itoa-reverse.asm

.type itos, @function
itos:
 pushl %ebp
 movl %esp, %ebp
  
 movl 8(%esp), %eax           # number
 movl $12, %edi
 leal (%esp, %edi, 1), %ebx   # buffer
 movl $0, %edi                # counter
 movl $0, %esi

 pushl $0x0
 jmp itos_loop 

itos_loop:
  movl $0, %edx

  movl $10, %ecx
  div %ecx
  
  addl $48, %edx
  pushl %edx 

  test %eax, %eax
  je itos_buffer_loop

  inc %edi

  jmp itos_loop

itos_buffer_loop:
  popl %ecx
  movb %cl, (%ebx, %esi, 1)

  test %edi, %edi
  je itos_end

  dec %edi
  inc %esi

  jmp itos_buffer_loop

itos_end:
  movl %ebx, %eax
  movl %ebp, %esp
  popl %ebp
  ret