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October 28, 2014 Using imm8 through inline assembler | ||||
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I'm trying to write (in DMD) the assembler that handles the function : __m256i _mm256_permute4x64_epi64(__m256i a, in int M); This translates to vpermq The closest thing I could find in DMD assembly is VPERMILPS, which is called with: asm { vpermilps YMM0, YMM1, IMM8; } However, I cannot find out how to make IMM8 with `in int M`. I can convert int -> short[4] -> ubyte, but I can't move it into imm8 asm { mov imm8, ub; } <-- Fails. Does anyone have an idea of what this is and how to define it? Thanks in advance. |
October 28, 2014 Re: Using imm8 through inline assembler | ||||
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Posted in reply to Etienne | On Tuesday, 28 October 2014 at 21:05:15 UTC, Etienne wrote: > I'm trying to write (in DMD) the assembler that handles the function : > > __m256i _mm256_permute4x64_epi64(__m256i a, in int M); > > This translates to vpermq > > The closest thing I could find in DMD assembly is VPERMILPS, which is called with: > > asm { vpermilps YMM0, YMM1, IMM8; } > > However, I cannot find out how to make IMM8 with `in int M`. I can convert int -> short[4] -> ubyte, but I can't move it into imm8 > > asm { mov imm8, ub; } <-- Fails. > > > Does anyone have an idea of what this is and how to define it? Disclaimer: I only know a little basic X86 assembler, and I'm just going of the first google result for "vpermilps" [1]. "imm8" is not a register. "imm" stands for "immediate", i.e. a constant, hard-coded value. E.g.: asm { vpermilps YMM0, YMM1, 0 /* no idea what would be a meaningful value */; } There are variants of vpermilps that work on three registers. The third register is a XMM/YMM register, too, then. E.g.: asm { vpermilps YMM0, YMM1, YMM2; } I think my CPU doesn't have AVX, so I can't test anything beyond compiling. When running all I get is "Illegal instruction (core dumped)". [1] http://www.felixcloutier.com/x86/VPERMILPS.html |
October 28, 2014 Re: Using imm8 through inline assembler | ||||
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Posted in reply to anonymous | > "imm8" is not a register. "imm" stands for "immediate", i.e. a
> constant, hard-coded value. E.g.:
>
> asm { vpermilps YMM0, YMM1, 0 /* no idea what would be a
> meaningful value */; }
>
Oh, well, that makes sense. This means I should use string mixins to insert the actual value.
I couldn't run AVX2 either, I have to work on this blindly until I get my hands on a new Xeon E5-2620 3rd generation processor. :/
> I think my CPU doesn't have AVX, so I can't test anything beyond
compiling. When running all I get is "Illegal instruction (core
dumped)".
My error is vmovdqu, I get:
Error: AVX vector types not supported
Anyone know what this is? I can't find a reference to it in the dmd compiler code.
Also, 'vpunpcklqdq _ymm, _ymm, _ymm' is undefined in DMD, so I get : avx2.d(23): Error: bad type/size of operands 'vpunpcklqdq'
Looks like abunch of work is needed to get avx2 working...
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