fltcalc.c 42.2 KB
Newer Older
1
2
3
4
5
6
7
8
9
10
/*
 * Project:     libFIRM
 * File name:   ir/tv/fltcalc.c
 * Purpose:
 * Author:
 * Modified by:
 * Created:     2003
 * CVS-ID:      $Id$
 * Copyright:   (c) 2003 Universitt Karlsruhe
 * Licence:     This file protected by GPL -  GNU GENERAL PUBLIC LICENSE.
11
12
 */

13

Boris Boesler's avatar
Boris Boesler committed
14
15
16
17
18
#ifdef HAVE_CONFIG_H
# include "config.h"
#endif


19
#include "fltcalc.h"
20
21
22
23
24
25
26
27
#include "strcalc.h"

#include <math.h>    /* need isnan() and isinf() (will be changed)*/
/* undef some reused constants defined by math.h */
#ifdef NAN
#  undef NAN
#endif

28
#ifdef HAVE_INTTYPES_H
29
#include <inttypes.h>
30
31
#endif

32
33
34
#include <string.h>
#include <stdlib.h>
#include <stdio.h>
35
#include <assert.h>
Boris Boesler's avatar
Boris Boesler committed
36
#ifdef HAVE_ALLOCA_H
Boris Boesler's avatar
Boris Boesler committed
37
38
# include <alloca.h>
#endif
39
40
41
#ifdef HAVE_MALLOC_H
# include <malloc.h>
#endif
42

43
typedef uint32_t UINT32;
Michael Beck's avatar
Tarval:    
Michael Beck committed
44

45
#ifdef HAVE_LONG_DOUBLE
46
#ifdef WORDS_BIGENDIAN
47
48
49
typedef union {
  struct {
    UINT32 high;
50
51
    UINT32 mid;
    UINT32 low;
52
53
54
55
56
57
58
  } val;
  volatile long double d;
} value_t;
#else
typedef union {
  struct {
    UINT32 low;
59
60
    UINT32 mid;
    UINT32 high;
61
62
63
64
65
  } val;
  volatile long double d;
} value_t;
#endif
#else
66
#ifdef WORDS_BIGENDIAN
67
68
69
typedef union {
  struct {
    UINT32 high;
70
    UINT32 low;
71
72
73
74
75
76
77
  } val;
  volatile double d;
} value_t;
#else
typedef union {
  struct {
    UINT32 low;
78
    UINT32 high;
79
80
81
82
83
  } val;
  volatile double d;
} value_t;
#endif
#endif
84

Michael Beck's avatar
Tarval:    
Michael Beck committed
85

86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
/********
 * globals
 ********/
typedef enum {
  NORMAL,
  ZERO,
  SUBNORMAL,
  INF,
  NAN,
} value_class_t;

typedef struct {
  char  exponent_size;
  char  mantissa_size;
  value_class_t  class;
} descriptor_t;

#define CLEAR_BUFFER(buffer) memset(buffer, 0, CALC_BUFFER_SIZE)

/* because variable sized structs are impossible, the internal
 * value is represented as a pseudo-struct char array, addressed
 * by macros
 * struct {
109
 *   char sign;             //  0 for positive, 1 for negative
110
111
112
113
114
115
116
117
118
 *   char exp[VALUE_SIZE];
 *   char mant[VALUE_SIZE];
 *   descriptor_t desc;
 * };
 */
#define _sign(a) (((char*)a)[SIGN_POS])
#define _exp(a) (&((char*)a)[EXPONENT_POS])
#define _mant(a) (&((char*)a)[MANTISSA_POS])
#define _desc(a) (*(descriptor_t *)&((char*)a)[DESCRIPTOR_POS])
Michael Beck's avatar
Tarval:    
Michael Beck committed
119

120
121
122
#define _save_result(x) memcpy((x), sc_get_buffer(), VALUE_SIZE)
#define _shift_right(x, y, b) sc_shr((x), (y), VALUE_SIZE*4, 0, (b))
#define _shift_left(x, y, b) sc_shl((x), (y), VALUE_SIZE*4, 0, (b))
Michael Beck's avatar
Tarval:    
Michael Beck committed
123

124
125
126
127
#define FC_DEFINE1(code) char* fc_##code(const void *a, void *result)                          \
                   {                                                                           \
                     return _calc((const char*)a, NULL, FC_##code, (char*)result);             \
                   }
Michael Beck's avatar
Tarval:    
Michael Beck committed
128

129
130
131
132
133
134
135
136
137
138
139
#define FC_DEFINE2(code) char* fc_##code(const void *a, const void *b, void *result)           \
                   {                                                                           \
                     return _calc((const char*)a, (const char*)b, FC_##code, (char*)result);   \
                   }

#define FUNC_PTR(code) fc_##code

#if FLTCALC_DEBUG
#  define DEBUGPRINTF(x) printf x
#else
#  define DEBUGPRINTF(x) ((void)0)
Michael Beck's avatar
Tarval:    
Michael Beck committed
140
141
#endif

142
143
144
145
146
#if FLTCALC_TRACE_CALC
#  define TRACEPRINTF(x) printf x
#else
#  define TRACEPRINTF(x) ((void)0)
#endif
147

148
static char *calc_buffer = NULL;
149

150
151
152
153
154
155
156
157
static fc_rounding_mode_t ROUNDING_MODE;

static int CALC_BUFFER_SIZE;
static int VALUE_SIZE;
static int SIGN_POS;
static int EXPONENT_POS;
static int MANTISSA_POS;
static int DESCRIPTOR_POS;
158

159
static int max_precision;
160
/********
161
 * private functions
162
 ********/
163
164
#if 0
static void _fail_char(const char *str, unsigned int len, int pos)
165
{
166
167
168
169
170
171
172
173
  if (*(str+pos))
    printf("ERROR: Unexpected character '%c'\n", *(str + pos));
  else
    printf("ERROR: Unexpected end of string\n");
  while (len-- && *str) printf("%c", *str++); printf("\n");
  while (pos--) printf(" "); printf("^\n");
  /* the front end has to to check constant strings */
  exit(-1);
174
}
175
#endif
176

177
/* pack machine-like */
178
static char* _pack(const char *int_float, char *packed)
179
{
180
181
182
  char *shift_val;
  char *temp;
  char *val_buffer;
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
  temp = alloca(VALUE_SIZE);
  shift_val = alloca(VALUE_SIZE);

  switch (_desc(int_float).class) {
    case NAN:
      val_buffer = alloca(CALC_BUFFER_SIZE);
      fc_get_qnan(_desc(int_float).exponent_size, _desc(int_float).mantissa_size, val_buffer);
      int_float = val_buffer;
      break;

    case INF:
      val_buffer = alloca(CALC_BUFFER_SIZE);
      fc_get_plusinf(_desc(int_float).exponent_size, _desc(int_float).mantissa_size, val_buffer);
      _sign(val_buffer) = _sign(int_float);
      int_float = val_buffer;
      break;

    default:
      break;
  }
  /* pack sign */
  sc_val_from_ulong(_sign(int_float), temp);

  sc_val_from_ulong(_desc(int_float).exponent_size + _desc(int_float).mantissa_size, NULL);
  _shift_left(temp, sc_get_buffer(), packed);

