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Fix bugs in &= and |= for vvp_vector4_t 

Someone got a bit too creative in reducing the original equations
I wrote to handle this. This patch reverts the previous code and
uses my original equations. This passes for both wide and narrow
vectors. The equations are slightly more complicated, but the old
z2x conversion had some overhead. I would expect the time to be
about the same, but you now get the correct results.
This commit is contained in:
Cary R 2009-06-04 11:02:59 -07:00 committed by Stephen Williams
parent 4479471278
commit 17decb3bb7
1 changed files with 34 additions and 39 deletions
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73
vvp/vvp_net.cc
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@ -1106,26 +1106,26 @@ void vvp_vector4_t::invert()
vvp_vector4_t& vvp_vector4_t::operator &= (const vvp_vector4_t&that)
{
// Make sure that all Z bits are turned into X bits.
change_z2x();
// This is sneaky. The truth table is:
// 00 01 11
// 00 00 00 00
// 01 00 01 11
// 11 00 11 11
// The truth table is:
// 00 01 11 10
// 00 00 00 00 00
// 01 00 01 11 11
// 11 00 11 11 11
// 10 00 11 11 11
if (size_ <= BITS_PER_WORD) {
// Each tmp bit is true if that is 1, X or Z.
unsigned long tmp = that.abits_val_ | that.bbits_val_;
abits_val_ &= that.abits_val_;
bbits_val_ = (bbits_val_ & tmp) | (abits_val_&that.bbits_val_);
unsigned long tmp1 = abits_val_ | bbits_val_;
unsigned long tmp2 = that.abits_val_ | that.bbits_val_;
abits_val_ = tmp1 & tmp2;
bbits_val_ = (tmp1 & that.bbits_val_) | (tmp2 & bbits_val_);
} else {
unsigned words = (size_ + BITS_PER_WORD - 1) / BITS_PER_WORD;
for (unsigned idx = 0; idx < words ; idx += 1) {
unsigned long tmp = that.abits_ptr_[idx]|that.bbits_ptr_[idx];
abits_ptr_[idx] &= that.abits_ptr_[idx];
bbits_ptr_[idx] = (bbits_ptr_[idx]&tmp) | (abits_ptr_[idx]&that.bbits_ptr_[idx]);
unsigned long tmp1 = abits_ptr_[idx] | bbits_ptr_[idx];
unsigned long tmp2 = that.abits_ptr_[idx] |
that.bbits_ptr_[idx];
abits_ptr_[idx] = tmp1 & tmp2;
bbits_ptr_[idx] = (tmp1 & that.bbits_ptr_[idx]) |
(tmp2 & bbits_ptr_[idx]);
}
}
@ -1134,34 +1134,29 @@ vvp_vector4_t& vvp_vector4_t::operator &= (const vvp_vector4_t&that)
vvp_vector4_t& vvp_vector4_t::operator |= (const vvp_vector4_t&that)
{
// Make sure that all Z bits are turned into X bits.
change_z2x();
// This is sneaky.
// The OR is 1 if either operand is 1.
// The OR is 0 if both operants are 0.
// Otherwise, the AND is X. The truth table is:
//
// 00 01 11
// 00 00 01 11
// 01 01 01 01
// 11 11 01 11
// The truth table is:
// 00 01 11 10
// 00 00 01 11 11
// 01 01 01 01 01
// 11 11 01 11 11
// 10 11 01 11 11
if (size_ <= BITS_PER_WORD) {
// Each tmp bit is true if that is 1, X or Z.
unsigned long tmp1 = abits_val_ | bbits_val_;
unsigned long tmp2 = that.abits_val_ | that.bbits_val_;
bbits_val_ = (bbits_val_& ~(that.abits_val_^that.bbits_val_))
| (that.bbits_val_& ~abits_val_);
abits_val_ = tmp1 | tmp2;
unsigned long tmp = abits_val_ | bbits_val_ |
that.abits_val_ | that.bbits_val_;
bbits_val_ = (~abits_val_ | bbits_val_) & that.bbits_val_ |
(~that.abits_val_ | that.bbits_val_) & bbits_val_;
abits_val_ = tmp;
} else {
unsigned words = (size_ + BITS_PER_WORD - 1) / BITS_PER_WORD;
for (unsigned idx = 0; idx < words ; idx += 1) {
unsigned long tmp1 = abits_ptr_[idx] | bbits_ptr_[idx];
unsigned long tmp2 = that.abits_ptr_[idx] | that.bbits_ptr_[idx];
bbits_ptr_[idx] = (bbits_ptr_[idx]& ~(that.abits_ptr_[idx]^that.bbits_ptr_[idx]))
| (that.bbits_ptr_[idx]& ~abits_ptr_[idx]);
abits_ptr_[idx] = tmp1 | tmp2;
unsigned long tmp = abits_ptr_[idx] | bbits_ptr_[idx] |
that.abits_ptr_[idx] | that.bbits_ptr_[idx];
bbits_ptr_[idx] = (~abits_ptr_[idx] | bbits_ptr_[idx]) &
that.bbits_ptr_[idx] |
(~that.abits_ptr_[idx] |
that.bbits_ptr_[idx]) & bbits_ptr_[idx];
abits_ptr_[idx] = tmp;
}
}