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Don't set DAZ on x86 in non-IEEE mode. 

I have no idea why we were using it in the first place; it doesn't match
the behavior of PPC NI flag.
This commit is contained in:
magumagu 2014-06-14 21:22:34 -07:00
parent d7736ac714
commit d905cbfd5d
4 changed files with 4 additions and 41 deletions
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1
Source/Core/Common/CPUDetect.h
View File

@ -77,7 +77,6 @@ struct CPUInfo
// Turn the cpu info into a string we can show
std::string Summarize();
bool IsUnsafe();
private:
// Detects the various cpu features

29
Source/Core/Common/x64CPUDetect.cpp
View File

@ -162,32 +162,10 @@ void CPUInfo::Detect()
if ((cpu_id[2] >> 22) & 1) bMOVBE = true;
if ((cpu_id[2] >> 25) & 1) bAES = true;
// To check DAZ support, we first need to check FXSAVE support.
if ((cpu_id[3] >> 24) & 1)
{
// We can use FXSAVE.
bFXSR = true;
GC_ALIGNED16(u8 fx_state[512]);
memset(fx_state, 0, sizeof(fx_state));
#ifdef _WIN32
#if _M_X86_32
_fxsave(fx_state);
#elif _M_X86_64
_fxsave64(fx_state);
#endif
#else
__asm__("fxsave %0" : "=m" (fx_state));
#endif
// lowest byte of MXCSR_MASK
if ((fx_state[0x1C] >> 6) & 1)
{
// On x86, the FTZ field (supported since SSE1) only flushes denormal _outputs_ to zero,
// now that we checked DAZ support (flushing denormal _inputs_ to zero),
// we can set our generic flag.
bFlushToZero = true;
}
}
// AVX support requires 3 separate checks:
@ -204,6 +182,9 @@ void CPUInfo::Detect()
}
}
}
bFlushToZero = bSSE;
if (max_ex_fn >= 0x80000004) {
// Extract brand string
__cpuid(cpu_id, 0x80000002);
@ -269,7 +250,3 @@ std::string CPUInfo::Summarize()
return sum;
}
bool CPUInfo::IsUnsafe()
{
return !bFlushToZero;
}

11
Source/Core/Common/x64FPURoundMode.cpp
View File

@ -62,8 +62,6 @@ namespace FPURoundMode
{
// OR-mask for disabling FPU exceptions (bits 7-12 in the MXCSR register)
const u32 EXCEPTION_MASK = 0x1F80;
// Denormals-Are-Zero (non-IEEE mode: denormal inputs are set to +/- 0)
const u32 DAZ = 0x40;
// Flush-To-Zero (non-IEEE mode: denormal outputs are set to +/- 0)
const u32 FTZ = 0x8000;
// lookup table for FPSCR.RN-to-MXCSR.RC translation
@ -76,16 +74,9 @@ namespace FPURoundMode
};
u32 csr = simd_rounding_table[rounding_mode];
// Some initial steppings of Pentium 4 CPUs support FTZ but not DAZ.
// They will not flush input operands but flushing outputs only is better than nothing.
static const u32 denormalLUT[2] =
{
FTZ, // flush-to-zero only
FTZ | DAZ, // flush-to-zero and denormals-are-zero (may not be supported)
};
if (non_ieee_mode)
{
csr |= denormalLUT[cpu_info.bFlushToZero];
csr |= FTZ;
}
_mm_setcsr(csr);
}

4
Source/Core/Core/Core.cpp
View File

@ -379,10 +379,6 @@ void EmuThread()
DisplayMessage(cpu_info.brand_string, 8000);
DisplayMessage(cpu_info.Summarize(), 8000);
DisplayMessage(_CoreParameter.m_strFilename, 3000);
if (cpu_info.IsUnsafe() && (NetPlay::IsNetPlayRunning() || Movie::IsRecordingInput() || Movie::IsPlayingInput()))
{
PanicAlertT("Warning: Netplay/movies will desync because your CPU does not support DAZ and Dolphin does not emulate it anymore.");
}
Movie::Init();