Commit | Line | Data |
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d16aafd8 | 1 | /* Floating point routines for GDB, the GNU debugger. |
f1908289 | 2 | |
6aba47ca DJ |
3 | Copyright (C) 1986, 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995, 1996, |
4 | 1997, 1998, 1999, 2000, 2001, 2003, 2004, 2005, 2007 | |
0a3e99f6 | 5 | Free Software Foundation, Inc. |
d16aafd8 AC |
6 | |
7 | This file is part of GDB. | |
8 | ||
9 | This program is free software; you can redistribute it and/or modify | |
10 | it under the terms of the GNU General Public License as published by | |
a9762ec7 | 11 | the Free Software Foundation; either version 3 of the License, or |
d16aafd8 AC |
12 | (at your option) any later version. |
13 | ||
14 | This program is distributed in the hope that it will be useful, | |
15 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
16 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
17 | GNU General Public License for more details. | |
18 | ||
19 | You should have received a copy of the GNU General Public License | |
a9762ec7 | 20 | along with this program. If not, see <http://www.gnu.org/licenses/>. */ |
d16aafd8 AC |
21 | |
22 | /* Support for converting target fp numbers into host DOUBLEST format. */ | |
23 | ||
24 | /* XXX - This code should really be in libiberty/floatformat.c, | |
25 | however configuration issues with libiberty made this very | |
26 | difficult to do in the available time. */ | |
27 | ||
28 | #include "defs.h" | |
29 | #include "doublest.h" | |
30 | #include "floatformat.h" | |
31 | #include "gdb_assert.h" | |
32 | #include "gdb_string.h" | |
96d2f608 | 33 | #include "gdbtypes.h" |
d16aafd8 AC |
34 | #include <math.h> /* ldexp */ |
35 | ||
36 | /* The odds that CHAR_BIT will be anything but 8 are low enough that I'm not | |
37 | going to bother with trying to muck around with whether it is defined in | |
38 | a system header, what we do if not, etc. */ | |
39 | #define FLOATFORMAT_CHAR_BIT 8 | |
40 | ||
fcab3fb5 RE |
41 | /* The number of bytes that the largest floating-point type that we |
42 | can convert to doublest will need. */ | |
43 | #define FLOATFORMAT_LARGEST_BYTES 16 | |
44 | ||
d16aafd8 AC |
45 | /* Extract a field which starts at START and is LEN bytes long. DATA and |
46 | TOTAL_LEN are the thing we are extracting it from, in byteorder ORDER. */ | |
47 | static unsigned long | |
108d6ead | 48 | get_field (const bfd_byte *data, enum floatformat_byteorders order, |
d16aafd8 AC |
49 | unsigned int total_len, unsigned int start, unsigned int len) |
50 | { | |
51 | unsigned long result; | |
52 | unsigned int cur_byte; | |
53 | int cur_bitshift; | |
54 | ||
fcab3fb5 RE |
55 | /* Caller must byte-swap words before calling this routine. */ |
56 | gdb_assert (order == floatformat_little || order == floatformat_big); | |
57 | ||
d16aafd8 | 58 | /* Start at the least significant part of the field. */ |
fcab3fb5 | 59 | if (order == floatformat_little) |
d16aafd8 AC |
60 | { |
61 | /* We start counting from the other end (i.e, from the high bytes | |
62 | rather than the low bytes). As such, we need to be concerned | |
63 | with what happens if bit 0 doesn't start on a byte boundary. | |
64 | I.e, we need to properly handle the case where total_len is | |
65 | not evenly divisible by 8. So we compute ``excess'' which | |
66 | represents the number of bits from the end of our starting | |
67 | byte needed to get to bit 0. */ | |
68 | int excess = FLOATFORMAT_CHAR_BIT - (total_len % FLOATFORMAT_CHAR_BIT); | |
69 | cur_byte = (total_len / FLOATFORMAT_CHAR_BIT) | |
70 | - ((start + len + excess) / FLOATFORMAT_CHAR_BIT); | |
