interleave.c

#include <stdio.h>
int main(void){
	unsigned long in = 0x00000003;
	unsigned long out;
	out = in;
	out = ((out & 0x0000ff00) << 8) | (out & 0x000000ff);
	out = ((out & 0x00f0f0f0) << 4) | (out & 0x000f0f0f);
	out = ((out & 0x0ccccccc) << 2) | (out & 0x03333333);
	out = ((out & 0xaaaaaaaa) << 1) | (out & 0x55555555);
	printf("in %lx out %lx\n",in, out);
}