  /* extract exponent */
  sc_val_from_ulong(_desc(int_float).mantissa_size, shift_val);

  _shift_left(_exp(int_float), shift_val, temp);

  sc_or(temp, packed, packed);

  /* extract mantissa */
  /* remove 2 rounding bits */
  sc_val_from_ulong(2, shift_val);
  _shift_right(_mant(int_float), shift_val, temp);

  /* remove leading 1 (or 0 if denormalized) */
  sc_max_from_bits(_desc(int_float).mantissa_size, 0, shift_val); /* all mantissa bits are 1's */
  sc_and(temp, shift_val, temp);

  /* save result */
  sc_or(temp, packed, packed);

  return packed;
230
231
}

232
char* _normalize(const char *in_val, char *out_val, int sticky)
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
  int hsb;
  char lsb, guard, round, round_dir = 0;
  char *temp;

  temp = alloca(VALUE_SIZE);

  /* +2: save two rounding bits at the end */
  hsb = 2 + _desc(in_val).mantissa_size - sc_get_highest_set_bit(_mant(in_val)) - 1;

  if (in_val != out_val)
  {
    _sign(out_val) = _sign(in_val);
    memcpy(&_desc(out_val), &_desc(in_val), sizeof(descriptor_t));
  }

  _desc(out_val).class = NORMAL;

  /* mantissa all zeroes, so zero exponent (because of explicit one)*/
  if (hsb == 2 + _desc(in_val).mantissa_size)
  {
    sc_val_from_ulong(0, _exp(out_val));
    hsb = -1;
  }

258
  /* shift the first 1 into the left of the radix point (i.e. hsb == -1) */
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
  if (hsb < -1)
  {
    /* shift right */
    sc_val_from_ulong(-hsb-1, temp);

    _shift_right(_mant(in_val), temp, _mant(out_val));

    /* remember if some bits were shifted away */
    if (!sticky) sticky = sc_had_carry();

    sc_add(_exp(in_val), temp, _exp(out_val));
  }
  else if (hsb > -1)
  {
    /* shift left */
    sc_val_from_ulong(hsb+1, temp);

    _shift_left(_mant(in_val), temp, _mant(out_val));

    sc_sub(_exp(in_val), temp, _exp(out_val));
  }

  /* check for exponent underflow */
  if (sc_is_negative(_exp(out_val)) || sc_is_zero(_exp(out_val))) {
    DEBUGPRINTF(("Exponent underflow!\n"));
    /* exponent underflow */
    /* shift the mantissa right to have a zero exponent */
    sc_val_from_ulong(1, temp);
    sc_sub(temp, _exp(out_val), NULL);

    _shift_right(_mant(out_val), sc_get_buffer(), _mant(out_val));
    if (!sticky) sticky = sc_had_carry();
    /* denormalized means exponent of zero */
    sc_val_from_ulong(0, _exp(out_val));

    _desc(out_val).class = SUBNORMAL;
  }

  /* perform rounding by adding a value that clears the guard bit and the round bit
   * and either causes a carry to round up or not */
  /* get the last 3 bits of the value */
  lsb = sc_sub_bits(_mant(out_val), _desc(out_val).mantissa_size + 2, 0) & 0x7;
  guard = (lsb&0x2)>>1;
  round = lsb&0x1;

  switch (ROUNDING_MODE)
  {
    case FC_TONEAREST:
      /* round to nearest representable value, if in doubt choose the version
       * with lsb == 0 */
      round_dir = guard && (sticky || round || lsb>>2);
      break;
    case FC_TOPOSITIVE:
      /* if positive: round to one if the exact value is bigger, else to zero */
      round_dir = (!_sign(out_val) && (guard || round || sticky));
      break;
    case FC_TONEGATIVE:
      /* if negative: round to one if the exact value is bigger, else to zero */
      round_dir = (_sign(out_val) && (guard || round || sticky));
      break;
    case FC_TOZERO:
      /* always round to 0 (chopping mode) */
      round_dir = 0;
      break;
  }
  DEBUGPRINTF(("Rounding (s%d, l%d, g%d, r%d, s%d) %s\n", _sign(out_val), lsb>>2, guard, round, sticky, (round_dir)?"up":"down"));

  if (round_dir == 1)
  {
    guard = (round^guard)<<1;
    lsb = !(round || guard)<<2 | guard | round;
  }
  else
  {
    lsb = -((guard<<1) | round);
  }

  /* add the rounded value */
  if (lsb != 0) {
    sc_val_from_long(lsb, temp);
    sc_add(_mant(out_val), temp, _mant(out_val));
  }

  /* could have rounded down to zero */
  if (sc_is_zero(_mant(out_val)) && (_desc(out_val).class == SUBNORMAL))
    _desc(out_val).class = ZERO;

  /* check for rounding overflow */
  hsb = 2 + _desc(out_val).mantissa_size - sc_get_highest_set_bit(_mant(out_val)) - 1;
  if ((_desc(out_val).class != SUBNORMAL) && (hsb < -1))
  {
    sc_val_from_ulong(1, temp);
    _shift_right(_mant(out_val), temp, _mant(out_val));

    sc_add(_exp(out_val), temp, _exp(out_val));
  }
  else if ((_desc(out_val).class == SUBNORMAL) && (hsb == -1))
  {
    /* overflow caused the matissa to be normal again,
     * so adapt the exponent accordingly */
    sc_val_from_ulong(1, temp);
    sc_add(_exp(out_val), temp, _exp(out_val));

    _desc(out_val).class = NORMAL;
  }
  /* no further rounding is needed, because rounding overflow means
   * the carry of the original rounding was propagated all the way
   * up to the bit left of the radix point. This implies the bits
   * to the right are all zeros (rounding is +1) */

  /* check for exponent overflow */
  sc_val_from_ulong((1 << _desc(out_val).exponent_size) - 1, temp);
  if (sc_comp(_exp(out_val), temp) != -1) {
    DEBUGPRINTF(("Exponent overflow!\n"));
    /* exponent overflow, reaction depends on rounding method:
     *
     * mode        | sign of value |  result
     *--------------------------------------------------------------
     * TO_NEAREST  |      +        |   +inf
     *             |      -        |   -inf
     *--------------------------------------------------------------
     * TO_POSITIVE |      +        |   +inf
     *             |      -        |   smallest representable value
     *--------------------------------------------------------------
     * TO_NEAGTIVE |      +        |   largest representable value
     *             |      -        |   -inf
     *--------------------------------------------------------------
     * TO_ZERO     |      +        |   largest representable value
     *             |      -        |   smallest representable value
     *--------------------------------------------------------------*/
    if (_sign(out_val) == 0)
    {
      /* value is positive */
      switch (ROUNDING_MODE) {
        case FC_TONEAREST:
        case FC_TOPOSITIVE:
          _desc(out_val).class = INF;
          break;

        case FC_TONEGATIVE:
        case FC_TOZERO:
          fc_get_max(_desc(out_val).exponent_size, _desc(out_val).mantissa_size, out_val);
      }
    } else {
      /* value is negative */
      switch (ROUNDING_MODE) {
        case FC_TONEAREST:
        case FC_TONEGATIVE:
          _desc(out_val).class = INF;
          break;

        case FC_TOPOSITIVE:
        case FC_TOZERO:
          fc_get_min(_desc(out_val).exponent_size, _desc(out_val).mantissa_size, out_val);
      }
    }
  }

  return out_val;
418
419
}

420
421
422
423
/*
 * calculate a + b, where a is the value with the bigger exponent
 */
static char* _add(const char* a, const char* b, char* result)
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
  char *temp;
  char *exp_diff;

  char sign;
  char sticky;

  if (_desc(a).class == NAN) {
    if (a != result) memcpy(result, a, CALC_BUFFER_SIZE);
    return result;
  }
  if (_desc(b).class == NAN) {
    if (b != result) memcpy(result, b, CALC_BUFFER_SIZE);
    return result;
  }

