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# 25may11abu
# (c) Software Lab. Alexander Burger
(if (== 64 64) (load "@lib/native.l") (from "/**/"))
(gcc "util" NIL
(crc (Len Lst) "crc" 'I Len (cons NIL (cons Len) Lst)) )
int crc(int len, char *p) {
int res, c, i;
for (res = 0; --len >=0;) {
c = *p++;
for (i = 0; i < 8; ++i) {
if ((c ^ res) & 1)
res ^= 0x14002; /* Polynom x**16 + x**15 + x**2 + 1 */
c >>= 1, res >>= 1;
}
}
return res;
}
/**/
(ifn (== 64 64) (load "@lib/gcc.l") (from "/**/"))
(gcc "crc" NIL 'crc)
any crc(any ex) {
any x;
int len, res, c, i;
len = evCnt(ex, x = cdr(ex));
x = cdr(x), x = EVAL(car(x));
for (res = 0; --len >=0; x = cdr(x)) {
c = (int)xCnt(ex,car(x));
for (i = 0; i < 8; ++i) {
if ((c ^ res) & 1)
res ^= 0x14002; /* Polynom x**16 + x**15 + x**2 + 1 */
c >>= 1, res >>= 1;
}
}
return boxCnt(res);
}
/**/
# vi:et:ts=3:sw=3
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