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floatformat.h (struct floatformat): Add split_half field.
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6599da04 1/* IEEE floating point support routines, for GDB, the GNU Debugger.
12c61ac3 2 Copyright 1991, 1994, 1999, 2000, 2003, 2005, 2006
e89b6c1c 3 Free Software Foundation, Inc.
6599da04
JM
4
5This file is part of GDB.
6
7This program is free software; you can redistribute it and/or modify
8it under the terms of the GNU General Public License as published by
9the Free Software Foundation; either version 2 of the License, or
10(at your option) any later version.
11
12This program is distributed in the hope that it will be useful,
13but WITHOUT ANY WARRANTY; without even the implied warranty of
14MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15GNU General Public License for more details.
16
17You should have received a copy of the GNU General Public License
18along with this program; if not, write to the Free Software
ee58dffd 19Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston, MA 02110-1301, USA. */
6599da04 20
bee6ab3e
ILT
21/* This is needed to pick up the NAN macro on some systems. */
22#define _GNU_SOURCE
23
24#ifdef HAVE_CONFIG_H
25#include "config.h"
26#endif
27
28#include <math.h>
29
30#ifdef HAVE_STRING_H
31#include <string.h>
32#endif
33
12c61ac3
RS
34/* On some platforms, <float.h> provides DBL_QNAN. */
35#ifdef STDC_HEADERS
36#include <float.h>
37#endif
38
c9ac9147 39#include "ansidecl.h"
bee6ab3e 40#include "libiberty.h"
6599da04 41#include "floatformat.h"
bee6ab3e
ILT
42
43#ifndef INFINITY
44#ifdef HUGE_VAL
45#define INFINITY HUGE_VAL
6599da04 46#else
bee6ab3e
ILT
47#define INFINITY (1.0 / 0.0)
48#endif
49#endif
50
51#ifndef NAN
12c61ac3
RS
52#ifdef DBL_QNAN
53#define NAN DBL_QNAN
54#else
bee6ab3e 55#define NAN (0.0 / 0.0)
6599da04 56#endif
12c61ac3 57#endif
6599da04 58
da59326f 59static int mant_bits_set (const struct floatformat *, const unsigned char *);
6da879de
GDR
60static unsigned long get_field (const unsigned char *,
61 enum floatformat_byteorders,
62 unsigned int,
63 unsigned int,
64 unsigned int);
65static int floatformat_always_valid (const struct floatformat *fmt,
e89b6c1c 66 const void *from);
83c07342
AC
67
68static int
6da879de 69floatformat_always_valid (const struct floatformat *fmt ATTRIBUTE_UNUSED,
e89b6c1c 70 const void *from ATTRIBUTE_UNUSED)
83c07342
AC
71{
72 return 1;
73}
74
6599da04
JM
75/* The odds that CHAR_BIT will be anything but 8 are low enough that I'm not
76 going to bother with trying to muck around with whether it is defined in
77 a system header, what we do if not, etc. */
78#define FLOATFORMAT_CHAR_BIT 8
79
80/* floatformats for IEEE single and double, big and little endian. */
81const struct floatformat floatformat_ieee_single_big =
82{
0b72c3df
AC
83 floatformat_big, 32, 0, 1, 8, 127, 255, 9, 23,
84 floatformat_intbit_no,
83c07342 85 "floatformat_ieee_single_big",
da59326f
JM
86 floatformat_always_valid,
87 NULL
6599da04
JM
88};
89const struct floatformat floatformat_ieee_single_little =
90{
0b72c3df
AC
91 floatformat_little, 32, 0, 1, 8, 127, 255, 9, 23,
92 floatformat_intbit_no,