  /* make sure result has a descriptor */
  if (result != a && result != b)
    memcpy(&_desc(result), &_desc(a), sizeof(descriptor_t));

  /* determine if this is an addition or subtraction */
  sign = _sign(a) ^ _sign(b);

  /* produce nan on inf - inf */
  if (sign && (_desc(a).class == INF) && (_desc(b).class == INF))
    return fc_get_qnan(_desc(a).exponent_size, _desc(b).mantissa_size, result);

  temp = alloca(VALUE_SIZE);
  exp_diff = alloca(VALUE_SIZE);

  /* get exponent difference */
  sc_sub(_exp(a), _exp(b), exp_diff);

  /* initially set sign to be the sign of a, special treatment of subtraction
   * when exponents are equal is required though.
   * Also special care about the sign is needed when the mantissas are equal
   * (+/- 0 ?) */
Michael Beck's avatar
Michael Beck committed
461
  if (sign && sc_val_to_long(exp_diff) == 0) {
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
    switch (sc_comp(_mant(a), _mant(b))) {
      case 1:  /* a > b */
        if (_sign(a)) _sign(result) = 1;  /* abs(a) is bigger and a is negative */
        else _sign(result) = 0;
        break;
      case 0:  /* a == b */
        if (ROUNDING_MODE == FC_TONEGATIVE)
          _sign(result) = 1;
        else
          _sign(result) = 0;
        break;
      case -1: /* a < b */
        if (_sign(b)) _sign(result) = 1; /* abs(b) is bigger and b is negative */
        else _sign(result) = 0;
        break;
      default:
        /* can't be reached */
        break;
    }
  } else {
    _sign(result) = _sign(a);
  }

  /* sign has been taken care of, check for special cases */
  if (_desc(a).class == ZERO) {
    if (b != result) memcpy(result+SIGN_POS+1, b+SIGN_POS+1, CALC_BUFFER_SIZE-SIGN_POS-1);
    return result;
  }
  if (_desc(b).class == ZERO) {
    if (a != result) memcpy(result+SIGN_POS+1, a+SIGN_POS+1, CALC_BUFFER_SIZE-SIGN_POS-1);
    return result;
  }

  if (_desc(a).class == INF) {
    if (a != result) memcpy(result+SIGN_POS+1, a+SIGN_POS+1, CALC_BUFFER_SIZE-SIGN_POS-1);
    return result;
  }
  if (_desc(b).class == INF) {
    if (b != result) memcpy(result+SIGN_POS+1, b+SIGN_POS+1, CALC_BUFFER_SIZE-SIGN_POS-1);
    return result;
  }

  /* shift the smaller value to the right to align the radix point */
  /* subnormals have their radix point shifted to the right,
   * take care of this first */
  if ((_desc(b).class == SUBNORMAL) && (_desc(a).class != SUBNORMAL))
  {
    sc_val_from_ulong(1, temp);
    sc_sub(exp_diff, temp, exp_diff);
  }

  _shift_right(_mant(b), exp_diff, temp);
  sticky = sc_had_carry();

  if (sticky && sign)
  {
    /* if subtracting a little more than the represented value or adding a little
     * more than the represented value to a negative value this, in addition to the
     * still set sticky bit, takes account of the 'little more' */
    char *temp1 = alloca(CALC_BUFFER_SIZE);
    sc_val_from_ulong(1, temp1);
    sc_add(temp, temp1, temp);
  }

  if (sign) {
    if (sc_comp(_mant(a), temp) == -1)
      sc_sub(temp, _mant(a), _mant(result));
    else
      sc_sub(_mant(a), temp, _mant(result));
  } else {
    sc_add(_mant(a), temp, _mant(result));
  }

  /* _normalize expects a 'normal' radix point, adding two subnormals
   * results in a subnormal radix point -> shifting before normalizing */
  if ((_desc(a).class == SUBNORMAL) && (_desc(b).class == SUBNORMAL))
  {
    sc_val_from_ulong(1, NULL);
    _shift_left(_mant(result), sc_get_buffer(), _mant(result));
  }

  /* resulting exponent is the bigger one */
  memmove(_exp(result), _exp(a), VALUE_SIZE);

  return _normalize(result, result, sticky);
547
548
}

549
static char* _mul(const char* a, const char* b, char* result)
550
{
551
  char *temp;
552

553
554
555
  if (_desc(a).class == NAN) {
    if (a != result) memcpy(result, a, CALC_BUFFER_SIZE);
    return result;
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
  if (_desc(b).class == NAN) {
    if (b != result) memcpy(result, b, CALC_BUFFER_SIZE);
    return result;
  }

  temp = alloca(VALUE_SIZE);

  if (result != a && result != b)
    memcpy(&_desc(result), &_desc(a), sizeof(descriptor_t));

  _sign(result) = _sign(a) ^ _sign(b);

  /* produce nan on 0 * inf */
  if (_desc(a).class == ZERO) {
    if (_desc(b).class == INF)
      fc_get_qnan(_desc(a).exponent_size, _desc(a).mantissa_size, result);
    else
      if (a != result) memcpy(result+SIGN_POS+1, a+SIGN_POS+1, CALC_BUFFER_SIZE-1);
    return result;
  }
  if (_desc(b).class == ZERO) {
    if (_desc(a).class == INF)
      fc_get_qnan(_desc(a).exponent_size, _desc(a).mantissa_size, result);
    else
      if (b != result) memcpy(result+SIGN_POS+1, b+SIGN_POS+1, CALC_BUFFER_SIZE-1);
    return result;
  }

  if (_desc(a).class == INF) {
    if (a != result) memcpy(result+SIGN_POS+1, a+SIGN_POS+1, CALC_BUFFER_SIZE-1);
    return result;
  }
  if (_desc(b).class == INF) {
    if (b != result) memcpy(result+SIGN_POS+1, b+SIGN_POS+1, CALC_BUFFER_SIZE-1);
    return result;
  }

  /* exp = exp(a) + exp(b) - excess */
  sc_add(_exp(a), _exp(b), _exp(result));

  sc_val_from_ulong((1<<_desc(a).exponent_size)/2-1, temp);
  sc_sub(_exp(result), temp, _exp(result));

