topic SSE intsruction _mm_insert_epi32 in Intel® ISA Extensions

SSE intsruction _mm_insert_epi32

inteleverywhere — Tue, 13 Jul 2010 11:51:07 GMT

if a register has to be filled with data upto an arbitrary byte/word/dword position is it possible? for example:

if cnt = 0 or 1 or 2 or 3. how can the following be done

for (int i=0; i < cnt; i++)
{
Register = _mm_insert_epi32(Register, i);
Register1 = _mm_slli_si128(Register1, i);
}

Both are being dissallowed since i is required to be a constant value. Is there a workaround?
suppose at run time only two values are to be filled (cnt = 2).

Thanks
Deepak

SSE intsruction _mm_insert_epi32

Arthur_Moroz — Tue, 13 Jul 2010 12:18:37 GMT

Use switch() operator

SSE intsruction _mm_insert_epi32

inteleverywhere — Wed, 14 Jul 2010 06:50:01 GMT

Would that notnegate the optimization? Also is there a way to do a bit shift (not byet shift) on an m128i bit value.

Reg
Deepak

SSE intsruction _mm_insert_epi32

Arthur_Moroz — Wed, 14 Jul 2010 07:16:11 GMT

My dear friend,

1) It is compiler who does optimisation, not you. For compiler switch() is as good optimizable as any other operator.

2) there's no way to bit shift whole register

SSE intsruction _mm_insert_epi32

inteleverywhere — Wed, 14 Jul 2010 12:24:38 GMT

Thank yousir.