83c07342 93 "floatformat_ieee_single_little",
da59326f
JM
94 floatformat_always_valid,
95 NULL
6599da04
JM
96};
97const struct floatformat floatformat_ieee_double_big =
98{
0b72c3df
AC
99 floatformat_big, 64, 0, 1, 11, 1023, 2047, 12, 52,
100 floatformat_intbit_no,
83c07342 101 "floatformat_ieee_double_big",
da59326f
JM
102 floatformat_always_valid,
103 NULL
6599da04
JM
104};
105const struct floatformat floatformat_ieee_double_little =
106{
0b72c3df
AC
107 floatformat_little, 64, 0, 1, 11, 1023, 2047, 12, 52,
108 floatformat_intbit_no,
83c07342 109 "floatformat_ieee_double_little",
da59326f
JM
110 floatformat_always_valid,
111 NULL
6599da04
JM
112};
113
114/* floatformat for IEEE double, little endian byte order, with big endian word
115 ordering, as on the ARM. */
116
117const struct floatformat floatformat_ieee_double_littlebyte_bigword =
118{
0b72c3df
AC
119 floatformat_littlebyte_bigword, 64, 0, 1, 11, 1023, 2047, 12, 52,
120 floatformat_intbit_no,
83c07342 121 "floatformat_ieee_double_littlebyte_bigword",
da59326f
JM
122 floatformat_always_valid,
123 NULL
6599da04
JM
124};
125
0432a5de
MK
126/* floatformat for VAX. Not quite IEEE, but close enough. */
127
128const struct floatformat floatformat_vax_f =
129{
130 floatformat_vax, 32, 0, 1, 8, 129, 0, 9, 23,
131 floatformat_intbit_no,
132 "floatformat_vax_f",
da59326f
JM
133 floatformat_always_valid,
134 NULL
0432a5de
MK
135};
136const struct floatformat floatformat_vax_d =
137{
138 floatformat_vax, 64, 0, 1, 8, 129, 0, 9, 55,
139 floatformat_intbit_no,
140 "floatformat_vax_d",
da59326f
JM
141 floatformat_always_valid,
142 NULL
0432a5de
MK
143};
144const struct floatformat floatformat_vax_g =
145{
146 floatformat_vax, 64, 0, 1, 11, 1025, 0, 12, 52,
147 floatformat_intbit_no,
148 "floatformat_vax_g",
da59326f
JM
149 floatformat_always_valid,
150 NULL
0432a5de
MK
151};
152
e89b6c1c
MK
153static int floatformat_i387_ext_is_valid (const struct floatformat *fmt,
154 const void *from);
83c07342
AC
155
156static int
e89b6c1c 157floatformat_i387_ext_is_valid (const struct floatformat *fmt, const void *from)
83c07342
AC
158{
159 /* In the i387 double-extended format, if the exponent is all ones,
160 then the integer bit must be set. If the exponent is neither 0
161 nor ~0, the intbit must also be set. Only if the exponent is
162 zero can it be zero, and then it must be zero. */
163 unsigned long exponent, int_bit;
573b07c7 164 const unsigned char *ufrom = (const unsigned char *) from;
e89b6c1c 165
83c07342
AC
166 exponent = get_field (ufrom, fmt->byteorder, fmt->totalsize,
167 fmt->exp_start, fmt->exp_len);
168 int_bit = get_field (ufrom, fmt->byteorder, fmt->totalsize,
169 fmt->man_start, 1);
e89b6c1c 170
83c07342
AC
171 if ((exponent == 0) != (int_bit == 0))
172 return 0;
173 else
174 return 1;
175}
176
6599da04
JM
177const struct floatformat floatformat_i387_ext =
178{
179 floatformat_little, 80, 0, 1, 15, 0x3fff, 0x7fff, 16, 64,
0b72c3df 180 floatformat_intbit_yes,
83c07342 181 "floatformat_i387_ext",
da59326f
JM
182 floatformat_i387_ext_is_valid,
183 NULL
6599da04
JM
184};
185const struct floatformat floatformat_m68881_ext =
186{
