fixed point integer division

reciprocaldiv.c

/// for int32.
/// a * (1/b) == (a * [(2^16 / b) + 1]) >> 16

#include <stdio.h>

int make_recip(int const b) {
	return ((1 << 16) / b) + 1;
}

int fast_div(int const a, int const recip) {
	return (a * recip) >> 16;
}

int main() {
	printf("1: %i\n", fast_div(80, make_recip(40)));
}