itoa.asm

# Convert number to string
# (number, buffer) => buffer
.type itoa, @function
itoa:
 pushl %ebp
 movl %esp, %ebp
 
 movl $12, %edi  
 leal (%esp, %edi, 1), %ebx  # buffer
 movl 8(%esp), %eax          # number
 movl $0, %edi               # counter

 pushl $0x0
 jmp itoa_loop 

itoa_loop:
  movl $0, %edx
  movl $10, %ecx

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

  movb (%esp), %cl
  movb %cl, (%ebx, %edi, 1)  # append byte to buffer

  test %eax, %eax
  je itoa_end

  dec %edi

  jmp itoa_loop

itoa_end:
  leal (%ebx, %edi, 1), %eax  # pointer to start of buffer
  movl %ebp, %esp
  popl %ebp
  ret