Training courses

Kernel and Embedded Linux

Bootlin training courses

Embedded Linux, kernel,
Yocto Project, Buildroot, real-time,
graphics, boot time, debugging...

Bootlin logo

Elixir Cross Referencer

  1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
/*
 * This file derives from SFMT 1.3.3
 * (http://www.math.sci.hiroshima-u.ac.jp/~m-mat/MT/SFMT/index.html), which was
 * released under the terms of the following license:
 *
 *   Copyright (c) 2006,2007 Mutsuo Saito, Makoto Matsumoto and Hiroshima
 *   University. All rights reserved.
 *
 *   Redistribution and use in source and binary forms, with or without
 *   modification, are permitted provided that the following conditions are
 *   met:
 *
 *       * Redistributions of source code must retain the above copyright
 *         notice, this list of conditions and the following disclaimer.
 *       * Redistributions in binary form must reproduce the above
 *         copyright notice, this list of conditions and the following
 *         disclaimer in the documentation and/or other materials provided
 *         with the distribution.
 *       * Neither the name of the Hiroshima University nor the names of
 *         its contributors may be used to endorse or promote products
 *         derived from this software without specific prior written
 *         permission.
 *
 *   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 *   "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 *   LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 *   A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 *   OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 *   SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 *   LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 *   DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 *   THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 *   (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 *   OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */
/**
 * @file  SFMT.c
 * @brief SIMD oriented Fast Mersenne Twister(SFMT)
 *
 * @author Mutsuo Saito (Hiroshima University)
 * @author Makoto Matsumoto (Hiroshima University)
 *
 * Copyright (C) 2006,2007 Mutsuo Saito, Makoto Matsumoto and Hiroshima
 * University. All rights reserved.
 *
 * The new BSD License is applied to this software, see LICENSE.txt
 */
#define SFMT_C_
#include "test/jemalloc_test.h"
#include "test/SFMT-params.h"

#if defined(JEMALLOC_BIG_ENDIAN) && !defined(BIG_ENDIAN64)
#define BIG_ENDIAN64 1
#endif
#if defined(__BIG_ENDIAN__) && !defined(__amd64) && !defined(BIG_ENDIAN64)
#define BIG_ENDIAN64 1
#endif
#if defined(HAVE_ALTIVEC) && !defined(BIG_ENDIAN64)
#define BIG_ENDIAN64 1
#endif
#if defined(ONLY64) && !defined(BIG_ENDIAN64)
  #if defined(__GNUC__)
    #error "-DONLY64 must be specified with -DBIG_ENDIAN64"
  #endif
#undef ONLY64
#endif
/*------------------------------------------------------
  128-bit SIMD data type for Altivec, SSE2 or standard C
  ------------------------------------------------------*/
#if defined(HAVE_ALTIVEC)
/** 128-bit data structure */
union W128_T {
    vector unsigned int s;
    uint32_t u[4];
};
/** 128-bit data type */
typedef union W128_T w128_t;

#elif defined(HAVE_SSE2)
/** 128-bit data structure */
union W128_T {
    __m128i si;
    uint32_t u[4];
};
/** 128-bit data type */
typedef union W128_T w128_t;

#else

/** 128-bit data structure */
struct W128_T {
    uint32_t u[4];
};
/** 128-bit data type */
typedef struct W128_T w128_t;

#endif

struct sfmt_s {
    /** the 128-bit internal state array */
    w128_t sfmt[N];
    /** index counter to the 32-bit internal state array */
    int idx;
    /** a flag: it is 0 if and only if the internal state is not yet
     * initialized. */
    int initialized;
};

/*--------------------------------------
  FILE GLOBAL VARIABLES
  internal state, index counter and flag
  --------------------------------------*/

/** a parity check vector which certificate the period of 2^{MEXP} */
static uint32_t parity[4] = {PARITY1, PARITY2, PARITY3, PARITY4};

