For God's Sake ... Help !!!!!

[ZaidGS]

i am starting to learn assembly,
but i am getting really frustrated !!!!!!!!!!!

the problem is with the assembler !!!

nthn seems right !!!

i have downloaded four assemblers so far, but
none seems to work fine !!!!

one is called a86, masm32v8, RadASM, AsmStudio.

well, all the examples wont assemble, syntax error are found.
if nnot link errors occur, especially "unresolved external symbol _mainCRTStartup"
this sucks guys !!!!!!

ok, lets say i just want the example in the FAQ to work:

	jmp	start
Message1	db "Hello World!$"

start:
	mov	ah, 09h
	mov	dx, offset Message1
	int	21h

	mov	ax, 4c00h
	int	21h

well, it worked once on a86, but nthn else worked.
also i am using RadASM most of the time,
how can i get that code to work on that assembler ???!

for god's sake just one thing that assembles and link !!!

i am taking aoa.pdf tutorial seriously, but cannot make any example
work ... what is the recommended assembler for that tutorial ???

[Darkwraith]

Each assembler has its little quirks. Some of NASM's syntax is different than MASM's syntax.

However, I do remember that this topic has been discussed in this forum already. Do a search in this forum for some of that code. (Sorry, I cannot remember the thread off the top of my mind. )

[ZaidGS]

well, i searched,
but..........
all the topics tell you there are different assemblers,
but none talked about "specific" syntax or instructions for
a specific assembler !!!!
or a specific assembler for a specific tutorial !!!!!!!

specifically, i'd like info for
art of assembly tutorial,
and\or RadASM (it specifies more than one assembler, i use masm and choose console application).

information about anyother tutorial or assembler appreciated
(but please just be ""specific"" )

also, any idea of how to specify __mainCRTStartup
to avoid linking problems (using RadASM/masm, to be specific )
(i guess this the same when you compile C++ code without
main() fuction, correct me if i am wrong )

[ZaidGS]

ok, maybe darkwraith talked about http://www.vbforums.com/showthread.p...hreadid=171253 thread.
i didnt find it very helpfull
ok, maybe its worth it to show some of my attempts to make it
work.

this code is for a windows application example found
in RadASM:

.386
.model flat, stdcall  ;32 bit memory model
option casemap :none  ;case sensitive

include Test Project.inc
;--------------------------------------------------------------------------------
;If you are doing source code breakpoints, this file must be included.
;You don't need it with int 3 breakpoints.
include \radasm\masm\inc\radbg.inc
;--------------------------------------------------------------------------------

.code

start:

	invoke GetModuleHandle,NULL
	mov		hInstance,eax

    invoke InitCommonControls
	invoke DialogBoxParam,hInstance,IDD_DIALOG1,NULL,addr DlgProc,NULL
	invoke ExitProcess,0

;########################################################################

DlgProc proc hWin:HWND,uMsg:UINT,wParam:WPARAM,lParam:LPARAM

	mov		eax,uMsg
	.if eax==WM_INITDIALOG

	.elseif eax==WM_COMMAND
		pushad
		invoke GetParent,0
		mov		eax,1
		invoke SetLastError,0
		mov		ebx,2
		mov		ecx,3
		xor		ebx,ebx
		popad
	.elseif eax==WM_CLOSE
		pushad
		xor		eax,eax
		dec		eax
		add		eax,2
		mov		ebx,2
		mov		ecx,3
		mov		edx,4
		mov		esi,5
		mov		edi,6
		mov		ebp,7
		popad
		invoke EndDialog,hWin,0
	.elseif eax==WM_SIZING
		mov		edx,lParam
		mov		eax,[edx].RECT.top
		add		eax,204
		mov		[edx].RECT.bottom,eax
		mov		eax,[edx].RECT.right
		sub		eax,[edx].RECT.left
		.if eax>400
			mov		eax,[edx].RECT.left
			add		eax,400
			mov		[edx].RECT.right,eax
;			mov		eax,TRUE
;			ret
		.endif
	.else
		mov		eax,FALSE
		ret
	.endif
	mov		eax,TRUE
	ret

DlgProc endp

end start

this code only has a button on a form, and i see nothing that happen
when i click on it.

accordingly, i tried to make a code like it:

; This is a simple program which displays "Hello World!"
; on the screen.
 
.386
.model flat, stdcall  ;32 bit memory model
option casemap :none  ;case sensitive

Message db "Hello World!$" 	; message to be display

.code 

start:

mov edx,OFFSET Message 	; offset of Message is in DX 
mov eax,SEG Message 	; segment of Message is in AX
mov ds,ax 		; DS:DX points to string 

mov ah,9 		; function 9 - display string 
int 21h 		; call dos service 
mov ax,4c00h 		; return to dos DOS 
int 21h 

END start 		;end here

but the line:
Message db "Hello World!$" ; message to be display
produced this error:
proj3.asm(9) : error A2034: must be in segment block

so i made this code:

; This is a simple program which displays "Hello World!"
; on the screen.
 
