fltcalc.c 43.5 KB
Newer Older
Christian Würdig's avatar
Christian Würdig committed
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
/*
 * Copyright (C) 1995-2007 University of Karlsruhe.  All right reserved.
 *
 * This file is part of libFirm.
 *
 * This file may be distributed and/or modified under the terms of the
 * GNU General Public License version 2 as published by the Free Software
 * Foundation and appearing in the file LICENSE.GPL included in the
 * packaging of this file.
 *
 * Licensees holding valid libFirm Professional Edition licenses may use
 * this file in accordance with the libFirm Commercial License.
 * Agreement provided with the Software.
 *
 * This file is provided AS IS with NO WARRANTY OF ANY KIND, INCLUDING THE
 * WARRANTY OF DESIGN, MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE.
 */

Michael Beck's avatar
Michael Beck committed
20
21
22
23
24
25
/**
 * @file
 * @brief    tarval floating point calculations
 * @date     2003
 * @author   Mathias Heil
 * @version  $Id$
26
27
 */

Boris Boesler's avatar
Boris Boesler committed
28
29
30
31
#ifdef HAVE_CONFIG_H
# include "config.h"
#endif

32
#include "fltcalc.h"
33
34
35
36
37
38
39
40
#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

41
#ifdef HAVE_INTTYPES_H
Michael Beck's avatar
Michael Beck committed
42
43
44
45
46
47
48
# include <inttypes.h>
#endif
#ifdef HAVE_STRING_H
# include <string.h>
#endif
#ifdef HAVE_STDLIB_H
# include <stdlib.h>
49
#endif
Michael Beck's avatar
Michael Beck committed
50
51
#include <stdio.h>
#include <assert.h>
52

53
54
#include "xmalloc.h"

55
typedef uint32_t UINT32;
Michael Beck's avatar
Tarval:    
Michael Beck committed
56

57
#ifdef HAVE_LONG_DOUBLE
58
#ifdef WORDS_BIGENDIAN
59
60
61
typedef union {
  struct {
    UINT32 high;
62
63
    UINT32 mid;
    UINT32 low;
64
65
66
67
68
69
70
  } val;
  volatile long double d;
} value_t;
#else
typedef union {
  struct {
    UINT32 low;
71
72
    UINT32 mid;
    UINT32 high;
73
74
75
76
77
  } val;
  volatile long double d;
} value_t;
#endif
#else
78
#ifdef WORDS_BIGENDIAN
79
80
81
typedef union {
  struct {
    UINT32 high;
82
    UINT32 low;
83
84
85
86
87
88
89
  } val;
  volatile double d;
} value_t;
#else
typedef union {
  struct {
    UINT32 low;
90
    UINT32 high;
91
92
93
94
95
  } val;
  volatile double d;
} value_t;
#endif
#endif
96

Michael Beck's avatar
Michael Beck committed
97
98
99
/**
 * possible float states
 */
100
typedef enum {
Michael Beck's avatar
Michael Beck committed
101
102
103
104
105
  NORMAL,       /**< normal representation, implicit 1 */
  ZERO,         /**< +/-0 */
  SUBNORMAL,    /**< denormals, implicit 0 */
  INF,          /**< +/-oo */
  NAN,          /**< Not A Number */
106
107
} value_class_t;

Michael Beck's avatar
Michael Beck committed
108
/** A descriptor for an IEEE float value. */
109
typedef struct {
Michael Beck's avatar
Michael Beck committed
110
111
112
  unsigned char exponent_size;    /**< size of exponent in bits */
  unsigned char mantissa_size;    /**< size of mantissa in bits */
  value_class_t clss;             /**< state of this float */
113
114
} descriptor_t;

115
#define CLEAR_BUFFER(buffer) memset(buffer, 0, calc_buffer_size)
116
117
118
119
120

/* because variable sized structs are impossible, the internal
 * value is represented as a pseudo-struct char array, addressed
 * by macros
 * struct {
121
 *   char sign;             //  0 for positive, 1 for negative
122
123
 *   char exp[value_size];
 *   char mant[value_size];
124
125
126
127
128
129
 *   descriptor_t desc;
 * };
 */
#define _sign(a) (((char*)a)[SIGN_POS])
#define _exp(a) (&((char*)a)[EXPONENT_POS])
#define _mant(a) (&((char*)a)[MANTISSA_POS])
Michael Beck's avatar
Michael Beck committed
130
#define _desc(a) (*(descriptor_t *)&((char *)a)[DESCRIPTOR_POS])
Michael Beck's avatar
Tarval:    
Michael Beck committed
131