  /* mixed normal, subnormal values introduce an error of 1, correct it */
  if ((_desc(a).class == SUBNORMAL) ^ (_desc(b).class == SUBNORMAL))
  {
    sc_val_from_ulong(1, temp);
    sc_add(_exp(result), temp, _exp(result));
  }

  sc_mul(_mant(a), _mant(b), _mant(result));

  /* realign result: after a multiplication the digits right of the radix
   * point are the sum of the factors' digits after the radix point. As all
   * values are normalized they both have the same amount of these digits,
   * which has to be restored by proper shifting
   * +2 because of the two rounding bits */
  sc_val_from_ulong(2 + _desc(result).mantissa_size, temp);

  _shift_right(_mant(result), temp, _mant(result));

  return _normalize(result, result, sc_had_carry());
619
620
}

621
static char* _div(const char* a, const char* b, char* result)
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
  char *temp, *dividend;

  if (_desc(a).class == NAN) {
    if (a != result) memcpy(result, a, CALC_BUFFER_SIZE);
    return result;
  }
  if (_desc(b).class == NAN) {
    if (b != result) memcpy(result, b, CALC_BUFFER_SIZE);
    return result;
  }

  temp = alloca(VALUE_SIZE);
  dividend = alloca(VALUE_SIZE);

  if (result != a && result != b)
    memcpy(&_desc(result), &_desc(a), sizeof(descriptor_t));

  _sign(result) = _sign(a) ^ _sign(b);

  /* produce nan on 0/0 and inf/inf */
  if (_desc(a).class == ZERO) {
    if (_desc(b).class == ZERO)
      /* 0/0 -> nan */
      fc_get_qnan(_desc(a).exponent_size, _desc(a).mantissa_size, result);
    else
      /* 0/x -> a */
      if (a != result) memcpy(result+SIGN_POS+1, a+SIGN_POS+1, CALC_BUFFER_SIZE-1);
    return result;
  }

  if (_desc(b).class == INF) {
    if (_desc(a).class == INF)
      /* inf/inf -> nan */
      fc_get_qnan(_desc(a).exponent_size, _desc(a).mantissa_size, result);
    else {
      /* x/inf -> 0 */
      sc_val_from_ulong(0, NULL);
      _save_result(_exp(result));
      _save_result(_mant(result));
      _desc(result).class = ZERO;
    }
    return result;
  }

  if (_desc(a).class == INF) {
    /* inf/x -> inf */
    if (a != result) memcpy(result+SIGN_POS+1, a+SIGN_POS+1, CALC_BUFFER_SIZE-1);
    return result;
  }
  if (_desc(b).class == ZERO) {
    /* division by zero */
    if (_sign(result))
      fc_get_minusinf(_desc(a).exponent_size, _desc(a).mantissa_size, result);
    else
      fc_get_plusinf(_desc(a).exponent_size, _desc(a).mantissa_size, result);
    return result;
  }

  /* exp = exp(a) - exp(b) + excess - 1*/
  sc_sub(_exp(a), _exp(b), _exp(result));
  sc_val_from_ulong((1 << _desc(a).exponent_size)/2-2, temp);
  sc_add(_exp(result), temp, _exp(result));

  /* mixed normal, subnormal values introduce an error of 1, correct it */
  if ((_desc(a).class == SUBNORMAL) ^ (_desc(b).class == SUBNORMAL))
688
  {
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
    sc_val_from_ulong(1, temp);
    sc_add(_exp(result), temp, _exp(result));
  }

  /* mant(res) = mant(a) / 1/2mant(b) */
  /* to gain more bits of precision in the result the dividend could be
   * shifted left, as this operation does not loose bits. This would not
   * fit into the integer precision, but due to the rounding bits (which
   * are always zero because the values are all normalized) the divisor
   * can be shifted right instead to achieve the same result */
  sc_val_from_ulong(2 + _desc(result).mantissa_size, temp);

  _shift_left(_mant(a), temp, dividend);

  {
    char *divisor = alloca(CALC_BUFFER_SIZE);
    sc_val_from_ulong(1, divisor);
    _shift_right(_mant(b), divisor, divisor);
    sc_div(dividend, divisor, _mant(result));
708
  }
709
710

  return _normalize(result, result, sc_had_carry());
711
712
}

713
void _power_of_ten(int exp, descriptor_t *desc, char *result)
714
{
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
  char *build;
  char *temp;

  /* positive sign */
  _sign(result) = 0;

  /* set new descriptor (else result is supposed to already have one) */
  if (desc != NULL)
    memcpy(&_desc(result), desc, sizeof(descriptor_t));

  build = alloca(VALUE_SIZE);
  temp = alloca(VALUE_SIZE);

  sc_val_from_ulong((1 << _desc(result).exponent_size)/2-1, _exp(result));

  if (exp > 0)
  {
    /* temp is value of ten now */
    sc_val_from_ulong(10, NULL);
    _save_result(temp);

    for (exp--; exp > 0; exp--) {
      _save_result(build);
      sc_mul(build, temp, NULL);
    }
    _save_result(build);

    /* temp is amount of leftshift needed to put the value left of the radix point */
    sc_val_from_ulong(_desc(result).mantissa_size + 2, temp);
744

745
746
747
748
    _shift_left(build, temp, _mant(result));

    _normalize(result, result, 0);
  }
749
750
}

751
static char* _trunc(const char *a, char *result)
752
{
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
  /* when exponent == 0 all bits left of the radix point
   * are the integral part of the value. For 15bit exp_size
   * this would require a leftshift of max. 16383 bits which
   * is too much.
   * But it is enough to ensure that no bit right of the radix
   * point remains set. This restricts the interesting
   * exponents to the interval [0, mant_size-1].
   * Outside this interval the truncated value is either 0 or
   * it is are already truncated */

  int exp_bias, exp_val;
  char *temp;

  temp = alloca(VALUE_SIZE);

  if (a != result)
    memcpy(&_desc(result), &_desc(a), sizeof(descriptor_t));

  exp_bias = (1<<_desc(a).exponent_size)/2-1;
Michael Beck's avatar
Michael Beck committed
772
  exp_val = sc_val_to_long(_exp(a)) - exp_bias;
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801

  if (exp_val < 0) {
    sc_val_from_ulong(0, NULL);
    _save_result(_exp(result));
    _save_result(_mant(result));
    _desc(result).class = ZERO;

    return result;
  }

  if (exp_val > _desc(a).mantissa_size) {
    if (a != result)
      memcpy(result, a, CALC_BUFFER_SIZE);

    return result;
  }

  /* set up a proper mask to delete all bits right of the
   * radix point if the mantissa had been shifted until exp == 0 */
  sc_max_from_bits(1 + exp_val, 0, temp);
  sc_val_from_long(_desc(a).mantissa_size - exp_val + 2, NULL);
  _shift_left(temp, sc_get_buffer(), temp);

