1 ;/*++ 2 ; 3 ;Copyright (c) 2006, Intel Corporation. All rights reserved.<BR> 4 ;This program and the accompanying materials 5 ;are licensed and made available under the terms and conditions of the BSD License 6 ;which accompanies this distribution. The full text of the license may be found at 7 ;http://opensource.org/licenses/bsd-license.php 8 ; 9 ;THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS, 10 ;WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED. 11 ; 12 ;Module Name: 13 ; 14 ; MultU64x32.c 15 ; 16 ;Abstract: 17 ; 18 ; 64-bit Multiplication function for IA-32 19 ; 20 ;--*/ 21 ;--------------------------------------------------------------------------- 22 .686 23 .model flat,C 24 .code 25 26 ;--------------------------------------------------------------------------- 27 28 ;UINT64 29 ;MultU64x32 ( 30 ; IN UINT64 Multiplicand, 31 ; IN UINTN Multiplier 32 ; ) 33 ;/*++ 34 ; 35 ;Routine Description: 36 ; 37 ; This routine allows a 64 bit value to be multiplied with a 32 bit 38 ; value returns 64bit result. 39 ; No checking if the result is greater than 64bits 40 ; 41 ;Arguments: 42 ; 43 ; Multiplicand - multiplicand 44 ; Multiplier - multiplier 45 ; 46 ;Returns: 47 ; 48 ; Multiplicand * Multiplier 49 ; 50 ;--*/ 51 MultU64x32 PROC 52 53 mov eax, [esp + 4]; dword ptr Multiplicand[0] 54 mul dword ptr [esp + 0Ch] ; Multiplier 55 push eax 56 push edx 57 mov eax, [esp + 10h]; dword ptr Multiplicand[4] 58 mul dword ptr [esp + 14h]; Multiplier 59 ; 60 ; The value in edx stored by second multiplication overflows 61 ; the output and should be discarded. So here we overwrite it 62 ; with the edx value of first multiplication. 63 ; 64 pop edx 65 add edx, eax 66 pop eax 67 68 ret 69 MultU64x32 ENDP 70 END 71