/*----------------
  STATIC FUNCTIONS
  ----------------*/
static inline int idxof(int i);
#if (!defined(HAVE_ALTIVEC)) && (!defined(HAVE_SSE2))
static inline void rshift128(w128_t *out,  w128_t const *in, int shift);
static inline void lshift128(w128_t *out,  w128_t const *in, int shift);
#endif
static inline void gen_rand_all(sfmt_t *ctx);
static inline void gen_rand_array(sfmt_t *ctx, w128_t *array, int size);
static inline uint32_t func1(uint32_t x);
static inline uint32_t func2(uint32_t x);
static void period_certification(sfmt_t *ctx);
#if defined(BIG_ENDIAN64) && !defined(ONLY64)
static inline void swap(w128_t *array, int size);
#endif

#if defined(HAVE_ALTIVEC)
  #include "test/SFMT-alti.h"
#elif defined(HAVE_SSE2)
  #include "test/SFMT-sse2.h"
#endif

/**
 * This function simulate a 64-bit index of LITTLE ENDIAN
 * in BIG ENDIAN machine.
 */
#ifdef ONLY64
static inline int idxof(int i) {
    return i ^ 1;
}
#else
static inline int idxof(int i) {
    return i;
}
#endif
/**
 * This function simulates SIMD 128-bit right shift by the standard C.
 * The 128-bit integer given in in is shifted by (shift * 8) bits.
 * This function simulates the LITTLE ENDIAN SIMD.
 * @param out the output of this function
 * @param in the 128-bit data to be shifted
 * @param shift the shift value
 */
#if (!defined(HAVE_ALTIVEC)) && (!defined(HAVE_SSE2))
#ifdef ONLY64
static inline void rshift128(w128_t *out, w128_t const *in, int shift) {
    uint64_t th, tl, oh, ol;

    th = ((uint64_t)in->u[2] << 32) | ((uint64_t)in->u[3]);
    tl = ((uint64_t)in->u[0] << 32) | ((uint64_t)in->u[1]);

    oh = th >> (shift * 8);
    ol = tl >> (shift * 8);
    ol |= th << (64 - shift * 8);
    out->u[0] = (uint32_t)(ol >> 32);
    out->u[1] = (uint32_t)ol;
    out->u[2] = (uint32_t)(oh >> 32);
    out->u[3] = (uint32_t)oh;
}
#else
static inline void rshift128(w128_t *out, w128_t const *in, int shift) {
    uint64_t th, tl, oh, ol;

    th = ((uint64_t)in->u[3] << 32) | ((uint64_t)in->u[2]);
    tl = ((uint64_t)in->u[1] << 32) | ((uint64_t)in->u[0]);

    oh = th >> (shift * 8);
    ol = tl >> (shift * 8);
    ol |= th << (64 - shift * 8);
    out->u[1] = (uint32_t)(ol >> 32);
    out->u[0] = (uint32_t)ol;
    out->u[3] = (uint32_t)(oh >> 32);
    out->u[2] = (uint32_t)oh;
}
#endif
/**
 * This function simulates SIMD 128-bit left shift by the standard C.
 * The 128-bit integer given in in is shifted by (shift * 8) bits.
 * This function simulates the LITTLE ENDIAN SIMD.
 * @param out the output of this function
 * @param in the 128-bit data to be shifted
 * @param shift the shift value
 */
#ifdef ONLY64
static inline void lshift128(w128_t *out, w128_t const *in, int shift) {
    uint64_t th, tl, oh, ol;

    th = ((uint64_t)in->u[2] << 32) | ((uint64_t)in->u[3]);
    tl = ((uint64_t)in->u[0] << 32) | ((uint64_t)in->u[1]);

    oh = th << (shift * 8);
    ol = tl << (shift * 8);
    oh |= tl >> (64 - shift * 8);
    out->u[0] = (uint32_t)(ol >> 32);
    out->u[1] = (uint32_t)ol;
    out->u[2] = (uint32_t)(oh >> 32);
    out->u[3] = (uint32_t)oh;
}
#else
static inline void lshift128(w128_t *out, w128_t const *in, int shift) {
    uint64_t th, tl, oh, ol;

    th = ((uint64_t)in->u[3] << 32) | ((uint64_t)in->u[2]);
    tl = ((uint64_t)in->u[1] << 32) | ((uint64_t)in->u[0]);

    oh = th << (shift * 8);
    ol = tl << (shift * 8);
    oh |= tl >> (64 - shift * 8);
    out->u[1] = (uint32_t)(ol >> 32);
    out->u[0] = (uint32_t)ol;
    out->u[3] = (uint32_t)(oh >> 32);
    out->u[2] = (uint32_t)oh;
}
#endif
#endif