71 | cur_bitshift = ((start + len + excess) % FLOATFORMAT_CHAR_BIT) | |
72 | - FLOATFORMAT_CHAR_BIT; | |
73 | } | |
74 | else | |
75 | { | |
76 | cur_byte = (start + len) / FLOATFORMAT_CHAR_BIT; | |
77 | cur_bitshift = | |
78 | ((start + len) % FLOATFORMAT_CHAR_BIT) - FLOATFORMAT_CHAR_BIT; | |
79 | } | |
80 | if (cur_bitshift > -FLOATFORMAT_CHAR_BIT) | |
81 | result = *(data + cur_byte) >> (-cur_bitshift); | |
82 | else | |
83 | result = 0; | |
84 | cur_bitshift += FLOATFORMAT_CHAR_BIT; | |
fcab3fb5 | 85 | if (order == floatformat_little) |
d16aafd8 AC |
86 | ++cur_byte; |
87 | else | |
88 | --cur_byte; | |
89 | ||
90 | /* Move towards the most significant part of the field. */ | |
91 | while (cur_bitshift < len) | |
92 | { | |
93 | result |= (unsigned long)*(data + cur_byte) << cur_bitshift; | |
94 | cur_bitshift += FLOATFORMAT_CHAR_BIT; | |
c35f4ffc AC |
95 | switch (order) |
96 | { | |
97 | case floatformat_little: | |
98 | ++cur_byte; | |
99 | break; | |
100 | case floatformat_big: | |
101 | --cur_byte; | |
102 | break; | |
c35f4ffc | 103 | } |
d16aafd8 AC |
104 | } |
105 | if (len < sizeof(result) * FLOATFORMAT_CHAR_BIT) | |
106 | /* Mask out bits which are not part of the field */ | |
107 | result &= ((1UL << len) - 1); | |
108 | return result; | |
109 | } | |
110 | ||
0a3e99f6 MK |
111 | /* Normalize the byte order of FROM into TO. If no normalization is |
112 | needed then FMT->byteorder is returned and TO is not changed; | |
113 | otherwise the format of the normalized form in TO is returned. */ | |
114 | ||
fcab3fb5 RE |
115 | static enum floatformat_byteorders |
116 | floatformat_normalize_byteorder (const struct floatformat *fmt, | |
117 | const void *from, void *to) | |
118 | { | |
119 | const unsigned char *swapin; | |
120 | unsigned char *swapout; | |
121 | int words; | |
122 | ||
123 | if (fmt->byteorder == floatformat_little | |
124 | || fmt->byteorder == floatformat_big) | |
125 | return fmt->byteorder; | |
126 | ||
fcab3fb5 RE |
127 | words = fmt->totalsize / FLOATFORMAT_CHAR_BIT; |
128 | words >>= 2; | |
129 | ||
130 | swapout = (unsigned char *)to; | |
131 | swapin = (const unsigned char *)from; | |
132 | ||
0a3e99f6 MK |
133 | if (fmt->byteorder == floatformat_vax) |
134 | { | |
135 | while (words-- > 0) | |
136 | { | |
137 | *swapout++ = swapin[1]; | |
138 | *swapout++ = swapin[0]; | |
139 | *swapout++ = swapin[3]; | |
140 | *swapout++ = swapin[2]; | |
141 | swapin += 4; | |
142 | } | |
143 | /* This may look weird, since VAX is little-endian, but it is | |
144 | easier to translate to big-endian than to little-endian. */ | |
145 | return floatformat_big; | |
146 | } | |
147 | else | |
fcab3fb5 | 148 | { |
0a3e99f6 MK |
149 | gdb_assert (fmt->byteorder == floatformat_littlebyte_bigword); |
150 | ||
151 | while (words-- > 0) | |
152 | { | |
153 | *swapout++ = swapin[3]; | |
154 | *swapout++ = swapin[2]; | |
155 | *swapout++ = swapin[1]; | |
156 | *swapout++ = swapin[0]; | |
157 | swapin += 4; | |
158 | } | |
159 | return floatformat_big; | |
fcab3fb5 | 160 | } |
fcab3fb5 RE |
161 | } |
162 | ||
d16aafd8 AC |
163 | /* Convert from FMT to a DOUBLEST. |
164 | FROM is the address of the extended float. | |
165 | Store the DOUBLEST in *TO. */ | |
166 | ||
c422e771 AC |
167 | static void |
168 | convert_floatformat_to_doublest (const struct floatformat *fmt, | |
169 | const void *from, | |
170 | DOUBLEST *to) | |
d16aafd8 AC |
171 | { |
172 | unsigned char *ufrom = (unsigned char *) from; | |
173 | DOUBLEST dto; | |
174 | long exponent; | |
175 | unsigned long mant; | |
176 | unsigned int mant_bits, mant_off; | |
177 | int mant_bits_left; | |
178 | int special_exponent; /* It's a NaN, denorm or zero */ | |