187 /* Note that the bits from 16 to 31 are unused. */
0b72c3df
AC
188 floatformat_big, 96, 0, 1, 15, 0x3fff, 0x7fff, 32, 64,
189 floatformat_intbit_yes,
83c07342 190 "floatformat_m68881_ext",
da59326f
JM
191 floatformat_always_valid,
192 NULL
6599da04
JM
193};
194const struct floatformat floatformat_i960_ext =
195{
196 /* Note that the bits from 0 to 15 are unused. */
197 floatformat_little, 96, 16, 17, 15, 0x3fff, 0x7fff, 32, 64,
0b72c3df 198 floatformat_intbit_yes,
83c07342 199 "floatformat_i960_ext",
da59326f
JM
200 floatformat_always_valid,
201 NULL
6599da04
JM
202};
203const struct floatformat floatformat_m88110_ext =
204{
0310e5ac
AC
205 floatformat_big, 80, 0, 1, 15, 0x3fff, 0x7fff, 16, 64,
206 floatformat_intbit_yes,
83c07342 207 "floatformat_m88110_ext",
da59326f
JM
208 floatformat_always_valid,
209 NULL
0310e5ac
AC
210};
211const struct floatformat floatformat_m88110_harris_ext =
212{
6599da04
JM
213 /* Harris uses raw format 128 bytes long, but the number is just an ieee
214 double, and the last 64 bits are wasted. */
215 floatformat_big,128, 0, 1, 11, 0x3ff, 0x7ff, 12, 52,
0b72c3df 216 floatformat_intbit_no,
83c07342 217 "floatformat_m88110_ext_harris",
da59326f
JM
218 floatformat_always_valid,
219 NULL
6599da04 220};
0310e5ac
AC
221const struct floatformat floatformat_arm_ext_big =
222{
223 /* Bits 1 to 16 are unused. */
224 floatformat_big, 96, 0, 17, 15, 0x3fff, 0x7fff, 32, 64,
225 floatformat_intbit_yes,
83c07342 226 "floatformat_arm_ext_big",
da59326f
JM
227 floatformat_always_valid,
228 NULL
0310e5ac
AC
229};
230const struct floatformat floatformat_arm_ext_littlebyte_bigword =
231{
232 /* Bits 1 to 16 are unused. */
233 floatformat_littlebyte_bigword, 96, 0, 17, 15, 0x3fff, 0x7fff, 32, 64,
234 floatformat_intbit_yes,
83c07342 235 "floatformat_arm_ext_littlebyte_bigword",
da59326f
JM
236 floatformat_always_valid,
237 NULL
0310e5ac
AC
238};
239const struct floatformat floatformat_ia64_spill_big =
240{
241 floatformat_big, 128, 0, 1, 17, 65535, 0x1ffff, 18, 64,
242 floatformat_intbit_yes,
83c07342 243 "floatformat_ia64_spill_big",
da59326f
JM
244 floatformat_always_valid,
245 NULL
0310e5ac
AC
246};
247const struct floatformat floatformat_ia64_spill_little =
248{
249 floatformat_little, 128, 0, 1, 17, 65535, 0x1ffff, 18, 64,
250 floatformat_intbit_yes,
83c07342 251 "floatformat_ia64_spill_little",
da59326f
JM
252 floatformat_always_valid,
253 NULL
0310e5ac
AC
254};
255const struct floatformat floatformat_ia64_quad_big =
256{
257 floatformat_big, 128, 0, 1, 15, 16383, 0x7fff, 16, 112,
258 floatformat_intbit_no,
83c07342 259 "floatformat_ia64_quad_big",
da59326f
JM
260 floatformat_always_valid,
261 NULL
0310e5ac
AC
262};
263const struct floatformat floatformat_ia64_quad_little =
264{
265 floatformat_little, 128, 0, 1, 15, 16383, 0x7fff, 16, 112,
266 floatformat_intbit_no,
83c07342 267 "floatformat_ia64_quad_little",
da59326f
JM
268 floatformat_always_valid,
269 NULL
270};
271
272static int
273floatformat_ibm_long_double_is_valid (const struct floatformat *fmt,
274 const void *from)
275{
276 const unsigned char *ufrom = (const unsigned char *) from;
277 const struct floatformat *hfmt = fmt->split_half;
