[FFmpeg-devel] [PATCH 1/8] configure: test whether x86 assembler supports AVX-512

James Darnley jdarnley at obe.tv
Mon Oct 30 19:50:40 EET 2017


On 2017-10-30 18:40, James Almer wrote:
> On 10/30/2017 10:08 AM, James Darnley wrote:
>> @@ -5669,6 +5672,7 @@ EOF
>>              elf*) enabled debug && append X86ASMFLAGS $x86asm_debug ;;
>>          esac
>>  
>> +        check_x86asm "vmovdqa32 [eax]{k1}{z}, zmm0"    || disable avx512_external
> 
> Afaik nasm had a lot of bugs in the first few versions with support for
> avx512, so maybe this check should make sure it accepts only NASM 2.13
> or 2.13.01 as a minimum? Assuming it doesn't already, in which case
> nevermind.

I will look into that.  I remember hearing similar things in the past.
However my brief conversation with Gramner last week led to to believe
that 2.13 is good and that this check from x264 is enough.



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