Commit | Line | Data |
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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" |
637ef8d9 | 39 | #include "../hash.h" |
1fbbf72e | 40 | |
16dc0710 JA |
41 | int arch_random; |
42 | ||
c3546b53 | 43 | static inline uint64_t __seed(uint64_t x, uint64_t m) |
1fbbf72e JA |
44 | { |
45 | return (x < m) ? x + m : x; | |
46 | } | |
47 | ||
c3546b53 | 48 | static void __init_rand32(struct taus88_state *state, unsigned int seed) |
2615cc4b JA |
49 | { |
50 | int cranks = 6; | |
51 | ||
52 | #define LCG(x, seed) ((x) * 69069 ^ (seed)) | |
53 | ||
54 | state->s1 = __seed(LCG((2^31) + (2^17) + (2^7), seed), 1); | |
55 | state->s2 = __seed(LCG(state->s1, seed), 7); | |
56 | state->s3 = __seed(LCG(state->s2, seed), 15); | |
57 | ||
58 | while (cranks--) | |
c3546b53 | 59 | __rand32(state); |
2615cc4b JA |
60 | } |
61 | ||
c3546b53 | 62 | static void __init_rand64(struct taus258_state *state, uint64_t seed) |
1fbbf72e | 63 | { |
c3546b53 JA |
64 | int cranks = 6; |
65 | ||
66 | #define LCG64(x, seed) ((x) * 6906969069ULL ^ (seed)) | |
67 | ||
68 | state->s1 = __seed(LCG64((2^31) + (2^17) + (2^7), seed), 1); | |
69 | state->s2 = __seed(LCG64(state->s1, seed), 7); | |
70 | state->s3 = __seed(LCG64(state->s2, seed), 15); | |
71 | state->s4 = __seed(LCG64(state->s3, seed), 33); | |
72 | state->s5 = __seed(LCG64(state->s4, seed), 49); | |
73 | ||
74 | while (cranks--) | |
75 | __rand64(state); | |
2615cc4b JA |
76 | } |
77 | ||
c3546b53 | 78 | void init_rand(struct frand_state *state, int use64) |
2615cc4b | 79 | { |
c3546b53 JA |
80 | state->use64 = use64; |
81 | ||
82 | if (!use64) | |
83 | __init_rand32(&state->state32, 1); | |
84 | else | |
85 | __init_rand64(&state->state64, 1); | |
86 | } | |
87 | ||
88 | void init_rand_seed(struct frand_state *state, unsigned int seed, int use64) | |
89 | { | |
90 | state->use64 = use64; | |
91 | ||
92 | if (!use64) | |
93 | __init_rand32(&state->state32, seed); | |
94 | else | |
95 | __init_rand64(&state->state64, seed); | |
1fbbf72e | 96 | } |
637ef8d9 | 97 | |
7d9fb455 | 98 | void __fill_random_buf(void *buf, unsigned int len, unsigned long seed) |
637ef8d9 | 99 | { |
6780906f | 100 | void *ptr = buf; |
637ef8d9 | 101 | |
6780906f | 102 | while (len) { |
74a92cdd JA |
103 | int this_len; |
104 | ||
6780906f JA |
105 | if (len >= sizeof(int64_t)) { |
106 | *((int64_t *) ptr) = seed; | |
74a92cdd | 107 | this_len = sizeof(int64_t); |
6780906f JA |
108 | } else if (len >= sizeof(int32_t)) { |
109 | *((int32_t *) ptr) = seed; | |
74a92cdd | 110 | this_len = sizeof(int32_t); |
6780906f JA |
111 | } else if (len >= sizeof(int16_t)) { |
112 | *((int16_t *) ptr) = seed; | |
74a92cdd | 113 | this_len = sizeof(int16_t); |
6780906f JA |
114 | } else { |
115 | *((int8_t *) ptr) = seed; | |
74a92cdd | 116 | this_len = sizeof(int8_t); |
6780906f | 117 | } |
74a92cdd JA |
118 | ptr += this_len; |
119 | len -= this_len; | |
7d9fb455 JA |
120 | seed *= GOLDEN_RATIO_PRIME; |
121 | seed >>= 3; | |
637ef8d9 JA |
122 | } |
123 | } | |
7d9fb455 | 124 | |
3545a109 JA |