fcab3fb5 RE |
179 | enum floatformat_byteorders order; |
180 | unsigned char newfrom[FLOATFORMAT_LARGEST_BYTES]; | |
20389057 | 181 | enum float_kind kind; |
fcab3fb5 RE |
182 | |
183 | gdb_assert (fmt->totalsize | |
184 | <= FLOATFORMAT_LARGEST_BYTES * FLOATFORMAT_CHAR_BIT); | |
d16aafd8 | 185 | |
20389057 DJ |
186 | /* For non-numbers, reuse libiberty's logic to find the correct |
187 | format. We do not lose any precision in this case by passing | |
188 | through a double. */ | |
189 | kind = floatformat_classify (fmt, from); | |
190 | if (kind == float_infinite || kind == float_nan) | |
191 | { | |
192 | double dto; | |
193 | floatformat_to_double (fmt, from, &dto); | |
194 | *to = (DOUBLEST) dto; | |
195 | return; | |
196 | } | |
197 | ||
fcab3fb5 | 198 | order = floatformat_normalize_byteorder (fmt, ufrom, newfrom); |
d16aafd8 | 199 | |
fcab3fb5 RE |
200 | if (order != fmt->byteorder) |
201 | ufrom = newfrom; | |
d16aafd8 | 202 | |
fcab3fb5 RE |
203 | exponent = get_field (ufrom, order, fmt->totalsize, fmt->exp_start, |
204 | fmt->exp_len); | |
d16aafd8 AC |
205 | /* Note that if exponent indicates a NaN, we can't really do anything useful |
206 | (not knowing if the host has NaN's, or how to build one). So it will | |
207 | end up as an infinity or something close; that is OK. */ | |
208 | ||
209 | mant_bits_left = fmt->man_len; | |
210 | mant_off = fmt->man_start; | |
211 | dto = 0.0; | |
212 | ||
213 | special_exponent = exponent == 0 || exponent == fmt->exp_nan; | |
214 | ||
38c52d5a DJ |
215 | /* Don't bias NaNs. Use minimum exponent for denorms. For simplicity, |
216 | we don't check for zero as the exponent doesn't matter. Note the cast | |
217 | to int; exp_bias is unsigned, so it's important to make sure the | |
218 | operation is done in signed arithmetic. */ | |
d16aafd8 AC |
219 | if (!special_exponent) |
220 | exponent -= fmt->exp_bias; | |
221 | else if (exponent == 0) | |
1c704f11 | 222 | exponent = 1 - fmt->exp_bias; |
d16aafd8 AC |
223 | |
224 | /* Build the result algebraically. Might go infinite, underflow, etc; | |
225 | who cares. */ | |
226 | ||
227 | /* If this format uses a hidden bit, explicitly add it in now. Otherwise, | |
228 | increment the exponent by one to account for the integer bit. */ | |
229 | ||
230 | if (!special_exponent) | |
231 | { | |
232 | if (fmt->intbit == floatformat_intbit_no) | |
233 | dto = ldexp (1.0, exponent); | |
234 | else | |
235 | exponent++; | |
236 | } | |
237 | ||
238 | while (mant_bits_left > 0) | |
239 | { | |
240 | mant_bits = min (mant_bits_left, 32); | |
241 | ||
fcab3fb5 | 242 | mant = get_field (ufrom, order, fmt->totalsize, mant_off, mant_bits); |
d16aafd8 AC |
243 | |
244 | dto += ldexp ((double) mant, exponent - mant_bits); | |
245 | exponent -= mant_bits; | |
246 | mant_off += mant_bits; | |
247 | mant_bits_left -= mant_bits; | |
248 | } | |
249 | ||
250 | /* Negate it if negative. */ | |
fcab3fb5 | 251 | if (get_field (ufrom, order, fmt->totalsize, fmt->sign_start, 1)) |
d16aafd8 AC |
252 | dto = -dto; |
253 | *to = dto; | |
254 | } | |
255 | \f | |
256 | static void put_field (unsigned char *, enum floatformat_byteorders, | |
257 | unsigned int, | |
258 | unsigned int, unsigned int, unsigned long); | |
259 | ||
260 | /* Set a field which starts at START and is LEN bytes long. DATA and | |
261 | TOTAL_LEN are the thing we are extracting it from, in byteorder ORDER. */ | |
262 | static void | |
263 | put_field (unsigned char *data, enum floatformat_byteorders order, | |
264 | unsigned int total_len, unsigned int start, unsigned int len, | |
265 | unsigned long stuff_to_put) | |
266 | { | |
