winamp/Src/libvpShared/corelibs/CpuID/Win32/D9xOSSupXMM.asm

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;//==========================================================================
;//
;// THIS CODE AND INFORMATION IS PROVIDED "AS IS" WITHOUT WARRANTY OF ANY
;// KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE
;// IMPLIED WARRANTIES OF MERCHANTABILITY AND/OR FITNESS FOR A PARTICULAR
;// PURPOSE.
;//
;// Copyright (c) 1999 - 2001 On2 Technologies Inc. All Rights Reserved.
;//
;//--------------------------------------------------------------------------
;
; **-Does9xOSSupportXMM
;
; This function will verify if the operating system supports the XMM
; instructions. According to Intel documentation
;
; Intel Architecture
; Software Developer
; Manual
; Volume 1:
; Basic Architecture
;
; The following needs to be true for the OS to suppor the XMM instructions
;
; CR0.EM(bit 2) = 0 (emulation disabled)
; CR4.OSFXSR(bit 9) = 1 (OS supports saving SIMD floating-point state during context
; switches)
;
; * * * N O T E * * * * * * N O T E * * * * * * N O T E * * * * * * N O T E * * * * * * N O T E * * * * * * N O T E * * *
;
; This function will NOT run on windows NT systems. The function reads control registers
; which are protected under Windows NT. If you attempt to run this function under Windows NT a
; protected mode access violation will be generated.
;
; * * * N O T E * * * * * * N O T E * * * * * * N O T E * * * * * * N O T E * * * * * * N O T E * * * * * * N O T E * * *
;
; Assumptions:
; Access to system control registers CR0 and CR4 are not protected
;
; Input:
; None
;
; Output:
; 1 Returned if OS supports XMM instructions
; 0 Returned if OS does not support XMM instructions
;
;
.586
.MODEL flat, SYSCALL, os_dos
.DATA
NAME x86cpuid
PUBLIC Does9xOSSupportXMM_
PUBLIC _Does9xOSSupportXMM
.CODE
; int Does9xOSSupportXMM( void )
Does9xOSSupportXMM_:
_Does9xOSSupportXMM:
push esi ;safety sh*&
push edi
push ebp
push ebx
push ecx
push edx
; check to see if OS supports SIMD instructions
mov edx,cr0
bt edx,2 ; ensure no emulation
jnae NoXMMSupport
mov edx,cr4
bt edx,9 ; OS support SIMD
jnc NoXMMSupport
; we support XMM instructions
mov eax,1
jmp Exit
NoXMMSupport:
; mov eax,0 ; OS does not support XMM instructions
Exit:
pop edx ;safety sh*&
pop ecx
pop ebx
pop ebp
pop edi
pop esi
ret
;************************************************
END