132
133
134
#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
135

Michael Beck's avatar
Michael Beck committed
136
137
138
139
#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
140

Michael Beck's avatar
Michael Beck committed
141
142
143
144
#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); \
}
145
146
147
148
149
150
151

#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
152
153
#endif

154
155
156
157
158
#if FLTCALC_TRACE_CALC
#  define TRACEPRINTF(x) printf x
#else
#  define TRACEPRINTF(x) ((void)0)
#endif
159

160
static char *calc_buffer = NULL;
161

162
static fc_rounding_mode_t rounding_mode;
163

164
165
static int calc_buffer_size;
static int value_size;
166
167
168
169
static int SIGN_POS;
static int EXPONENT_POS;
static int MANTISSA_POS;
static int DESCRIPTOR_POS;
170

171
static int max_precision;
172
/********
173
 * private functions
174
 ********/
175
176
#if 0
static void _fail_char(const char *str, unsigned int len, int pos)
177
{
178
179
180
181
182
183
184
185
  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);
186
}
187
#endif
188

Michael Beck's avatar
Michael Beck committed
189
/** pack machine-like */
190
static char* _pack(const char *int_float, char *packed)
191
{
192
193
194
  char *shift_val;
  char *temp;
  char *val_buffer;
195

196
197
  temp = alloca(value_size);
  shift_val = alloca(value_size);
198

Michael Beck's avatar
Michael Beck committed
199
  switch (_desc(int_float).clss) {
200
    case NAN:
201
      val_buffer = alloca(calc_buffer_size);
202
203
204
205
206
      fc_get_qnan(_desc(int_float).exponent_size, _desc(int_float).mantissa_size, val_buffer);
      int_float = val_buffer;
      break;

    case INF:
207
      val_buffer = alloca(calc_buffer_size);
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
      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;
242
243
}

244
char* _normalize(const char *in_val, char *out_val, int sticky)
245
{
246
247
248
249
  int hsb;
  char lsb, guard, round, round_dir = 0;
  char *temp;

250
  temp = alloca(value_size);
251
252
253
254
255
256
257
258
259
260

  /* +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));
  }

Michael Beck's avatar
Michael Beck committed
261
  _desc(out_val).clss = NORMAL;
262

263
  /* mantissa all zeros, so zero exponent (because of explicit one)*/
264
265
266
267
268
269
  if (hsb == 2 + _desc(in_val).mantissa_size)
  {
    sc_val_from_ulong(0, _exp(out_val));
    hsb = -1;
  }

270
  /* shift the first 1 into the left of the radix point (i.e. hsb == -1) */
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
  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));

Michael Beck's avatar
Michael Beck committed
306
    _desc(out_val).clss = SUBNORMAL;
307
308
309
310
311
312
313
314
315
  }

  /* 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;

316
  switch (rounding_mode)
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
  {
    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 */
Michael Beck's avatar
Michael Beck committed
355
356
  if (sc_is_zero(_mant(out_val)) && (_desc(out_val).clss == SUBNORMAL))
    _desc(out_val).clss = ZERO;
357
358
359

  /* check for rounding overflow */
  hsb = 2 + _desc(out_val).mantissa_size - sc_get_highest_set_bit(_mant(out_val)) - 1;
Michael Beck's avatar
Michael Beck committed
360
  if ((_desc(out_val).clss != SUBNORMAL) && (hsb < -1))
361
362
363
364
365
366
  {
    sc_val_from_ulong(1, temp);
    _shift_right(_mant(out_val), temp, _mant(out_val));

    sc_add(_exp(out_val), temp, _exp(out_val));
  }
Michael Beck's avatar
Michael Beck committed
367
  else if ((_desc(out_val).clss == SUBNORMAL) && (hsb == -1))
368
  {
Michael Beck's avatar
Michael Beck committed
369
    /* overflow caused the mantissa to be normal again,
370
371
372
373
     * so adapt the exponent accordingly */
    sc_val_from_ulong(1, temp);
    sc_add(_exp(out_val), temp, _exp(out_val));

