1/*
2 * This file derives from SFMT 1.3.3
3 * (http://www.math.sci.hiroshima-u.ac.jp/~m-mat/MT/SFMT/index.html), which was
4 * released under the terms of the following license:
5 *
6 *   Copyright (c) 2006,2007 Mutsuo Saito, Makoto Matsumoto and Hiroshima
7 *   University. All rights reserved.
8 *
9 *   Redistribution and use in source and binary forms, with or without
10 *   modification, are permitted provided that the following conditions are
11 *   met:
12 *
13 *       * Redistributions of source code must retain the above copyright
14 *         notice, this list of conditions and the following disclaimer.
15 *       * Redistributions in binary form must reproduce the above
16 *         copyright notice, this list of conditions and the following
17 *         disclaimer in the documentation and/or other materials provided
18 *         with the distribution.
19 *       * Neither the name of the Hiroshima University nor the names of
20 *         its contributors may be used to endorse or promote products
21 *         derived from this software without specific prior written
22 *         permission.
23 *
24 *   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
25 *   "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
26 *   LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
27 *   A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
28 *   OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
29 *   SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
30 *   LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
31 *   DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
32 *   THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
33 *   (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
34 *   OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
35 */
36/**
37 * @file  SFMT.c
38 * @brief SIMD oriented Fast Mersenne Twister(SFMT)
39 *
40 * @author Mutsuo Saito (Hiroshima University)
41 * @author Makoto Matsumoto (Hiroshima University)
42 *
43 * Copyright (C) 2006,2007 Mutsuo Saito, Makoto Matsumoto and Hiroshima
44 * University. All rights reserved.
45 *
46 * The new BSD License is applied to this software, see LICENSE.txt
47 */
48#define	SFMT_C_
49#include "test/jemalloc_test.h"
50#include "test/SFMT-params.h"
51
52#if defined(JEMALLOC_BIG_ENDIAN) && !defined(BIG_ENDIAN64)
53#define BIG_ENDIAN64 1
54#endif
55#if defined(__BIG_ENDIAN__) && !defined(__amd64) && !defined(BIG_ENDIAN64)
56#define BIG_ENDIAN64 1
57#endif
58#if defined(HAVE_ALTIVEC) && !defined(BIG_ENDIAN64)
59#define BIG_ENDIAN64 1
60#endif
61#if defined(ONLY64) && !defined(BIG_ENDIAN64)
62  #if defined(__GNUC__)
63    #error "-DONLY64 must be specified with -DBIG_ENDIAN64"
64  #endif
65#undef ONLY64
66#endif
67/*------------------------------------------------------
68  128-bit SIMD data type for Altivec, SSE2 or standard C
69  ------------------------------------------------------*/
70#if defined(HAVE_ALTIVEC)
71/** 128-bit data structure */
72union W128_T {
73    vector unsigned int s;
74    uint32_t u[4];
75};
76/** 128-bit data type */
77typedef union W128_T w128_t;
78
79#elif defined(HAVE_SSE2)
80/** 128-bit data structure */
81union W128_T {
82    __m128i si;
83    uint32_t u[4];
84};
85/** 128-bit data type */
86typedef union W128_T w128_t;
87
88#else
89
90/** 128-bit data structure */
91struct W128_T {
92    uint32_t u[4];
93};
94/** 128-bit data type */
