Going from high to low lever language I got to assembly. Now at the very beginning, I wrote a simple age program (I'm not clear how to get system time yet so I just used another input). I get Segmentation Fault (core dumped) after I enter the final input. Here is my code:
section .text
global _start
_start:
mov edx, lenask
mov ecx, ask
mov ebx, 1
mov eax, 4
int 0x80
mov edx, 5
mov ecx, input
mov ebx, 2
mov eax, 3
int 0x80
mov edx, lenask2
mov ecx, ask2
mov ebx, 1
mov eax, 4
int 0x80
mov edx, 5
mov ecx, input2
mov ebx, 2
mov eax, 3
int 0x80
mov eax, input2
mov ebx, input
sub eax, ebx
push eax
mov edx, lenanswer
mov ecx, answer
mov ebx, 1
mov eax, 4
int 0x80
pop eax
mov edx, 7
mov ecx, eax
mov ebx, 1
mov eax, 4
int 0x80
section .data
ask db "What is your age?"
lenask equ $-ask
ask2 db "What is today's year?"
lenask2 equ $-ask2
answer db "The age you were born was: "
lenanswer equ $-answer
section .bss
input resb 5
input2 resb 5
An example of what happens:
What is your age?45
What is today's year?2015
The age you were born was: Segmentation fault
It should have done:
What is your age?45
What is today's year?2015
The age you were born was: 1970