/**
 * This function represents the recursion formula.
 * @param r output
 * @param a a 128-bit part of the internal state array
 * @param b a 128-bit part of the internal state array
 * @param c a 128-bit part of the internal state array
 * @param d a 128-bit part of the internal state array
 */
#if (!defined(HAVE_ALTIVEC)) && (!defined(HAVE_SSE2))
#ifdef ONLY64
static inline void do_recursion(w128_t *r, w128_t *a, w128_t *b, w128_t *c,
				w128_t *d) {
    w128_t x;
    w128_t y;

    lshift128(&x, a, SL2);
    rshift128(&y, c, SR2);
    r->u[0] = a->u[0] ^ x.u[0] ^ ((b->u[0] >> SR1) & MSK2) ^ y.u[0]
	^ (d->u[0] << SL1);
    r->u[1] = a->u[1] ^ x.u[1] ^ ((b->u[1] >> SR1) & MSK1) ^ y.u[1]
	^ (d->u[1] << SL1);
    r->u[2] = a->u[2] ^ x.u[2] ^ ((b->u[2] >> SR1) & MSK4) ^ y.u[2]
	^ (d->u[2] << SL1);
    r->u[3] = a->u[3] ^ x.u[3] ^ ((b->u[3] >> SR1) & MSK3) ^ y.u[3]
	^ (d->u[3] << SL1);
}
#else
static inline void do_recursion(w128_t *r, w128_t *a, w128_t *b, w128_t *c,
				w128_t *d) {
    w128_t x;
    w128_t y;

    lshift128(&x, a, SL2);
    rshift128(&y, c, SR2);
    r->u[0] = a->u[0] ^ x.u[0] ^ ((b->u[0] >> SR1) & MSK1) ^ y.u[0]
	^ (d->u[0] << SL1);
    r->u[1] = a->u[1] ^ x.u[1] ^ ((b->u[1] >> SR1) & MSK2) ^ y.u[1]
	^ (d->u[1] << SL1);
    r->u[2] = a->u[2] ^ x.u[2] ^ ((b->u[2] >> SR1) & MSK3) ^ y.u[2]
	^ (d->u[2] << SL1);
    r->u[3] = a->u[3] ^ x.u[3] ^ ((b->u[3] >> SR1) & MSK4) ^ y.u[3]
	^ (d->u[3] << SL1);
}
#endif
#endif

#if (!defined(HAVE_ALTIVEC)) && (!defined(HAVE_SSE2))
/**
 * This function fills the internal state array with pseudorandom
 * integers.
 */
static inline void gen_rand_all(sfmt_t *ctx) {
    int i;
    w128_t *r1, *r2;

    r1 = &ctx->sfmt[N - 2];
    r2 = &ctx->sfmt[N - 1];
    for (i = 0; i < N - POS1; i++) {
	do_recursion(&ctx->sfmt[i], &ctx->sfmt[i], &ctx->sfmt[i + POS1], r1,
	  r2);
	r1 = r2;
	r2 = &ctx->sfmt[i];
    }
    for (; i < N; i++) {
	do_recursion(&ctx->sfmt[i], &ctx->sfmt[i], &ctx->sfmt[i + POS1 - N], r1,
	  r2);
	r1 = r2;
	r2 = &ctx->sfmt[i];
    }
}

/**
 * This function fills the user-specified array with pseudorandom
 * integers.
 *
 * @param array an 128-bit array to be filled by pseudorandom numbers.
 * @param size number of 128-bit pseudorandom numbers to be generated.
 */
static inline void gen_rand_array(sfmt_t *ctx, w128_t *array, int size) {
    int i, j;
    w128_t *r1, *r2;

    r1 = &ctx->sfmt[N - 2];
    r2 = &ctx->sfmt[N - 1];
    for (i = 0; i < N - POS1; i++) {
	do_recursion(&array[i], &ctx->sfmt[i], &ctx->sfmt[i + POS1], r1, r2);
	r1 = r2;
	r2 = &array[i];
    }
    for (; i < N; i++) {
	do_recursion(&array[i], &ctx->sfmt[i], &array[i + POS1 - N], r1, r2);
	r1 = r2;
	r2 = &array[i];
    }
    for (; i < size - N; i++) {
	do_recursion(&array[i], &array[i - N], &array[i + POS1 - N], r1, r2);
	r1 = r2;
	r2 = &array[i];
    }
    for (j = 0; j < 2 * N - size; j++) {
	ctx->sfmt[j] = array[j + size - N];
    }
    for (; i < size; i++, j++) {
	do_recursion(&array[i], &array[i - N], &array[i + POS1 - N], r1, r2);
	r1 = r2;
	r2 = &array[i];
	ctx->sfmt[j] = array[i];
    }
}
#endif