95typedef struct W128_T w128_t;
96
97#endif
98
99struct sfmt_s {
100    /** the 128-bit internal state array */
101    w128_t sfmt[N];
102    /** index counter to the 32-bit internal state array */
103    int idx;
104    /** a flag: it is 0 if and only if the internal state is not yet
105     * initialized. */
106    int initialized;
107};
108
109/*--------------------------------------
110  FILE GLOBAL VARIABLES
111  internal state, index counter and flag
112  --------------------------------------*/
113
114/** a parity check vector which certificate the period of 2^{MEXP} */
115static uint32_t parity[4] = {PARITY1, PARITY2, PARITY3, PARITY4};
116
117/*----------------
118  STATIC FUNCTIONS
119  ----------------*/
120JEMALLOC_INLINE_C int idxof(int i);
121#if (!defined(HAVE_ALTIVEC)) && (!defined(HAVE_SSE2))
122JEMALLOC_INLINE_C void rshift128(w128_t *out,  w128_t const *in, int shift);
123JEMALLOC_INLINE_C void lshift128(w128_t *out,  w128_t const *in, int shift);
124#endif
125JEMALLOC_INLINE_C void gen_rand_all(sfmt_t *ctx);
126JEMALLOC_INLINE_C void gen_rand_array(sfmt_t *ctx, w128_t *array, int size);
127JEMALLOC_INLINE_C uint32_t func1(uint32_t x);
128JEMALLOC_INLINE_C uint32_t func2(uint32_t x);
129static void period_certification(sfmt_t *ctx);
130#if defined(BIG_ENDIAN64) && !defined(ONLY64)
131JEMALLOC_INLINE_C void swap(w128_t *array, int size);
132#endif
133
134#if defined(HAVE_ALTIVEC)
135  #include "test/SFMT-alti.h"
136#elif defined(HAVE_SSE2)
137  #include "test/SFMT-sse2.h"
138#endif
139
140/**
141 * This function simulate a 64-bit index of LITTLE ENDIAN
142 * in BIG ENDIAN machine.
143 */
144#ifdef ONLY64
145JEMALLOC_INLINE_C int idxof(int i) {
146    return i ^ 1;
147}
148#else
149JEMALLOC_INLINE_C int idxof(int i) {
150    return i;
151}
152#endif
153/**
154 * This function simulates SIMD 128-bit right shift by the standard C.
155 * The 128-bit integer given in in is shifted by (shift * 8) bits.
156 * This function simulates the LITTLE ENDIAN SIMD.
157 * @param out the output of this function
158 * @param in the 128-bit data to be shifted
159 * @param shift the shift value
160 */
161#if (!defined(HAVE_ALTIVEC)) && (!defined(HAVE_SSE2))
162#ifdef ONLY64
163JEMALLOC_INLINE_C void rshift128(w128_t *out, w128_t const *in, int shift) {
164    uint64_t th, tl, oh, ol;
165
166    th = ((uint64_t)in->u[2] << 32) | ((uint64_t)in->u[3]);
167    tl = ((uint64_t)in->u[0] << 32) | ((uint64_t)in->u[1]);
168
169    oh = th >> (shift * 8);
170    ol = tl >> (shift * 8);
171    ol |= th << (64 - shift * 8);
172    out->u[0] = (uint32_t)(ol >> 32);
173    out->u[1] = (uint32_t)ol;
174    out->u[2] = (uint32_t)(oh >> 32);
175    out->u[3] = (uint32_t)oh;
176}
177#else
178JEMALLOC_INLINE_C void rshift128(w128_t *out, w128_t const *in, int shift) {
179    uint64_t th, tl, oh, ol;
180
181    th = ((uint64_t)in->u[3] << 32) | ((uint64_t)in->u[2]);
182    tl = ((uint64_t)in->u[1] << 32) | ((uint64_t)in->u[0]);
183
184    oh = th >> (shift * 8);
185    ol = tl >> (shift * 8);
186    ol |= th << (64 - shift * 8);
187    out->u[1] = (uint32_t)(ol >> 32);
188    out->u[0] = (uint32_t)ol;
189    out->u[3] = (uint32_t)(oh >> 32);
190    out->u[2] = (uint32_t)oh;
191}
192#endif
193/**
194 * This function simulates SIMD 128-bit left shift by the standard C.
195 * The 128-bit integer given in in is shifted by (shift * 8) bits.
196 * This function simulates the LITTLE ENDIAN SIMD.