267 | unsigned int cur_byte; | |
268 | int cur_bitshift; | |
269 | ||
fcab3fb5 RE |
270 | /* Caller must byte-swap words before calling this routine. */ |
271 | gdb_assert (order == floatformat_little || order == floatformat_big); | |
272 | ||
d16aafd8 | 273 | /* Start at the least significant part of the field. */ |
fcab3fb5 | 274 | if (order == floatformat_little) |
d16aafd8 AC |
275 | { |
276 | int excess = FLOATFORMAT_CHAR_BIT - (total_len % FLOATFORMAT_CHAR_BIT); | |
277 | cur_byte = (total_len / FLOATFORMAT_CHAR_BIT) | |
278 | - ((start + len + excess) / FLOATFORMAT_CHAR_BIT); | |
279 | cur_bitshift = ((start + len + excess) % FLOATFORMAT_CHAR_BIT) | |
280 | - FLOATFORMAT_CHAR_BIT; | |
281 | } | |
282 | else | |
283 | { | |
284 | cur_byte = (start + len) / FLOATFORMAT_CHAR_BIT; | |
285 | cur_bitshift = | |
286 | ((start + len) % FLOATFORMAT_CHAR_BIT) - FLOATFORMAT_CHAR_BIT; | |
287 | } | |
288 | if (cur_bitshift > -FLOATFORMAT_CHAR_BIT) | |
289 | { | |
290 | *(data + cur_byte) &= | |
291 | ~(((1 << ((start + len) % FLOATFORMAT_CHAR_BIT)) - 1) | |
292 | << (-cur_bitshift)); | |
293 | *(data + cur_byte) |= | |
294 | (stuff_to_put & ((1 << FLOATFORMAT_CHAR_BIT) - 1)) << (-cur_bitshift); | |
295 | } | |
296 | cur_bitshift += FLOATFORMAT_CHAR_BIT; | |
fcab3fb5 | 297 | if (order == floatformat_little) |
d16aafd8 AC |
298 | ++cur_byte; |
299 | else | |
300 | --cur_byte; | |
301 | ||
302 | /* Move towards the most significant part of the field. */ | |
303 | while (cur_bitshift < len) | |
304 | { | |
305 | if (len - cur_bitshift < FLOATFORMAT_CHAR_BIT) | |
306 | { | |
307 | /* This is the last byte. */ | |
308 | *(data + cur_byte) &= | |
309 | ~((1 << (len - cur_bitshift)) - 1); | |
310 | *(data + cur_byte) |= (stuff_to_put >> cur_bitshift); | |
311 | } | |
312 | else | |
313 | *(data + cur_byte) = ((stuff_to_put >> cur_bitshift) | |
314 | & ((1 << FLOATFORMAT_CHAR_BIT) - 1)); | |
315 | cur_bitshift += FLOATFORMAT_CHAR_BIT; | |
fcab3fb5 | 316 | if (order == floatformat_little) |
d16aafd8 AC |
317 | ++cur_byte; |
318 | else | |
319 | --cur_byte; | |
320 | } | |
321 | } | |
322 | ||
323 | #ifdef HAVE_LONG_DOUBLE | |
324 | /* Return the fractional part of VALUE, and put the exponent of VALUE in *EPTR. | |
325 | The range of the returned value is >= 0.5 and < 1.0. This is equivalent to | |
326 | frexp, but operates on the long double data type. */ | |
327 | ||
328 | static long double ldfrexp (long double value, int *eptr); | |
329 | ||
330 | static long double | |
331 | ldfrexp (long double value, int *eptr) | |
332 | { | |
333 | long double tmp; | |
334 | int exp; | |
335 | ||
336 | /* Unfortunately, there are no portable functions for extracting the exponent | |
337 | of a long double, so we have to do it iteratively by multiplying or dividing | |
338 | by two until the fraction is between 0.5 and 1.0. */ | |
339 | ||
340 | if (value < 0.0l) | |
341 | value = -value; | |
342 | ||
343 | tmp = 1.0l; | |
344 | exp = 0; | |
345 | ||
346 | if (value >= tmp) /* Value >= 1.0 */ | |
347 | while (value >= tmp) | |
348 | { | |
349 | tmp *= 2.0l; | |
350 | exp++; | |
351 | } | |
352 | else if (value != 0.0l) /* Value < 1.0 and > 0.0 */ | |
353 | { | |
354 | while (value < tmp) | |
355 | { | |
356 | tmp /= 2.0l; | |
357 | exp--; | |
358 | } | |
359 | tmp *= 2.0l; | |
360 | exp++; | |
361 | } | |
362 | ||
363 | *eptr = exp; | |
364 | return value / tmp; | |
365 | } | |
366 | #endif /* HAVE_LONG_DOUBLE */ | |
367 | ||
368 | ||
0a3e99f6 MK |
369 | /* The converse: convert the DOUBLEST *FROM to an extended float and |
370 | store where TO points. Neither FROM nor TO have any alignment | |
d16aafd8 AC |
