#include <u.h>#include <libc.h>#include <libg.h>#include <fb.h>int nbit, npix;RGB map[256];/* replicate (from top) value in v (n bits) until it fills a ulong */ulong rep(ulong v, int n){	int o;	ulong rv;	rv=0;	for(o=32-n;o>=0;o-=n) rv|=v<<o;	if(o!=-n) rv|=v>>-o;	return rv;}void putcmap(uchar cmap[256*3]){	int i, j;	for(j=0;j!=npix;j++){		i=3*255*j/(npix-1);		map[npix-1-j].red=rep(cmap[i], 8);		map[npix-1-j].green=rep(cmap[i+1], 8);		map[npix-1-j].blue=rep(cmap[i+2], 8);	}	wrcolmap(&screen, map);}void main(int argc, char *argv[]){	uchar cmapbuf[256*3];	if(argc!=2){		fprint(2, "Usage: %s colormap\n", argv[0]);		exits("usage");	}	if(!getcmap(argv[1], cmapbuf)){		fprint(2, "%s: can't find %s\n", argv[0], argv[1]);		exits("not found");	}	binit(0,0,0);	nbit=1<<screen.ldepth;	npix=1<<nbit;	putcmap(cmapbuf);	exits(0);}