AT&T Assembly Code

_test:
        pushl %ebp ;Push old %ebp
        movl %esp, %ebp ;Set %ebp as frame pointer
        subl $24, %esp ;Allocate 24 bytes on the stack
        movl 8(%ebp), %eax ;Get the first argument which was provided to function
        movl %eax, -4(%ebp) ;Store test's argument as arg1 for strlen
        movl -4(%ebp), %eax ;Load back into register
        movl %eax, (%esp) ;Store on stack
        call _strlen ;Call to procedure stringlength.
        movl %eax, -16(%ebp) ;Obtained length of string.
        movl -16(%ebp), %eax ;Load address %ebp-16, i.e., length value back in accumulator.
        cmpl $1, %eax ;Stringlength minus 1?
        jg LBB1_2 ;Jump to LBB1_2 if the result is positive.
        movl $1, -12(%ebp) ;Move immediate operand 1 to location ebp-12
        jmp LBB1_5

LBB1_2:
        movl -4(%ebp), %eax ;Load string's address back into accumulator.
        movb (%eax), %al ;Move string's address given by %eax to %al.
        movl -16(%ebp), %ecx ;Load address %ebp-16, i.e, of length value into %ecx.
        subl $1, %ecx ;Subtract value by 1.
        movl -4(%ebp), %edx ;Load address %ebp-4 into %edx (the string).
        movb (%edx,%ecx), %cl ;Moves the LAST character (string address + length - 1) to cl.
        cmpb %cl, %al ;Compares the first character(string address points to first char) and last char.
        je LBB1_4 ;If the two are equal, jump to LBB1_4
        movl $0, -12(%ebp) ;Write a 0 value to ebp-12.
        jmp LBB1_5 ;Jump to LBB1_5.

LBB1_4:
        movl -16(%ebp), %eax ;Length address.
        subl $1, %eax ;Subtract one from length.
        movl -4(%ebp), %ecx ;String address
        movb $0, (%ecx,%eax) ;Stores a zero over the last character.
        movl -4(%ebp), %eax ;String address to accumulator
        addl $1, %eax
        movl %eax, (%esp) ;Store on stack
        call _test ;Recursion??
        movl %eax, -12(%ebp) ;Move the result (1 or 0) from accumulator to ebp-12

LBB1_5:
        movl -12(%ebp), %eax ;Load value 1 or 0 back into accumulator
        movl %eax, -8(%ebp) ;Move accumulator value to ebp-8
        movl -8(%ebp), %eax ;Set return value
        addl $24, %esp ;Delete 24 bytes from stack
        popl %ebp ;Pop the current frame.
        ret