FASM - how to do this without stack? - fasm

Question

I wrote program that asking user for his name and displaying it on screen in FASM. I used stack, but I was wondering how I can do it without it.
This is working code:
format elf executable
entry _start
segment readable
msg db 'What is your name: '
msg.length = $-msg
msg2 db 'Your name is: '
msg2.length = $-msg2
segment readable writeable
name db ?
segment readable executable
_start:
mov eax,4
mov ebx,1
mov ecx,msg
mov edx,msg.length
int 80h
mov eax,3
mov ebx,1
mov ecx,name
mov edx,20
int 80h
push eax
mov eax,4
mov ebx,1
mov ecx,msg2
mov edx,msg2.length
int 80h
mov eax,4
mov ebx,1
mov ecx,name
pop edx
int 80h
mov eax,1
mov ebx,0
int 80h
I tried to do something like that:
format elf executable
entry _start
segment readable
msg db 'What is your name: '
msg.length = $-msg
msg2 db 'Your name is: '
msg2.length = $-msg2
segment readable writeable
name db ?
name.length db ?
segment readable executable
_start:
mov eax,4
mov ebx,1
mov ecx,msg
mov edx,msg.length
int 80h
mov eax,3
mov ebx,1
mov ecx,name
mov edx,20
int 80h
mov dword [name.length],eax
mov eax,4
mov ebx,1
mov ecx,msg2
mov edx,msg2.length
int 80h
mov eax,4
mov ebx,1
mov ecx,name
mov edx,dword [name.length]
int 80h
mov eax,1
mov ebx,0
int 80h
Code is compiling without errors, but when I'm running it and when I input the name (e.g "debos") I'm getting:
Your name is: d and some weird char at the end
instead of:
Your name is debos like with the first code.
Can someone tell me what is wrong with my code?

Answer 1

name should be declared as an array of bytes, not as a single byte (db).
segment readable writeable
name db 100 dup(?) ;or simply name rb 100
name.length dd ?
name.length should be a dword, not a byte. In FASM executable format, the code segment comes right after the last byte of the data segment, so it explains why it prints garbage characters because it overlaps. This is just the nature of the ELF executable format.

Answer 2

msg.length is a constant so you can not overwrite it. If you want so, you should store this in a variable.