197 * @param out the output of this function
198 * @param in the 128-bit data to be shifted
199 * @param shift the shift value
200 */
201#ifdef ONLY64
202JEMALLOC_INLINE_C void lshift128(w128_t *out, w128_t const *in, int shift) {
203    uint64_t th, tl, oh, ol;
204
205    th = ((uint64_t)in->u[2] << 32) | ((uint64_t)in->u[3]);
206    tl = ((uint64_t)in->u[0] << 32) | ((uint64_t)in->u[1]);
207
208    oh = th << (shift * 8);
209    ol = tl << (shift * 8);
210    oh |= tl >> (64 - shift * 8);
211    out->u[0] = (uint32_t)(ol >> 32);
212    out->u[1] = (uint32_t)ol;
213    out->u[2] = (uint32_t)(oh >> 32);
214    out->u[3] = (uint32_t)oh;
215}
216#else
217JEMALLOC_INLINE_C void lshift128(w128_t *out, w128_t const *in, int shift) {
218    uint64_t th, tl, oh, ol;
219
220    th = ((uint64_t)in->u[3] << 32) | ((uint64_t)in->u[2]);
221    tl = ((uint64_t)in->u[1] << 32) | ((uint64_t)in->u[0]);
222
223    oh = th << (shift * 8);
224    ol = tl << (shift * 8);
225    oh |= tl >> (64 - shift * 8);
226    out->u[1] = (uint32_t)(ol >> 32);
227    out->u[0] = (uint32_t)ol;
228    out->u[3] = (uint32_t)(oh >> 32);
229    out->u[2] = (uint32_t)oh;
230}
231#endif
232#endif
233
234/**
235 * This function represents the recursion formula.
236 * @param r output
237 * @param a a 128-bit part of the internal state array
238 * @param b a 128-bit part of the internal state array
239 * @param c a 128-bit part of the internal state array
240 * @param d a 128-bit part of the internal state array
241 */
242#if (!defined(HAVE_ALTIVEC)) && (!defined(HAVE_SSE2))
243#ifdef ONLY64
244JEMALLOC_INLINE_C void do_recursion(w128_t *r, w128_t *a, w128_t *b, w128_t *c,
245				w128_t *d) {
246    w128_t x;
247    w128_t y;
248
249    lshift128(&x, a, SL2);
250    rshift128(&y, c, SR2);
251    r->u[0] = a->u[0] ^ x.u[0] ^ ((b->u[0] >> SR1) & MSK2) ^ y.u[0]
252	^ (d->u[0] << SL1);
253    r->u[1] = a->u[1] ^ x.u[1] ^ ((b->u[1] >> SR1) & MSK1) ^ y.u[1]
254	^ (d->u[1] << SL1);
255    r->u[2] = a->u[2] ^ x.u[2] ^ ((b->u[2] >> SR1) & MSK4) ^ y.u[2]
256	^ (d->u[2] << SL1);
257    r->u[3] = a->u[3] ^ x.u[3] ^ ((b->u[3] >> SR1) & MSK3) ^ y.u[3]
258	^ (d->u[3] << SL1);
259}
260#else
261JEMALLOC_INLINE_C void do_recursion(w128_t *r, w128_t *a, w128_t *b, w128_t *c,
262				w128_t *d) {
263    w128_t x;
264    w128_t y;
265
266    lshift128(&x, a, SL2);
267    rshift128(&y, c, SR2);
268    r->u[0] = a->u[0] ^ x.u[0] ^ ((b->u[0] >> SR1) & MSK1) ^ y.u[0]
269	^ (d->u[0] << SL1);
270    r->u[1] = a->u[1] ^ x.u[1] ^ ((b->u[1] >> SR1) & MSK2) ^ y.u[1]
271	^ (d->u[1] << SL1);
272    r->u[2] = a->u[2] ^ x.u[2] ^ ((b->u[2] >> SR1) & MSK3) ^ y.u[2]
273	^ (d->u[2] << SL1);
274    r->u[3] = a->u[3] ^ x.u[3] ^ ((b->u[3] >> SR1) & MSK4) ^ y.u[3]
275	^ (d->u[3] << SL1);
276}
277#endif
278#endif
279
280#if (!defined(HAVE_ALTIVEC)) && (!defined(HAVE_SSE2))
281/**
282 * This function fills the internal state array with pseudorandom
283 * integers.
