#include "boot.h" /* * from Rob Warnock */static	ulong	crc32tab[256];	/* initialised on first call to crc32 */ enum {	CRC32POLY = 0x04c11db7     /* AUTODIN II, Ethernet, & FDDI */}; /* * Build auxiliary table for parallel byte-at-a-time CRC-32. */static voidinitcrc32(void){	int i, j;	ulong c; 	for(i = 0; i < 256; i++) {		for(c = i << 24, j = 8; j > 0; j--)			if(c & (1<<31))				c = (c<<1) ^ CRC32POLY;			else				c <<= 1;		crc32tab[i] = c;	}} ulongcrc32(void *buf, int n, ulong crc){	uchar *p; 	if(crc32tab[1] == 0)		initcrc32();	crc = ~crc;	for(p = buf; --n >= 0;)		crc = (crc << 8) ^ crc32tab[(crc >> 24) ^ *p++];	return ~crc;}