diff options
| -rw-r--r-- | techlibs/xilinx/dsp_map.v | 2 | ||||
| -rw-r--r-- | techlibs/xilinx/synth_xilinx.cc | 8 |
2 files changed, 4 insertions, 6 deletions
diff --git a/techlibs/xilinx/dsp_map.v b/techlibs/xilinx/dsp_map.v index 28e456898..32f570935 100644 --- a/techlibs/xilinx/dsp_map.v +++ b/techlibs/xilinx/dsp_map.v @@ -1,4 +1,4 @@ -module \$__MUL25X18 (input [24:0] A, input [17:0] B, output [42:0] Y); +module \$__MUL25X18 (input signed [24:0] A, input signed [17:0] B, output signed [42:0] Y); wire [47:0] P_48; DSP48E1 #( // Disable all registers diff --git a/techlibs/xilinx/synth_xilinx.cc b/techlibs/xilinx/synth_xilinx.cc index bfce922db..2e2fbbd9d 100644 --- a/techlibs/xilinx/synth_xilinx.cc +++ b/techlibs/xilinx/synth_xilinx.cc @@ -284,12 +284,10 @@ struct SynthXilinxPass : public ScriptPass run("techmap -map +/cmp2lut.v -D LUT_WIDTH=6"); - // The actual behaviour of the Xilinx DSP is a signed 25x18 multiply - // Due to current limitations of mul2dsp, we are actually mapping as a 24x17 - // unsigned multiply with MSBs set to 1'b0 - - if (!nodsp || help_mode) + if (!nodsp || help_mode) { + // NB: Xilinx multipliers are signed only run("techmap -map +/mul2dsp.v -D DSP_A_MAXWIDTH=25 -D DSP_A_SIGNEDONLY=1 -D DSP_B_MAXWIDTH=18 -D DSP_B_SIGNEDONLY=1 -D DSP_NAME=$__MUL25X18"); + } run("alumacc"); run("share"); |