Question

Write an Assembly code to input two integer numbers from keyboard, computes the division of two numbers WITHOUT using division operator and print out the reminder and quotient to the screen.

Note: program using “division operator” will earn no credit for this task. You are ALLOWED to use the “print” and “read” macro

Answer 1

An assembly language is a low-level language understood by the machine. Any C/C++ program is converted into an assembly language in a compiler. The platform I used was Ubuntu, Virtual Box.

In order to convert any code from C to assembly, use the following syntax in the command prompt:

$ gcc -S -o filename.asm filename.c

$ gedit filename.asm

C program :

#include <stdio.h>
#include <limits.h>

// Function to perform division (x / y) of two numbers x and y without
// using division operator in the code
int divide(int x, int y)
{
   // handle divisibility by 0
   if (y == 0)
   {
       printf("Error!! Divisible by 0");
       exit(1);
   }

   // store sign of the result
   int sign = 1;
   if (x * y < 0)
       sign = -1;

   // convert both dividend and divisor to positive
   x = abs(x), y = abs(y);

   // initialize quotient by 0
   int quotient = 0;

   // loop till dividend x is more than the divisor y
   while (x >= y)
   {
   x = x - y;       // perform reduction on dividend
   quotient++;       // increase quotient by 1
   }

   printf("Remainder is %d\n", x);

   return sign * quotient;
}

// main function to perform division of two numbers
int main(void)
{
   int dividend = 5;
   int divisor = 2;

   printf("Quotient is %d\n", divide(dividend, divisor));

   return 0;
}

Assembly Code:

   .file   "P0.c"
   .section   .rodata
.LC0:
   .string   "Error!! Divisible by 0"
.LC1:
   .string   "Remainder is %d\n"
   .text
   .globl   divide
   .type   divide, @function
divide:
.LFB2:
   .cfi_startproc
   pushq   %rbp
   .cfi_def_cfa_offset 16
   .cfi_offset 6, -16
   movq   %rsp, %rbp
   .cfi_def_cfa_register 6
   subq   $32, %rsp
   movl   %edi, -20(%rbp)
   movl   %esi, -24(%rbp)
   cmpl   $0, -24(%rbp)
   jne   .L2
   movl   $.LC0, %edi
   movl   $0, %eax
   call   printf
   movl   $1, %edi
   call   exit
.L2:
   movl   $1, -8(%rbp)
   movl   -20(%rbp), %eax
   imull   -24(%rbp), %eax
   testl   %eax, %eax
   jns   .L3
   movl   $-1, -8(%rbp)
.L3:
   movl   -20(%rbp), %eax
   sarl   $31, %eax
   xorl   %eax, -20(%rbp)
   subl   %eax, -20(%rbp)
   movl   -24(%rbp), %eax
   sarl   $31, %eax
   xorl   %eax, -24(%rbp)
   subl   %eax, -24(%rbp)
   movl   $0, -4(%rbp)
   jmp   .L4
.L5:
   movl   -24(%rbp), %eax
   subl   %eax, -20(%rbp)
   addl   $1, -4(%rbp)
.L4:
   movl   -20(%rbp), %eax
   cmpl   -24(%rbp), %eax
   jge   .L5
   movl   -20(%rbp), %eax
   movl   %eax, %esi
   movl   $.LC1, %edi
   movl   $0, %eax
   call   printf
   movl   -8(%rbp), %eax
   imull   -4(%rbp), %eax
   leave
   .cfi_def_cfa 7, 8
   ret
   .cfi_endproc
.LFE2:
   .size   divide, .-divide
   .section   .rodata
.LC2:
   .string   "Quotient is %d\n"
   .text
   .globl   main
   .type   main, @function
main:
.LFB3:
   .cfi_startproc
   pushq   %rbp
   .cfi_def_cfa_offset 16
   .cfi_offset 6, -16
   movq   %rsp, %rbp
   .cfi_def_cfa_register 6
   subq   $16, %rsp
   movl   $22, -8(%rbp)
   movl   $-7, -4(%rbp)
   movl   -4(%rbp), %edx
   movl   -8(%rbp), %eax
   movl   %edx, %esi
   movl   %eax, %edi
   call   divide
   movl   %eax, %esi
   movl   $.LC2, %edi
   movl   $0, %eax
   call   printf
   movl   $0, %eax
   leave
   .cfi_def_cfa 7, 8
   ret
   .cfi_endproc
.LFE3:
   .size   main, .-main
   .ident   "GCC: (Ubuntu 5.4.0-6ubuntu1~16.04.4) 5.4.0 20160609"
   .section   .note.GNU-stack,"",@progbits

I hope your problem was solved and you like my answer, for any further questions kindly leave a comment below. Have a great day!