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Improve accuracy of FPU emulation slightly - still no F-Zero improvements :(

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Generic code cleanup.

git-svn-id: https://dolphin-emu.googlecode.com/svn/trunk@3458 8ced0084-cf51-0410-be5f-012b33b47a6e
This commit is contained in:
hrydgard
2009-06-15 21:10:11 +00:00
parent dcae21f692
commit 4dba267775
16 changed files with 355 additions and 383 deletions
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49
Source/Core/Common/Src/MathUtil.cpp
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@ -32,7 +32,7 @@ static const u32 default_sse_state = _mm_getcsr();
namespace MathUtil
{
int ClassifyFP(double dvalue)
int ClassifyDouble(double dvalue)
{
// TODO: Optimize the below to be as fast as possible.
IntDouble value;
@ -79,6 +79,53 @@ int ClassifyFP(double dvalue)
return 0x4;
}
int ClassifyFloat(float fvalue)
{
// TODO: Optimize the below to be as fast as possible.
IntFloat value;
value.f = fvalue;
// 5 bits (C, <, >, =, ?)
// easy cases first
if (value.i == 0) {
// positive zero
return 0x2;
} else if (value.i == 0x80000000) {
// negative zero
return 0x12;
} else if (value.i == 0x7F800000) {
// positive inf
return 0x5;
} else if (value.i == 0xFF800000) {
// negative inf
return 0x9;
} else {
// OK let's dissect this thing.
int sign = value.i >> 31;
int exp = (int)((value.i >> 23) & 0xFF);
if (exp >= 1 && exp <= 254) {
// Nice normalized number.
if (sign) {
return 0x8; // negative
} else {
return 0x4; // positive
}
}
u64 mantissa = value.i & 0x007FFFFF;
if (exp == 0 && mantissa) {
// Denormalized number.
if (sign) {
return 0x18;
} else {
return 0x14;
}
} else if (exp == 0xFF && mantissa /* && mantissa_top*/) {
return 0x11; // Quiet NAN
}
}
return 0x4;
}
} // namespace
void LoadDefaultSSEState()