Revert "x64FPURoundMode: always set x87 precision"

This reverts commit 9de77b7c23.
Setting x87 precision control is only supported on x86 platforms (not ARM or x64).
This commit is contained in:
Shawn Hoffman 2014-05-10 20:21:07 -07:00
parent adbb4c4a0c
commit 700c135386

View File

@ -34,6 +34,10 @@ namespace FPURoundMode
void SetPrecisionMode(PrecisionMode mode)
{
#ifdef _M_X86_32
// 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
@ -43,10 +47,14 @@ namespace FPURoundMode
2 << 8, // 53 bits
3 << 8, // 64 bits
};
unsigned short cw;
asm ("fnstcw %0" : "=m" (cw));
cw = (cw & ~PRECISION_MASK) | precision_table[mode];
asm ("fldcw %0" : : "m" (cw));
unsigned short _mode;
asm ("fstcw %0" : "=m" (_mode));
_mode = (_mode & ~PRECISION_MASK) | precision_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
}