hexdump.asm

SECTION .bss
BUFFLEN equ 16
Buff: resb BUFFLEN
SECTION .data
HexStr: db " 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00",10 
HEXLEN equ $-HexStr
Digits: db "0123456789ABCDEF"
SECTION .text
global _start
_start:
nop
Read:
mov eax,3
mov ebx,0
mov ecx,Buff
mov edx,BUFFLEN
int 80h 
mov ebp,eax
cmp eax,0
je Done
mov esi,Buff
mov edi,HexStr
xor ecx,ecx


Scan:
xor eax,eax
mov edx,ecx
shl edx,1
add edx,ecx
mov al,byte [esi+ecx]
mov ebx,eax
and al,0Fh
mov al,byte [Digits+eax]
mov byte [HexStr+edx+2],al
shr bl,4
mov bl,byte [Digits+ebx]
mov byte [HexStr+edx+1],bl
inc ecx
cmp ecx,ebp
jna Scan
mov eax,4
mov ebx,1
mov ecx,HexStr
mov edx,HEXLEN
int 80h
jmp Read

Done:
mov eax,1
mov ebx,0
int 80H