371 | restrictions. */ |
372 | ||
c422e771 AC |
373 | static void |
374 | convert_doublest_to_floatformat (CONST struct floatformat *fmt, | |
0a3e99f6 | 375 | const DOUBLEST *from, void *to) |
d16aafd8 AC |
376 | { |
377 | DOUBLEST dfrom; | |
378 | int exponent; | |
379 | DOUBLEST mant; | |
380 | unsigned int mant_bits, mant_off; | |
381 | int mant_bits_left; | |
382 | unsigned char *uto = (unsigned char *) to; | |
fcab3fb5 | 383 | enum floatformat_byteorders order = fmt->byteorder; |
0a3e99f6 | 384 | unsigned char newto[FLOATFORMAT_LARGEST_BYTES]; |
fcab3fb5 | 385 | |
0a3e99f6 | 386 | if (order != floatformat_little) |
fcab3fb5 | 387 | order = floatformat_big; |
d16aafd8 | 388 | |
0a3e99f6 MK |
389 | if (order != fmt->byteorder) |
390 | uto = newto; | |
391 | ||
d16aafd8 AC |
392 | memcpy (&dfrom, from, sizeof (dfrom)); |
393 | memset (uto, 0, (fmt->totalsize + FLOATFORMAT_CHAR_BIT - 1) | |
394 | / FLOATFORMAT_CHAR_BIT); | |
395 | if (dfrom == 0) | |
396 | return; /* Result is zero */ | |
397 | if (dfrom != dfrom) /* Result is NaN */ | |
398 | { | |
399 | /* From is NaN */ | |
fcab3fb5 | 400 | put_field (uto, order, fmt->totalsize, fmt->exp_start, |
d16aafd8 AC |
401 | fmt->exp_len, fmt->exp_nan); |
402 | /* Be sure it's not infinity, but NaN value is irrel */ | |
fcab3fb5 | 403 | put_field (uto, order, fmt->totalsize, fmt->man_start, |
d16aafd8 | 404 | 32, 1); |
fcab3fb5 | 405 | goto finalize_byteorder; |
d16aafd8 AC |
406 | } |
407 | ||
408 | /* If negative, set the sign bit. */ | |
409 | if (dfrom < 0) | |
410 | { | |
fcab3fb5 | 411 | put_field (uto, order, fmt->totalsize, fmt->sign_start, 1, 1); |
d16aafd8 AC |
412 | dfrom = -dfrom; |
413 | } | |
414 | ||
415 | if (dfrom + dfrom == dfrom && dfrom != 0.0) /* Result is Infinity */ | |
416 | { | |
417 | /* Infinity exponent is same as NaN's. */ | |
fcab3fb5 | 418 | put_field (uto, order, fmt->totalsize, fmt->exp_start, |
d16aafd8 AC |
419 | fmt->exp_len, fmt->exp_nan); |
420 | /* Infinity mantissa is all zeroes. */ | |
fcab3fb5 | 421 | put_field (uto, order, fmt->totalsize, fmt->man_start, |
d16aafd8 | 422 | fmt->man_len, 0); |
fcab3fb5 | 423 | goto finalize_byteorder; |
d16aafd8 AC |
424 | } |
425 | ||
426 | #ifdef HAVE_LONG_DOUBLE | |
427 | mant = ldfrexp (dfrom, &exponent); | |
428 | #else | |
429 | mant = frexp (dfrom, &exponent); | |
430 | #endif | |
431 | ||
fcab3fb5 | 432 | put_field (uto, order, fmt->totalsize, fmt->exp_start, fmt->exp_len, |
d16aafd8 AC |
433 | exponent + fmt->exp_bias - 1); |
434 | ||
435 | mant_bits_left = fmt->man_len; | |
436 | mant_off = fmt->man_start; | |
437 | while (mant_bits_left > 0) | |
438 | { | |
439 | unsigned long mant_long; | |
440 | mant_bits = mant_bits_left < 32 ? mant_bits_left : 32; | |
441 | ||
442 | mant *= 4294967296.0; | |
443 | mant_long = ((unsigned long) mant) & 0xffffffffL; | |
444 | mant -= mant_long; | |
445 | ||
446 | /* If the integer bit is implicit, then we need to discard it. | |
447 | If we are discarding a zero, we should be (but are not) creating | |
448 | a denormalized number which means adjusting the exponent | |
449 | (I think). */ | |
450 | if (mant_bits_left == fmt->man_len | |
451 | && fmt->intbit == floatformat_intbit_no) | |
452 | { | |
453 | mant_long <<= 1; | |
454 | mant_long &= 0xffffffffL; | |
06194148 JJ |
455 | /* If we are processing the top 32 mantissa bits of a doublest |
456 | so as to convert to a float value with implied integer bit, | |
457 | we will only be putting 31 of those 32 bits into the | |
458 | final value due to the discarding of the top bit. In the | |
459 | case of a small float value where the number of mantissa | |
