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#/*++
#
#Copyright (c) 2006, Intel Corporation
#All rights reserved. This program and the accompanying materials
#are licensed and made available under the terms and conditions of the BSD License
#which accompanies this distribution. The full text of the license may be found at
#http://opensource.org/licenses/bsd-license.php
#
#THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
#WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
#
#Module Name:
#
# GetPowerOfTwo.c
#
#Abstract:
#
# Calculates the largest integer that is both
# a power of two and less than Input
#
#--*/
#include "EfiBind.h"
#---------------------------------------------------------------------------
.686:
#.MODEL flat,C
.code:
#---------------------------------------------------------------------------
.globl ASM_PFX(GetPowerOfTwo)
#UINT64
#GetPowerOfTwo (
# IN UINT64 Input
# )
#/*++
#
#Routine Description:
#
# Calculates the largest integer that is both
# a power of two and less than Input
#
#Arguments:
#
# Input - value to calculate power of two
#
#Returns:
#
# the largest integer that is both a power of
# two and less than Input
#
#--*/
ASM_PFX(GetPowerOfTwo):
xorl %eax, %eax
movl %eax, %edx
movl 8(%esp), %ecx # dword ptr Input[4]
jecxz _F
bsrl %ecx, %ecx
btsl %ecx, %edx
jmp _Exit
_F:
movl 4(%esp), %ecx # dword ptr Input[0]
jecxz _Exit
bsrl %ecx, %ecx
btsl %ecx, %eax
_Exit:
ret
#GetPowerOfTwo ENDP
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