  /* and the mask and return the result */
  sc_and(_mant(a), temp, _mant(result));

  if (a != result) memcpy(_exp(result), _exp(a), VALUE_SIZE);

  return result;
802
803
}

804
805
806
807
808
/*
 * This does value sanity checking(or should do it), sets up any prerequisites,
 * calls the proper internal functions, clears up and returns
 * the result */
char* _calc(const char *a, const char *b, int opcode, char *result)
809
{
810
811
812
813
814
815
816
817
818
  char *temp;
#ifdef FLTCALC_TRACE_CALC
  char *buffer;

  buffer = alloca(100);
#endif

  if (result == NULL) result = calc_buffer;

819
  TRACEPRINTF(("%s ", fc_print(a, buffer, 100, FC_PACKED)));
820
821
  switch (opcode)
  {
822
823
    case FC_add:
      /* make the value with the bigger exponent the first one */
824
      TRACEPRINTF(("+ %s ", fc_print(b, buffer, 100, FC_PACKED)));
825
826
827
828
829
830
      if (sc_comp(_exp(a), _exp(b)) == -1)
        _add(b, a, result);
      else
        _add(a, b, result);
      break;
    case FC_sub:
831
      TRACEPRINTF(("- %s ", fc_print(b, buffer, 100, FC_PACKED)));
832
833
834
835
836
837
838
      temp = alloca(CALC_BUFFER_SIZE);
      memcpy(temp, b, CALC_BUFFER_SIZE);
      _sign(temp) = !_sign(b);
      if (sc_comp(_exp(a), _exp(temp)) == -1)
        _add(temp, a, result);
      else
        _add(a, temp, result);
839
      break;
840
    case FC_mul:
841
      TRACEPRINTF(("* %s ", fc_print(b, buffer, 100, FC_PACKED)));
842
      _mul(a, b, result);
843
      break;
844
    case FC_div:
845
      TRACEPRINTF(("/ %s ", fc_print(b, buffer, 100, FC_PACKED)));
846
      _div(a, b, result);
847
      break;
848
849
850
851
    case FC_neg:
      TRACEPRINTF(("negated "));
      if (a != result) memcpy(result, a, CALC_BUFFER_SIZE);
      _sign(result) = !_sign(a);
852
      break;
853
854
855
856
    case FC_int:
      _trunc(a, result);
      break;
    case FC_rnd:
857
      break;
858
  }
859

860
  TRACEPRINTF(("= %s\n", fc_print(result, buffer, 100, FC_PACKED)));
861
  return result;
862
863
}

864
865
866
867
/********
 * functions defined in fltcalc.h
 ********/
const void *fc_get_buffer(void)
868
{
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
  return calc_buffer;
}

const int fc_get_buffer_length(void)
{
  return CALC_BUFFER_SIZE;
}

char* fc_val_from_str(const char *str, unsigned int len, char exp_size, char mant_size, char *result)
{
#if 0
  enum {
    START,
    LEFT_OF_DOT,
    RIGHT_OF_DOT,
    EXP_START,
    EXPONENT,
    END
  };

  char exp_sign;
  int exp_int, hsb, state;

  const char *old_str;

  int pos;
  char *mant_str, *exp_val, *power_val;

  if (result == NULL) result = calc_buffer;

  exp_val = alloca(VALUE_SIZE);
  power_val = alloca(CALC_BUFFER_SIZE);
  mant_str = alloca((len)?(len):(strlen(str)));

  _desc(result).exponent_size = exp_size;
  _desc(result).mantissa_size = mant_size;
  _desc(result).class = NORMAL;

  old_str = str;
  pos = 0;
  exp_int = 0;
  state = START;

  while (len == 0 || str-old_str < len)
  {
    switch (state) {
      case START:
        switch (*str) {
          case '+':
            _sign(result) = 0;
            state = LEFT_OF_DOT;
            str++;
            break;

          case '-':
            _sign(result) = 1;
            state = LEFT_OF_DOT;
            str++;
            break;

          case '0': case '1': case '2': case '3': case '4': case '5': case '6': case '7': case '8': case '9':
            _sign(result) = 0;
            state = LEFT_OF_DOT;
            break;

          case '.':
            _sign(result) = 0;
            state = RIGHT_OF_DOT;
            str++;
            break;

          case 'n':
          case 'N':
          case 'i':
          case 'I':
            break;

          default:
            _fail_char(old_str, len, str - old_str);
        }
        break;

      case LEFT_OF_DOT:
        switch (*str) {
          case '0': case '1': case '2': case '3': case '4': case '5': case '6': case '7': case '8': case '9':
            mant_str[pos++] = *(str++);
            break;

          case '.':
            state = RIGHT_OF_DOT;
            str++;
            break;

          case 'e':
          case 'E':
            state = EXP_START;
            str++;
            break;

          case '\0':
            mant_str[pos] = '\0';
            goto done;

          default:
            _fail_char(old_str, len, str - old_str);
        }
        break;

      case RIGHT_OF_DOT:
        switch (*str) {
          case '0': case '1': case '2': case '3': case '4': case '5': case '6': case '7': case '8': case '9':
            mant_str[pos++] = *(str++);
            exp_int++;
            break;

          case 'e':
          case 'E':
            state = EXP_START;
            str++;
            break;

          case '\0':
            mant_str[pos] = '\0';
            goto done;

          default:
            _fail_char(old_str, len, str - old_str);
        }
        break;

      case EXP_START:
        switch (*str) {
          case '-':
            exp_sign = 1;
            /* fall through */
          case '+':
            if (*(str-1) != 'e' && *(str-1) != 'E') _fail_char(old_str, len, str - old_str);
            str++;
            break;

          case '0': case '1': case '2': case '3': case '4': case '5': case '6': case '7': case '8': case '9':
            mant_str[pos] = '\0';
            pos = 1;
            str++;
            state = EXPONENT;
            break;

          default:
            _fail_char(old_str, len, str - old_str);
        }
        break;

      case EXPONENT:
        switch (*str) {
          case '0': case '1': case '2': case '3': case '4': case '5': case '6': case '7': case '8': case '9':
            pos++;
            str++;
            break;

          case '\0': goto done;

          default:
            _fail_char(old_str, len, str - old_str);
        }
    }
1034
  } /*  switch(state) */
1035
1036
1037

done:
  sc_val_from_str(mant_str, strlen(mant_str), _mant(result));
1038

1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
  /* shift to put value left of radix point */
  sc_val_from_ulong(mant_size + 2, exp_val);

  _shift_left(_mant(result), exp_val, _mant(result));

  sc_val_from_ulong((1 << exp_size)/2-1, _exp(result));

  _normalize(result, result, 0);

  if (state == EXPONENT) {
    exp_int -= atoi(str-pos);
  }

  _power_of_ten(exp_int, &_desc(result), power_val);

  _div(result, power_val, result);

  return result;
#else

  /* XXX excuse of an implementation to make things work */
  LLDBL val;
#ifdef HAVE_LONG_DOUBLE
  val = strtold(str, NULL);
#else
  val = strtod(str, NULL);
#endif

