fesetround with MSVC x64

Posted by mr grumpy on Stack Overflow See other posts from Stack Overflow or by mr grumpy
Published on 2010-06-05T14:11:17Z Indexed on 2010/06/05 14:12 UTC
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I'm porting some code to Windows (sigh) and need to use fesetround. MSVC doesn't support C99, so for x86 I copied an implementation from MinGW and hacked it about:

 //__asm__ volatile ("fnstcw %0;": "=m" (_cw));
 __asm { fnstcw _cw }
 _cw &= ~(FE_TONEAREST | FE_DOWNWARD | FE_UPWARD | FE_TOWARDZERO);
 _cw |= mode;
 //__asm__ volatile ("fldcw %0;" : : "m" (_cw));
 __asm { fldcw _cw }
 if (has_sse) {
  unsigned int _mxcsr;
  //__asm__ volatile ("stmxcsr %0" : "=m" (_mxcsr));
  __asm { stmxcsr _mxcsr }
  _mxcsr &= ~ 0x6000;
  _mxcsr |= (mode <<  __MXCSR_ROUND_FLAG_SHIFT);
  //__asm__ volatile ("ldmxcsr %0" : : "m" (_mxcsr));
  __asm { ldmxcsr _mxcsr }
 }

The commented lines are the originals for gcc; uncommented for msvc. This appears to work.

However the x64 cl.exe doesn't support inline asm, so I'm stuck. Is there some code out there I can "borrow" for this? (I've spent hours with Google). Or will I have to go on a 2 week detour to learn some assembly and figure out how to get/use MASM? Any advice is appreciated. Thank you.

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