Michael Beck's avatar
Michael Beck committed
374
    _desc(out_val).clss = NORMAL;
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
  }
  /* 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 */
404
      switch (rounding_mode) {
405
406
        case FC_TONEAREST:
        case FC_TOPOSITIVE:
Michael Beck's avatar
Michael Beck committed
407
          _desc(out_val).clss = INF;
408
409
410
411
412
413
414
415
          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 */
416
      switch (rounding_mode) {
417
418
        case FC_TONEAREST:
        case FC_TONEGATIVE:
Michael Beck's avatar
Michael Beck committed
419
          _desc(out_val).clss = INF;
420
421
422
423
424
425
426
427
428
429
          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;
430
431
}

Michael Beck's avatar
Michael Beck committed
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
/**
 * Operations involving NaN's must return NaN
 */
#define handle_NAN(a, b, result) \
do {                                                      \
  if (_desc(a).clss == NAN) {                             \
    if (a != result) memcpy(result, a, calc_buffer_size); \
    return result;                                        \
  }                                                       \
  if (_desc(b).clss == NAN) {                             \
    if (b != result) memcpy(result, b, calc_buffer_size); \
    return result;                                        \
  }                                                       \
}while (0)


/**
449
450
 * calculate a + b, where a is the value with the bigger exponent
 */
Michael Beck's avatar
Michael Beck committed
451
static char* _fadd(const char* a, const char* b, char* result)
452
{
453
454
455
456
457
458
  char *temp;
  char *exp_diff;

  char sign;
  char sticky;

Michael Beck's avatar
Michael Beck committed
459
  handle_NAN(a, b, result);
460
461
462
463
464
465
466
467

  /* 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);

Michael Beck's avatar
Michael Beck committed
468
  /* produce NaN on inf - inf */
Michael Beck's avatar
Michael Beck committed
469
  if (sign && (_desc(a).clss == INF) && (_desc(b).clss == INF))
470
471
    return fc_get_qnan(_desc(a).exponent_size, _desc(b).mantissa_size, result);

Michael Beck's avatar
Michael Beck committed
472
  temp     = alloca(value_size);
473
  exp_diff = alloca(value_size);
474
475
476
477
478
479
480
481

  /* 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
482
  if (sign && sc_val_to_long(exp_diff) == 0) {
483
484
    switch (sc_comp(_mant(a), _mant(b))) {
      case 1:  /* a > b */
Michael Beck's avatar
Michael Beck committed
485
        _sign(result) = _sign(a);  /* abs(a) is bigger and a is negative */
486
487
        break;
      case 0:  /* a == b */
Michael Beck's avatar
Michael Beck committed
488
        _sign(result) = (rounding_mode == FC_TONEGATIVE);
489
490
        break;
      case -1: /* a < b */
Michael Beck's avatar
Michael Beck committed
491
        _sign(result) = _sign(b); /* abs(b) is bigger and b is negative */
492
493
494
495
496
497
        break;
      default:
        /* can't be reached */
        break;
    }
  }
Michael Beck's avatar
Michael Beck committed
498
499
  else
    _sign(result) = _sign(a);
500
501

  /* sign has been taken care of, check for special cases */
Michael Beck's avatar
Michael Beck committed
502
  if (_desc(a).clss == ZERO) {
503
    if (b != result) memcpy(result+SIGN_POS+1, b+SIGN_POS+1, calc_buffer_size-SIGN_POS-1);
504
505
    return result;
  }
Michael Beck's avatar
Michael Beck committed
506
  if (_desc(b).clss == ZERO) {
507
    if (a != result) memcpy(result+SIGN_POS+1, a+SIGN_POS+1, calc_buffer_size-SIGN_POS-1);
508
509
510
    return result;
  }

Michael Beck's avatar
Michael Beck committed
511
  if (_desc(a).clss == INF) {
512
    if (a != result) memcpy(result+SIGN_POS+1, a+SIGN_POS+1, calc_buffer_size-SIGN_POS-1);
513
514
    return result;
  }
Michael Beck's avatar
Michael Beck committed
515
  if (_desc(b).clss == INF) {
516
    if (b != result) memcpy(result+SIGN_POS+1, b+SIGN_POS+1, calc_buffer_size-SIGN_POS-1);
517
518
519
520
521
522
    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 */
Michael Beck's avatar
Michael Beck committed
523
  if ((_desc(b).clss == SUBNORMAL) && (_desc(a).clss != SUBNORMAL))
524
525
526
527
528
529
530
531
532
533
534
535
536
  {
    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' */
537
    char *temp1 = alloca(calc_buffer_size);
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
    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 */
Michael Beck's avatar
Michael Beck committed
553
  if ((_desc(a).clss == SUBNORMAL) && (_desc(b).clss == SUBNORMAL))
554
555
556
557
558
559
  {
    sc_val_from_ulong(1, NULL);
    _shift_left(_mant(result), sc_get_buffer(), _mant(result));
  }