278 long top_exp, bot_exp;
279 int top_nan = 0;
280
281 top_exp = get_field (ufrom, hfmt->byteorder, hfmt->totalsize,
282 hfmt->exp_start, hfmt->exp_len);
283 bot_exp = get_field (ufrom + 8, hfmt->byteorder, hfmt->totalsize,
284 hfmt->exp_start, hfmt->exp_len);
285
286 if (top_exp == hfmt->exp_nan)
287 top_nan = mant_bits_set (hfmt, ufrom);
288
289 /* A NaN is valid with any low part. */
290 if (top_nan)
291 return 1;
292
293 /* An infinity, zero or denormal requires low part 0 (positive or
294 negative). */
295 if (top_exp == hfmt->exp_nan || top_exp == 0)
296 {
297 unsigned int mant_bits, mant_off;
298 int mant_bits_left;
299
300 if (bot_exp != 0)
301 return 0;
302
303 return !mant_bits_set (hfmt, ufrom + 8);
304 }
305
306 /* The top part is now a finite normal value. The long double value
307 is the sum of the two parts, and the top part must equal the
308 result of rounding the long double value to nearest double. Thus
309 the bottom part must be <= 0.5ulp of the top part in absolute
310 value, and if it is < 0.5ulp then the long double is definitely
311 valid. */
312 if (bot_exp < top_exp - 53)
313 return 1;
314 if (bot_exp > top_exp - 53 && bot_exp != 0)
315 return 0;
316 if (bot_exp == 0)
317 {
318 /* The bottom part is 0 or denormal. Determine which, and if
319 denormal the first two set bits. */
320 int first_bit = -1, second_bit = -1, cur_bit;
321 for (cur_bit = 0; cur_bit < hfmt->man_len; cur_bit++)
322 if (get_field (ufrom + 8, hfmt->byteorder, hfmt->totalsize,
323 hfmt->man_start + cur_bit, 1))
324 {
325 if (first_bit == -1)
326 first_bit = cur_bit;
327 else
328 {
329 second_bit = cur_bit;
330 break;
331 }
332 }
333 /* Bottom part 0 is OK. */
334 if (first_bit == -1)
335 return 1;
336 /* The real exponent of the bottom part is -first_bit. */
337 if (-first_bit < top_exp - 53)
338 return 1;
339 if (-first_bit > top_exp - 53)
340 return 0;
341 /* The bottom part is at least 0.5ulp of the top part. For this
342 to be OK, the bottom part must be exactly 0.5ulp (i.e. no
343 more bits set) and the top part must have last bit 0. */
344 if (second_bit != -1)
345 return 0;
346 return !get_field (ufrom, hfmt->byteorder, hfmt->totalsize,
347 hfmt->man_start + hfmt->man_len - 1, 1);
348 }
349 else
350 {
351 /* The bottom part is at least 0.5ulp of the top part. For this
352 to be OK, it must be exactly 0.5ulp (i.e. no explicit bits
353 set) and the top part must have last bit 0. */
354 if (get_field (ufrom, hfmt->byteorder, hfmt->totalsize,
355 hfmt->man_start + hfmt->man_len - 1, 1))
356 return 0;
357 return !mant_bits_set (hfmt, ufrom + 8);
358 }
359}
360
361const struct floatformat floatformat_ibm_long_double =
362{
363 floatformat_big, 128, 0, 1, 11, 1023, 2047, 12, 52,
364 floatformat_intbit_no,
365 "floatformat_ibm_long_double",
366 floatformat_always_valid,
367 &floatformat_ieee_double_big
0310e5ac 368};
6599da04 369\f
36b82060
JB
370
371#ifndef min
372#define min(a, b) ((a) < (b) ? (a) : (b))
373#endif
374
da59326f
JM
375/* Return 1 if any bits are explicitly set in the mantissa of UFROM,
376 format FMT, 0 otherwise. */
377static int
378mant_bits_set (const struct floatformat *fmt, const unsigned char *ufrom)
