FD.io VPP  v21.01.1
Vector Packet Processing
random_isaac.c
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1 /*
2  * Copyright (c) 2015 Cisco and/or its affiliates.
3  * Licensed under the Apache License, Version 2.0 (the "License");
4  * you may not use this file except in compliance with the License.
5  * You may obtain a copy of the License at:
6  *
7  * http://www.apache.org/licenses/LICENSE-2.0
8  *
9  * Unless required by applicable law or agreed to in writing, software
10  * distributed under the License is distributed on an "AS IS" BASIS,
11  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12  * See the License for the specific language governing permissions and
13  * limitations under the License.
14  */
15 /*
16  ------------------------------------------------------------------------------
17  By Bob Jenkins, 1996, Public Domain
18  MODIFIED:
19  960327: Creation (addition of randinit, really)
20  970719: use context, not global variables, for internal state
21  980324: renamed seed to flag
22  980605: recommend ISAAC_LOG2_SIZE=4 for noncryptography.
23  010626: note this is public domain
24  ------------------------------------------------------------------------------
25 
26  Modified for CLIB by Eliot Dresselhaus.
27  Dear Bob, Thanks for all the great work. - Eliot
28 
29  modifications copyright (c) 2003 Eliot Dresselhaus
30 
31  Permission is hereby granted, free of charge, to any person obtaining
32  a copy of this software and associated documentation files (the
33  "Software"), to deal in the Software without restriction, including
34  without limitation the rights to use, copy, modify, merge, publish,
35  distribute, sublicense, and/or sell copies of the Software, and to
36  permit persons to whom the Software is furnished to do so, subject to
37  the following conditions:
38 
39  The above copyright notice and this permission notice shall be
40  included in all copies or substantial portions of the Software.
41 
42  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
43  EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
44  MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
45  NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
46  LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
47  OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
48  WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
49 */
50 
51 /* ISAAC is Bob Jenkins' random number generator.
52  http://burtleburtle.net/bob/rand/isaacafa.html */
53 
54 #include <vppinfra/random_isaac.h>
55 
56 #if uword_bits != 32 && uword_bits != 64
57 #error "isaac only works for 32 or 64 bit words"
58 #endif
59 
60 #if uword_bits == 32
61 
62 #define ind32(mm,x) (*(u32 *)((u8 *)(mm) + ((x) & ((ISAAC_SIZE-1)<<2))))
63 #define rngstep32(mix,a,b,mm,m,m2,r,x,y) \
64 { \
65  x = *m; \
66  a = (a^(mix)) + *(m2++); \
67  *(m++) = y = ind32(mm,x) + a + b; \
68  *(r++) = b = ind32(mm,y>>ISAAC_LOG2_SIZE) + x; \
69 }
70 
71 void
72 isaac (isaac_t * ctx, uword * results)
73 {
74  u32 a, b, c, x, y, *m, *mm, *m2, *r, *mend;
75 
76  mm = ctx->memory;
77  r = results;
78  a = ctx->a;
79  b = ctx->b;
80  c = ctx->c;
81 
82  b += ++c;
83  mend = m2 = mm + ARRAY_LEN (ctx->memory) / 2;
84  m = mm;
85  while (m < mend)
86  {
87  rngstep32 (a << 13, a, b, mm, m, m2, r, x, y);
88  rngstep32 (a >> 6, a, b, mm, m, m2, r, x, y);