  /* resulting exponent is the bigger one */
560
  memmove(_exp(result), _exp(a), value_size);
561
562

  return _normalize(result, result, sticky);
563
564
}

Michael Beck's avatar
Michael Beck committed
565
566
567
568
/**
 * calculate a * b
 */
static char* _fmul(const char* a, const char* b, char* result)
569
{
570
  char *temp;
571

Michael Beck's avatar
Michael Beck committed
572
  handle_NAN(a, b, result);
573

574
  temp = alloca(value_size);
575
576
577
578
579
580

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

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

Michael Beck's avatar
Michael Beck committed
581
  /* produce NaN on 0 * inf */
Michael Beck's avatar
Michael Beck committed
582
583
  if (_desc(a).clss == ZERO) {
    if (_desc(b).clss == INF)
584
585
      fc_get_qnan(_desc(a).exponent_size, _desc(a).mantissa_size, result);
    else
586
      if (a != result) memcpy(result+SIGN_POS+1, a+SIGN_POS+1, calc_buffer_size-1);
587
588
    return result;
  }
Michael Beck's avatar
Michael Beck committed
589
590
  if (_desc(b).clss == ZERO) {
    if (_desc(a).clss == INF)
591
592
      fc_get_qnan(_desc(a).exponent_size, _desc(a).mantissa_size, result);
    else
593
      if (b != result) memcpy(result+SIGN_POS+1, b+SIGN_POS+1, calc_buffer_size-1);
594
595
596
    return result;
  }

Michael Beck's avatar
Michael Beck committed
597
  if (_desc(a).clss == INF) {
598
    if (a != result) memcpy(result+SIGN_POS+1, a+SIGN_POS+1, calc_buffer_size-1);
599
600
    return result;
  }
Michael Beck's avatar
Michael Beck committed
601
  if (_desc(b).clss == INF) {
602
    if (b != result) memcpy(result+SIGN_POS+1, b+SIGN_POS+1, calc_buffer_size-1);
603
604
605
606
607
608
609
610
611
612
    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 */
Michael Beck's avatar
Michael Beck committed
613
  if ((_desc(a).clss == SUBNORMAL) ^ (_desc(b).clss == SUBNORMAL))
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
  {
    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());
631
632
}

Michael Beck's avatar
Michael Beck committed
633
634
635
636
/**
 * calculate a / b
 */
static char* _fdiv(const char* a, const char* b, char* result)
637
{
638
639
  char *temp, *dividend;

Michael Beck's avatar
Michael Beck committed
640
  handle_NAN(a, b, result);
641

642
643
  temp = alloca(value_size);
  dividend = alloca(value_size);
644
645
646
647
648
649
650

  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 */
Michael Beck's avatar
Michael Beck committed
651
652
  if (_desc(a).clss == ZERO) {
    if (_desc(b).clss == ZERO)
653
654
655
656
      /* 0/0 -> nan */
      fc_get_qnan(_desc(a).exponent_size, _desc(a).mantissa_size, result);
    else
      /* 0/x -> a */
657
      if (a != result) memcpy(result+SIGN_POS+1, a+SIGN_POS+1, calc_buffer_size-1);
658
659
660
    return result;
  }

Michael Beck's avatar
Michael Beck committed
661
662
  if (_desc(b).clss == INF) {
    if (_desc(a).clss == INF)
663
664
665
666
667
668
669
      /* 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));
Michael Beck's avatar
Michael Beck committed
670
      _desc(result).clss = ZERO;
671
672
673
674
    }
    return result;
  }

Michael Beck's avatar
Michael Beck committed
675
  if (_desc(a).clss == INF) {
676
    /* inf/x -> inf */
677
    if (a != result) memcpy(result+SIGN_POS+1, a+SIGN_POS+1, calc_buffer_size-1);
678
679
    return result;
  }
Michael Beck's avatar
Michael Beck committed
680
  if (_desc(b).clss == ZERO) {
681
682
683
684
685
686
687
688
689
690
691
692
693
694
    /* 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 */
Michael Beck's avatar
Michael Beck committed
695
  if ((_desc(a).clss == SUBNORMAL) ^ (_desc(b).clss == SUBNORMAL))
696
  {
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
    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);

