Author Topic: problem with avx instruction  (Read 405 times)

aw27

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Re: problem with avx instruction
« Reply #15 on: November 04, 2017, 11:19:35 PM »
I just tried it, was not expecting it to be so easy, and simply worked on my SandyBridge which does not support AVX2.

sde -- myTest.exe

Siekmanski

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Re: problem with avx instruction
« Reply #16 on: November 04, 2017, 11:57:44 PM »
Hi Jochen,

vpshufd = 512 bit.
vshufpd = 256 bit.

aw27

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Re: problem with avx instruction
« Reply #17 on: November 05, 2017, 12:19:35 AM »
Hi Jochen,

vpshufd = 512 bit.
vshufpd = 256 bit.

vpshufd is AVX2 instruction not AVX-512 instruction. AVX-512 added BW, VL, F extensions.

jj2007

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Re: problem with avx instruction
« Reply #18 on: November 05, 2017, 12:53:19 AM »
I got SDE running, but it seems a bit buggy. Olly stops in the middle of nowhere, etc. However, the simple demo manages to go beyond the "illegal instruction" line when e.g. -skl is specified.

But -slm chokes with SDE-ERROR: Executed instruction not valid for specified chip (SILVERMONT): 0x401201: vmovdqa

Siekmanski

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Re: problem with avx instruction
« Reply #19 on: November 05, 2017, 12:59:10 AM »
aw27, you are right, vpshufd is avx2 and not a 512 bit instruction.  :icon_redface: I'm awake now.

aw27

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Re: problem with avx instruction
« Reply #20 on: November 05, 2017, 01:44:47 AM »
I got SDE running, but it seems a bit buggy. Olly stops in the middle of nowhere, etc. However, the simple demo manages to go beyond the "illegal instruction" line when e.g. -skl is specified.

But -slm chokes with SDE-ERROR: Executed instruction not valid for specified chip (SILVERMONT): 0x401201: vmovdqa

I have not explored much, but is good to know we have something when we have nothing else.
However, I believe it is not compatible with debuggers, because emulators set the processor into single step mode.

"The Silvermont supports the SSE4.2 instruction set, but not AVX and AVX2" - Agner Fog

aw27

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Re: problem with avx instruction
« Reply #21 on: November 05, 2017, 01:46:40 AM »

jj2007

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Re: problem with avx instruction
« Reply #22 on: November 05, 2017, 02:32:49 AM »
I believe it is not compatible with debuggers, because emulators set the processor into single step mode.

Once I got it running with Olly, but after a small change somewhere it stopped working. I see your logic but not sure what it means in practice.

aw27

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Re: problem with avx instruction
« Reply #23 on: November 05, 2017, 03:28:30 AM »
It practice may mean that debugging emulated code may depend on facilities provided by the emulator.
I dont know if you have already read the Help or the Manual. :icon_cool: