something like a crc calculator?

crc.c

#include <stdlib.h>
#include <stdio.h>
#include <stdint.h>

typedef struct {
	unsigned long val : 48;
} uint48;

uint48 add48(uint48 a, uint48 b)
{
	uint48 c;
	c.val = a.val +  b.val;
	return c;
}

uint48 mul48(uint48 a, uint48 b)
{
	uint48 c;
	c.val = a.val * b.val;
	return c;
}

const uint48 ZERO = { 0 };
const uint48 ONE = { 1 };

uint48 pow48(uint48 a, unsigned int by)
{
	if(by == 0) {
		return ONE;
	} else {
		uint48 accum = a;
		while(by-- > 1) {
			accum = mul48(accum, a);
		}
		return accum;
	}
}

uint48 p(uint48 a) {
	uint48 r = ZERO;
	r = add48(r, pow48(a, 32));
	r = add48(r, pow48(a, 26));
	r = add48(r, pow48(a, 23));
	r = add48(r, pow48(a, 22));
	r = add48(r, pow48(a, 16));
	r = add48(r, pow48(a, 12));
	r = add48(r, pow48(a, 11));
	r = add48(r, pow48(a, 10));
	r = add48(r, pow48(a, 8));
	r = add48(r, pow48(a, 7));
	r = add48(r, pow48(a, 5));
	r = add48(r, pow48(a, 4));
	r = add48(r, pow48(a, 2));
	r = add48(r, pow48(a, 1));
	r = add48(r, pow48(a, 1));
	return r;
}

void main(void)
{
	uint48 a;
	unsigned long temp;
	scanf("%lx\n", &temp);
	printf("Got %lX\n", temp);
	a.val = temp;

	uint48 r = p(a);
	printf("CRC %lX\n", r.val);

}