EdkCompatibilityPkg/Foundation/Library/EfiCommonLib/Ia32/MultU64x32.asm

;/*++
;
;Copyright (c) 2006, Intel Corporation. All rights reserved.<BR>
;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
;
;--*/
;---------------------------------------------------------------------------
    .686
    .model  flat,C
    .code

;---------------------------------------------------------------------------

;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
;
;--*/
MultU64x32 PROC

    mov    eax, [esp + 4]; dword ptr Multiplicand[0]
    mul    dword ptr [esp + 0Ch] ; Multiplier
    push   eax
    push   edx
    mov    eax, [esp + 10h]; dword ptr Multiplicand[4]
    mul    dword ptr [esp + 14h]; 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

    ret
MultU64x32 ENDP
	END