hello, i am new to MASM32 and new to assembly language too, currently i am trying to learn this language and working out with the sample program as following and the results generated was "777, 444, -2". Where the "-2" come from? i understand that neg is for negative but why "2" has been generated for eax? please help.
include \masm32\include\masm32rt.inc
include \masm32\macros\macros.asm
includelib \masm32\lib\masm32.lib
includelib \masm32\lib\gdi32.lib
includelib \masm32\lib\user32.lib
includelib \masm32\lib\kernel32.lib
.data
first dd 333
second dd 444
.code
start:
mov eax, first
mov ebx, second
add eax, ebx
print str$(eax), 10,13
print str$(ebx), 10,13
neg eax
print str$(eax), 10,13 ;this line is generating "-2" in result
exit
end start
the print and str$ macros destroy the contents of EAX, ECX, and EDX
many masm32 functions, macros, and windows functions will destroy the contents of those 3 registers
use PUSH and POP around calls - or store it in EBX, ESI, EDI (or even EBP in this case)
Give this a try. Its common to try and use registers as variables but you have to be careful with how you use them as the transient registers are normally overwritten by any other procedure call, both "print" and "ustr$() or sstr$()".
include \masm32\include\masm32rt.inc
; include \masm32\macros\macros.asm
; includelib \masm32\lib\masm32.lib
; includelib \masm32\lib\gdi32.lib
; includelib \masm32\lib\user32.lib
; includelib \masm32\lib\kernel32.lib
.data
first dd 333
second dd 444
result dd 0
.code
start:
; mov eax, first
; mov ebx, second
; add eax, ebx
; print str$(eax), 10,13
; print str$(ebx), 10,13
; neg eax
; print str$(eax), 10,13 ;this line is generating "-2" in result
; exit
mov eax, first
add eax, second
mov result, eax
print ustr$(first),13,10
print ustr$(second),13,10
print ustr$(result),13,10
mov eax, result
neg eax
print sstr$(eax),13,10
inkey
exit
end start
Where does one look for info on stuff like "ustr$() or sstr$()"? I don't recall seeing this stuff in my MASM32 help.
Look in the "macros.asm" file.