dolphin/Source/Core/Common/Src/x64FPURoundMode.cpp

108 lines
2.4 KiB
C++

// Copyright 2013 Dolphin Emulator Project
// Licensed under GPLv2
// Refer to the license.txt file included.
#include "Common.h"
#include "FPURoundMode.h"
#ifndef _WIN32
static const unsigned short FPU_ROUND_NEAR = 0 << 10;
static const unsigned short FPU_ROUND_DOWN = 1 << 10;
static const unsigned short FPU_ROUND_UP = 2 << 10;
static const unsigned short FPU_ROUND_CHOP = 3 << 10;
static const unsigned short FPU_ROUND_MASK = 3 << 10;
#include <xmmintrin.h>
#endif
const u32 MASKS = 0x1F80; // mask away the interrupts.
const u32 DAZ = 0x40;
const u32 FTZ = 0x8000;
namespace FPURoundMode
{
// Get the default SSE states here.
static u32 saved_sse_state = _mm_getcsr();
static const u32 default_sse_state = _mm_getcsr();
void SetRoundMode(u32 mode)
{
// Set FPU rounding mode to mimic the PowerPC's
#ifdef _M_IX86
// This shouldn't really be needed anymore since we use SSE
#ifdef _WIN32
const int table[4] =
{
_RC_NEAR,
_RC_CHOP,
_RC_UP,
_RC_DOWN
};
_set_controlfp(_MCW_RC, table[mode]);
#else
const unsigned short table[4] =
{
FPU_ROUND_NEAR,
FPU_ROUND_CHOP,
FPU_ROUND_UP,
FPU_ROUND_DOWN
};
unsigned short _mode;
asm ("fstcw %0" : "=m" (_mode) : );
_mode = (_mode & ~FPU_ROUND_MASK) | table[mode];
asm ("fldcw %0" : : "m" (_mode));
#endif
#endif
}
void SetPrecisionMode(u32 mode)
{
#ifdef _M_IX86
// sets the floating-point lib to 53-bit
// PowerPC has a 53bit floating pipeline only
// eg: sscanf is very sensitive
#ifdef _WIN32
_control87(_PC_53, MCW_PC);
#else
const unsigned short table[4] = {
0 << 8, // FPU_PREC_24
2 << 8, // FPU_PREC_53
3 << 8, // FPU_PREC_64
3 << 8, // FPU_PREC_MASK
};
unsigned short _mode;
asm ("fstcw %0" : "=m" (_mode));
_mode = (_mode & ~table[3]) | table[mode];
asm ("fldcw %0" : : "m" (_mode));
#endif
#else
//x64 doesn't need this - fpu is done with SSE
//but still - set any useful sse options here
#endif
}
void SetSIMDMode(u32 mode)
{
static const u32 ssetable[4] =
{
(0 << 13) | MASKS,
(3 << 13) | MASKS,
(2 << 13) | MASKS,
(1 << 13) | MASKS,
};
u32 csr = ssetable[mode];
_mm_setcsr(csr);
}
void SaveSIMDState()
{
saved_sse_state = _mm_getcsr();
}
void LoadSIMDState()
{
_mm_setcsr(saved_sse_state);
}
void LoadDefaultSIMDState()
{
_mm_setcsr(default_sse_state);
}
}