cpuid.h

来自「开放源码的编译器open watcom 1.6.0版的源代码」· C头文件 代码 · 共 66 行

/****************************************************************************
*
*                            Open Watcom Project
*
*    Portions Copyright (c) 1983-2002 Sybase, Inc. All Rights Reserved.
*
*  ========================================================================
*
*    This file contains Original Code and/or Modifications of Original
*    Code as defined in and that are subject to the Sybase Open Watcom
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* Description:  WHEN YOU FIGURE OUT WHAT THIS FILE DOES, PLEASE
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****************************************************************************/


extern int cpu_id( void );

#pragma aux cpu_id = \
    "           .586            " \
    "           pushfd          " /* save flags register */ \
    "           mov eax,3       " /* assume 386 */ \
    "           pushfd          " \
    "           pop ebx         " \
    "           xor ebx,040000h " /* change AC bit */ \
    "           push ebx        " \
    "           popfd           " \
    "           pushfd          " \
    "           pop edx         " \
    "           xor ebx, edx    " \
    "           test ebx,040000h" /* check if AC bit changed */ \
    "           jne done        " \
    "           mov eax,4       " /* at least a 486 */ \
    "           pushfd          " \
    "           pop ebx         " \
    "           xor ebx,200000h " /* change ID bit */ \
    "           push ebx        " \
    "           popfd           " \
    "           pushfd          " \
    "           pop edx         " \
    "           xor ebx, edx    " \
    "           test ebx,200000h" /* check if ID bit changed */ \
    "           jne done        " \
    "           mov eax,1       " /* want version information */ \
    "           cpuid           " \
    "           shr eax,8       " /* get family bits into bottom of eax */ \
    "           and eax,0Fh     " \
    " done:     popfd           " \
    modify exact [ ebx edx eax ] value [eax];