kc3-lang/libjpeg-turbo/simd/x86_64/jsimdcpu.asm

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• Hash : 6abd3916
  Author :
  Date : 2016-11-15T08:47:43
  

  Unified CMake-based build system
  
  See #56 for discussion.
  
  Fixes #21, Fixes #29, Fixes #37, Closes #56, Fixes #58, Closes #73
  Obviates #82
  
  See also:
  https://sourceforge.net/p/libjpeg-turbo/feature-requests/5/
  https://sourceforge.net/p/libjpeg-turbo/patches/5/
  

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• simd/x86_64/jsimdcpu.asm

• ;
  ; jsimdcpu.asm - SIMD instruction support check
  ;
  ; Copyright 2009 Pierre Ossman <ossman@cendio.se> for Cendio AB
  ; Copyright (C) 2016, D. R. Commander.
  ;
  ; Based on
  ; x86 SIMD extension for IJG JPEG library
  ; Copyright (C) 1999-2006, MIYASAKA Masaru.
  ; For conditions of distribution and use, see copyright notice in jsimdext.inc
  ;
  ; This file should be assembled with NASM (Netwide Assembler),
  ; can *not* be assembled with Microsoft's MASM or any compatible
  ; assembler (including Borland's Turbo Assembler).
  ; NASM is available from http://nasm.sourceforge.net/ or
  ; http://sourceforge.net/project/showfiles.php?group_id=6208
  ;
  ; [TAB8]
  
  %include "jsimdext.inc"
  
  ; --------------------------------------------------------------------------
      SECTION     SEG_TEXT
      BITS        64
  ;
  ; Check if the CPU supports SIMD instructions
  ;
  ; GLOBAL(unsigned int)
  ; jpeg_simd_cpu_support (void)
  ;
  
      align       32
      global      EXTN(jpeg_simd_cpu_support)
  
  EXTN(jpeg_simd_cpu_support):
      push        rbx
      push        rdi
  
      xor         rdi, rdi                ; simd support flag
  
      ; Check for AVX2 instruction support
      mov         rax, 7
      xor         rcx, rcx
      cpuid
      mov         rax, rbx                ; rax = Extended feature flags
  
      or          rdi, JSIMD_SSE2
      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
  
      xor         rcx, rcx
      xgetbv
      test        rax, 6                  ; O/S does not manage XMM/YMM state
                                          ; using XSAVE
      jz          short .return
  
      or          rdi, JSIMD_AVX2
  
  .return:
      mov         rax, rdi
  
      pop         rdi
      pop         rbx
      ret
  
  ; For some reason, the OS X linker does not honor the request to align the
  ; segment unless we do this.
      align       32
  

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