125 | unsigned long fill_random_buf(struct frand_state *fs, void *buf, |
126 | unsigned int len) | |
7d9fb455 | 127 | { |
3545a109 | 128 | unsigned long r = __rand(fs); |
7d9fb455 JA |
129 | |
130 | if (sizeof(int) != sizeof(long *)) | |
3545a109 | 131 | r *= (unsigned long) __rand(fs); |
7d9fb455 JA |
132 | |
133 | __fill_random_buf(buf, len, r); | |
134 | return r; | |
135 | } | |
9c42684e | 136 | |
d1af2894 JA |
137 | void fill_pattern(void *p, unsigned int len, char *pattern, |
138 | unsigned int pattern_bytes) | |
139 | { | |
140 | switch (pattern_bytes) { | |
141 | case 0: | |
142 | assert(0); | |
143 | break; | |
144 | case 1: | |
145 | memset(p, pattern[0], len); | |
146 | break; | |
147 | default: { | |
148 | unsigned int i = 0, size = 0; | |
149 | unsigned char *b = p; | |
150 | ||
151 | while (i < len) { | |
152 | size = pattern_bytes; | |
153 | if (size > (len - i)) | |
154 | size = len - i; | |
155 | memcpy(b+i, pattern, size); | |
156 | i += size; | |
157 | } | |
158 | break; | |
159 | } | |
160 | } | |
161 | } | |
162 | ||
bc769898 JA |
163 | void __fill_random_buf_percentage(unsigned long seed, void *buf, |
164 | unsigned int percentage, | |
165 | unsigned int segment, unsigned int len, | |
166 | char *pattern, unsigned int pbytes) | |
9c42684e | 167 | { |
811ac503 | 168 | unsigned int this_len; |
9c42684e | 169 | |
811ac503 | 170 | if (percentage == 100) { |
d1af2894 JA |
171 | if (pbytes) |
172 | fill_pattern(buf, len, pattern, pbytes); | |
173 | else | |
174 | memset(buf, 0, len); | |
bc769898 | 175 | return; |
811ac503 JA |
176 | } |
177 | ||
178 | if (segment > len) | |
179 | segment = len; | |
9c42684e | 180 | |
9c42684e JA |
181 | while (len) { |
182 | /* | |
183 | * Fill random chunk | |
184 | */ | |
185 | this_len = (segment * (100 - percentage)) / 100; | |
186 | if (this_len > len) | |
187 | this_len = len; | |
188 | ||
bc769898 | 189 | __fill_random_buf(buf, this_len, seed); |
9c42684e JA |
190 | |
191 | len -= this_len; | |
6780906f JA |
192 | if (!len) |
193 | break; | |
9c42684e JA |
194 | buf += this_len; |
195 | ||
811ac503 JA |
196 | if (this_len > len) |
197 | this_len = len; | |
6780906f JA |
198 | else if (len - this_len <= sizeof(long)) |
199 | this_len = len; | |
9c42684e | 200 | |
d1af2894 JA |
201 | if (pbytes) |
202 | fill_pattern(buf, this_len, pattern, pbytes); | |
203 | else | |
204 | memset(buf, 0, this_len); | |
bc769898 | 205 | |
98836539 JA |
206 | len -= this_len; |
207 | buf += this_len; | |
9c42684e | 208 | } |
bc769898 JA |
209 | } |
210 | ||
211 | unsigned long fill_random_buf_percentage(struct frand_state *fs, void *buf, | |
212 | unsigned int percentage, | |
213 | unsigned int segment, unsigned int len, | |
214 | char *pattern, unsigned int pbytes) | |
215 | { | |
216 | unsigned long r = __rand(fs); | |
217 | ||
218 | if (sizeof(int) != sizeof(long *)) | |
219 | r *= (unsigned long) __rand(fs); | |
9c42684e | 220 | |
bc769898 JA |
221 | __fill_random_buf_percentage(r, buf, percentage, segment, len, |
222 | pattern, pbytes); | |
9c42684e JA |
223 | return r; |
224 | } |