379{
380 unsigned int mant_bits, mant_off;
381 int mant_bits_left;
382
383 mant_off = fmt->man_start;
384 mant_bits_left = fmt->man_len;
385 while (mant_bits_left > 0)
386 {
387 mant_bits = min (mant_bits_left, 32);
388
389 if (get_field (ufrom, fmt->byteorder, fmt->totalsize,
390 mant_off, mant_bits) != 0)
391 return 1;
392
393 mant_off += mant_bits;
394 mant_bits_left -= mant_bits;
395 }
396 return 0;
397}
398
9c8860c3 399/* Extract a field which starts at START and is LEN bits long. DATA and
6599da04
JM
400 TOTAL_LEN are the thing we are extracting it from, in byteorder ORDER. */
401static unsigned long
6da879de
GDR
402get_field (const unsigned char *data, enum floatformat_byteorders order,
403 unsigned int total_len, unsigned int start, unsigned int len)
6599da04 404{
36b82060 405 unsigned long result = 0;
6599da04 406 unsigned int cur_byte;
36b82060
JB
407 int lo_bit, hi_bit, cur_bitshift = 0;
408 int nextbyte = (order == floatformat_little) ? 1 : -1;
409
410 /* Start is in big-endian bit order! Fix that first. */
411 start = total_len - (start + len);
6599da04
JM
412
413 /* Start at the least significant part of the field. */
6599da04 414 if (order == floatformat_little)
36b82060 415 cur_byte = start / FLOATFORMAT_CHAR_BIT;
6599da04 416 else
36b82060 417 cur_byte = (total_len - start - 1) / FLOATFORMAT_CHAR_BIT;
6599da04 418
36b82060
JB
419 lo_bit = start % FLOATFORMAT_CHAR_BIT;
420 hi_bit = min (lo_bit + len, FLOATFORMAT_CHAR_BIT);
421
422 do
6599da04 423 {
36b82060
JB
424 unsigned int shifted = *(data + cur_byte) >> lo_bit;
425 unsigned int bits = hi_bit - lo_bit;
426 unsigned int mask = (1 << bits) - 1;
427 result |= (shifted & mask) << cur_bitshift;
428 len -= bits;
429 cur_bitshift += bits;
430 cur_byte += nextbyte;
431 lo_bit = 0;
432 hi_bit = min (len, FLOATFORMAT_CHAR_BIT);
6599da04 433 }
36b82060
JB
434 while (len != 0);
435
6599da04
JM
436 return result;
437}
438
6599da04
JM
439/* Convert from FMT to a double.
440 FROM is the address of the extended float.
441 Store the double in *TO. */
442
443void
6da879de 444floatformat_to_double (const struct floatformat *fmt,
e89b6c1c 445 const void *from, double *to)
6599da04 446{
573b07c7 447 const unsigned char *ufrom = (const unsigned char *) from;
6599da04
JM
448 double dto;
449 long exponent;
450 unsigned long mant;
451 unsigned int mant_bits, mant_off;
452 int mant_bits_left;
453 int special_exponent; /* It's a NaN, denorm or zero */
454
da59326f
JM
455 /* Split values are not handled specially, since the top half has
456 the correctly rounded double value (in the only supported case of
457 split values). */
458
6599da04
JM
459 exponent = get_field (ufrom, fmt->byteorder, fmt->totalsize,
460 fmt->exp_start, fmt->exp_len);
bee6ab3e
ILT
461
462 /* If the exponent indicates a NaN, we don't have information to
463 decide what to do. So we handle it like IEEE, except that we
464 don't try to preserve the type of NaN. FIXME. */
465 if ((unsigned long) exponent == fmt->exp_nan)
466 {
da59326f 467 int nan = mant_bits_set (fmt, ufrom);
bee6ab3e 468
72f93778
BE
469 /* On certain systems (such as GNU/Linux), the use of the
