i want to write a simple character printing program using NASM plz help !

rhklinux · 07-27-2010, 01:19 AM

I am a newbie is asm !
i tried a code to accept a character and print the same !
i can accept it with following code but its not working with printing that character
i use NASM version 2.07
code:

Code:

segment .data
msg1: db 'Enter a key',10
msg1len: equ $-msg1

msg2: db 'the key entred is',10
msg2len: equ $-msg2



segment .text
global _start

_start:

mov eax,4
mov ebx,1
mov ecx,msg1
mov edx,msg1len
int 80h

call getchar
call putchar

mov eax,1
mov ebx,0
int 80h

getchar:

pushad 

pushfd 

mov eax, 3 

mov ebx, 0 

mov ecx, esi 

mov edx, 2 

int 80h 

popfd 

popad 

ret 

putchar:

pushad

pushfd

mov eax,4
mov ebx,1
mov ecx,esi
mov edx,2
int 80h

popfd

popad

ret

resetreset · 07-27-2010, 02:01 AM

I'm not familiar with system call parameters under Linux, so can't help you with most of your program, but what are the "mov ecx,esi"'s for? YOu don't do anything with ESI in the rest of the program, as far as I can see - are you hoping it'll have some particular value which the "int 80h" will need?

rhklinux · 07-27-2010, 08:53 AM

actually i got this code from a forum !

resetreset · 07-28-2010, 01:52 AM

so, answer my question

(and also answer the email I sent you

)