audk/EdkCompatibilityPkg/Foundation/Library/EfiCommonLib/Ia32/MultU64x32.c

65 lines
1.7 KiB
C

/*++
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:
MultU64x32.c
Abstract:
64-bit Multiplication function for IA-32
--*/
#include "Tiano.h"
UINT64
MultU64x32 (
IN UINT64 Multiplicand,
IN UINTN Multiplier
)
/*++
Routine Description:
This routine allows a 64 bit value to be multiplied with a 32 bit
value returns 64bit result.
No checking if the result is greater than 64bits
Arguments:
Multiplicand - multiplicand
Multiplier - multiplier
Returns:
Multiplicand * Multiplier
--*/
{
__asm {
mov eax, dword ptr Multiplicand[0]
mul Multiplier
push eax
push edx
mov eax, dword ptr Multiplicand[4]
mul Multiplier
;
; The value in edx stored by second multiplication overflows
; the output and should be discarded. So here we overwrite it
; with the edx value of first multiplication.
;
pop edx
add edx, eax
pop eax
}
}