460 | bits is less than 32, discarding the top bit does not alter | |
461 | the number of bits we will be adding to the result. */ | |
462 | if (mant_bits == 32) | |
463 | mant_bits -= 1; | |
d16aafd8 AC |
464 | } |
465 | ||
466 | if (mant_bits < 32) | |
467 | { | |
468 | /* The bits we want are in the most significant MANT_BITS bits of | |
469 | mant_long. Move them to the least significant. */ | |
470 | mant_long >>= 32 - mant_bits; | |
471 | } | |
472 | ||
fcab3fb5 | 473 | put_field (uto, order, fmt->totalsize, |
d16aafd8 AC |
474 | mant_off, mant_bits, mant_long); |
475 | mant_off += mant_bits; | |
476 | mant_bits_left -= mant_bits; | |
477 | } | |
fcab3fb5 RE |
478 | |
479 | finalize_byteorder: | |
480 | /* Do we need to byte-swap the words in the result? */ | |
481 | if (order != fmt->byteorder) | |
0a3e99f6 | 482 | floatformat_normalize_byteorder (fmt, newto, to); |
d16aafd8 AC |
483 | } |
484 | ||
485 | /* Check if VAL (which is assumed to be a floating point number whose | |
486 | format is described by FMT) is negative. */ | |
487 | ||
488 | int | |
108d6ead AC |
489 | floatformat_is_negative (const struct floatformat *fmt, |
490 | const bfd_byte *uval) | |
d16aafd8 | 491 | { |
fcab3fb5 RE |
492 | enum floatformat_byteorders order; |
493 | unsigned char newfrom[FLOATFORMAT_LARGEST_BYTES]; | |
494 | ||
069e84fd | 495 | gdb_assert (fmt != NULL); |
fcab3fb5 RE |
496 | gdb_assert (fmt->totalsize |
497 | <= FLOATFORMAT_LARGEST_BYTES * FLOATFORMAT_CHAR_BIT); | |
498 | ||
499 | order = floatformat_normalize_byteorder (fmt, uval, newfrom); | |
500 | ||
501 | if (order != fmt->byteorder) | |
502 | uval = newfrom; | |
503 | ||
504 | return get_field (uval, order, fmt->totalsize, fmt->sign_start, 1); | |
d16aafd8 AC |
505 | } |
506 | ||
507 | /* Check if VAL is "not a number" (NaN) for FMT. */ | |
508 | ||
20389057 DJ |
509 | enum float_kind |
510 | floatformat_classify (const struct floatformat *fmt, | |
511 | const bfd_byte *uval) | |
d16aafd8 | 512 | { |
d16aafd8 AC |
513 | long exponent; |
514 | unsigned long mant; | |
515 | unsigned int mant_bits, mant_off; | |
516 | int mant_bits_left; | |
fcab3fb5 RE |
517 | enum floatformat_byteorders order; |
518 | unsigned char newfrom[FLOATFORMAT_LARGEST_BYTES]; | |
20389057 | 519 | int mant_zero; |
fcab3fb5 | 520 | |
069e84fd | 521 | gdb_assert (fmt != NULL); |
fcab3fb5 RE |
522 | gdb_assert (fmt->totalsize |
523 | <= FLOATFORMAT_LARGEST_BYTES * FLOATFORMAT_CHAR_BIT); | |
524 | ||
525 | order = floatformat_normalize_byteorder (fmt, uval, newfrom); | |
526 | ||
527 | if (order != fmt->byteorder) | |
528 | uval = newfrom; | |
069e84fd | 529 | |
fcab3fb5 RE |
530 | exponent = get_field (uval, order, fmt->totalsize, fmt->exp_start, |
531 | fmt->exp_len); | |
d16aafd8 | 532 | |
d16aafd8 AC |
533 | mant_bits_left = fmt->man_len; |
534 | mant_off = fmt->man_start; | |
535 | ||
20389057 | 536 | mant_zero = 1; |
d16aafd8 AC |
537 | while (mant_bits_left > 0) |
538 | { | |
539 | mant_bits = min (mant_bits_left, 32); | |
540 | ||
fcab3fb5 | 541 | mant = get_field (uval, order, fmt->totalsize, mant_off, mant_bits); |
d16aafd8 AC |
542 | |
543 | /* If there is an explicit integer bit, mask it off. */ | |
544 | if (mant_off == fmt->man_start | |
545 | && fmt->intbit == floatformat_intbit_yes) | |
546 | mant &= ~(1 << (mant_bits - 1)); | |
547 | ||
548 | if (mant) | |
20389057 DJ |
549 | { |
550 | mant_zero = 0; | |
551 | break; | |
552 | } | |
d16aafd8 AC |
553 | |
554 | mant_off += mant_bits; | |
555 | mant_bits_left -= mant_bits; | |
556 | } | |
557 | ||
20389057 DJ |
558 | /* If exp_nan is not set, assume that inf, NaN, and subnormals are not |
559 | supported. */ | |