#if defined(BIG_ENDIAN64) && !defined(ONLY64) && !defined(HAVE_ALTIVEC)
static inline void swap(w128_t *array, int size) {
    int i;
    uint32_t x, y;

    for (i = 0; i < size; i++) {
	x = array[i].u[0];
	y = array[i].u[2];
	array[i].u[0] = array[i].u[1];
	array[i].u[2] = array[i].u[3];
	array[i].u[1] = x;
	array[i].u[3] = y;
    }
}
#endif
/**
 * This function represents a function used in the initialization
 * by init_by_array
 * @param x 32-bit integer
 * @return 32-bit integer
 */
static uint32_t func1(uint32_t x) {
    return (x ^ (x >> 27)) * (uint32_t)1664525UL;
}

/**
 * This function represents a function used in the initialization
 * by init_by_array
 * @param x 32-bit integer
 * @return 32-bit integer
 */
static uint32_t func2(uint32_t x) {
    return (x ^ (x >> 27)) * (uint32_t)1566083941UL;
}

/**
 * This function certificate the period of 2^{MEXP}
 */
static void period_certification(sfmt_t *ctx) {
    int inner = 0;
    int i, j;
    uint32_t work;
    uint32_t *psfmt32 = &ctx->sfmt[0].u[0];

    for (i = 0; i < 4; i++)
	inner ^= psfmt32[idxof(i)] & parity[i];
    for (i = 16; i > 0; i >>= 1)
	inner ^= inner >> i;
    inner &= 1;
    /* check OK */
    if (inner == 1) {
	return;
    }
    /* check NG, and modification */
    for (i = 0; i < 4; i++) {
	work = 1;
	for (j = 0; j < 32; j++) {
	    if ((work & parity[i]) != 0) {
		psfmt32[idxof(i)] ^= work;
		return;
	    }
	    work = work << 1;
	}
    }
}

/*----------------
  PUBLIC FUNCTIONS
  ----------------*/
/**
 * This function returns the identification string.
 * The string shows the word size, the Mersenne exponent,
 * and all parameters of this generator.
 */
const char *get_idstring(void) {
    return IDSTR;
}

/**
 * This function returns the minimum size of array used for \b
 * fill_array32() function.
 * @return minimum size of array used for fill_array32() function.
 */
int get_min_array_size32(void) {
    return N32;
}

/**
 * This function returns the minimum size of array used for \b
 * fill_array64() function.
 * @return minimum size of array used for fill_array64() function.
 */
int get_min_array_size64(void) {
    return N64;
}

#ifndef ONLY64
/**
 * This function generates and returns 32-bit pseudorandom number.
 * init_gen_rand or init_by_array must be called before this function.
 * @return 32-bit pseudorandom number
 */
uint32_t gen_rand32(sfmt_t *ctx) {
    uint32_t r;
    uint32_t *psfmt32 = &ctx->sfmt[0].u[0];

    assert(ctx->initialized);
    if (ctx->idx >= N32) {
	gen_rand_all(ctx);
	ctx->idx = 0;
    }
    r = psfmt32[ctx->idx++];
    return r;
}