  DEBUGPRINTF(("val_from_str(%s)\n", str));
  return fc_val_from_float(val, exp_size, mant_size, result);
#endif
}

char* fc_val_from_float(LLDBL l, char exp_size, char mant_size, char* result)
{
  char *temp;
1075
  int bias_res, bias_val, mant_val;
1076
  value_t srcval;
Michael Beck's avatar
Michael Beck committed
1077
  UINT32 sign, exponent, mantissa0, mantissa1;
1078
1079

  srcval.d = l;
1080
  bias_res = ((1<<exp_size)/2-1);
1081
1082

#ifdef HAVE_LONG_DOUBLE
Michael Beck's avatar
Michael Beck committed
1083
1084
1085
1086
1087
1088
  mant_val  = 64;
  bias_val  = 0x3fff;
  sign      = (srcval.val.high & 0x00008000) != 0;
  exponent  = (srcval.val.high & 0x00007FFF) ;
  mantissa0 = srcval.val.mid;
  mantissa1 = srcval.val.low;
1089
#else /* no long double */
Michael Beck's avatar
Michael Beck committed
1090
1091
1092
1093
1094
1095
  mant_val  = 52;
  bias_val  = 0x3ff;
  sign      = (srcval.val.high & 0x80000000) != 0;
  exponent  = (srcval.val.high & 0x7FF00000) >> 20;
  mantissa0 = srcval.val.high & 0x000FFFFF;
  mantissa1 = srcval.val.low;
1096
1097
1098
#endif

#ifdef HAVE_LONG_DOUBLE
1099
  TRACEPRINTF(("val_from_float(%.8X%.8X%.8X)\n", ((int*)&l)[2], ((int*)&l)[1], ((int*)&l)[0]));/* srcval.val.high, srcval.val.mid, srcval.val.low)); */
1100
1101
  DEBUGPRINTF(("(%d-%.4X-%.8X%.8X)\n", sign, exponent, mantissa0, mantissa1));
#else
1102
  TRACEPRINTF(("val_from_float(%.8X%.8X)\n", srcval.val.high, srcval.val.low));
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
  DEBUGPRINTF(("(%d-%.3X-%.5X%.8X)\n", sign, exponent, mantissa0, mantissa1));
#endif

  if (result == NULL) result = calc_buffer;
  temp = alloca(VALUE_SIZE);

  _desc(result).exponent_size = exp_size;
  _desc(result).mantissa_size = mant_size;

  /* extract sign */
  _sign(result) = sign;

  /* sign and flag suffice to identify nan or inf, no exponent/mantissa
   * encoding is needed. the function can return immediately in these cases */
  if (isnan(l)) {
    _desc(result).class = NAN;
    TRACEPRINTF(("val_from_float resulted in NAN\n"));
    return result;
1121
  }
1122
1123
1124
1125
  else if (isinf(l)) {
    _desc(result).class = INF;
    TRACEPRINTF(("val_from_float resulted in %sINF\n", (_sign(result)==1)?"-":""));
    return result;
1126
  }
1127

1128
1129
1130
1131
1132
1133
1134
  /* build exponent, because input and output exponent and mantissa sizes may differ
   * this looks more complicated than it is: unbiased input exponent + output bias,
   * minus the mantissa difference which is added again later when the output float
   * becomes normalized */
#ifdef HAVE_EXPLICIT_ONE
  sc_val_from_long((exponent-bias_val+bias_res)-(mant_val-mant_size-1), _exp(result));
#else
1135
  sc_val_from_long((exponent-bias_val+bias_res)-(mant_val-mant_size), _exp(result));
1136
#endif
1137

1138
1139
  /* build mantissa representation */
#ifndef HAVE_EXPLICIT_ONE
1140
1141
1142
1143
1144
1145
  if (exponent != 0)
  {
    /* insert the hidden bit */
    sc_val_from_ulong(1, temp);
    sc_val_from_ulong(mant_val + 2, NULL);
    _shift_left(temp, sc_get_buffer(), NULL);
1146
  }
1147
  else
1148
#endif
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
  {
    sc_val_from_ulong(0, NULL);
  }

  _save_result(_mant(result));

  /* bits from the upper word */
  sc_val_from_ulong(mantissa0, temp);
  sc_val_from_ulong(34, NULL);
  _shift_left(temp, sc_get_buffer(), temp);
  sc_or(_mant(result), temp, _mant(result));

  /* bits from the lower word */
  sc_val_from_ulong(mantissa1, temp);
  sc_val_from_ulong(2, NULL);
  _shift_left(temp, sc_get_buffer(), temp);
  sc_or(_mant(result), temp, _mant(result));

  /* _normalize expects the radix point to be normal, so shift mantissa of subnormal
   * origin one to the left */
  if (exponent == 0)
  {
    sc_val_from_ulong(1, NULL);
    _shift_left(_mant(result), sc_get_buffer(), _mant(result));
  }

  _normalize(result, result, 0);

1177
  TRACEPRINTF(("val_from_float results in %s\n", fc_print(result, temp, CALC_BUFFER_SIZE, FC_PACKED)));
1178
1179

  return result;
1180
1181
}

1182
LLDBL fc_val_to_float(const void *val)
1183
{
1184
1185
1186
1187
  const char *value;
  char *temp = NULL;

  int byte_offset;
1188

1189
1190
1191
1192
1193
1194
1195
1196
1197
  UINT32 sign;
  UINT32 exponent;
  UINT32 mantissa0;
  UINT32 mantissa1;

  value_t buildval;

#ifdef HAVE_LONG_DOUBLE
  char result_exponent = 15;
1198
  char result_mantissa = 64;
Michael Beck's avatar
Tarval:    
Michael Beck committed
1199
#else
1200
  char result_exponent = 11;
1201
  char result_mantissa = 52;
Michael Beck's avatar
Tarval:    
Michael Beck committed
1202
#endif
1203

1204
  temp = alloca(CALC_BUFFER_SIZE);
1205
1206
1207
#ifdef HAVE_EXPLICIT_ONE
  value = fc_cast(val, result_exponent, result_mantissa-1, temp);
#else
1208
  value = fc_cast(val, result_exponent, result_mantissa, temp);
1209
#endif
1210
1211

  sign = _sign(value);
1212
1213

  /* @@@ long double exponent is 15bit, so the use of sc_val_to_long should not
1214
   * lead to wrong results */
Michael Beck's avatar
Michael Beck committed
1215
  exponent = sc_val_to_long(_exp(value)) ;
1216

1217
1218
  sc_val_from_ulong(2, NULL);
  _shift_right(_mant(value), sc_get_buffer(), _mant(value));
1219
1220
1221
1222
1223

  mantissa0 = 0;
  mantissa1 = 0;

  for (byte_offset = 0; byte_offset < 4; byte_offset++)
1224
    mantissa1 |= sc_sub_bits(_mant(value), result_mantissa, byte_offset) << (byte_offset<<3);
1225
1226

  for (; (byte_offset<<3) < result_mantissa; byte_offset++)
1227
    mantissa0 |= sc_sub_bits(_mant(value), result_mantissa, byte_offset) << ((byte_offset-4)<<3);
1228
1229

