Hi Azrael998.
section .text
global _start ;must be declared for using gcc
_start: ;tell linker entry point
mov ecx, [num1] ;compare num1 and num2
cmp ecx, [num2]
jg compare_num3_and_num4
mov ecx, [num2]
compare_num3_and_num4:
mov edx, [num3]
cmp edx, [num4]
jg _exit
mov ecx, [num3]
_exit:
mov [smallest], ecx
mov ecx,msg
mov edx, len
mov ebx,1 ;file descriptor (stdout)
mov eax,4 ;system call number (sys_write)
int 0x80 ;call kernel
mov ecx,smallest
mov edx, 2
mov ebx,1 ;file descriptor (stdout)
mov eax,4 ;system call number (sys_write)
int 0x80 ;call kernel
mov eax, 1
int 80h
section .data
msg db "The smallest digit is: ", 0xA,0xD
len equ $- msg
num1 dd '53'
num2 dd '42'
num3 dd '9'
num4 dd '21'
segment .bss
smallest resb 2
The biggest issue I see is that you haven't got numbers there, you've got text strings. Comparing text strings may give the result you want, but it isn't what you say you're doing. Remove the quote marks to make 'em numbers.
Then... you compare the first two strings and then switch to edx and compare the last two. You never do find the smallest of all four. In this case, it works out right, but if you change the order it won't. I'd stick with ecx.
At the end you've got "resb 2". This gives you only 2 bytes and you're putting a 4 byte register into it. Since it's the last variable in the program, you don't see the error. but if there were another it would be clobbered by the overflow. This just isn't right! "resb 4" or "resd 1" would fix it. They do the same thing, 4 bytes, 1 doubleword is what you need.
More subtly, "jg" and "jl" work with signed numbers. "ja" and "jb" work with unsigned numbers. If you want to allow negative numbers, you need "jg". If you want to limit your program to positive numbers you might be better off with "ja".
Linux usually doesn't use carriage returns (0xD) but it probably doesn't hurt.
I don't know how you hope to improve your code, so I don't know if any of that helps.
Best,
Frank
