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| author | David Shah <dave@ds0.me> | 2020-12-02 22:07:25 +0000 |
|---|---|---|
| committer | GitHub <noreply@github.com> | 2020-12-02 22:07:25 +0000 |
| commit | c3eb346e1ecbed57200458d7bd0fdfd5add88ba4 (patch) | |
| tree | 80a55b4e642f5d96bd52c582b7ce1f8efde90177 | |
| parent | 2945e27020ee36227ecad23f490d3205b21d040b (diff) | |
| parent | 264e924abb85424a70daf50662700e3aceada689 (diff) | |
| download | yosys-c3eb346e1ecbed57200458d7bd0fdfd5add88ba4.tar.gz yosys-c3eb346e1ecbed57200458d7bd0fdfd5add88ba4.tar.bz2 yosys-c3eb346e1ecbed57200458d7bd0fdfd5add88ba4.zip | |
Merge pull request #2467 from YosysHQ/dave/nexus-carry-fix
nexus: More efficient CO mapping
| -rw-r--r-- | techlibs/nexus/arith_map.v | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/techlibs/nexus/arith_map.v b/techlibs/nexus/arith_map.v index fd9d61be3..ce14a15ea 100644 --- a/techlibs/nexus/arith_map.v +++ b/techlibs/nexus/arith_map.v @@ -88,9 +88,9 @@ module _80_nexus_alu (A, B, CI, BI, X, Y, CO); .COUT(FCO[i+2]) ); - assign CO[i] = (AA[i] && BB[i]) || (((i == 0) ? CI : CO[i-1]) && (AA[i] || BB[i])); + assign CO[i] = (AA[i] && BB[i]) || ((Y[i] ^ AA[i] ^ BB[i]) && (AA[i] || BB[i])); if (i+1 < Y_WIDTH) begin - assign CO[i+1] = (AA[i+1] && BB[i+1]) || (CO[i] && (AA[i+1] || BB[i+1])); + assign CO[i + 1] = (AA[i] && BB[i]) || ((Y[i] ^ AA[i] ^ BB[i]) && (AA[i] || BB[i])); assign Y[i+1] = Y1[i]; end end endgenerate |