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Performance fix for new $__lcu techmap rule

This commit is contained in:
Clifford Wolf 2014-08-18 00:27:54 +02:00
parent 4b3834e0cc
commit 6f33fc3e87
1 changed files with 5 additions and 7 deletions
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12
techlibs/common/techmap.v
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@ -293,7 +293,7 @@ module \$__lcu (P, G, CI, CO);
output reg [WIDTH:0] CO;
integer i, j, k;
integer i, j;
reg [WIDTH-1:0] p, g;
wire [1023:0] _TECHMAP_DO_ = "proc; opt -fast";
@ -312,18 +312,16 @@ module \$__lcu (P, G, CI, CO);
// Main tree
for (i = 1; i <= $clog2(WIDTH); i = i+1) begin
for (j = 2**i - 1; j < WIDTH; j = j + 2**i) begin
k = j - 2**(i-1);
g[j] = g[j] | p[j] & g[k];
p[j] = p[j] & p[k];
g[j] = g[j] | p[j] & g[j - 2**(i-1)];
p[j] = p[j] & p[j - 2**(i-1)];
end
end
// Inverse tree
for (i = $clog2(WIDTH); i > 0; i = i-1) begin
for (j = 2**i + 2**(i-1) - 1; j < WIDTH; j = j + 2**i) begin
k = j - 2**(i-1);
g[j] = g[j] | p[j] & g[k];
p[j] = p[j] & p[k];
g[j] = g[j] | p[j] & g[j - 2**(i-1)];
p[j] = p[j] & p[j - 2**(i-1)];
end
end
end