mirror of https://github.com/acidanthera/audk.git
69 lines
1.8 KiB
ArmAsm
69 lines
1.8 KiB
ArmAsm
#/*++
|
|
#
|
|
#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
|
|
|