The Tor Browser: media/libjpeg/simd/jsimdcpu.asm@b8a032363ba2

Incorporate requested changes from Mozilla in review:
https://bugzilla.mozilla.org/show_bug.cgi?id=1123480#c6

1 ;

     2 ; jsimdcpu.asm - SIMD instruction support check

3 ;

     4 ; Copyright 2009 Pierre Ossman <ossman@cendio.se> for Cendio AB

5 ;

     6 ; Based on

     7 ; x86 SIMD extension for IJG JPEG library

     8 ; Copyright (C) 1999-2006, MIYASAKA Masaru.

     9 ; For conditions of distribution and use, see copyright notice in jsimdext.inc

    10 ;

    11 ; This file should be assembled with NASM (Netwide Assembler),

    12 ; can *not* be assembled with Microsoft's MASM or any compatible

    13 ; assembler (including Borland's Turbo Assembler).

    14 ; NASM is available from http://nasm.sourceforge.net/ or

    15 ; http://sourceforge.net/project/showfiles.php?group_id=6208

    16 ;

    17 ; [TAB8]

    19 %include "jsimdext.inc"

    21 ; --------------------------------------------------------------------------

    22 	SECTION	SEG_TEXT

    23 	BITS	32

    24 ;

    25 ; Check if the CPU supports SIMD instructions

    26 ;

    27 ; GLOBAL(unsigned int)

    28 ; jpeg_simd_cpu_support (void)

    29 ;

    31 	align	16

    32 	global	EXTN(jpeg_simd_cpu_support)

    34 EXTN(jpeg_simd_cpu_support):

    35 	push	ebx

    36 ;	push	ecx		; need not be preserved

    37 ;	push	edx		; need not be preserved

    38 ;	push	esi		; unused

    39 	push	edi

    41 	xor	edi,edi			; simd support flag

    43 	pushfd

    44 	pop	eax

    45 	mov	edx,eax

    46 	xor	eax, 1<<21		; flip ID bit in EFLAGS

    47 	push	eax

    48 	popfd

    49 	pushfd

    50 	pop	eax

    51 	xor	eax,edx

    52 	jz	short .return		; CPUID is not supported

    54 	; Check for MMX instruction support

    55 	xor	eax,eax

    56 	cpuid

    57 	test	eax,eax

    58 	jz	short .return

    60 	xor	eax,eax

    61 	inc	eax

    62 	cpuid

    63 	mov	eax,edx			; eax = Standard feature flags

    65 	test	eax, 1<<23		; bit23:MMX

    66 	jz	short .no_mmx

    67 	or	edi, byte JSIMD_MMX

    68 .no_mmx:

    69 	test	eax, 1<<25		; bit25:SSE

    70 	jz	short .no_sse

    71 	or	edi, byte JSIMD_SSE

    72 .no_sse:

    73 	test	eax, 1<<26		; bit26:SSE2

    74 	jz	short .no_sse2

    75 	or	edi, byte JSIMD_SSE2

    76 .no_sse2:

    78 	; Check for 3DNow! instruction support

    79 	mov	eax, 0x80000000

    80 	cpuid

    81 	cmp	eax, 0x80000000

    82 	jbe	short .return

    84 	mov	eax, 0x80000001

    85 	cpuid

    86 	mov	eax,edx			; eax = Extended feature flags

    88 	test	eax, 1<<31		; bit31:3DNow!(vendor independent)

    89 	jz	short .no_3dnow

    90 	or	edi, byte JSIMD_3DNOW

    91 .no_3dnow:

    93 .return:

    94 	mov	eax,edi

    96 	pop	edi

    97 ;	pop	esi		; unused

    98 ;	pop	edx		; need not be preserved

    99 ;	pop	ecx		; need not be preserved

   100 	pop	ebx

   101 	ret

   103 ; For some reason, the OS X linker does not honor the request to align the

   104 ; segment unless we do this.

   105 	align	16

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