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      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 */
     72 union W128_T {
     73     vector unsigned int s;
     74     uint32_t u[4];
     75 };
     76 /** 128-bit data type */
     77 typedef union W128_T w128_t;
     78 
     79 #elif defined(HAVE_SSE2)
     80 /** 128-bit data structure */
     81 union W128_T {
     82     __m128i si;
     83     uint32_t u[4];
     84 };
     85 /** 128-bit data type */
     86 typedef union W128_T w128_t;
     87 
     88 #else
     89 
     90 /** 128-bit data structure */
     91 struct W128_T {
     92     uint32_t u[4];
     93 };
     94 /** 128-bit data type */
     95 typedef struct W128_T w128_t;
     96 
     97 #endif
     98 
     99 struct 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} */
    115 static uint32_t parity[4] = {PARITY1, PARITY2, PARITY3, PARITY4};
    116 
    117 /*----------------
    118   STATIC FUNCTIONS
    119   ----------------*/
    120 JEMALLOC_INLINE_C int idxof(int i);
    121 #if (!defined(HAVE_ALTIVEC)) && (!defined(HAVE_SSE2))
    122 JEMALLOC_INLINE_C void rshift128(w128_t *out,  w128_t const *in, int shift);
    123 JEMALLOC_INLINE_C void lshift128(w128_t *out,  w128_t const *in, int shift);
    124 #endif
    125 JEMALLOC_INLINE_C void gen_rand_all(sfmt_t *ctx);
    126 JEMALLOC_INLINE_C void gen_rand_array(sfmt_t *ctx, w128_t *array, int size);
    127 JEMALLOC_INLINE_C uint32_t func1(uint32_t x);
    128 JEMALLOC_INLINE_C uint32_t func2(uint32_t x);
    129 static void period_certification(sfmt_t *ctx);
    130 #if defined(BIG_ENDIAN64) && !defined(ONLY64)
    131 JEMALLOC_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
    145 JEMALLOC_INLINE_C int idxof(int i) {
    146     return i ^ 1;
    147 }
    148 #else
    149 JEMALLOC_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
    163 JEMALLOC_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
    178 JEMALLOC_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
    202 JEMALLOC_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
    217 JEMALLOC_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
    244 JEMALLOC_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
    261 JEMALLOC_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  */
    285 JEMALLOC_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  */
    312 JEMALLOC_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)
    346 JEMALLOC_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  */
    366 static 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  */
    376 static 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  */
    383 static 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  */
    419 const 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  */
    428 int 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  */
    437 int 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  */
    447 uint32_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). */
    461 uint32_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  */
    482 uint64_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). */
    511 uint64_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  */
    551 void 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  */
    587 void 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  */
    607 sfmt_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  */
    638 sfmt_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 
    714 void fini_gen_rand(sfmt_t *ctx) {
    715     assert(ctx != NULL);
    716 
    717     ctx->initialized = 0;
    718     free(ctx);
    719 }
    720