#ifdef HAVE_LONG_DOUBLE
1230
1231
1232
1233
  buildval.val.high = sign << 15;
  buildval.val.high |= exponent;
  buildval.val.mid = mantissa0;
  buildval.val.low = mantissa1;
1234
#else /* no long double */
Michael Beck's avatar
Michael Beck committed
1235
  mantissa0 &= 0x000FFFFF;  /* get rid of garbage */
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
  buildval.val.high = sign << 31;
  buildval.val.high |= exponent << 20;
  buildval.val.high |= mantissa0;
  buildval.val.low = mantissa1;
#endif

  TRACEPRINTF(("val_to_float: %d-%x-%x%x\n", sign, exponent, mantissa0, mantissa1));
  return buildval.d;
}

char* fc_cast(const void *val, char exp_size, char mant_size, char *result)
{
  const char *value = (const char*) val;
  char *temp;
  int exp_offset, val_bias, res_bias;

  if (result == NULL) result = calc_buffer;
1253
  temp = alloca(VALUE_SIZE);
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273

  if (_desc(value).exponent_size == exp_size && _desc(value).mantissa_size == mant_size)
  {
    if (value != result) memcpy(result, value, CALC_BUFFER_SIZE);
    return result;
  }

  /* set the descriptor of the new value */
  _desc(result).exponent_size = exp_size;
  _desc(result).mantissa_size = mant_size;
  _desc(result).class = _desc(value).class;

  _sign(result) = _sign(value);

  /* when the mantissa sizes differ normalizing has to shift to align it.
   * this would change the exponent, which is unwanted. So calculate this
   * offset and add it */
  val_bias = (1<<_desc(value).exponent_size)/2-1;
  res_bias = (1<<exp_size)/2-1;

1274
  exp_offset = (res_bias - val_bias) - (_desc(value).mantissa_size - mant_size);
1275
1276
1277
  sc_val_from_long(exp_offset, temp);
  sc_add(_exp(value), temp, _exp(result));

1278
1279
1280
1281
1282
1283
1284
1285
1286
  /* _normalize expects normalized radix point */
  if (_desc(val).class == SUBNORMAL) {
    sc_val_from_ulong(1, NULL);
    _shift_left(_mant(val), sc_get_buffer(), _mant(result));
  } else if (value != result) {
    memcpy(_mant(result), _mant(value), VALUE_SIZE);
  } else {
    memmove(_mant(result), _mant(value), VALUE_SIZE);
  }
1287

1288
1289
1290
  _normalize(result, result, 0);
  TRACEPRINTF(("Cast results in %s\n", fc_print(result, temp, VALUE_SIZE, FC_PACKED)));
  return result;
1291
1292
1293
1294
1295
1296
1297
1298
1299
1300
1301
1302
1303
1304
1305
1306
1307
1308
1309
1310
1311
1312
1313
1314
1315
1316
1317
1318
1319
1320
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
1344
1345
1346
1347
1348
1349
1350
1351
1352
1353
1354
1355
1356
1357
1358
1359
1360
1361
1362
1363
1364
1365
1366
1367
1368
1369
1370
1371
1372
1373
1374
1375
1376
1377
1378
1379
1380
1381
1382
1383
1384
1385
1386
1387
1388
1389
1390
1391
1392
1393
1394
1395
1396
1397
1398
1399
1400
1401
1402
1403
1404
1405
1406
1407
1408
1409
1410
1411
1412
1413
}

char* fc_get_max(unsigned int exponent_size, unsigned int mantissa_size, char* result)
{
  if (result == NULL) result = calc_buffer;

  _desc(result).exponent_size = exponent_size;
  _desc(result).mantissa_size = mantissa_size;
  _desc(result).class = NORMAL;

  _sign(result) = 0;

  sc_val_from_ulong((1<<exponent_size) - 2, _exp(result));

  sc_max_from_bits(mantissa_size + 1, 0, _mant(result));
  sc_val_from_ulong(2, NULL);
  _shift_left(_mant(result), sc_get_buffer(), _mant(result));

  return result;
}

char* fc_get_min(unsigned int exponent_size, unsigned int mantissa_size, char *result)
{
  if (result == NULL) result = calc_buffer;

  fc_get_max(exponent_size, mantissa_size, result);
  _sign(result) = 1;

  return result;
}

char* fc_get_snan(unsigned int exponent_size, unsigned int mantissa_size, char *result)
{
  if (result == NULL) result = calc_buffer;

  _desc(result).exponent_size = exponent_size;
  _desc(result).mantissa_size = mantissa_size;
  _desc(result).class = NAN;

  _sign(result) = 0;

  sc_val_from_ulong((1<<exponent_size)-1, _exp(result));

  /* signalling nan has non-zero mantissa with msb not set */
  sc_val_from_ulong(1, _mant(result));

  return result;
}

char* fc_get_qnan(unsigned int exponent_size, unsigned int mantissa_size, char *result)
{
  if (result == NULL) result = calc_buffer;

  _desc(result).exponent_size = exponent_size;
  _desc(result).mantissa_size = mantissa_size;
  _desc(result).class = NAN;

  _sign(result) = 0;

  sc_val_from_ulong((1<<exponent_size)-1, _exp(result));

  /* quiet nan has the msb of the mantissa set, so shift one there */
  sc_val_from_ulong(1, _mant(result));
  /* mantissa_size >+< 1 because of two extra rounding bits */
  sc_val_from_ulong(mantissa_size + 1, NULL);
  _shift_left(_mant(result), sc_get_buffer(), _mant(result));

  return result;
}

char* fc_get_plusinf(unsigned int exponent_size, unsigned int mantissa_size, char *result)
{
  if (result == NULL) result = calc_buffer;

  _desc(result).exponent_size = exponent_size;
  _desc(result).mantissa_size = mantissa_size;
  _desc(result).class = NORMAL;

  _sign(result) = 0;

  sc_val_from_ulong((1<<exponent_size)-1, _exp(result));

  sc_val_from_ulong(0, _mant(result));

  return result;
}

char* fc_get_minusinf(unsigned int exponent_size, unsigned int mantissa_size, char *result)
{
  if (result == NULL) result = calc_buffer;

  fc_get_plusinf(exponent_size, mantissa_size, result);
  _sign(result) = 1;

  return result;
}

int fc_comp(const void *a, const void *b)
{
  const char *val_a = (const char*)a;
  const char *val_b = (const char*)b;