  {
712
    char *divisor = alloca(calc_buffer_size);
713
714
715
    sc_val_from_ulong(1, divisor);
    _shift_right(_mant(b), divisor, divisor);
    sc_div(dividend, divisor, _mant(result));
716
  }
717
718

  return _normalize(result, result, sc_had_carry());
719
720
}

Matthias Braun's avatar
Matthias Braun committed
721
#if 0
Michael Beck's avatar
Michael Beck committed
722
static void _power_of_ten(int exp, descriptor_t *desc, char *result)
723
{
724
725
726
727
728
729
730
731
732
733
  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));

734
735
  build = alloca(value_size);
  temp = alloca(value_size);
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750

  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);

Michael Beck's avatar
Michael Beck committed
751
    /* temp is amount of left shift needed to put the value left of the radix point */
752
    sc_val_from_ulong(_desc(result).mantissa_size + 2, temp);
753

754
755
756
757
    _shift_left(build, temp, _mant(result));

    _normalize(result, result, 0);
  }
758
}
Matthias Braun's avatar
Matthias Braun committed
759
#endif
760

Michael Beck's avatar
Michael Beck committed
761
762
763
764
765
/**
 * Truncate the fractional part away.
 *
 * This does not clip to any integer rang.
 */
766
static char* _trunc(const char *a, char *result)
767
{
Michael Beck's avatar
Michael Beck committed
768
769
  /*
   * When exponent == 0 all bits left of the radix point
770
   * are the integral part of the value. For 15bit exp_size
Michael Beck's avatar
Michael Beck committed
771
   * this would require a left shift of max. 16383 bits which
772
773
774
775
776
   * 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
Michael Beck's avatar
Michael Beck committed
777
778
   * it does not have fractional parts.
   */
779
780
781
782

  int exp_bias, exp_val;
  char *temp;

783
  temp = alloca(value_size);
784
785
786
787
788

  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
789
  exp_val  = sc_val_to_long(_exp(a)) - exp_bias;
790
791
792
793
794

  if (exp_val < 0) {
    sc_val_from_ulong(0, NULL);
    _save_result(_exp(result));
    _save_result(_mant(result));
Michael Beck's avatar
Michael Beck committed
795
    _desc(result).clss = ZERO;
796
797
798
799
800
801

    return result;
  }

  if (exp_val > _desc(a).mantissa_size) {
    if (a != result)
802
      memcpy(result, a, calc_buffer_size);
803
804
805
806
807
808
809
810
811
812
813
814
815

    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));

816
  if (a != result) memcpy(_exp(result), _exp(a), value_size);
817
818

  return result;
819
820
}

821
822
823
/*
 * This does value sanity checking(or should do it), sets up any prerequisites,
 * calls the proper internal functions, clears up and returns
Michael Beck's avatar
Michael Beck committed
824
825
 * the result
 */
826
char* _calc(const char *a, const char *b, int opcode, char *result)
827
{
828
829
830
831
832
833
834
835
836
  char *temp;
#ifdef FLTCALC_TRACE_CALC
  char *buffer;

  buffer = alloca(100);
#endif

  if (result == NULL) result = calc_buffer;

