compilation problem

[Beginner]

 :'(

i m a beginer and not able to compile this program

include WIN.INC


.data

rval sdword ?
xval sdword 26
yval sdword 30
zval sdword 40

.code
main PROC

mov ax,1000h
inc ax
dec ax

;experssion rval= -xval+(yval-zval)

mov eax,xval
reg eax
mov ebx,yval
sub ebx,zval
add eax,ebx
mov rval,eax

;zero flag example

mov cx,1
sub cx,1
mov ax,0ffffh
inc ax

;sign flah example

mov cx,0
sub cx,1
mov ax,7fffh
add ax,2


;carry flag example

mov al,0ffh
add al,1

;overflow flag example

mov al,-127
add al,1
mov al,-128
sub al,1
exit
main ENDP

END main

i m using MASM611 with its IDE (pwb)
please pin point the faults.  :( please help.


Regards,
Beginner

[n-w]

; read Iczelion tutorials:  www.win32asm.cjb.net !!!
; try MASM32 Version 8.2 [32 Bit Macro Assembler]: http://www.codingcrew.de/masm32/index.php
; and RasAsm: http://radasm.visualassembler.com/


.386                     ; that you can use the 386 instructions
.model flat, stdcall                 ; memory modell for win32
option casemap:none            ; case sensitive link
   
;include WIN.INC
include kernel32.inc            ; for api ExitProcess
includelib kernel32.lib


.data

rval sdword ?
xval sdword 26                  
yval sdword 30
zval sdword 40

.code
start:                               ; programm entry point
call main                                 ; call your main proc
                           ; you can also remove "call main" and write the content of your main function there -> I did it
                           ; only this way, because you wanted your code in a function
invoke ExitProcess, 0                                ; exit programm (you can also use ret)
   
main PROC                     

mov ax,1000h
inc ax
dec ax

;experssion rval= -xval+(yval-zval)

mov eax,xval
;reg eax                        ; I never heard of that command
mov ebx,yval
sub ebx,zval
add eax,ebx
mov rval,eax

;zero flag example

mov cx,1
sub cx,1
mov ax,0ffffh
inc ax

;sign flah example

mov cx,0
sub cx,1
mov ax,7fffh
add ax,2


;carry flag example

mov al,0ffh
add al,1

;overflow flag example

mov al,-127
add al,1
mov al,-128
sub al,1
;exit                        ; to exit use ret
ret
main ENDP

;END main
end start                     ; programm code ends here

[pro3carp3]

In addition to n-w's post, the *rval sdword ?* needs to be in the .data? (uninitialized) section:

Code Select Expand


.data?
rval sdword ?

.data
xval sdword 26                 
yval sdword 30
zval sdword 40


[pbrennick]

Change:

reg eax

to:

neg eax

Paul