284 */
285JEMALLOC_INLINE_C void gen_rand_all(sfmt_t *ctx) {
286    int i;
287    w128_t *r1, *r2;
288
289    r1 = &ctx->sfmt[N - 2];
290    r2 = &ctx->sfmt[N - 1];
291    for (i = 0; i < N - POS1; i++) {
292	do_recursion(&ctx->sfmt[i], &ctx->sfmt[i], &ctx->sfmt[i + POS1], r1,
293	  r2);
294	r1 = r2;
295	r2 = &ctx->sfmt[i];
296    }
297    for (; i < N; i++) {
298	do_recursion(&ctx->sfmt[i], &ctx->sfmt[i], &ctx->sfmt[i + POS1 - N], r1,
299	  r2);
300	r1 = r2;
301	r2 = &ctx->sfmt[i];
302    }
303}
304
305/**
306 * This function fills the user-specified array with pseudorandom
307 * integers.
308 *
309 * @param array an 128-bit array to be filled by pseudorandom numbers.
310 * @param size number of 128-bit pseudorandom numbers to be generated.
311 */
312JEMALLOC_INLINE_C void gen_rand_array(sfmt_t *ctx, w128_t *array, int size) {
313    int i, j;
314    w128_t *r1, *r2;
315
316    r1 = &ctx->sfmt[N - 2];
317    r2 = &ctx->sfmt[N - 1];
318    for (i = 0; i < N - POS1; i++) {
319	do_recursion(&array[i], &ctx->sfmt[i], &ctx->sfmt[i + POS1], r1, r2);
320	r1 = r2;
321	r2 = &array[i];
322    }
323    for (; i < N; i++) {
324	do_recursion(&array[i], &ctx->sfmt[i], &array[i + POS1 - N], r1, r2);
325	r1 = r2;
326	r2 = &array[i];
327    }
328    for (; i < size - N; i++) {
329	do_recursion(&array[i], &array[i - N], &array[i + POS1 - N], r1, r2);
330	r1 = r2;
331	r2 = &array[i];
332    }
333    for (j = 0; j < 2 * N - size; j++) {
334	ctx->sfmt[j] = array[j + size - N];
335    }
336    for (; i < size; i++, j++) {
337	do_recursion(&array[i], &array[i - N], &array[i + POS1 - N], r1, r2);
338	r1 = r2;
339	r2 = &array[i];
340	ctx->sfmt[j] = array[i];
341    }
342}
343#endif
344
345#if defined(BIG_ENDIAN64) && !defined(ONLY64) && !defined(HAVE_ALTIVEC)
346JEMALLOC_INLINE_C void swap(w128_t *array, int size) {
347    int i;
348    uint32_t x, y;
349
350    for (i = 0; i < size; i++) {
351	x = array[i].u[0];
352	y = array[i].u[2];
353	array[i].u[0] = array[i].u[1];
354	array[i].u[2] = array[i].u[3];
355	array[i].u[1] = x;
356	array[i].u[3] = y;
357    }
358}
359#endif
360/**
361 * This function represents a function used in the initialization
362 * by init_by_array
363 * @param x 32-bit integer
364 * @return 32-bit integer
365 */
366static uint32_t func1(uint32_t x) {
367    return (x ^ (x >> 27)) * (uint32_t)1664525UL;
368}
369
370/**
371 * This function represents a function used in the initialization
372 * by init_by_array
373 * @param x 32-bit integer
374 * @return 32-bit integer
375 */
376static uint32_t func2(uint32_t x) {
377    return (x ^ (x >> 27)) * (uint32_t)1566083941UL;
378}
379
380/**
381 * This function certificate the period of 2^{MEXP}
382 */
383static void period_certification(sfmt_t *ctx) {
384    int inner = 0;
385    int i, j;
386    uint32_t work;
387    uint32_t *psfmt32 = &ctx->sfmt[0].u[0];
388
389    for (i = 0; i < 4; i++)
390	inner ^= psfmt32[idxof(i)] & parity[i];
391    for (i = 16; i > 0; i >>= 1)
392	inner ^= inner >> i;
393    inner &= 1;
394    /* check OK */
395    if (inner == 1) {
396	return;
397    }
398    /* check NG, and modification */
399    for (i = 0; i < 4; i++) {
400	work = 1;
401	for (j = 0; j < 32; j++) {
402	    if ((work & parity[i]) != 0) {
403		psfmt32[idxof(i)] ^= work;
404		return;
405	    }
406	    work = work << 1;
407	}
408    }
409}
410
411/*----------------
412  PUBLIC FUNCTIONS
413  ----------------*/
414/**
415 * This function returns the identification string.