560 | if (! fmt->exp_nan) | |
561 | { | |
562 | if (mant_zero) | |
563 | return float_zero; | |
564 | else | |
565 | return float_normal; | |
566 | } | |
567 | ||
568 | if (exponent == 0 && !mant_zero) | |
569 | return float_subnormal; | |
570 | ||
571 | if (exponent == fmt->exp_nan) | |
572 | { | |
573 | if (mant_zero) | |
574 | return float_infinite; | |
575 | else | |
576 | return float_nan; | |
577 | } | |
578 | ||
579 | if (mant_zero) | |
580 | return float_zero; | |
581 | ||
582 | return float_normal; | |
d16aafd8 AC |
583 | } |
584 | ||
585 | /* Convert the mantissa of VAL (which is assumed to be a floating | |
586 | point number whose format is described by FMT) into a hexadecimal | |
587 | and store it in a static string. Return a pointer to that string. */ | |
588 | ||
108d6ead AC |
589 | const char * |
590 | floatformat_mantissa (const struct floatformat *fmt, | |
591 | const bfd_byte *val) | |
d16aafd8 AC |
592 | { |
593 | unsigned char *uval = (unsigned char *) val; | |
594 | unsigned long mant; | |
595 | unsigned int mant_bits, mant_off; | |
596 | int mant_bits_left; | |
597 | static char res[50]; | |
598 | char buf[9]; | |
27df76f3 | 599 | int len; |
fcab3fb5 RE |
600 | enum floatformat_byteorders order; |
601 | unsigned char newfrom[FLOATFORMAT_LARGEST_BYTES]; | |
602 | ||
603 | gdb_assert (fmt != NULL); | |
604 | gdb_assert (fmt->totalsize | |
605 | <= FLOATFORMAT_LARGEST_BYTES * FLOATFORMAT_CHAR_BIT); | |
606 | ||
607 | order = floatformat_normalize_byteorder (fmt, uval, newfrom); | |
608 | ||
609 | if (order != fmt->byteorder) | |
610 | uval = newfrom; | |
611 | ||
612 | if (! fmt->exp_nan) | |
613 | return 0; | |
d16aafd8 AC |
614 | |
615 | /* Make sure we have enough room to store the mantissa. */ | |
616 | gdb_assert (sizeof res > ((fmt->man_len + 7) / 8) * 2); | |
617 | ||
618 | mant_off = fmt->man_start; | |
619 | mant_bits_left = fmt->man_len; | |
620 | mant_bits = (mant_bits_left % 32) > 0 ? mant_bits_left % 32 : 32; | |
621 | ||
fcab3fb5 | 622 | mant = get_field (uval, order, fmt->totalsize, mant_off, mant_bits); |
d16aafd8 | 623 | |
27df76f3 | 624 | len = xsnprintf (res, sizeof res, "%lx", mant); |
d16aafd8 AC |
625 | |
626 | mant_off += mant_bits; | |
627 | mant_bits_left -= mant_bits; | |
27df76f3 | 628 | |
d16aafd8 AC |
629 | while (mant_bits_left > 0) |
630 | { | |
fcab3fb5 | 631 | mant = get_field (uval, order, fmt->totalsize, mant_off, 32); |
d16aafd8 | 632 | |
27df76f3 MK |
633 | xsnprintf (buf, sizeof buf, "%08lx", mant); |
634 | gdb_assert (len + strlen (buf) <= sizeof res); | |
d16aafd8 AC |
635 | strcat (res, buf); |
636 | ||
637 | mant_off += 32; | |
638 | mant_bits_left -= 32; | |
639 | } | |
640 | ||
641 | return res; | |
642 | } | |
643 | ||
d16aafd8 | 644 | \f |
c422e771 AC |
645 | /* Convert TO/FROM target to the hosts DOUBLEST floating-point format. |
646 | ||
647 | If the host and target formats agree, we just copy the raw data | |
648 | into the appropriate type of variable and return, letting the host | |
649 | increase precision as necessary. Otherwise, we call the conversion | |
650 | routine and let it do the dirty work. */ | |
651 | ||
c35f4ffc AC |
652 | static const struct floatformat *host_float_format = GDB_HOST_FLOAT_FORMAT; |
653 | static const struct floatformat *host_double_format = GDB_HOST_DOUBLE_FORMAT; | |
654 | static const struct floatformat *host_long_double_format = GDB_HOST_LONG_DOUBLE_FORMAT; | |
c422e771 AC |
655 | |
656 | void | |
657 | floatformat_to_doublest (const struct floatformat *fmt, | |
658 | const void *in, DOUBLEST *out) | |
659 | { | |
660 | gdb_assert (fmt != NULL); | |
661 | if (fmt == host_float_format) | |
