Commit | Line | Data |
---|---|---|
79c94bd3 JA |
1 | /* |
2 | This is a maximally equidistributed combined Tausworthe generator | |
3 | based on code from GNU Scientific Library 1.5 (30 Jun 2004) | |
4 | ||
5 | x_n = (s1_n ^ s2_n ^ s3_n) | |
6 | ||
7 | s1_{n+1} = (((s1_n & 4294967294) <<12) ^ (((s1_n <<13) ^ s1_n) >>19)) | |
8 | s2_{n+1} = (((s2_n & 4294967288) << 4) ^ (((s2_n << 2) ^ s2_n) >>25)) | |
9 | s3_{n+1} = (((s3_n & 4294967280) <<17) ^ (((s3_n << 3) ^ s3_n) >>11)) | |
10 | ||
11 | The period of this generator is about 2^88. | |
12 | ||
13 | From: P. L'Ecuyer, "Maximally Equidistributed Combined Tausworthe | |
14 | Generators", Mathematics of Computation, 65, 213 (1996), 203--213. | |
15 | ||
16 | This is available on the net from L'Ecuyer's home page, | |
17 | ||
18 | http://www.iro.umontreal.ca/~lecuyer/myftp/papers/tausme.ps | |
19 | ftp://ftp.iro.umontreal.ca/pub/simulation/lecuyer/papers/tausme.ps | |
20 | ||
21 | There is an erratum in the paper "Tables of Maximally | |
22 | Equidistributed Combined LFSR Generators", Mathematics of | |
23 | Computation, 68, 225 (1999), 261--269: | |
24 | http://www.iro.umontreal.ca/~lecuyer/myftp/papers/tausme2.ps | |
25 | ||
26 | ... the k_j most significant bits of z_j must be non- | |
27 | zero, for each j. (Note: this restriction also applies to the | |
28 | computer code given in [4], but was mistakenly not mentioned in | |
29 | that paper.) | |
30 | ||
31 | This affects the seeding procedure by imposing the requirement | |
32 | s1 > 1, s2 > 7, s3 > 15. | |
33 | ||
34 | */ | |
35 | ||
9c42684e | 36 | #include <string.h> |
d1af2894 | 37 | #include <assert.h> |
1fbbf72e | 38 | #include "rand.h" |
2cac8fcb | 39 | #include "lib/pattern.h" |
637ef8d9 | 40 | #include "../hash.h" |
1fbbf72e | 41 | |
16dc0710 JA |
42 | int arch_random; |
43 | ||
c3546b53 | 44 | static inline uint64_t __seed(uint64_t x, uint64_t m) |
1fbbf72e JA |
45 | { |
46 | return (x < m) ? x + m : x; | |
47 | } | |
48 | ||
5f2f3569 | 49 | static void __init_rand32(struct taus88_state *state, unsigned int seed) |
2615cc4b JA |
50 | { |
51 | int cranks = 6; | |
52 | ||
53 | #define LCG(x, seed) ((x) * 69069 ^ (seed)) | |
54 | ||
55 | state->s1 = __seed(LCG((2^31) + (2^17) + (2^7), seed), 1); | |
56 | state->s2 = __seed(LCG(state->s1, seed), 7); | |
57 | state->s3 = __seed(LCG(state->s2, seed), 15); | |
58 | ||
59 | while (cranks--) | |
c3546b53 | 60 | __rand32(state); |
2615cc4b JA |
61 | } |
62 | ||
5f2f3569 | 63 | static void __init_rand64(struct taus258_state *state, uint64_t seed) |
1fbbf72e | 64 | { |
c3546b53 JA |
65 | int cranks = 6; |
66 | ||
67 | #define LCG64(x, seed) ((x) * 6906969069ULL ^ (seed)) | |
68 | ||
69 | state->s1 = __seed(LCG64((2^31) + (2^17) + (2^7), seed), 1); | |
70 | state->s2 = __seed(LCG64(state->s1, seed), 7); | |
71 | state->s3 = __seed(LCG64(state->s2, seed), 15); | |
72 | state->s4 = __seed(LCG64(state->s3, seed), 33); | |
73 | state->s5 = __seed(LCG64(state->s4, seed), 49); | |
74 | ||
75 | while (cranks--) | |
76 | __rand64(state); | |
2615cc4b JA |
77 | } |
78 | ||
de4096e8 | 79 | void init_rand(struct frand_state *state, bool use64) |
2615cc4b | 80 | { |
c3546b53 JA |
81 | state->use64 = use64; |
82 | ||
83 | if (!use64) | |
84 | __init_rand32(&state->state32, 1); | |
85 | else | |
86 | __init_rand64(&state->state64, 1); | |
87 | } | |
88 | ||
de4096e8 | 89 | void init_rand_seed(struct frand_state *state, unsigned int seed, bool use64) |
c3546b53 JA |
90 | { |
91 | state->use64 = use64; | |
92 | ||
93 | if (!use64) | |
94 | __init_rand32(&state->state32, seed); | |
