rand: add 64-bit tausworthe variant with a 2^258 cycle

[fio.git] / lib / rand.h

diff --git a/lib/rand.h b/lib/rand.h
index 363e7b6d9651d5970c9b7b8592f61a9bc0a0962b..cab91585cac9e63fc76dd14d21a507deb179c8c6 100644 (file)
--- a/lib/rand.h
+++ b/lib/rand.h
@@ -1,13 +1,69 @@
 #ifndef FIO_RAND_H
 #define FIO_RAND_H
 
-struct frand_state {
+#include <inttypes.h>
+#include "../arch/arch.h"
+
+#define FRAND32_MAX    (-1U)
+#define FRAND64_MAX    (-1ULL)
+
+struct taus88_state {
        unsigned int s1, s2, s3;
 };
 
-extern struct frand_state __fio_rand_state;
+struct taus258_state {
+       uint64_t s1, s2, s3, s4, s5;
+};
+
+struct frand_state {
+       unsigned int use64;
+       union {
+               struct taus88_state state32;
+               struct taus258_state state64;
+       };
+};
+
+struct frand64_state {
+       uint64_t s1, s2, s3, s4, s5;
+};
+
+static inline uint64_t rand_max(struct frand_state *state)
+{
+       if (state->use64)
+               return FRAND64_MAX;
+       else
+               return FRAND32_MAX;
+}
+
+static inline void __frand32_copy(struct taus88_state *dst,
+                                 struct taus88_state *src)
+{
+       dst->s1 = src->s1;
+       dst->s2 = src->s2;
+       dst->s3 = src->s3;
+}
+
+static inline void __frand64_copy(struct taus258_state *dst,
+                                 struct taus258_state *src)
+{
+       dst->s1 = src->s1;
+       dst->s2 = src->s2;
+       dst->s3 = src->s3;
+       dst->s4 = src->s4;
+       dst->s5 = src->s5;
+}
+
+static inline void frand_copy(struct frand_state *dst, struct frand_state *src)
+{
+       if (src->use64)
+               __frand64_copy(&dst->state64, &src->state64);
+       else
+               __frand32_copy(&dst->state32, &src->state32);
+
+       dst->use64 = src->use64;
+}
 
-static inline unsigned int __rand(struct frand_state *state)
+static inline unsigned int __rand32(struct taus88_state *state)
 {
 #define TAUSWORTHE(s,a,b,c,d) ((s&c)<<d) ^ (((s <<a) ^ s)>>b)
 
@@ -18,6 +74,42 @@ static inline unsigned int __rand(struct frand_state *state)
        return (state->s1 ^ state->s2 ^ state->s3);
 }
 
-extern void init_rand(struct frand_state *);
+static inline uint64_t __rand64(struct taus258_state *state)
+{
+       uint64_t xval;
+
+       xval = ((state->s1 <<  1) ^ state->s1) >> 53;
+       state->s1 = ((state->s1 & 18446744073709551614ULL) << 10) ^ xval;
+
+       xval = ((state->s2 << 24) ^ state->s2) >> 50;
+       state->s2 = ((state->s2 & 18446744073709551104ULL) <<  5) ^ xval;
+
+       xval = ((state->s3 <<  3) ^ state->s3) >> 23;
+       state->s3 = ((state->s3 & 18446744073709547520ULL) << 29) ^ xval;
+
+       xval = ((state->s4 <<  5) ^ state->s4) >> 24;
+       state->s4 = ((state->s4 & 18446744073709420544ULL) << 23) ^ xval;
+
+       xval = ((state->s5 <<  3) ^ state->s5) >> 33;
+       state->s5 = ((state->s5 & 18446744073701163008ULL) <<  8) ^ xval;
+
+       return (state->s1 ^ state->s2 ^ state->s3 ^ state->s4 ^ state->s5);
+}
+
+static inline uint64_t __rand(struct frand_state *state)
+{
+       if (state->use64)
+               return __rand64(&state->state64);
+       else
+               return __rand32(&state->state32);
+}
+
+extern void init_rand(struct frand_state *, int);
+extern void init_rand_seed(struct frand_state *, unsigned int seed, int);
+extern void __fill_random_buf(void *buf, unsigned int len, unsigned long seed);
+extern unsigned long fill_random_buf(struct frand_state *, void *buf, unsigned int len);
+extern void __fill_random_buf_percentage(unsigned long, void *, unsigned int, unsigned int, unsigned int, char *, unsigned int);
+extern unsigned long fill_random_buf_percentage(struct frand_state *, void *, unsigned int, unsigned int, unsigned int, char *, unsigned int);
+extern void fill_pattern(void *p, unsigned int len, char *pattern, unsigned int pattern_bytes);
 
 #endif