simple code below
DWORD test_convW2B( LONGLONG v )
{
__m64 mm0 = *(__m64 *)&v;
mm0 = _m_packuswb( mm0, mm0 );
DWORD ret = _m_to_int( mm0 );
_m_empty();
return( ret );
}
compiler: running on IA-32, Version 12.0.1.096 Build 20101116
with -O3 -Ob2 -Oi -Ot -Oy -Qip -FAs
generates asm code below
movq mm0, QWORD PTR [4+esp]
emms
packuswb mm0, mm0
movd eax, mm0
ret
this instruction position of EMMS is wrong.
it must be
movq mm0, QWORD PTR [4+esp]
packuswb mm0, mm0
movd eax, mm0
emms
ret
i couldn't find out a way how to avoid this problem.
