Print Page - adding 64bit numbers

Title: adding 64bit numbers
Post by: onlycurious on October 31, 2006, 10:56:20 PM

Hello,

I was wondering how you would add 64 bit numbers in MASM with adc. Can someone show me a few SIMPLE examples ( I am a beginner).

Title: Re: adding 64bit numbers
Post by: GregL on November 01, 2006, 03:04:28 AM

onlycurious,

Hello, and welcome. Here is an example:

Code Select


.386
.MODEL FLAT,STDCALL
OPTION CASEMAP:NONE

INCLUDE windows.inc

INCLUDE kernel32.inc
INCLUDE user32.inc

INCLUDELIB kernel32.lib
INCLUDELIB user32.lib

.DATA

    QW1 QWORD 4294967296
    QW2 QWORD 2147483648
    QW3 QWORD 0

.CODE

start:

    ; Add QWORDs (QW1 + QW2 = QW3)
    mov eax, DWORD PTR [QW1+0]   ; Low DWORD of QW1 
    mov edx, DWORD PTR [QW1+4]   ; High DWORD of QW1 
    
    add eax, DWORD PTR [QW2+0]   ; Low DWORD of QW2 
    adc edx, DWORD PTR [QW2+4]   ; High DWORD of QW2
    
    mov DWORD PTR [QW3+0], eax
    mov DWORD PTR [QW3+4], edx
    
    
    ; Subtract QWORDS (QW1 - QW2 = QW3)
    mov eax, DWORD PTR [QW1+0]   ; Low DWORD of QW1 
    mov edx, DWORD PTR [QW1+4]   ; High DWORD of QW1 

    sub eax, DWORD PTR [QW2+0]   ; Low DWORD of QW2
    sbb edx, DWORD PTR [QW2+4]   ; High DWORD of QW2
    
    mov DWORD PTR [QW3+0], eax
    mov DWORD PTR [QW3+4], edx
    
    INVOKE ExitProcess, 0
    
END start

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General Forums => The Campus => Topic started by: onlycurious on October 31, 2006, 10:56:20 PM