/* Generate a random integer in [0..limit). */
uint32_t gen_rand32_range(sfmt_t *ctx, uint32_t limit) {
    uint32_t ret, above;

    above = 0xffffffffU - (0xffffffffU % limit);
    while (1) {
	ret = gen_rand32(ctx);
	if (ret < above) {
	    ret %= limit;
	    break;
	}
    }
    return ret;
}
#endif
/**
 * This function generates and returns 64-bit pseudorandom number.
 * init_gen_rand or init_by_array must be called before this function.
 * The function gen_rand64 should not be called after gen_rand32,
 * unless an initialization is again executed.
 * @return 64-bit pseudorandom number
 */
uint64_t gen_rand64(sfmt_t *ctx) {
#if defined(BIG_ENDIAN64) && !defined(ONLY64)
    uint32_t r1, r2;
    uint32_t *psfmt32 = &ctx->sfmt[0].u[0];
#else
    uint64_t r;
    uint64_t *psfmt64 = (uint64_t *)&ctx->sfmt[0].u[0];
#endif

    assert(ctx->initialized);
    assert(ctx->idx % 2 == 0);

    if (ctx->idx >= N32) {
	gen_rand_all(ctx);
	ctx->idx = 0;
    }
#if defined(BIG_ENDIAN64) && !defined(ONLY64)
    r1 = psfmt32[ctx->idx];
    r2 = psfmt32[ctx->idx + 1];
    ctx->idx += 2;
    return ((uint64_t)r2 << 32) | r1;
#else
    r = psfmt64[ctx->idx / 2];
    ctx->idx += 2;
    return r;
#endif
}

/* Generate a random integer in [0..limit). */
uint64_t gen_rand64_range(sfmt_t *ctx, uint64_t limit) {
    uint64_t ret, above;

    above = KQU(0xffffffffffffffff) - (KQU(0xffffffffffffffff) % limit);
    while (1) {
	ret = gen_rand64(ctx);
	if (ret < above) {
	    ret %= limit;
	    break;
	}
    }
    return ret;
}

#ifndef ONLY64
/**
 * This function generates pseudorandom 32-bit integers in the
 * specified array[] by one call. The number of pseudorandom integers
 * is specified by the argument size, which must be at least 624 and a
 * multiple of four.  The generation by this function is much faster
 * than the following gen_rand function.
 *
 * For initialization, init_gen_rand or init_by_array must be called
 * before the first call of this function. This function can not be
 * used after calling gen_rand function, without initialization.
 *
 * @param array an array where pseudorandom 32-bit integers are filled
 * by this function.  The pointer to the array must be \b "aligned"
 * (namely, must be a multiple of 16) in the SIMD version, since it
 * refers to the address of a 128-bit integer.  In the standard C
 * version, the pointer is arbitrary.
 *
 * @param size the number of 32-bit pseudorandom integers to be
 * generated.  size must be a multiple of 4, and greater than or equal
 * to (MEXP / 128 + 1) * 4.
 *
 * @note \b memalign or \b posix_memalign is available to get aligned
 * memory. Mac OSX doesn't have these functions, but \b malloc of OSX
 * returns the pointer to the aligned memory block.
 */
void fill_array32(sfmt_t *ctx, uint32_t *array, int size) {
    assert(ctx->initialized);
    assert(ctx->idx == N32);
    assert(size % 4 == 0);
    assert(size >= N32);

    gen_rand_array(ctx, (w128_t *)array, size / 4);
    ctx->idx = N32;
}
#endif

/**
 * This function generates pseudorandom 64-bit integers in the
 * specified array[] by one call. The number of pseudorandom integers
 * is specified by the argument size, which must be at least 312 and a
 * multiple of two.  The generation by this function is much faster
 * than the following gen_rand function.
 *
 * For initialization, init_gen_rand or init_by_array must be called
 * before the first call of this function. This function can not be
 * used after calling gen_rand function, without initialization.
 *
 * @param array an array where pseudorandom 64-bit integers are filled
 * by this function.  The pointer to the array must be "aligned"
 * (namely, must be a multiple of 16) in the SIMD version, since it
 * refers to the address of a 128-bit integer.  In the standard C
 * version, the pointer is arbitrary.
 *
 * @param size the number of 64-bit pseudorandom integers to be
 * generated.  size must be a multiple of 2, and greater than or equal
 * to (MEXP / 128 + 1) * 2
 *
 * @note \b memalign or \b posix_memalign is available to get aligned
 * memory. Mac OSX doesn't have these functions, but \b malloc of OSX
 * returns the pointer to the aligned memory block.
 */
void fill_array64(sfmt_t *ctx, uint64_t *array, int size) {
    assert(ctx->initialized);
    assert(ctx->idx == N32);
    assert(size % 2 == 0);
    assert(size >= N64);

    gen_rand_array(ctx, (w128_t *)array, size / 2);
    ctx->idx = N32;