89  rngstep32 (a << 2, a, b, mm, m, m2, r, x, y);
90  rngstep32 (a >> 16, a, b, mm, m, m2, r, x, y);
91  }
92 
93  m2 = mm;
94  while (m2 < mend)
95  {
96  rngstep32 (a << 13, a, b, mm, m, m2, r, x, y);
97  rngstep32 (a >> 6, a, b, mm, m, m2, r, x, y);
98  rngstep32 (a << 2, a, b, mm, m, m2, r, x, y);
99  rngstep32 (a >> 16, a, b, mm, m, m2, r, x, y);
100  }
101 
102  ctx->a = a;
103  ctx->b = b;
104  ctx->c = c;
105 }
106 
107 /* Perform 2 isaac runs with different contexts simultaneously. */
108 void
109 isaac2 (isaac_t * ctx, uword * results)
110 {
111 #define _(n) \
112  u32 a##n, b##n, c##n, x##n, y##n, * m##n, * mm##n, * m2##n, * r##n, * mend##n
113 
114  _(0);
115  _(1);
116  (void) mend1; /* "set but unused variable" error on mend1 with gcc 4.9 */
117 #undef _
118 
119 #define _(n) \
120 do { \
121  mm##n = ctx[(n)].memory; \
122  r##n = results + (n) * ISAAC_SIZE; \
123  a##n = ctx[(n)].a; \
124  b##n = ctx[(n)].b; \
125  c##n = ctx[(n)].c; \
126  b##n += ++c##n; \
127  mend##n = m2##n = mm##n + ARRAY_LEN (ctx[(n)].memory) / 2; \
128  m##n = mm##n; \
129 } while (0)
130 
131  _(0);
132  _(1);
133 
134 #undef _
135 
136  while (m0 < mend0)
137  {
138  rngstep32 (a0 << 13, a0, b0, mm0, m0, m20, r0, x0, y0);
139  rngstep32 (a1 << 13, a1, b1, mm1, m1, m21, r1, x1, y1);
140  rngstep32 (a0 >> 6, a0, b0, mm0, m0, m20, r0, x0, y0);
141  rngstep32 (a1 >> 6, a1, b1, mm1, m1, m21, r1, x1, y1);
142  rngstep32 (a0 << 2, a0, b0, mm0, m0, m20, r0, x0, y0);
143  rngstep32 (a1 << 2, a1, b1, mm1, m1, m21, r1, x1, y1);
144  rngstep32 (a0 >> 16, a0, b0, mm0, m0, m20, r0, x0, y0);
145  rngstep32 (a1 >> 16, a1, b1, mm1, m1, m21, r1, x1, y1);
146  }
147 
148  m20 = mm0;
149  m21 = mm1;
150  while (m20 < mend0)
151  {
152  rngstep32 (a0 << 13, a0, b0, mm0, m0, m20, r0, x0, y0);
153  rngstep32 (a1 << 13, a1, b1, mm1, m1, m21, r1, x1, y1);
154  rngstep32 (a0 >> 6, a0, b0, mm0, m0, m20, r0, x0, y0);
155  rngstep32 (a1 >> 6, a1, b1, mm1, m1, m21, r1, x1, y1);
156  rngstep32 (a0 << 2, a0, b0, mm0, m0, m20, r0, x0, y0);
157  rngstep32 (a1 << 2, a1, b1, mm1, m1, m21, r1, x1, y1);
158  rngstep32 (a0 >> 16, a0, b0, mm0, m0, m20, r0, x0, y0);
159  rngstep32 (a1 >> 16, a1, b1, mm1, m1, m21, r1, x1, y1);
160  }
161 
162  ctx[0].a = a0;
163  ctx[0].b = b0;
164  ctx[0].c = c0;
165  ctx[1].a = a1;
166  ctx[1].b = b1;
167  ctx[1].c = c1;
168 }
169 
170 #define mix32(a,b,c,d,e,f,g,h) \
171 { \
172  a^=b<<11; d+=a; b+=c; \
173  b^=c>>2; e+=b; c+=d; \
174  c^=d<<8; f+=c; d+=e; \
175  d^=e>>16; g+=d; e+=f; \
176  e^=f<<10; h+=e; f+=g; \
177  f^=g>>4; a+=f; g+=h; \
178  g^=h<<8; b+=g; h+=a; \
179  h^=a>>9; c+=h; a+=b; \
180 }
181 
182 void
183 isaac_init (isaac_t * ctx, uword * seeds)
184 {
185  word i;
186  u32 a, b, c, d, e, f, g, h, *m, *r;
187 
188  ctx->a = ctx->b = ctx->c = 0;
189  m = ctx->memory;
190  r = seeds;
191 
192  a = b = c = d = e = f = g = h = 0x9e3779b9; /* the golden ratio */
193 
194  for (i = 0; i < 4; ++i) /* scramble it */
195  mix32 (a, b, c, d, e, f, g, h);
196 
197  /* initialize using the contents of r[] as the seed */
198  for (i = 0; i < ISAAC_SIZE; i += 8)
199  {
200  a += r[i];
201  b += r[i + 1];
202  c += r[i + 2];
203  d += r[i + 3];
204  e += r[i + 4];
205  f += r[i + 5];
206  g += r[i + 6];
207  h += r[i + 7];
208  mix32 (a, b, c, d, e, f, g, h);
209  m[i] = a;
210  m[i + 1] = b;
211  m[i + 2] = c;
