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authorDavid Shah <dave@ds0.me>2020-12-02 17:08:39 +0000
committerDavid Shah <dave@ds0.me>2020-12-02 17:08:39 +0000
commit264e924abb85424a70daf50662700e3aceada689 (patch)
tree0038b6fe8b1a0c4aa2702678a0457843008274ab /techlibs
parentef5b2777c3a6e3abaa0aa24012bd47e2a2c8a4db (diff)
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nexus: More efficient CO mapping
Signed-off-by: David Shah <dave@ds0.me>
Diffstat (limited to 'techlibs')
-rw-r--r--techlibs/nexus/arith_map.v4
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