416 * The string shows the word size, the Mersenne exponent,
417 * and all parameters of this generator.
418 */
419const char *get_idstring(void) {
420    return IDSTR;
421}
422
423/**
424 * This function returns the minimum size of array used for \b
425 * fill_array32() function.
426 * @return minimum size of array used for fill_array32() function.
427 */
428int get_min_array_size32(void) {
429    return N32;
430}
431
432/**
433 * This function returns the minimum size of array used for \b
434 * fill_array64() function.
435 * @return minimum size of array used for fill_array64() function.
436 */
437int get_min_array_size64(void) {
438    return N64;
439}
440
441#ifndef ONLY64
442/**
443 * This function generates and returns 32-bit pseudorandom number.
444 * init_gen_rand or init_by_array must be called before this function.
445 * @return 32-bit pseudorandom number
446 */
447uint32_t gen_rand32(sfmt_t *ctx) {
448    uint32_t r;
449    uint32_t *psfmt32 = &ctx->sfmt[0].u[0];
450
451    assert(ctx->initialized);
452    if (ctx->idx >= N32) {
453	gen_rand_all(ctx);
454	ctx->idx = 0;
455    }
456    r = psfmt32[ctx->idx++];
457    return r;
458}
459
460/* Generate a random integer in [0..limit). */
461uint32_t gen_rand32_range(sfmt_t *ctx, uint32_t limit) {
462    uint32_t ret, above;
463
464    above = 0xffffffffU - (0xffffffffU % limit);
465    while (1) {
466	ret = gen_rand32(ctx);
467	if (ret < above) {
468	    ret %= limit;
469	    break;
470	}
471    }
472    return ret;
473}
474#endif
475/**
476 * This function generates and returns 64-bit pseudorandom number.
477 * init_gen_rand or init_by_array must be called before this function.
478 * The function gen_rand64 should not be called after gen_rand32,
479 * unless an initialization is again executed.
480 * @return 64-bit pseudorandom number
481 */
482uint64_t gen_rand64(sfmt_t *ctx) {
483#if defined(BIG_ENDIAN64) && !defined(ONLY64)
484    uint32_t r1, r2;
485    uint32_t *psfmt32 = &ctx->sfmt[0].u[0];
486#else
487    uint64_t r;
488    uint64_t *psfmt64 = (uint64_t *)&ctx->sfmt[0].u[0];
489#endif
490
491    assert(ctx->initialized);
492    assert(ctx->idx % 2 == 0);
493
494    if (ctx->idx >= N32) {
495	gen_rand_all(ctx);
496	ctx->idx = 0;
497    }
498#if defined(BIG_ENDIAN64) && !defined(ONLY64)
499    r1 = psfmt32[ctx->idx];
500    r2 = psfmt32[ctx->idx + 1];
501    ctx->idx += 2;
502    return ((uint64_t)r2 << 32) | r1;
503#else
504    r = psfmt64[ctx->idx / 2];
505    ctx->idx += 2;
506    return r;
507#endif
508}
509
510/* Generate a random integer in [0..limit). */
511uint64_t gen_rand64_range(sfmt_t *ctx, uint64_t limit) {
512    uint64_t ret, above;
513
514    above = KQU(0xffffffffffffffff) - (KQU(0xffffffffffffffff) % limit);
515    while (1) {
516	ret = gen_rand64(ctx);
517	if (ret < above) {
518	    ret %= limit;
519	    break;
520	}
521    }
522    return ret;
523}
524
525#ifndef ONLY64
526/**
527 * This function generates pseudorandom 32-bit integers in the
528 * specified array[] by one call. The number of pseudorandom integers
529 * is specified by the argument size, which must be at least 624 and a
530 * multiple of four.  The generation by this function is much faster
531 * than the following gen_rand function.