  /* unordered */
  if (_desc(val_a).class == NAN || _desc(val_b).class == NAN) return 2;
  /* zero is equal independent of sign */
  if ((_desc(val_a).class == ZERO) && (_desc(val_b).class == ZERO)) return 0;
  /* different signs make compare easy */
  if (_sign(val_a) != _sign(val_b)) return (_sign(val_a)==0)?(1):(-1);
  /* both infinity means equality */
  if ((_desc(val_a).class == INF) && (_desc(val_b).class == INF)) return 0;
  /* infinity is bigger than the rest */
  if (_desc(val_a).class == INF) return _sign(val_a)?(-1):(1);
  if (_desc(val_b).class == INF) return _sign(val_b)?(1):(-1);

  switch (sc_comp(_exp(val_a), _exp(val_b))) {
    case -1:
      return -1;
    case  1:
      return  1;
    case  0:
      return sc_comp(_mant(val_a), _mant(val_b));
    default:
      return 2;
1414
  }
1415
1416
1417
1418
1419
1420
1421
1422
1423
1424
1425
1426
1427
1428
1429
1430
1431
1432
1433
1434
1435
}

int fc_is_zero(const void *a)
{
  return _desc((const char*)a).class == ZERO;
}

int fc_is_negative(const void *a)
{
  return _sign((const char*)a);
}

int fc_is_inf(const void *a)
{
  return _desc(a).class == INF;
}

int fc_is_nan(const void *a)
{
  return _desc(a).class == NAN;
}
1436

1437
1438
1439
1440
1441
1442
1443
1444
1445
1446
1447
1448
1449
1450
1451
1452
1453
1454
1455
1456
1457
1458
1459
1460
1461
1462
1463
1464
1465
1466
1467
1468
1469
1470
1471
1472
1473
int fc_is_subnormal(const void *a)
{
  return _desc(a).class == SUBNORMAL;
}

char *fc_print(const void *a, char *buf, int buflen, unsigned base)
{
  const char *val;
  char *mul_1;

  val = (const char*)a;

  mul_1 = alloca(CALC_BUFFER_SIZE);

  switch (base) {
    case FC_DEC:
      switch (_desc(val).class) {
        case INF:
          if (buflen >= 8+_sign(val)) sprintf(buf, "%sINFINITY", _sign(val)?"-":"");
          else snprintf(buf, buflen, "%sINF", _sign(val)?"-":NULL);
          break;
        case NAN:
          snprintf(buf, buflen, "NAN");
          break;
        case ZERO:
          snprintf(buf, buflen, "0.0");
          break;
        default:
          /* XXX to be implemented */
#ifdef HAVE_LONG_DOUBLE
          /* XXX 30 is arbitrary */
          snprintf(buf, buflen, "%.30LE", fc_val_to_float(val));
#else
          snprintf(buf, buflen, "%.18E", fc_val_to_float(val));
#endif
      }
      break;
1474

1475
    case FC_HEX:
1476
1477
1478
1479
1480
1481
1482
1483
1484
1485
1486
1487
1488
1489
1490
1491
1492
1493
1494
1495
1496
1497
1498
      switch (_desc(val).class) {
        case INF:
          if (buflen >= 8+_sign(val)) sprintf(buf, "%sINFINITY", _sign(val)?"-":"");
          else snprintf(buf, buflen, "%sINF", _sign(val)?"-":NULL);
          break;
        case NAN:
          snprintf(buf, buflen, "NAN");
          break;
        case ZERO:
          snprintf(buf, buflen, "0.0");
          break;
        default:
#ifdef HAVE_LONG_DOUBLE
          snprintf(buf, buflen, "%LA", fc_val_to_float(val));
#else
          snprintf(buf, buflen, "%A", fc_val_to_float(val));
#endif
      }
      break;

    case FC_PACKED:
    default:
      snprintf(buf, buflen, "%s", sc_print(_pack(val, mul_1), VALUE_SIZE*4, SC_HEX));
1499
1500
      break;
  }
1501
1502
  return buf;
}
1503
1504
1505

unsigned char fc_sub_bits(const void *value, unsigned num_bits, unsigned byte_ofs)
{
1506
1507
1508
1509
1510
1511
1512
1513
1514
1515
1516
1517
1518
1519
1520
  /* this is used to cache the packed version of the value */
  static char *pack = NULL;

  if (pack == NULL) pack = malloc(VALUE_SIZE);

  if (value != NULL)
    _pack((const char*)value, pack);

  return sc_sub_bits(pack, num_bits, byte_ofs);
}

fc_rounding_mode_t fc_set_rounding_mode(fc_rounding_mode_t mode)
{
  if (mode == FC_TONEAREST || mode == FC_TOPOSITIVE || mode == FC_TONEGATIVE || mode == FC_TOZERO)
      ROUNDING_MODE = mode;
1521

1522
1523
  return ROUNDING_MODE;
}
1524

1525
1526
1527
1528
fc_rounding_mode_t fc_get_rounding_mode(void)
{
  return ROUNDING_MODE;
}
1529

1530
1531
1532
1533
1534
void init_fltcalc(int precision)
{
  if (calc_buffer == NULL) {
    /* does nothing if already init */
    if (precision == 0) precision = FC_DEFAULT_PRECISION;
1535

1536
    init_strcalc(precision + 4);
1537

1538
1539
1540
1541
1542
    /* needs additionally two bits to round, a bit as explicit 1., and one for
     * addition overflow */
    max_precision = sc_get_precision() - 4;
    if (max_precision < precision)
      printf("WARING: not enough precision available, using %d\n", max_precision);
1543

1544
1545
1546
1547
1548
1549
1550
1551
1552
1553
    ROUNDING_MODE = FC_TONEAREST;
    VALUE_SIZE = sc_get_buffer_length();
    SIGN_POS = 0;
    EXPONENT_POS = SIGN_POS + sizeof(char);
    MANTISSA_POS = EXPONENT_POS + VALUE_SIZE;
    DESCRIPTOR_POS = MANTISSA_POS + VALUE_SIZE;
    CALC_BUFFER_SIZE = DESCRIPTOR_POS + sizeof(descriptor_t);

    calc_buffer = malloc(CALC_BUFFER_SIZE);
    DEBUGPRINTF(("init fltcalc:\n\tVALUE_SIZE = %d\n\tSIGN_POS = %d\n\tEXPONENT_POS = %d\n\tMANTISSA_POS = %d\n\tDESCRIPTOR_POS = %d\n\tCALC_BUFFER_SIZE = %d\n\tcalc_buffer = %p\n\n", VALUE_SIZE, SIGN_POS, EXPONENT_POS, MANTISSA_POS, DESCRIPTOR_POS, CALC_BUFFER_SIZE, calc_buffer));
1554
1555
1556
1557
1558
1559
1560
1561
1562
1563
#ifdef HAVE_LONG_DOUBLE
    DEBUGPRINTF(("\tUsing long double (1-15-64) interface\n"));
#else
    DEBUGPRINTF(("\tUsing double (1-11-52) interface\n"));
#endif
#ifdef WORDS_BIGENDIAN
    DEBUGPRINTF(("\tWord order is big endian\n\n"));
#else
    DEBUGPRINTF(("\tWord order is little endian\n\n"));
#endif
1564
  }
1565
}
1566

1567
1568
1569
1570
void finish_fltcalc (void) {
  free(calc_buffer); calc_buffer = NULL;
}

1571
1572
1573
1574
1575
1576
1577
1578
/* definition of interface functions */
FC_DEFINE2(add)
FC_DEFINE2(sub)
FC_DEFINE2(mul)
FC_DEFINE2(div)
FC_DEFINE1(neg)
FC_DEFINE1(int)
FC_DEFINE1(rnd)