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AVX2: Verify O/S support for AVX2 before enabling

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This fixes crashes that would occur when attempting to use
libjpeg-turbo's AVX2 extensions on older O/S's (such as Windows XP or
RHEL 5.)  Even if the CPU supports AVX2, the O/S has to also support
saving/restoring YMM registers when switching contexts.
This commit is contained in:
DRC
2016-07-11 20:21:46 -05:00
parent 1be87b6273
commit 3dcb85ee9a
2 changed files with 20 additions and 0 deletions
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10
simd/jsimdcpu-64.asm
View File

@@ -48,6 +48,16 @@ EXTN(jpeg_simd_cpu_support):
or rdi, JSIMD_SSE
test rax, 1<<5 ; bit5:AVX2
jz short .return
; Check for AVX2 O/S support
mov rax, 1
xor rcx, rcx
cpuid
test rcx, 1<<27
jz short .return ; O/S does not support XSAVE
test rcx, 1<<28
jz short .return ; CPU does not support AVX2
or rdi, JSIMD_AVX2
.return:

10
simd/jsimdcpu.asm
View File

@@ -82,6 +82,16 @@ EXTN(jpeg_simd_cpu_support):
mov eax, ebx
test eax, 1<<5 ; bit5:AVX2
jz short .no_avx2
; Check for AVX2 O/S support
mov eax, 1
xor ecx, ecx
cpuid
test ecx, 1<<27
jz short .no_avx2 ; O/S does not support XSAVE
test ecx, 1<<28
jz short .no_avx2 ; CPU does not support AVX2
or edi, JSIMD_AVX2
.no_avx2: