Square a number in NASM assembly without multiplication

Question

Is it possible to square a number stored in a register (say eax) without doing any multiplication (by using shifts, etc)? I will be squaring a 16-bit number in 32-bit assembly so overflow shouldn't be an issue. I am using NASM x86 assembly to create the program. Thanks in advance for your help.

Answer 1

In C:

int square(int n) {
    int i, r = 0;
    for (i = n; i; i >>= 1, n <<= 1)
        if (i & 1)
            r += n;
    return r;
}

I'll leave the NASM to you.

Answer 2

Shift and Add is always a good starting point for doing multiplications on computers without involving multiplication instructions.

Precomputing a table is another option that could be suitable for this problem.

Answer 3

A little late answer. Here is the logic:- The square of N can be obtained by adding first N odd numbers.

In C,

int sqr(int num){
    int j=1; 
    int sum=0;
    while(num>0){
        sum += j;
        j += 2; 
        num--;
    }
    return sum;
 }

but applicable only for integers.