95 | else | |
96 | __init_rand64(&state->state64, seed); | |
1fbbf72e | 97 | } |
637ef8d9 | 98 | |
7d9fb455 | 99 | void __fill_random_buf(void *buf, unsigned int len, unsigned long seed) |
637ef8d9 | 100 | { |
6780906f | 101 | void *ptr = buf; |
637ef8d9 | 102 | |
6780906f | 103 | while (len) { |
74a92cdd JA |
104 | int this_len; |
105 | ||
6780906f JA |
106 | if (len >= sizeof(int64_t)) { |
107 | *((int64_t *) ptr) = seed; | |
74a92cdd | 108 | this_len = sizeof(int64_t); |
6780906f JA |
109 | } else if (len >= sizeof(int32_t)) { |
110 | *((int32_t *) ptr) = seed; | |
74a92cdd | 111 | this_len = sizeof(int32_t); |
6780906f JA |
112 | } else if (len >= sizeof(int16_t)) { |
113 | *((int16_t *) ptr) = seed; | |
74a92cdd | 114 | this_len = sizeof(int16_t); |
6780906f JA |
115 | } else { |
116 | *((int8_t *) ptr) = seed; | |
74a92cdd | 117 | this_len = sizeof(int8_t); |
6780906f | 118 | } |
74a92cdd JA |
119 | ptr += this_len; |
120 | len -= this_len; | |
7d9fb455 JA |
121 | seed *= GOLDEN_RATIO_PRIME; |
122 | seed >>= 3; | |
637ef8d9 JA |
123 | } |
124 | } | |
7d9fb455 | 125 | |
3545a109 JA |
126 | unsigned long fill_random_buf(struct frand_state *fs, void *buf, |
127 | unsigned int len) | |
7d9fb455 | 128 | { |
3545a109 | 129 | unsigned long r = __rand(fs); |
7d9fb455 JA |
130 | |
131 | if (sizeof(int) != sizeof(long *)) | |
3545a109 | 132 | r *= (unsigned long) __rand(fs); |
7d9fb455 JA |
133 | |
134 | __fill_random_buf(buf, len, r); | |
135 | return r; | |
136 | } | |
9c42684e | 137 | |
bc769898 JA |
138 | void __fill_random_buf_percentage(unsigned long seed, void *buf, |
139 | unsigned int percentage, | |
140 | unsigned int segment, unsigned int len, | |
141 | char *pattern, unsigned int pbytes) | |
9c42684e | 142 | { |
811ac503 | 143 | unsigned int this_len; |
9c42684e | 144 | |
811ac503 | 145 | if (percentage == 100) { |
d1af2894 | 146 | if (pbytes) |
2cac8fcb | 147 | (void)cpy_pattern(pattern, pbytes, buf, len); |
d1af2894 JA |
148 | else |
149 | memset(buf, 0, len); | |
bc769898 | 150 | return; |
811ac503 JA |
151 | } |
152 | ||
153 | if (segment > len) | |
154 | segment = len; | |
9c42684e | 155 | |
9c42684e JA |
156 | while (len) { |
157 | /* | |
158 | * Fill random chunk | |
159 | */ | |
160 | this_len = (segment * (100 - percentage)) / 100; | |
161 | if (this_len > len) | |
162 | this_len = len; | |
163 | ||
bc769898 | 164 | __fill_random_buf(buf, this_len, seed); |
9c42684e JA |
165 | |
166 | len -= this_len; | |
6780906f JA |
167 | if (!len) |
168 | break; | |
9c42684e JA |
169 | buf += this_len; |
170 | ||
811ac503 JA |
171 | if (this_len > len) |
172 | this_len = len; | |
6780906f JA |
173 | else if (len - this_len <= sizeof(long)) |
174 | this_len = len; | |
9c42684e | 175 | |
d1af2894 | 176 | if (pbytes) |
2cac8fcb | 177 | (void)cpy_pattern(pattern, pbytes, buf, this_len); |
d1af2894 JA |
178 | else |
179 | memset(buf, 0, this_len); | |
bc769898 | 180 | |
98836539 JA |
181 | len -= this_len; |
182 | buf += this_len; | |
9c42684e | 183 | } |
bc769898 JA |
184 | } |
185 | ||
186 | unsigned long fill_random_buf_percentage(struct frand_state *fs, void *buf, | |
187 | unsigned int percentage, | |
188 | unsigned int segment, unsigned int len, | |
189 | char *pattern, unsigned int pbytes) | |
190 | { | |
191 | unsigned long r = __rand(fs); | |
192 | ||
193 | if (sizeof(int) != sizeof(long *)) | |
194 | r *= (unsigned long) __rand(fs); | |
9c42684e | 195 | |
bc769898 JA |
196 | __fill_random_buf_percentage(r, buf, percentage, segment, len, |
197 | pattern, pbytes); | |
9c42684e JA |
198 | return r; |
199 | } |