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#ifndef CRC32_BRAID_COMB_P_H_
#define CRC32_BRAID_COMB_P_H_
/*
Return a(x) multiplied by b(x) modulo p(x), where p(x) is the CRC polynomial,
reflected. For speed, this requires that a not be zero.
*/
static uint32_t multmodp(uint32_t a, uint32_t b) {
uint32_t m, p;
m = (uint32_t)1 << 31;
p = 0;
for (;;) {
if (a & m) {
p ^= b;
if ((a & (m - 1)) == 0)
break;
}
m >>= 1;
b = b & 1 ? (b >> 1) ^ POLY : b >> 1;
}
return p;
}
/*
Return x^(n * 2^k) modulo p(x). Requires that x2n_table[] has been
initialized.
*/
static uint32_t x2nmodp(z_off64_t n, unsigned k) {
uint32_t p;
p = (uint32_t)1 << 31; /* x^0 == 1 */
while (n) {
if (n & 1)
p = multmodp(x2n_table[k & 31], p);
n >>= 1;
k++;
}
return p;
}
#endif /* CRC32_BRAID_COMB_P_H_ */
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