470 INFINITY macro below may generate a warning that can not be
471 silenced due to a bug in GCC (PR preprocessor/11931). The
472 preprocessor fails to recognise the __extension__ keyword in
473 conjunction with the GNU/C99 extension for hexadecimal
474 floating point constants and will issue a warning when
475 compiling with -pedantic. */
bee6ab3e
ILT
476 if (nan)
477 dto = NAN;
478 else
479 dto = INFINITY;
480
481 if (get_field (ufrom, fmt->byteorder, fmt->totalsize, fmt->sign_start, 1))
482 dto = -dto;
483
484 *to = dto;
485
486 return;
487 }
6599da04
JM
488
489 mant_bits_left = fmt->man_len;
490 mant_off = fmt->man_start;
491 dto = 0.0;
492
5ad5a984 493 special_exponent = exponent == 0 || (unsigned long) exponent == fmt->exp_nan;
6599da04
JM
494
495 /* Don't bias zero's, denorms or NaNs. */
496 if (!special_exponent)
497 exponent -= fmt->exp_bias;
498
499 /* Build the result algebraically. Might go infinite, underflow, etc;
500 who cares. */
501
502 /* If this format uses a hidden bit, explicitly add it in now. Otherwise,
503 increment the exponent by one to account for the integer bit. */
504
505 if (!special_exponent)
087aa398
KG
506 {
507 if (fmt->intbit == floatformat_intbit_no)
508 dto = ldexp (1.0, exponent);
509 else
510 exponent++;
511 }
6599da04
JM
512
513 while (mant_bits_left > 0)
514 {
515 mant_bits = min (mant_bits_left, 32);
516
517 mant = get_field (ufrom, fmt->byteorder, fmt->totalsize,
518 mant_off, mant_bits);
519
bee6ab3e
ILT
520 /* Handle denormalized numbers. FIXME: What should we do for
521 non-IEEE formats? */
9fff6432 522 if (special_exponent && exponent == 0 && mant != 0)
bee6ab3e
ILT
523 dto += ldexp ((double)mant,
524 (- fmt->exp_bias
525 - mant_bits
526 - (mant_off - fmt->man_start)
527 + 1));
528 else
529 dto += ldexp ((double)mant, exponent - mant_bits);
530 if (exponent != 0)
531 exponent -= mant_bits;
6599da04
JM
532 mant_off += mant_bits;
533 mant_bits_left -= mant_bits;
534 }
535
536 /* Negate it if negative. */
537 if (get_field (ufrom, fmt->byteorder, fmt->totalsize, fmt->sign_start, 1))
538 dto = -dto;
539 *to = dto;
540}
541\f
6da879de
GDR
542static void put_field (unsigned char *, enum floatformat_byteorders,
543 unsigned int,
544 unsigned int,
545 unsigned int,
546 unsigned long);
6599da04 547
9c8860c3 548/* Set a field which starts at START and is LEN bits long. DATA and
6599da04
JM
549 TOTAL_LEN are the thing we are extracting it from, in byteorder ORDER. */
550static void
6da879de
GDR
551put_field (unsigned char *data, enum floatformat_byteorders order,
552 unsigned int total_len, unsigned int start, unsigned int len,
553 unsigned long stuff_to_put)
6599da04
JM
554{
555 unsigned int cur_byte;
36b82060
JB
556 int lo_bit, hi_bit;
557 int nextbyte = (order == floatformat_little) ? 1 : -1;
558
559 /* Start is in big-endian bit order! Fix that first. */
560 start = total_len - (start + len);
6599da04
JM
561
562 /* Start at the least significant part of the field. */
6599da04 563 if (order == floatformat_little)
36b82060 564 cur_byte = start / FLOATFORMAT_CHAR_BIT;
6599da04 565 else
36b82060 566 cur_byte = (total_len - start - 1) / FLOATFORMAT_CHAR_BIT;
6599da04 567
36b82060
JB
