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