diff options
Diffstat (limited to 'lib/libc/stdlib/random.h')
| -rw-r--r-- | lib/libc/stdlib/random.h | 39 |
1 files changed, 39 insertions, 0 deletions
diff --git a/lib/libc/stdlib/random.h b/lib/libc/stdlib/random.h index ae5f662dfde2..01a28319f482 100644 --- a/lib/libc/stdlib/random.h +++ b/lib/libc/stdlib/random.h @@ -27,6 +27,44 @@ #pragma once +/* + * For each of the currently supported random number generators, we have a + * break value on the amount of state information (you need at least this + * many bytes of state info to support this random number generator), a degree + * for the polynomial (actually a trinomial) that the R.N.G. is based on, and + * the separation between the two lower order coefficients of the trinomial. + */ +#define TYPE_0 0 /* linear congruential */ +#define BREAK_0 8 +#define DEG_0 0 +#define SEP_0 0 + +#define TYPE_1 1 /* x**7 + x**3 + 1 */ +#define BREAK_1 32 +#define DEG_1 7 +#define SEP_1 3 + +#define TYPE_2 2 /* x**15 + x + 1 */ +#define BREAK_2 64 +#define DEG_2 15 +#define SEP_2 1 + +#define TYPE_3 3 /* x**31 + x**3 + 1 */ +#define BREAK_3 128 +#define DEG_3 31 +#define SEP_3 3 + +#define TYPE_4 4 /* x**63 + x + 1 */ +#define BREAK_4 256 +#define DEG_4 63 +#define SEP_4 1 + +/* + * Array versions of the above information to make code run faster -- + * relies on fact that TYPE_i == i. + */ +#define MAX_TYPES 5 /* max number of types above */ + /* A full instance of the random(3) generator. */ struct __random_state { uint32_t *rst_fptr; @@ -40,6 +78,7 @@ struct __random_state { uint32_t rst_randtbl[]; }; +struct __random_state *allocatestate(unsigned type); int initstate_r(struct __random_state *, unsigned, uint32_t *, size_t); long random_r(struct __random_state *); void srandom_r(struct __random_state *, unsigned); |