loop.asm

 ; Basic OS X calls to glibc
 ;
 ; compile with:
 ; nasm -g -f macho malloc.asm
 ; gcc -o a.out malloc.o
 ;
 
 ; glibc stuff
 extern _puts, _printf, _malloc, _free
 
 ; static data
 segment .data
 
 hello_world_str db "Hello world!", 10, 0
 int_str db "Address %x", 10, 0
 
 ; code
 segment .text
 
 global _main
 
 _main:
         push ebp ; setup the frame
         mov  ebp, esp
 
         sub  esp, 4 ; align the stack
         push dword hello_world_str
         call _puts
         add  esp, 4
 
         ; malloc 16 bytes
         push  dword 16
         call  _malloc
         add  esp, 4
 
         ; check if the malloc failed
         test  eax, eax
         jz    fail_exit
 
         sub   esp, 0xC ; align the stack
         mov   ebx, eax
         push  ebx
         push  dword int_str
         call  _printf
         add   esp, 8
         add   esp, 0xC
 
         ; print "A\nB\n..."     
         mov   [ebx], dword 0xD41 ; 'A\n'
 
         mov   edi, 10
           push  ebx
 _loop:
         call  _puts
         inc  dword [ebx]
         dec  edi
         jnz  _loop
 
         add  esp, 4
 
         ; free the malloc'd memory
         push  ebx
         call  _free
         add  esp, 4
         add  esp, 4 ; cleanup the stack 
         pop  ebp
         ret
 
 fail_exit:
         mov  eax, 1
         pop  ebp
         ret