568 lo_bit = start % FLOATFORMAT_CHAR_BIT;
569 hi_bit = min (lo_bit + len, FLOATFORMAT_CHAR_BIT);
570
571 do
6599da04 572 {
36b82060
JB
573 unsigned char *byte_ptr = data + cur_byte;
574 unsigned int bits = hi_bit - lo_bit;
575 unsigned int mask = ((1 << bits) - 1) << lo_bit;
576 *byte_ptr = (*byte_ptr & ~mask) | ((stuff_to_put << lo_bit) & mask);
577 stuff_to_put >>= bits;
578 len -= bits;
579 cur_byte += nextbyte;
580 lo_bit = 0;
581 hi_bit = min (len, FLOATFORMAT_CHAR_BIT);
6599da04 582 }
36b82060 583 while (len != 0);
6599da04
JM
584}
585
586/* The converse: convert the double *FROM to an extended float
587 and store where TO points. Neither FROM nor TO have any alignment
588 restrictions. */
589
590void
6da879de 591floatformat_from_double (const struct floatformat *fmt,
e89b6c1c 592 const double *from, void *to)
6599da04
JM
593{
594 double dfrom;
595 int exponent;
596 double mant;
597 unsigned int mant_bits, mant_off;
598 int mant_bits_left;
573b07c7 599 unsigned char *uto = (unsigned char *) to;
6599da04 600
bee6ab3e 601 dfrom = *from;
6599da04 602 memset (uto, 0, fmt->totalsize / FLOATFORMAT_CHAR_BIT);
bee6ab3e 603
da59326f
JM
604 /* Split values are not handled specially, since a bottom half of
605 zero is correct for any value representable as double (in the
606 only supported case of split values). */
607
bee6ab3e
ILT
608 /* If negative, set the sign bit. */
609 if (dfrom < 0)
610 {
611 put_field (uto, fmt->byteorder, fmt->totalsize, fmt->sign_start, 1, 1);
612 dfrom = -dfrom;
613 }
614
6599da04 615 if (dfrom == 0)
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ILT
616 {
617 /* 0.0. */
618 return;
619 }
620
6599da04
JM
621 if (dfrom != dfrom)
622 {
bee6ab3e 623 /* NaN. */
6599da04
JM
624 put_field (uto, fmt->byteorder, fmt->totalsize, fmt->exp_start,
625 fmt->exp_len, fmt->exp_nan);
bee6ab3e 626 /* Be sure it's not infinity, but NaN value is irrelevant. */
6599da04
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627 put_field (uto, fmt->byteorder, fmt->totalsize, fmt->man_start,
628 32, 1);
629 return;
630 }
631
bee6ab3e 632 if (dfrom + dfrom == dfrom)
6599da04 633 {
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ILT
634 /* This can only happen for an infinite value (or zero, which we
635 already handled above). */
636 put_field (uto, fmt->byteorder, fmt->totalsize, fmt->exp_start,
637 fmt->exp_len, fmt->exp_nan);
638 return;
6599da04
JM
639 }
640
6599da04 641 mant = frexp (dfrom, &exponent);
bee6ab3e
ILT
642 if (exponent + fmt->exp_bias - 1 > 0)
643 put_field (uto, fmt->byteorder, fmt->totalsize, fmt->exp_start,
644 fmt->exp_len, exponent + fmt->exp_bias - 1);
645 else
646 {
647 /* Handle a denormalized number. FIXME: What should we do for
648 non-IEEE formats? */
649 put_field (uto, fmt->byteorder, fmt->totalsize, fmt->exp_start,
650 fmt->exp_len, 0);
651 mant = ldexp (mant, exponent + fmt->exp_bias - 1);
652 }
6599da04
JM
653
654 mant_bits_left = fmt->man_len;
655 mant_off = fmt->man_start;
656 while (mant_bits_left > 0)
657 {
658 unsigned long mant_long;
659 mant_bits = mant_bits_left < 32 ? mant_bits_left : 32;
660
661 mant *= 4294967296.0;
662 mant_long = (unsigned long)mant;
