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Expression width rework.

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This patch is a major rework of expression elaboration and
evaluation in the compiler, aimed at better compliance with
the IEEE standard.
This commit is contained in:
Martin Whitaker
2011-03-01 18:13:26 -08:00
committed by Stephen Williams
parent 2df6850824
commit 312b4da46f
25 changed files with 1500 additions and 2686 deletions
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verinum.cc
+36 -1
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@@ -287,7 +287,7 @@ verinum::verinum(const verinum&that)
verinum::verinum(const verinum&that, unsigned nbits)
{
string_flag_ = false;
string_flag_ = that.string_flag_ && (that.nbits_ == nbits);
nbits_ = nbits;
bits_ = new V[nbits_];
has_len_ = true;
@@ -591,6 +591,39 @@ verinum pad_to_width(const verinum&that, unsigned width)
return val;
}
verinum cast_to_width(const verinum&that, unsigned width)
{
if (that.has_len() && (that.len() == width))
return that;
if (that.len() >= width)
return verinum(that, width);
if (that.len() == 0) {
verinum val (verinum::V0, width, true);
val.has_sign(that.has_sign());
return val;
}
verinum::V pad = that[that.len()-1];
if (pad==verinum::V1 && !that.has_sign())
pad = verinum::V0;
if (that.has_len() && !that.has_sign()) {
if (pad==verinum::Vx)
pad = verinum::V0;
if (pad==verinum::Vz)
pad = verinum::V0;
}
verinum val(pad, width, true);
for (unsigned idx = 0 ; idx < that.len() ; idx += 1)
val.set(idx, that[idx]);
val.has_sign(that.has_sign());
return val;
}
/*
* This function returns a version of the verinum that has only as
* many bits as are needed to accurately represent the value. It takes
@@ -1097,6 +1130,7 @@ verinum pow(const verinum&left, const verinum&right)
verinum operator << (const verinum&that, unsigned shift)
{
verinum result(verinum::V0, that.len() + shift, that.has_len());
result.has_sign(that.has_sign());
for (unsigned idx = 0 ; idx < that.len() ; idx += 1)
result.set(idx+shift, that.get(idx));
@@ -1119,6 +1153,7 @@ verinum operator >> (const verinum&that, unsigned shift)
verinum result(that.has_sign()? that.get(that.len()-1) : verinum::V0,
that.len() - shift, that.has_len());
result.has_sign(that.has_sign());
for (unsigned idx = shift ; idx < that.len() ; idx += 1)
result.set(idx-shift, that.get(idx));