count-char.s

   1 .type count_chars, @function
   2 .globl count_chars
   3
   4 .equ ST_STRING_START_ADDRESS, 8
   5 count_chars:
   6 pushl %ebp
   7 movl %esp, %ebp
   8
   9 movl $0, %ecx
  10 movl ST_STRING_START_ADDRESS(%ebp), %edx
  11
  12 count_loop_begin:
  13 movb  (%edx), %al
  14 cmpb $0, %al
  15 je count_loop_end
  16 incl %ecx
  17 incl %edx
  18 jmp count_loop_begin
  19
  20 count_loop_end:
  21 movl %ecx, %eax
  22 popl %ebp
  23 ret
  24