIDTH; - localparam n = n_floored + (n_floored*`DSP_B_MAXWIDTH < B_WIDTH ? 1 : 0); +`ifdef DSP_B_SIGNEDONLY + localparam sign_headroom = 1; +`else + localparam sign_headroom = 0; +`endif + localparam n_floored = B_WIDTH/(`DSP_B_MAXWIDTH - sign_headroom); + localparam n = n_floored + (n_floored*(`DSP_B_MAXWIDTH - sign_headroom) < B_WIDTH ? 1 : 0); wire [A_WIDTH+`DSP_B_MAXWIDTH-1:0] partial [n-1:1]; wire [Y_WIDTH-1:0] partial_sum [n-2:0]; localparam int_yw = `MIN(Y_WIDTH, A_WIDTH+`DSP_B_MAXWIDTH); \$__mul_gen #( .A_SIGNED(A_SIGNED), - .B_SIGNED(B_SIGNED), + .B_SIGNED(0), .A_WIDTH(A_WIDTH), .B_WIDTH(`DSP_B_MAXWIDTH), .Y_WIDTH(int_yw) ) mul_first ( .A(A), - .B(B[`DSP_B_MAXWIDTH-1:0]), + .B({{sign_headroom{1'b0}}, B[(`DSP_B_MAXWIDTH - sign_headroom)-1:0]}), .Y(partial_sum[0][int_yw-1:0]) ); if (Y_WIDTH > int_yw) - assign partial_sum[0][Y_WIDTH-1:A_WIDTH+`DSP_B_MAXWIDTH]=0; + assign partial_sum[0][Y_WIDTH-1:int_yw]=0; for (i = 1; i < n-1; i=i+1) begin:slice \$__mul_gen #( .A_SIGNED(A_SIGNED), - .B_SIGNED(B_SIGNED), + .B_SIGNED(0), .A_WIDTH(A_WIDTH), .B_WIDTH(`DSP_B_MAXWIDTH), .Y_WIDTH(int_yw) ) mul ( .A(A), - .B(B[(i+1)*`DSP_B_MAXWIDTH-1:i*`DSP_B_MAXWIDTH]), + .B({{sign_headroom{1'b0}}, B[(i+1)*(`DSP_B_MAXWIDTH - sign_headroom)-1:i*(`DSP_B_MAXWIDTH - sign_headroom)]}), .Y(partial[i][int_yw-1:0]) ); //assign partial_sum[i] = (partial[i] << i*`DSP_B_MAXWIDTH) + partial_sum[i-1]; @@ -191,8 +201,8 @@ module \$__mul_gen (A, B, Y); // partial_sum[i-1][A_WIDTH+((i-1)*`DSP_B_MAXWIDTH):0] assign partial_sum[i] = { partial[i][int_yw-1:0] - + partial_sum[i-1][Y_WIDTH-1:(i*`DSP_B_MAXWIDTH)], - partial_sum[i-1][(i*`DSP_B_MAXWIDTH)-1:0] + + partial_sum[i-1][Y_WIDTH-1:(i*(`DSP_B_MAXWIDTH - sign_headroom))], + partial_sum[i-1][(i*(`DSP_B_MAXWIDTH - sign_headroom))-1:0] }; end @@ -200,12 +210,12 @@ module \$__mul_gen (A, B, Y); .A_SIGNED(A_SIGNED), .B_SIGNED(B_SIGNED), .A_WIDTH(A_WIDTH), - .B_WIDTH(B_WIDTH-(n-1)*`DSP_B_MAXWIDTH), - .Y_WIDTH(`MIN(Y_WIDTH, A_WIDTH+B_WIDTH-(n-1)*`DSP_B_MAXWIDTH)) + .B_WIDTH(B_WIDTH-(n-1)*(`DSP_B_MAXWIDTH - sign_headroom)), + .Y_WIDTH(`MIN(Y_WIDTH, A_WIDTH+B_WIDTH-(n-1)*(`DSP_B_MAXWIDTH - sign_headroom))) ) mul_last ( .A(A), - .B(B[B_WIDTH-1:(n-1)*`DSP_B_MAXWIDTH]), - .Y(partial[n-1][`MIN(Y_WIDTH, A_WIDTH+B_WIDTH-(n-1)*`DSP_B_MAXWIDTH)-1:0]) + .B(B[B_WIDTH-1:(n-1)*(`DSP_B_MAXWIDTH - sign_headroom)]), + .Y(partial[n-1][`MIN(Y_WIDTH, A_WIDTH+B_WIDTH-(n-1)*(`DSP_B_MAXWIDTH - sign_headroom))-1:0]) ); // AMD: this came comment out -- looks closer to right answer //assign Y = (partial[n-1] << (n-1)*`DSP_B_MAXWIDTH) + partial_sum[n-2]; @@ -215,9 +225,9 @@ module \$__mul_gen (A, B, Y); // partial[n-1][`DSP_B_MAXWIDTH-1:0] + partial_sum[n-2][A_WIDTH+((n-1)*`DSP_B_MAXWIDTH)-1:A_WIDTH+((n-2)*`DSP_B_MAXWIDTH)], // partial_sum[n-2][A_WIDTH+((n-2)*`DSP_B_MAXWIDTH):0] assign Y = { - partial[n-1][`MIN(Y_WIDTH, A_WIDTH+B_WIDTH-(n-1)*`DSP_B_MAXWIDTH)-1:0] - + partial_sum[n-2][Y_WIDTH-1:((n-1)*`DSP_B_MAXWIDTH)], - partial_sum[n-2][((n-1)*`DSP_B_MAXWIDTH)-1:0] + partial[n-1][`MIN(Y_WIDTH, A_WIDTH+B_WIDTH-(n-1)*(`DSP_B_MAXWIDTH - sign_headroom))-1:0] + + partial_sum[n-2][Y_WIDTH-1:((n-1)*(`DSP_B_MAXWIDTH - sign_headroom))], + partial_sum[n-2][((n-1)*(`DSP_B_MAXWIDTH - sign_headroom))-1:0] }; end else begin -- 2.30.2