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Fix the calculation of top pad in overlapped part select 

If the part select is too wide in both the top and bottom ends,
this patch fixes the calculation of the top pad. The compiler
was generating too much pad if the select also extended below
the expression.
This commit is contained in:
Stephen Williams 2009-09-22 21:42:59 -07:00
parent 6cc16711db
commit 2c0b105de7
1 changed files with 4 additions and 2 deletions
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6
expr_synth.cc
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@ -1006,11 +1006,12 @@ NetNet* NetESelect::synthesize(Design *des, NetScope*scope, NetExpr*root)
}
long base_val = base_tmp.as_long();
unsigned below_width = 0;
// Any below X bits?
NetNet*below = 0;
if (base_val < 0) {
unsigned below_width = abs(base_val);
below_width = abs(base_val);
base_val = 0;
if (below_width > select_width) {
below_width = select_width;
@ -1033,7 +1034,8 @@ NetNet* NetESelect::synthesize(Design *des, NetScope*scope, NetExpr*root)
} else {
select_width = sub->vector_width() - base_val;
}
unsigned above_width = expr_width() - select_width;
ivl_assert(*this, expr_width() > (select_width+below_width));
unsigned above_width = expr_width() - select_width - below_width;
above = make_const_x(des, scope, above_width);
above->set_line(*this);