Division and Multiplication in Assembly Language (MIPS32 ISA)

li   $sp, 0x7ffffffc    # Setting the stack to highest stack address

Multiplication:

First, we'll attempt to include this C logic in the MIPS assembly program for the Multiplication.

Multiply(a, b) {
    int res = 0
    for(int i=0;i<b;i++) res += a
}

This is a simple program that can be implemented in MIPS32.

Here is the code for Multiplication (MIPS32 ISA)

MULTIPLY:
    # While (idx < b) result += A

    add $sp, $sp, -16                # Allocating Stack Memory
    sw  $s3, 12($sp)                # Storing register values
    sw  $s2,  8($sp)
    sw  $s1,  4($sp)
    sw  $s0,  0($sp)

    add  $s0, $zero, $zero            # Result = 0
    addi $s1, $zero, 0                # idx (t0) = 0
    add  $s2, $zero, $a0            # s2 = A
    add  $s3, $zero, $a1            # s3 = B
MULTIPLY_LOOP:
    beq  $s3, $s1, EXIT_MULTIPLY    # if (idx == b) Break
    add  $s0, $s0, $s2                # result += A
    addi $s1, $s1, 1                # idx++
    j MULTIPLY_LOOP
EXIT_MULTIPLY:
    add $v0, $zero, $s0                # v0 = Result

    lw  $s3, 12($sp)                # restoring register values
    lw  $s2,  8($sp)
    lw  $s1,  4($sp)
    lw  $s0,  0($sp)

    add $sp, $sp, 16                # restoring stack pointer
    jr   $ra

Division:

First, we'll attempt to include this C logic in the MIPS assembly program for the Division.

division(a, b) {
    int res = 0;
    while(a >= b){
        a -= b;
        res += 1;
    }

    return res;
}

Here is the code for Division (MIPS32 ISA)

DIVISION:
    # While (A >= B) A -= B; result++
    add  $sp, $sp, -12                # Allocating Stack Memory
    sw   $s2, 8($sp)                # Storing register values
    sw   $s1, 4($sp)                
    sw   $s0, 0($sp)

    addi $s0, $zero, 0                # result (s0) = 0
    add  $s1, $zero, $a0            # s1 = A
    add  $s2, $zero, $a1            # s2 = B
DIV_LOOP:
    blt  $s1, $s2, EXIT_DIV            # If (A < B) break
    sub  $s1, $s1, $s2                # A -= B
    addi $s0, $s0, 1                # result++
    j DIV_LOOP
EXIT_DIV:
    add $v0, $zero, $s0                # v0 = result

    lw   $s2, 8($sp)                # restoring register values
    lw   $s1, 4($sp)                
    lw   $s0, 0($sp)
    addi $sp, $sp, 12                # restoring stack pointer

    jr $ra

Conclusion:

In this article, you have learned to implement division and multiplication in Mips32 ISA