532 *
533 * For initialization, init_gen_rand or init_by_array must be called
534 * before the first call of this function. This function can not be
535 * used after calling gen_rand function, without initialization.
536 *
537 * @param array an array where pseudorandom 32-bit integers are filled
538 * by this function.  The pointer to the array must be \b "aligned"
539 * (namely, must be a multiple of 16) in the SIMD version, since it
540 * refers to the address of a 128-bit integer.  In the standard C
541 * version, the pointer is arbitrary.
542 *
543 * @param size the number of 32-bit pseudorandom integers to be
544 * generated.  size must be a multiple of 4, and greater than or equal
545 * to (MEXP / 128 + 1) * 4.
546 *
547 * @note \b memalign or \b posix_memalign is available to get aligned
548 * memory. Mac OSX doesn't have these functions, but \b malloc of OSX
549 * returns the pointer to the aligned memory block.
550 */
551void fill_array32(sfmt_t *ctx, uint32_t *array, int size) {
552    assert(ctx->initialized);
553    assert(ctx->idx == N32);
554    assert(size % 4 == 0);
555    assert(size >= N32);
556
557    gen_rand_array(ctx, (w128_t *)array, size / 4);
558    ctx->idx = N32;
559}
560#endif
561
562/**
563 * This function generates pseudorandom 64-bit integers in the
564 * specified array[] by one call. The number of pseudorandom integers
565 * is specified by the argument size, which must be at least 312 and a
566 * multiple of two.  The generation by this function is much faster
567 * than the following gen_rand function.
568 *
569 * For initialization, init_gen_rand or init_by_array must be called
570 * before the first call of this function. This function can not be
571 * used after calling gen_rand function, without initialization.
572 *
573 * @param array an array where pseudorandom 64-bit integers are filled
574 * by this function.  The pointer to the array must be "aligned"
575 * (namely, must be a multiple of 16) in the SIMD version, since it
576 * refers to the address of a 128-bit integer.  In the standard C
577 * version, the pointer is arbitrary.
578 *
579 * @param size the number of 64-bit pseudorandom integers to be
580 * generated.  size must be a multiple of 2, and greater than or equal
581 * to (MEXP / 128 + 1) * 2
582 *
583 * @note \b memalign or \b posix_memalign is available to get aligned
584 * memory. Mac OSX doesn't have these functions, but \b malloc of OSX
585 * returns the pointer to the aligned memory block.
586 */
587void fill_array64(sfmt_t *ctx, uint64_t *array, int size) {
588    assert(ctx->initialized);
589    assert(ctx->idx == N32);
590    assert(size % 2 == 0);
591    assert(size >= N64);
592
593    gen_rand_array(ctx, (w128_t *)array, size / 2);
594    ctx->idx = N32;
595
596#if defined(BIG_ENDIAN64) && !defined(ONLY64)
597    swap((w128_t *)array, size /2);
598#endif
599}
600
601/**
602 * This function initializes the internal state array with a 32-bit
603 * integer seed.
604 *
605 * @param seed a 32-bit integer used as the seed.