837
  TRACEPRINTF(("%s ", fc_print(a, buffer, 100, FC_PACKED)));
838
839
  switch (opcode)
  {
840
841
    case FC_add:
      /* make the value with the bigger exponent the first one */
842
      TRACEPRINTF(("+ %s ", fc_print(b, buffer, 100, FC_PACKED)));
843
      if (sc_comp(_exp(a), _exp(b)) == -1)
Michael Beck's avatar
Michael Beck committed
844
        _fadd(b, a, result);
845
      else
Michael Beck's avatar
Michael Beck committed
846
        _fadd(a, b, result);
847
848
      break;
    case FC_sub:
849
      TRACEPRINTF(("- %s ", fc_print(b, buffer, 100, FC_PACKED)));
850
851
      temp = alloca(calc_buffer_size);
      memcpy(temp, b, calc_buffer_size);
852
853
      _sign(temp) = !_sign(b);
      if (sc_comp(_exp(a), _exp(temp)) == -1)
Michael Beck's avatar
Michael Beck committed
854
        _fadd(temp, a, result);
855
      else
Michael Beck's avatar
Michael Beck committed
856
        _fadd(a, temp, result);
857
      break;
858
    case FC_mul:
859
      TRACEPRINTF(("* %s ", fc_print(b, buffer, 100, FC_PACKED)));
Michael Beck's avatar
Michael Beck committed
860
      _fmul(a, b, result);
861
      break;
862
    case FC_div:
863
      TRACEPRINTF(("/ %s ", fc_print(b, buffer, 100, FC_PACKED)));
Michael Beck's avatar
Michael Beck committed
864
      _fdiv(a, b, result);
865
      break;
866
867
    case FC_neg:
      TRACEPRINTF(("negated "));
868
      if (a != result) memcpy(result, a, calc_buffer_size);
869
      _sign(result) = !_sign(a);
870
      break;
871
    case FC_int:
Michael Beck's avatar
Michael Beck committed
872
      TRACEPRINTF(("truncated to integer "));
873
874
875
      _trunc(a, result);
      break;
    case FC_rnd:
Michael Beck's avatar
Michael Beck committed
876
877
      TRACEPRINTF(("rounded to integer "));
      assert(0);
878
      break;
879
  }
880

881
  TRACEPRINTF(("= %s\n", fc_print(result, buffer, 100, FC_PACKED)));
882
  return result;
883
884
}

885
886
887
888
/********
 * functions defined in fltcalc.h
 ********/
const void *fc_get_buffer(void)
889
{
890
891
892
  return calc_buffer;
}

Michael Beck's avatar
Michael Beck committed
893
int fc_get_buffer_length(void)
894
{
895
  return calc_buffer_size;
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
}

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;

Michael Beck's avatar
Michael Beck committed
918
  (void) len;
919
920
  if (result == NULL) result = calc_buffer;

921
922
  exp_val = alloca(value_size);
  power_val = alloca(calc_buffer_size);
923
924
925
926
  mant_str = alloca((len)?(len):(strlen(str)));

  _desc(result).exponent_size = exp_size;
  _desc(result).mantissa_size = mant_size;
Michael Beck's avatar
Michael Beck committed
927
  _desc(result).clss = NORMAL;
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
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055

  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);
        }
    }
1056
  } /*  switch(state) */
1057
1058
1059

done:
  sc_val_from_str(mant_str, strlen(mant_str), _mant(result));
1060

1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
  /* 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);

Michael Beck's avatar
Michael Beck committed
1076
  _fdiv(result, power_val, result);
1077
1078
1079
1080
1081

  return result;
#else
  /* XXX excuse of an implementation to make things work */
  LLDBL val;
1082
  char *tmp = alloca(calc_buffer_size);
Michael Beck's avatar
Michael Beck committed
1083
1084
  (void) len;

1085
1086
#ifdef HAVE_LONG_DOUBLE
  val = strtold(str, NULL);
1087
1088
  DEBUGPRINTF(("val_from_str(%s)\n", str));
  fc_val_from_float(val, 15, 64, tmp);
1089
1090
1091
#else
  val = strtod(str, NULL);
  DEBUGPRINTF(("val_from_str(%s)\n", str));
1092
1093
1094
  fc_val_from_float(val, 11, 52, tmp);
#endif /* HAVE_LONG_DOUBLE */
  return fc_cast(tmp, exp_size, mant_size, result);
1095
1096
1097
1098
1099
1100
#endif
}

char* fc_val_from_float(LLDBL l, char exp_size, char mant_size, char* result)
{
  char *temp;
1101
  int bias_res, bias_val, mant_val;
1102
  value_t srcval;
Michael Beck's avatar
Michael Beck committed
1103
  UINT32 sign, exponent, mantissa0, mantissa1;
1104
1105

  srcval.d = l;
1106
  bias_res = ((1<<exp_size)/2-1);
1107
1108

#ifdef HAVE_LONG_DOUBLE
Michael Beck's avatar
Michael Beck committed
1109
1110
1111
1112
1113
1114
  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;
1115
#else /* no long double */
Michael Beck's avatar
Michael Beck committed
1116
1117
1118
1119
1120
1121
  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;
1122
1123
1124
#endif

