Improve LFSR implementation
[fio.git] / lib / lfsr.h
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1#ifndef FIO_LFSR_H
2#define FIO_LFSR_H
3
4#include <inttypes.h>
5
d474cbc9 6#define FIO_MAX_TAPS 6
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7
8struct lfsr_taps {
9 unsigned int length;
10 unsigned int taps[FIO_MAX_TAPS];
11};
12
13
14struct fio_lfsr {
d474cbc9 15 uint64_t xormask;
8055e41d 16 uint64_t last_val;
d474cbc9 17 uint64_t cached_bit;
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18 uint64_t max_val;
19 uint64_t num_vals;
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20 uint64_t cycle_length;
21 unsigned int spin;
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22};
23
74776733 24int lfsr_next(struct fio_lfsr *fl, uint64_t *off, uint64_t);
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25int lfsr_init(struct fio_lfsr *fl, uint64_t size,
26 unsigned long seed, unsigned int spin);
27int lfsr_reset(struct fio_lfsr *fl, unsigned long seed);
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28
29#endif