606 */
607sfmt_t *init_gen_rand(uint32_t seed) {
608    void *p;
609    sfmt_t *ctx;
610    int i;
611    uint32_t *psfmt32;
612
613    if (posix_memalign(&p, sizeof(w128_t), sizeof(sfmt_t)) != 0) {
614	return NULL;
615    }
616    ctx = (sfmt_t *)p;
617    psfmt32 = &ctx->sfmt[0].u[0];
618
619    psfmt32[idxof(0)] = seed;
620    for (i = 1; i < N32; i++) {
621	psfmt32[idxof(i)] = 1812433253UL * (psfmt32[idxof(i - 1)]
622					    ^ (psfmt32[idxof(i - 1)] >> 30))
623	    + i;
624    }
625    ctx->idx = N32;
626    period_certification(ctx);
627    ctx->initialized = 1;
628
629    return ctx;
630}
631
632/**
633 * This function initializes the internal state array,
634 * with an array of 32-bit integers used as the seeds
635 * @param init_key the array of 32-bit integers, used as a seed.
636 * @param key_length the length of init_key.
637 */
638sfmt_t *init_by_array(uint32_t *init_key, int key_length) {
639    void *p;
640    sfmt_t *ctx;
641    int i, j, count;
642    uint32_t r;
643    int lag;
644    int mid;
645    int size = N * 4;
646    uint32_t *psfmt32;
647
648    if (posix_memalign(&p, sizeof(w128_t), sizeof(sfmt_t)) != 0) {
649	return NULL;
650    }
651    ctx = (sfmt_t *)p;
652    psfmt32 = &ctx->sfmt[0].u[0];
653
654    if (size >= 623) {
655	lag = 11;
656    } else if (size >= 68) {
657	lag = 7;
658    } else if (size >= 39) {
659	lag = 5;
660    } else {
661	lag = 3;
662    }
663    mid = (size - lag) / 2;
664
665    memset(ctx->sfmt, 0x8b, sizeof(ctx->sfmt));
666    if (key_length + 1 > N32) {
667	count = key_length + 1;
668    } else {
669	count = N32;
670    }
671    r = func1(psfmt32[idxof(0)] ^ psfmt32[idxof(mid)]
672	      ^ psfmt32[idxof(N32 - 1)]);
673    psfmt32[idxof(mid)] += r;
674    r += key_length;
675    psfmt32[idxof(mid + lag)] += r;
676    psfmt32[idxof(0)] = r;
677
678    count--;
679    for (i = 1, j = 0; (j < count) && (j < key_length); j++) {
680	r = func1(psfmt32[idxof(i)] ^ psfmt32[idxof((i + mid) % N32)]
681		  ^ psfmt32[idxof((i + N32 - 1) % N32)]);
682	psfmt32[idxof((i + mid) % N32)] += r;
683	r += init_key[j] + i;
684	psfmt32[idxof((i + mid + lag) % N32)] += r;
685	psfmt32[idxof(i)] = r;
686	i = (i + 1) % N32;
687    }
688    for (; j < count; j++) {
689	r = func1(psfmt32[idxof(i)] ^ psfmt32[idxof((i + mid) % N32)]
690		  ^ psfmt32[idxof((i + N32 - 1) % N32)]);
691	psfmt32[idxof((i + mid) % N32)] += r;
692	r += i;
693	psfmt32[idxof((i + mid + lag) % N32)] += r;
694	psfmt32[idxof(i)] = r;
695	i = (i + 1) % N32;
696    }
697    for (j = 0; j < N32; j++) {
698	r = func2(psfmt32[idxof(i)] + psfmt32[idxof((i + mid) % N32)]
699		  + psfmt32[idxof((i + N32 - 1) % N32)]);
700	psfmt32[idxof((i + mid) % N32)] ^= r;
701	r -= i;
702	psfmt32[idxof((i + mid + lag) % N32)] ^= r;
703	psfmt32[idxof(i)] = r;
704	i = (i + 1) % N32;
705    }
706
707    ctx->idx = N32;
708    period_certification(ctx);
709    ctx->initialized = 1;
710
711    return ctx;
712}
713
714void fini_gen_rand(sfmt_t *ctx) {
715    assert(ctx != NULL);
716
717    ctx->initialized = 0;
718    free(ctx);
719}
720