.global supersum
supersum:
    // eax - pointer to A
    // ebx - pointer to B
    // ecx - pointer to C
    // esi - size A
    // edi - size B
    pushl %ebp
    pushl %edx
    pushl %esi
    pushl %edi
    pushl %ebx


    cmpl %esi, %edi // edi > esi (size B > size A) go to start
    jg start_loop_first
    //swap A, B
    movl %esi, %ebp
    movl %edi, %esi
    movl %ebp, %edi

    movl %eax, %ebp
    movl %ebx, %eax
    movl %ebp, %ebx


    // use ebp as itearator
start_loop_first:

    xor %ebp, %ebp // i = 0
loop_first:
    cmpl %esi, %ebp // i > size A
    jg finish_first_loop
    movb $0, (%ecx, %ebp) // C[i] = 0
    addl $1, %ebp // i++
    jmp loop_first

finish_first_loop:
    xor %ebp, %ebp // i = 0
loop_second:
    cmpl %edi, %ebp // i > size B
    jg finish_second_loop
    movb $0, (%ecx, %ebp) // C[i] = 0
    addl $1, %ebp // i++
    jmp loop_second

finish_second_loop:
    xor %ebp, %ebp // i = 0
    clc // CF = 0
    pushf
loop_add_a:
    cmpl %esi, %ebp // i >= size A
    jge finish_add_a
    movb (%eax, %ebp), %dl // tmp (dl) = A[i]
    popf
    adcb %dl, (%ecx, %ebp) // C[i] += tmp + CF
    pushf
    addl $1, %ebp // i++
    jmp loop_add_a

finish_add_a:
    popf
    adcb $0, (%ecx, %ebp) // C[i] += CF

    xor %ebp, %ebp // i = 0
    clc // CF = 0
    pushf
loop_add_b:
    cmpl %edi, %ebp // i >= size B
    jge finish_add_b
    movb (%ebx, %ebp), %dl // tmp (dl) = B[i]
    popf
    adcb %dl, (%ecx, %ebp) // C[i] += tmp + CF
    pushf
    addl $1, %ebp // i++
    jmp loop_add_b

finish_add_b:
    popf
    adcb $0, (%ecx, %ebp) // C[i] += CF

    // C = A + B
    // now need to find length
    cmpl %edi, %esi // esi > edi
    jg swap_registers
    //edi >= esi
    movl %edi, %ebp
    jmp find_loop

swap_registers: // esi > edi
    movl %esi, %ebp
find_loop: // ebp - iterator to last
    cmpl $0, %ebp
    jz finish_program // if ebp == 0
    cmpb $0, (%ecx, %ebp) // C[i] != 0
    jnz finish_program
    subl $1, %ebp // --i
    jmp find_loop


finish_program:
    cmpb $0, (%ecx, %ebp) // C[i] == 0
    jz zeroo
    jmp finish_last

zeroo:
    movl $-1, %ebp

finish_last:
    addl $1, %ebp

    movl %ebp, %eax
    popl %ebx
    popl %edi
    popl %esi
    popl %edx
    popl %ebp
    ret