#ifdef HAVE_LONG_DOUBLE
1125
  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)); */
1126
1127
  DEBUGPRINTF(("(%d-%.4X-%.8X%.8X)\n", sign, exponent, mantissa0, mantissa1));
#else
1128
  TRACEPRINTF(("val_from_float(%.8X%.8X)\n", srcval.val.high, srcval.val.low));
1129
1130
1131
1132
  DEBUGPRINTF(("(%d-%.3X-%.5X%.8X)\n", sign, exponent, mantissa0, mantissa1));
#endif

  if (result == NULL) result = calc_buffer;
1133
  temp = alloca(value_size);
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143

  _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)) {
Michael Beck's avatar
Michael Beck committed
1144
    _desc(result).clss = NAN;
1145
1146
    TRACEPRINTF(("val_from_float resulted in NAN\n"));
    return result;
1147
  }
1148
  else if (isinf(l)) {
Michael Beck's avatar
Michael Beck committed
1149
    _desc(result).clss = INF;
1150
1151
    TRACEPRINTF(("val_from_float resulted in %sINF\n", (_sign(result)==1)?"-":""));
    return result;
1152
  }
1153

1154
1155
1156
1157
1158
1159
1160
  /* 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
1161
  sc_val_from_long((exponent-bias_val+bias_res)-(mant_val-mant_size), _exp(result));
1162
#endif
1163

1164
1165
  /* build mantissa representation */
#ifndef HAVE_EXPLICIT_ONE
1166
1167
1168
1169
1170
1171
  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);
1172
  }
1173
  else
1174
#endif
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
  {
    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);

1203
  TRACEPRINTF(("val_from_float results in %s\n", fc_print(result, temp, calc_buffer_size, FC_PACKED)));
1204
1205

  return result;
1206
1207
}

1208
LLDBL fc_val_to_float(const void *val)
1209
{
1210
1211
1212
1213
  const char *value;
  char *temp = NULL;

  int byte_offset;
1214

1215
1216
1217
1218
1219
1220
1221
1222
1223
  UINT32 sign;
  UINT32 exponent;
  UINT32 mantissa0;
  UINT32 mantissa1;

  value_t buildval;

#ifdef HAVE_LONG_DOUBLE
  char result_exponent = 15;
1224
  char result_mantissa = 64;
Michael Beck's avatar
Tarval:    
Michael Beck committed
1225
#else
1226
  char result_exponent = 11;
1227
  char result_mantissa = 52;
Michael Beck's avatar
Tarval:    
Michael Beck committed
1228
#endif
1229

1230
  temp = alloca(calc_buffer_size);
1231
1232
1233
#ifdef HAVE_EXPLICIT_ONE
  value = fc_cast(val, result_exponent, result_mantissa-1, temp);
#else
1234
  value = fc_cast(val, result_exponent, result_mantissa, temp);
1235
#endif
1236
1237

  sign = _sign(value);
1238
1239

  /* @@@ long double exponent is 15bit, so the use of sc_val_to_long should not
1240
   * lead to wrong results */
Michael Beck's avatar
Michael Beck committed
1241
  exponent = sc_val_to_long(_exp(value)) ;
1242

1243
1244
  sc_val_from_ulong(2, NULL);
  _shift_right(_mant(value), sc_get_buffer(), _mant(value));
1245
1246
1247
1248
1249

  mantissa0 = 0;
  mantissa1 = 0;

  for (byte_offset = 0; byte_offset < 4; byte_offset++)
1250
    mantissa1 |= sc_sub_bits(_mant(value), result_mantissa, byte_offset) << (byte_offset<<3);
1251
1252

  for (; (byte_offset<<3) < result_mantissa; byte_offset++)
1253
    mantissa0 |= sc_sub_bits(_mant(value), result_mantissa, byte_offset) << ((byte_offset-4)<<3);
1254
1255

#ifdef HAVE_LONG_DOUBLE
1256
1257
1258
1259
  buildval.val.high = sign << 15;
  buildval.val.high |= exponent;
  buildval.val.mid = mantissa0;
  buildval.val.low = mantissa1;
1260
#else /* no long double */
Michael Beck's avatar
Michael Beck committed
1261
  mantissa0 &= 0x000FFFFF;  /* get rid of garbage */
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
  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;
1279
  temp = alloca(value_size);
1280
1281
1282

  if (_desc(value).exponent_size == exp_size && _desc(value).mantissa_size == mant_size)
  {