663 mant -= mant_long;
664
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ILT
665 /* If the integer bit is implicit, and we are not creating a
666 denormalized number, then we need to discard it. */
5ad5a984 667 if ((unsigned int) mant_bits_left == fmt->man_len
bee6ab3e
ILT
668 && fmt->intbit == floatformat_intbit_no
669 && exponent + fmt->exp_bias - 1 > 0)
6599da04
JM
670 {
671 mant_long &= 0x7fffffff;
672 mant_bits -= 1;
673 }
674 else if (mant_bits < 32)
675 {
676 /* The bits we want are in the most significant MANT_BITS bits of
677 mant_long. Move them to the least significant. */
678 mant_long >>= 32 - mant_bits;
679 }
680
681 put_field (uto, fmt->byteorder, fmt->totalsize,
682 mant_off, mant_bits, mant_long);
683 mant_off += mant_bits;
684 mant_bits_left -= mant_bits;
685 }
686}
687
9c8860c3
DJ
688/* Return non-zero iff the data at FROM is a valid number in format FMT. */
689
690int
e89b6c1c 691floatformat_is_valid (const struct floatformat *fmt, const void *from)
9c8860c3 692{
83c07342 693 return fmt->is_valid (fmt, from);
9c8860c3
DJ
694}
695
6599da04
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696
697#ifdef IEEE_DEBUG
698
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699#include <stdio.h>
700
6599da04
JM
701/* This is to be run on a host which uses IEEE floating point. */
702
703void
6da879de 704ieee_test (double n)
6599da04
JM
705{
706 double result;
6599da04 707
e89b6c1c 708 floatformat_to_double (&floatformat_ieee_double_little, &n, &result);
bee6ab3e
ILT
709 if ((n != result && (! isnan (n) || ! isnan (result)))
710 || (n < 0 && result >= 0)
711 || (n >= 0 && result < 0))
6599da04 712 printf ("Differ(to): %.20g -> %.20g\n", n, result);
bee6ab3e 713
e89b6c1c 714 floatformat_from_double (&floatformat_ieee_double_little, &n, &result);
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ILT
715 if ((n != result && (! isnan (n) || ! isnan (result)))
716 || (n < 0 && result >= 0)
717 || (n >= 0 && result < 0))
6599da04
JM
718 printf ("Differ(from): %.20g -> %.20g\n", n, result);
719
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ILT
720#if 0
721 {
722 char exten[16];
723
724 floatformat_from_double (&floatformat_m68881_ext, &n, exten);
725 floatformat_to_double (&floatformat_m68881_ext, exten, &result);
726 if (n != result)
727 printf ("Differ(to+from): %.20g -> %.20g\n", n, result);
728 }
729#endif
6599da04
JM
730
731#if IEEE_DEBUG > 1
732 /* This is to be run on a host which uses 68881 format. */
733 {
734 long double ex = *(long double *)exten;
735 if (ex != n)
736 printf ("Differ(from vs. extended): %.20g\n", n);
737 }
738#endif
739}
740
741int
6da879de 742main (void)
6599da04 743{
bee6ab3e 744 ieee_test (0.0);
6599da04
JM
745 ieee_test (0.5);
746 ieee_test (256.0);
747 ieee_test (0.12345);
748 ieee_test (234235.78907234);
749 ieee_test (-512.0);
750 ieee_test (-0.004321);
bee6ab3e
ILT
751 ieee_test (1.2E-70);
752 ieee_test (1.2E-316);
753 ieee_test (4.9406564584124654E-324);
754 ieee_test (- 4.9406564584124654E-324);
755 ieee_test (- 0.0);
756 ieee_test (- INFINITY);
757 ieee_test (- NAN);
758 ieee_test (INFINITY);
759 ieee_test (NAN);
6599da04
JM
760 return 0;
761}
762#endif