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#
# Copyright (C) 2001-2004 Jakub Jermar
# All rights reserved.
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions
# are met:
#
# - Redistributions of source code must retain the above copyright
#   notice, this list of conditions and the following disclaimer.
# - Redistributions in binary form must reproduce the above copyright
#   notice, this list of conditions and the following disclaimer in the
#   documentation and/or other materials provided with the distribution.
# - The name of the author may not be used to endorse or promote products
#   derived from this software without specific prior written permission.
#
# THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
# IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
# OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
# IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
# INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
# NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
# THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
#

#
# CPU identification functions.
# The code below just interfaces the CPUID instruction.
# CPU recognition logic is contained in higher-level functions.

.text

.global has_cpuid
.global cpuid
.global rdtsc

has_cpuid:
    push %ebx
    
    pushf           # store flags
    popl %eax       # read flags
    movl %eax,%ebx      # copy flags
    btcl $21,%ebx       # swap the ID bit
    pushl %ebx
    popf            # propagate the change into flags
    pushf
    popl %ebx       # read flags    
    andl $(1<<21),%eax  # interested only in ID bit
    andl $(1<<21),%ebx
    xorl %ebx,%eax      # 0 if not supported, 1 if supported
    
    pop %ebx
    ret

# cpuid(__u32 cmd, struct cpu_info *info)
cpuid:
    pushl %ebp
    movl %esp,%ebp
    pusha

    movl 8(%ebp),%eax   # load the command into %eax
    movl 12(%ebp),%esi  # laod the address of the info struct

    cpuid   
    movl %eax,0(%esi)
    movl %ebx,4(%esi)
    movl %ecx,8(%esi)
    movl %edx,12(%esi)
    
    popa
    popl %ebp
    ret

rdtsc:
    rdtsc
    ret