#ifndef MPU_SIEVE_H
#define MPU_SIEVE_H
#include "EXTERN.h"
#include "perl.h"
extern unsigned char* sieve_erat30(UV end);
extern int sieve_segment(unsigned char* mem, UV startd, UV endd);
static const UV wheel30[] = {1, 7, 11, 13, 17, 19, 23, 29};
/* Used for moving between primes */
static const unsigned char nextwheel30[30] = {
1, 7, 7, 7, 7, 7, 7, 11, 11, 11, 11, 13, 13, 17, 17,
17, 17, 19, 19, 23, 23, 23, 23, 29, 29, 29, 29, 29, 29, 1 };
static const unsigned char prevwheel30[30] = {
29, 29, 1, 1, 1, 1, 1, 1, 7, 7, 7, 7, 11, 11, 13,
13, 13, 13, 17, 17, 19, 19, 19, 19, 23, 23, 23, 23, 23, 23 };
/* The bit mask within a byte */
static const unsigned char masktab30[30] = {
0, 1, 0, 0, 0, 0, 0, 2, 0, 0, 0, 4, 0, 8, 0,
0, 0, 16, 0, 32, 0, 0, 0, 64, 0, 0, 0, 0, 0,128 };
/* Add this to a number and you'll ensure you're on a wheel location */
static const unsigned char distancewheel30[30] =
{1,0,5,4,3,2,1,0,3,2,1,0,1,0,3,2,1,0,1,0,3,2,1,0,5,4,3,2,1,0};
/* Once on the wheel, add this to get to next spot. In p space, not m. */
static const unsigned char wheeladvance30[30] =
{0,6,0,0,0,0,0,4,0,0,0,2,0,4,0,0,0,2,0,4,0,0,0,6,0,0,0,0,0,2};
static int is_prime_in_sieve(const unsigned char* sieve, UV p) {
UV d = p/30;
UV m = p - d*30;
/* If m isn't part of the wheel, we return 0 */
return ( (masktab30[m] != 0) && ((sieve[d] & masktab30[m]) == 0) );
}
/* Warning -- can go off the end of the sieve */
static UV next_prime_in_sieve(const unsigned char* sieve, UV p) {
UV d, m;
if (p < 7)
return (p < 2) ? 2 : (p < 3) ? 3 : (p < 5) ? 5 : 7;
d = p/30;
m = p - d*30;
do {
if (m==29) { d++; m = 1; while (sieve[d] == 0xFF) d++; }
else { m = nextwheel30[m]; }
} while (sieve[d] & masktab30[m]);
return(d*30+m);
}
static UV prev_prime_in_sieve(const unsigned char* sieve, UV p) {
UV d, m;
if (p <= 7)
return (p <= 2) ? 0 : (p <= 3) ? 2 : (p <= 5) ? 3 : 5;
d = p/30;
m = p - d*30;
do {
m = prevwheel30[m]; if (m==29) { if (d == 0) return 0; d--; }
} while (sieve[d] & masktab30[m]);
return(d*30+m);
}
/* Useful macros for the wheel-30 sieve array */
#define START_DO_FOR_EACH_SIEVE_PRIME(sieve, a, b) \
{ \
UV p = a; \
UV l_ = b; \
UV d_ = p/30; \
UV m_ = p-d_*30; \
m_ += distancewheel30[m_]; \
p = d_*30 + m_; \
while ( p <= l_ ) { \
if ((sieve[d_] & masktab30[m_]) == 0)
#define END_DO_FOR_EACH_SIEVE_PRIME \
m_ = nextwheel30[m_]; if (m_ == 1) { d_++; } \
p = d_*30+m_; \
} \
}
#endif