212  m[i + 3] = d;
213  m[i + 4] = e;
214  m[i + 5] = f;
215  m[i + 6] = g;
216  m[i + 7] = h;
217  }
218 
219  /* do a second pass to make all of the seed affect all of m */
220  for (i = 0; i < ISAAC_SIZE; i += 8)
221  {
222  a += m[i];
223  b += m[i + 1];
224  c += m[i + 2];
225  d += m[i + 3];
226  e += m[i + 4];
227  f += m[i + 5];
228  g += m[i + 6];
229  h += m[i + 7];
230  mix32 (a, b, c, d, e, f, g, h);
231  m[i] = a;
232  m[i + 1] = b;
233  m[i + 2] = c;
234  m[i + 3] = d;
235  m[i + 4] = e;
236  m[i + 5] = f;
237  m[i + 6] = g;
238  m[i + 7] = h;
239  }
240 }
241 #endif /* uword_bits == 32 */
242 
243 #if uword_bits == 64
244 
245 #define ind64(mm,x) (*(u64 *)((u8 *)(mm) + ((x) & ((ISAAC_SIZE-1)<<3))))
246 #define rngstep64(mix,a,b,mm,m,m2,r,x,y) \
247 { \
248  x = *m; \
249  a = (mix) + *(m2++); \
250  *(m++) = y = ind64(mm,x) + a + b; \
251  *(r++) = b = ind64(mm,y>>ISAAC_LOG2_SIZE) + x; \
252 }
253 
254 void
255 isaac (isaac_t * ctx, uword * results)
256 {
257  u64 a, b, c, x, y, *m, *mm, *m2, *r, *mend;
258 
259  mm = ctx->memory;
260  r = results;
261  a = ctx->a;
262  b = ctx->b;
263  c = ctx->c;
264 
265  b += ++c;
266  mend = m2 = mm + ARRAY_LEN (ctx->memory) / 2;
267  m = mm;
268  while (m < mend)
269  {
270  rngstep64 (~(a ^ (a << 21)), a, b, mm, m, m2, r, x, y);
271  rngstep64 (a ^ (a >> 5), a, b, mm, m, m2, r, x, y);
272  rngstep64 (a ^ (a << 12), a, b, mm, m, m2, r, x, y);
273  rngstep64 (a ^ (a >> 33), a, b, mm, m, m2, r, x, y);
274  }
275 
276  m2 = mm;
277  while (m2 < mend)
278  {
279  rngstep64 (~(a ^ (a << 21)), a, b, mm, m, m2, r, x, y);
280  rngstep64 (a ^ (a >> 5), a, b, mm, m, m2, r, x, y);
281  rngstep64 (a ^ (a << 12), a, b, mm, m, m2, r, x, y);
282  rngstep64 (a ^ (a >> 33), a, b, mm, m, m2, r, x, y);
283  }
284 
285  ctx->a = a;
286  ctx->b = b;
287  ctx->c = c;
288 }
289 
290 /* Perform 2 isaac runs with different contexts simultaneously. */
291 void
292 isaac2 (isaac_t * ctx, uword * results)
293 {
294 #define _(n) \
295  u64 a##n, b##n, c##n, x##n, y##n, * m##n, * mm##n, * m2##n, * r##n, * mend##n
296 
297  _(0);
298  _(1);
299 
300 #undef _
301 
302 #define _(n) \
303 do { \
304  mm##n = ctx[(n)].memory; \
305  r##n = results + (n) * ISAAC_SIZE; \
306  a##n = ctx[(n)].a; \
307  b##n = ctx[(n)].b; \
308  c##n = ctx[(n)].c; \
309  b##n += ++c##n; \
310  mend##n = m2##n = mm##n + ARRAY_LEN (ctx[(n)].memory) / 2; \
311  m##n = mm##n; \
312 } while (0)
313 
314  _(0);
315  _(1);
316 
317 #undef _
318 
319  (void) mend1; /* compiler warning */
320 
321  while (m0 < mend0)
322  {
323  rngstep64 (~(a0 ^ (a0 << 21)), a0, b0, mm0, m0, m20, r0, x0, y0);
324  rngstep64 (~(a1 ^ (a1 << 21)), a1, b1, mm1, m1, m21, r1, x1, y1);
325  rngstep64 (a0 ^ (a0 >> 5), a0, b0, mm0, m0, m20, r0, x0, y0);
326  rngstep64 (a1 ^ (a1 >> 5), a1, b1, mm1, m1, m21, r1, x1, y1);
327  rngstep64 (a0 ^ (a0 << 12), a0, b0, mm0, m0, m20, r0, x0, y0);
328  rngstep64 (a1 ^ (a1 << 12), a1, b1, mm1, m1, m21, r1, x1, y1);
329  rngstep64 (a0 ^ (a0 >> 33), a0, b0, mm0, m0, m20, r0, x0, y0);
330  rngstep64 (a1 ^ (a1 >> 33), a1, b1, mm1, m1, m21, r1, x1, y1);
331  }
332 
333  m20 = mm0;
334  m21 = mm1;
335  while (m20 < mend0)
336  {
337  rngstep64 (~(a0 ^ (a0 << 21)), a0, b0, mm0, m0, m20, r0, x0, y0);
338  rngstep64 (~(a1 ^ (a1 << 21)), a1, b1, mm1, m1, m21, r1, x1, y1);
