Javanian:
Please are there any Assembly Language Programmers here? Preferably the x86 family, but any would do.

soldierdollar:
I program microcontrollers with assembly language

Jasi7:


I need ur help bro on a question pls

Javanian:


Cool. Please can i ask you some questions? I'm having difficulty grasping some of it.

nodata segment
db ?
nodata ends
text segment
assume cs:text, ds:nodata
mov ax, seg nodata
mov ds, ax
inc bx
mov cx, bx
push bx

Javanian:

nodata segment
db ?
nodata ends
text segment
assume cs:text, ds:nodata
mov ax, seg nodata
mov ds, ax
inc bx
mov cx, bx
push bx

This is a code snippet culled from a program. I didn't paste the complete code. Please at line 9, what is the value of bx before and after 'inc bx' is called? Does it mean the bx register is given some default value by the operating system or is it by the programmer?

CodeHouse:



From my rusty knowledge of AL, The inc instruction will increase any operand by 1..depending on if you got the complete code or not where bx register was assigned a value somewhere

Javanian:


I know exactly what Inc does. The issue is that in the code nothing is assigned to bx before it is incremented but yet the code still works.

CodeHouse:


I expected it to run when I saw your code, assume it to be default increament on the 32-bit register since the syntax for inc is:

INC operand
Thesame way INC [Count] will run to cause increament in the count variable

BlueMagnificent:
If the code worked as u expected it to then the os definitely must have initialized the bx register to 0 though its usually advised to initialize ur registers (general purpose registers) before using them to avoid undefined behaviour.
Check this link for a brief info [url]stackoverflow.com/questions/9147455/what-is-default-register-state-when-program-launches-asm-linux[/url]

Javanian:


Another question.
How can i check the values of all my registers at run time? How can i print to console?

e.g

mov ax, 6
mov cx, 5
mov bx, 6
add ax, bx

How can i display the values of all this registers to console?

I know how to use

mov dl, 'x'
mov ah, 02h
int 21h

to print characters

and also how to use

lea dx, string
mov ah, 09h
int 21h

to print strings, but i can't get them to print values of my registers.

BlueMagnificent:


That seems to be really difficult to do using dos-asm api but if you are working with win32 asm all u have to do is call the console output routine after pushing the value of the intended register unto the stack as parameter

Javanian:


I know exactly what Inc does. The issue is that in the code nothing is assigned to bx before it is incremented but yet the code still works.

tsleazy:
that awkward moment, that may have already seen you in Uniben....physical science...lol

Javanian:


I am using masm32. How can i do this?

invoke StdOut, eax

BlueMagnificent:


I'm trying to get my rusty asm head running lol...

Try and see if this works:

invoke StdOut, eax

assuming the value is store in eax. eax is the 32 bit equivalent of ax (actually ax is the lower order word of eax).

Javanian:
Thanks but i am getting an 'undefiened symbol' compile assemble time error for both 'dwtoa' and 'StdOut'. Aren't they supposed to be declared somewhere?

BlueMagnificent:


include this file to the asm file:
\masm32\include\masm32rt.inc

Javanian:


please how? Sorry if my questions are too many or too silly. Assembly language is just one hell of a language.

Javanian:
Yeah i am using Microsoft Assembler. I have included the file and i am getting another error but i think this one has to do with the structure of my code before invoking dwtoa and StdOut. Please can i get a simple code snippet that prints out the value of any register? Lets say cx register, a code i would be able to assemble and run so i can see where i went wrong.

include masm32rt.inc

.data?
stringValue dd 5 dup(?)
.code 

main:
	mov ebx, 12
	invoke dwtoa, ebx, addr stringValue
	invoke StdOut, addr stringValue

	invoke ExitProcess, eax

end main

Javanian:
Thanks, i actually already used visual studio. It works now, Words cannot express my gratitude. You have been immensely helpful. Thanks a lot.

BlueMagnificent:


You are welcomed

Gaara101:


Hey.
Sorry to disturb. This is an old thred but do you still use Assembly?