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|
;
; 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
%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_FUNCTION(jpeg_simd_cpu_support)
EXTN(jpeg_simd_cpu_support):
push rbx
push rdi
xor rdi, rdi ; simd support flag
; Assume that all x86-64 processors support SSE & SSE2 instructions
or rdi, JSIMD_SSE2
or rdi, JSIMD_SSE
; Check whether CPUID leaf 07H is supported
; (leaf 07H is used to check for AVX2 instruction support)
mov rax, 0
cpuid
cmp rax, 7
jl short .return ; Maximum leaf < 07H
; Check for AVX2 instruction support
mov rax, 7
xor rcx, rcx
cpuid
mov rax, rbx ; rax = Extended feature flags
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
and rax, 6
cmp rax, 6 ; O/S does not manage XMM/YMM state
; using XSAVE
jnz 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
|