339  rngstep64 (a0 ^ (a0 >> 5), a0, b0, mm0, m0, m20, r0, x0, y0);
340  rngstep64 (a1 ^ (a1 >> 5), a1, b1, mm1, m1, m21, r1, x1, y1);
341  rngstep64 (a0 ^ (a0 << 12), a0, b0, mm0, m0, m20, r0, x0, y0);
342  rngstep64 (a1 ^ (a1 << 12), a1, b1, mm1, m1, m21, r1, x1, y1);
343  rngstep64 (a0 ^ (a0 >> 33), a0, b0, mm0, m0, m20, r0, x0, y0);
344  rngstep64 (a1 ^ (a1 >> 33), a1, b1, mm1, m1, m21, r1, x1, y1);
345  }
346 
347  ctx[0].a = a0;
348  ctx[0].b = b0;
349  ctx[0].c = c0;
350  ctx[1].a = a1;
351  ctx[1].b = b1;
352  ctx[1].c = c1;
353 }
354 
355 #define mix64(a,b,c,d,e,f,g,h) \
356 { \
357  a-=e; f^=h>>9; h+=a; \
358  b-=f; g^=a<<9; a+=b; \
359  c-=g; h^=b>>23; b+=c; \
360  d-=h; a^=c<<15; c+=d; \
361  e-=a; b^=d>>14; d+=e; \
362  f-=b; c^=e<<20; e+=f; \
363  g-=c; d^=f>>17; f+=g; \
364  h-=d; e^=g<<14; g+=h; \
365 }
366 
367 void
368 isaac_init (isaac_t * ctx, uword * seeds)
369 {
370  word i;
371  u64 a, b, c, d, e, f, g, h, *m, *r;
372 
373  ctx->a = ctx->b = ctx->c = 0;
374  m = ctx->memory;
375  r = seeds;
376 
377  a = b = c = d = e = f = g = h = 0x9e3779b97f4a7c13LL; /* the golden ratio */
378 
379  for (i = 0; i < 4; ++i) /* scramble it */
380  mix64 (a, b, c, d, e, f, g, h);
381 
382  for (i = 0; i < ISAAC_SIZE; i += 8) /* fill in mm[] with messy stuff */
383  {
384  a += r[i];
385  b += r[i + 1];
386  c += r[i + 2];
387  d += r[i + 3];
388  e += r[i + 4];
389  f += r[i + 5];
390  g += r[i + 6];
391  h += r[i + 7];
392  mix64 (a, b, c, d, e, f, g, h);
393  m[i] = a;
394  m[i + 1] = b;
395  m[i + 2] = c;
396  m[i + 3] = d;
397  m[i + 4] = e;
398  m[i + 5] = f;
399  m[i + 6] = g;
400  m[i + 7] = h;
401  }
402 
403  /* do a second pass to make all of the seed affect all of mm */
404  for (i = 0; i < ISAAC_SIZE; i += 8)
405  {
406  a += m[i];
407  b += m[i + 1];
408  c += m[i + 2];
409  d += m[i + 3];
410  e += m[i + 4];
411  f += m[i + 5];
412  g += m[i + 6];
413  h += m[i + 7];
414  mix64 (a, b, c, d, e, f, g, h);
415  m[i] = a;
416  m[i + 1] = b;
417  m[i + 2] = c;
418  m[i + 3] = d;
419  m[i + 4] = e;
420  m[i + 5] = f;
421  m[i + 6] = g;
422  m[i + 7] = h;
423  }
424 }
425 #endif /* uword_bits == 64 */
426 
427 
428 /*
429  * fd.io coding-style-patch-verification: ON
430  *
431  * Local Variables:
432  * eval: (c-set-style "gnu")
433  * End:
434  */
isaac_t::a
uword a
Definition: random_isaac.h:64
a
a
Definition: bitmap.h:544
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void isaac_init(isaac_t *ctx, uword *results)
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Definition: types.h:89
isaac_t::memory
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Definition: random_isaac.h:63
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void isaac2(isaac_t *ctx, uword *results)
isaac_t::c
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Definition: random_isaac.h:64
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Definition: types.h:111
random_isaac.h
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unsigned int u32
Definition: types.h:88
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void isaac(isaac_t *ctx, uword *results)
h
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Definition: random_isaac.h:64
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#define ISAAC_SIZE
Definition: random_isaac.h:59
uword
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Definition: types.h:112