#if defined(BIG_ENDIAN64) && !defined(ONLY64)
    swap((w128_t *)array, size /2);
#endif
}

/**
 * This function initializes the internal state array with a 32-bit
 * integer seed.
 *
 * @param seed a 32-bit integer used as the seed.
 */
sfmt_t *init_gen_rand(uint32_t seed) {
    void *p;
    sfmt_t *ctx;
    int i;
    uint32_t *psfmt32;

    if (posix_memalign(&p, sizeof(w128_t), sizeof(sfmt_t)) != 0) {
	return NULL;
    }
    ctx = (sfmt_t *)p;
    psfmt32 = &ctx->sfmt[0].u[0];

    psfmt32[idxof(0)] = seed;
    for (i = 1; i < N32; i++) {
	psfmt32[idxof(i)] = 1812433253UL * (psfmt32[idxof(i - 1)]
					    ^ (psfmt32[idxof(i - 1)] >> 30))
	    + i;
    }
    ctx->idx = N32;
    period_certification(ctx);
    ctx->initialized = 1;

    return ctx;
}

/**
 * This function initializes the internal state array,
 * with an array of 32-bit integers used as the seeds
 * @param init_key the array of 32-bit integers, used as a seed.
 * @param key_length the length of init_key.
 */
sfmt_t *init_by_array(uint32_t *init_key, int key_length) {
    void *p;
    sfmt_t *ctx;
    int i, j, count;
    uint32_t r;
    int lag;
    int mid;
    int size = N * 4;
    uint32_t *psfmt32;

    if (posix_memalign(&p, sizeof(w128_t), sizeof(sfmt_t)) != 0) {
	return NULL;
    }
    ctx = (sfmt_t *)p;
    psfmt32 = &ctx->sfmt[0].u[0];

    if (size >= 623) {
	lag = 11;
    } else if (size >= 68) {
	lag = 7;
    } else if (size >= 39) {
	lag = 5;
    } else {
	lag = 3;
    }
    mid = (size - lag) / 2;

    memset(ctx->sfmt, 0x8b, sizeof(ctx->sfmt));
    if (key_length + 1 > N32) {
	count = key_length + 1;
    } else {
	count = N32;
    }
    r = func1(psfmt32[idxof(0)] ^ psfmt32[idxof(mid)]
	      ^ psfmt32[idxof(N32 - 1)]);
    psfmt32[idxof(mid)] += r;
    r += key_length;
    psfmt32[idxof(mid + lag)] += r;
    psfmt32[idxof(0)] = r;

    count--;
    for (i = 1, j = 0; (j < count) && (j < key_length); j++) {
	r = func1(psfmt32[idxof(i)] ^ psfmt32[idxof((i + mid) % N32)]
		  ^ psfmt32[idxof((i + N32 - 1) % N32)]);
	psfmt32[idxof((i + mid) % N32)] += r;
	r += init_key[j] + i;
	psfmt32[idxof((i + mid + lag) % N32)] += r;
	psfmt32[idxof(i)] = r;
	i = (i + 1) % N32;
    }
    for (; j < count; j++) {
	r = func1(psfmt32[idxof(i)] ^ psfmt32[idxof((i + mid) % N32)]
		  ^ psfmt32[idxof((i + N32 - 1) % N32)]);
	psfmt32[idxof((i + mid) % N32)] += r;
	r += i;
	psfmt32[idxof((i + mid + lag) % N32)] += r;
	psfmt32[idxof(i)] = r;
	i = (i + 1) % N32;
    }
    for (j = 0; j < N32; j++) {
	r = func2(psfmt32[idxof(i)] + psfmt32[idxof((i + mid) % N32)]
		  + psfmt32[idxof((i + N32 - 1) % N32)]);
	psfmt32[idxof((i + mid) % N32)] ^= r;
	r -= i;
	psfmt32[idxof((i + mid + lag) % N32)] ^= r;
	psfmt32[idxof(i)] = r;
	i = (i + 1) % N32;
    }

    ctx->idx = N32;
    period_certification(ctx);
    ctx->initialized = 1;

    return ctx;
}

void fini_gen_rand(sfmt_t *ctx) {
    assert(ctx != NULL);

    ctx->initialized = 0;
    free(ctx);
}