.386
.model flat, stdcall  ;32 bit memory model
option casemap :none  ;case sensitive

;Message db "Hello World!$" 	; message to be display

.code 

start:

mov edx,OFFSET "Hello World!$" 	; offset of Message is in DX 
mov eax,SEG "Hello World!$" 	; segment of Message is in AX
mov ds,ax 		; DS:DX points to string 

mov ah,9 		; function 9 - display string 
int 21h 		; call dos service 
mov ax,4c00h 		; return to dos DOS 
int 21h 

END start 		;end here

replacing the db command with the text itself.
but the lines:
mov edx,OFFSET "Hello World!$" ; offset of Message is in DX
mov eax,SEG "Hello World!$" ; segment of Message is in AX

produced this error each:
proj3.asm(15) : error A2084: constant value too large
proj3.asm(16) : error A2084: constant value too large


for my good the only code that assembles that i could make was:

END

it didnt even link, because :
LINK : error LNK2001: unresolved external symbol _mainCRTStartup
proj2.exe : fatal error LNK1120: 1 unresolved externals



could you with the help of the example make one that works ???

PS: i wrote that code for console application, not windows application.

[ZaidGS]

today, i tried:

; This is a simple program which displays "Hello World!"
; on the screen.
 
.386
.model flat, stdcall  ;32 bit memory model
option casemap :none  ;case sensitive

.data
Message1 db "Hello World!$" 	; message to be display

.code 

start:

	mov	ah, 09h
	mov	edx, offset Message1
	int	21h

	mov	ax, 4c00h
	int	21h


END start 		;end here

which assembled, and linked, but produced the suck
message, known on windows,

proj.exe encountered a problem and needs to close,
we are sorry for the inconvieniece

i chose debug (in c++ dessambler):
it said:

Unhandled exception at 0x00401017 in proj3.exe: 0xC0000005: Access violation reading location 0xffffffff.

the disassembler showed:

@ILT+0(_start):
00401005 jmp _start (401010h)
0040100A int 3
0040100B int 3
0040100C int 3
0040100D int 3
0040100E int 3
0040100F int 3
_start:
00401010 mov ah,9
00401012 mov edx,offset _start-10h (404000h)
00401017 int 21h ;this line produced error
00401019 mov ax,offset _start+0Bh (40101Bh)
0040101D int 21h
0040101F int 3
00401020 int 3
00401021 int 3
00401022 int 3
00401023 int 3
00401024 int 3

with (int 21h) that produced the error.
what gives ??

[ZaidGS]

this is another odd thing that happened to me:

i considered another tutorial,
which for the good's sake used the "debug" in MS-dos
for its first example.

one of its examples was to type in command prompt:
debug
a 100

mov ax,2
mov bx,4
add ax,bx
nop

then use ""t"" to trace the process.

that worked fine.

i tried to use that for the RadASM/masm:

.386
.model flat, stdcall  ;32 bit memory model
option casemap :none  ;case sensitive

.code
start:
mov ax,2
mov bx,4
add ax,bx
nop
END start

and this problem happened as described by the c++ disassembler:

Unhandled exception at 0x0040100c in att.exe: 0xC0000005: Access violation writing location 0x00000006.e]

the dissaembler showed:

00400FF2 add byte ptr [eax],al
00400FF4 add byte ptr [eax],al
00400FF6 add byte ptr [eax],al
00400FF8 add byte ptr [eax],al
00400FFA add byte ptr [eax],al
00400FFC add byte ptr [eax],al
00400FFE add byte ptr [eax],al
00401000 mov ax,2
00401004 mov bx,4
00401008 add ax,bx
0040100B nop
0040100C add byte ptr [eax],al ;this line caused the error
0040100E add byte ptr [eax],al
00401010 add byte ptr [eax],al
00401012 add byte ptr [eax],al
00401014 add byte ptr [eax],al
00401016 add byte ptr [eax],al
00401018 add byte ptr [eax],al
0040101A add byte ptr [eax],al
0040101C add byte ptr [eax],al
0040101E add byte ptr [eax],al

strangely enough (at least strange for me) this line is
AFTER the end of the program !!!!

any explanation of why this happens, and how to get around
this ????!!!

help apreciated over this question, or any of my previous questions !

==================
==================
ohh, i solved this one by adding "ret" command before the "end" command.
STUPID ME !!!!
but still need help in other stuff

[packetVB]

ZaidGS,

Hi
Let me start by saying that doing asm for DOS and Windows are alot different.
In DOS you have alot more to worry about, like segments, and Windows is alot easier.

I think RadAsm was developed around creating windows apps.
Couldnt give you any pointer in doing the DOS apps as Ive only did windows apps.

A good tutorial for windows applications is Iczelion's Win32 Assembly Tutorial available at:
http://win32assembly.online.fr/tutorials.html

Best Regards

[ZaidGS]

so thats why (int 21h) produces an exception ???

[Darkwraith]

I found that you cannot do interrupts in VC++ (probably because it is in Windows still. This aspect has been discussed, but we are not quite certain as of yet. ) I also tried it in Borland C++ 5.02 and I got the same results.

Try doing the code in NASM or MASM and it should work. (However if you do find a way to do interrupts in VC++, please post. )