662 | { | |
663 | float val; | |
664 | memcpy (&val, in, sizeof (val)); | |
665 | *out = val; | |
666 | } | |
667 | else if (fmt == host_double_format) | |
668 | { | |
669 | double val; | |
670 | memcpy (&val, in, sizeof (val)); | |
671 | *out = val; | |
672 | } | |
673 | else if (fmt == host_long_double_format) | |
674 | { | |
675 | long double val; | |
676 | memcpy (&val, in, sizeof (val)); | |
677 | *out = val; | |
678 | } | |
679 | else | |
680 | convert_floatformat_to_doublest (fmt, in, out); | |
681 | } | |
682 | ||
683 | void | |
684 | floatformat_from_doublest (const struct floatformat *fmt, | |
685 | const DOUBLEST *in, void *out) | |
686 | { | |
687 | gdb_assert (fmt != NULL); | |
688 | if (fmt == host_float_format) | |
689 | { | |
690 | float val = *in; | |
691 | memcpy (out, &val, sizeof (val)); | |
692 | } | |
693 | else if (fmt == host_double_format) | |
694 | { | |
695 | double val = *in; | |
696 | memcpy (out, &val, sizeof (val)); | |
697 | } | |
698 | else if (fmt == host_long_double_format) | |
699 | { | |
700 | long double val = *in; | |
701 | memcpy (out, &val, sizeof (val)); | |
702 | } | |
703 | else | |
704 | convert_doublest_to_floatformat (fmt, in, out); | |
705 | } | |
d16aafd8 | 706 | |
c422e771 | 707 | \f |
87ffba60 | 708 | /* Return a floating-point format for a floating-point variable of |
47b3f456 AC |
709 | length LEN. If no suitable floating-point format is found, an |
710 | error is thrown. | |
d16aafd8 | 711 | |
87ffba60 MK |
712 | We need this functionality since information about the |
713 | floating-point format of a type is not always available to GDB; the | |
714 | debug information typically only tells us the size of a | |
715 | floating-point type. | |
716 | ||
717 | FIXME: kettenis/2001-10-28: In many places, particularly in | |
718 | target-dependent code, the format of floating-point types is known, | |
719 | but not passed on by GDB. This should be fixed. */ | |
720 | ||
b9362cc7 | 721 | static const struct floatformat * |
87ffba60 | 722 | floatformat_from_length (int len) |
d16aafd8 | 723 | { |
47b3f456 | 724 | const struct floatformat *format; |
ea06eb3d UW |
725 | if (len * TARGET_CHAR_BIT == gdbarch_float_bit (current_gdbarch)) |
726 | format = gdbarch_float_format (current_gdbarch) | |
727 | [gdbarch_byte_order (current_gdbarch)]; | |
728 | else if (len * TARGET_CHAR_BIT == gdbarch_double_bit (current_gdbarch)) | |
729 | format = gdbarch_double_format (current_gdbarch) | |
730 | [gdbarch_byte_order (current_gdbarch)]; | |
731 | else if (len * TARGET_CHAR_BIT == gdbarch_long_double_bit (current_gdbarch)) | |
732 | format = gdbarch_long_double_format (current_gdbarch) | |
733 | [gdbarch_byte_order (current_gdbarch)]; | |
ddbfdd06 PM |
734 | /* On i386 the 'long double' type takes 96 bits, |
735 | while the real number of used bits is only 80, | |
736 | both in processor and in memory. | |
737 | The code below accepts the real bit size. */ | |
ea06eb3d | 738 | else if ((gdbarch_long_double_format (current_gdbarch) != NULL) |
ddbfdd06 | 739 | && (len * TARGET_CHAR_BIT == |
ea06eb3d UW |
740 | gdbarch_long_double_format (current_gdbarch)[0]->totalsize)) |
741 | format = gdbarch_long_double_format (current_gdbarch) | |
742 | [gdbarch_byte_order (current_gdbarch)]; | |
47b3f456 AC |
743 | else |
744 | format = NULL; | |
745 | if (format == NULL) | |
8a3fe4f8 | 746 | error (_("Unrecognized %d-bit floating-point type."), |
9b0dea39 | 747 | len * TARGET_CHAR_BIT); |
47b3f456 | 748 | return format; |
87ffba60 MK |
749 | } |
750 | ||
c2f05ac9 AC |
751 | const struct floatformat * |
752 | floatformat_from_type (const struct type *type) | |
753 | { | |
754 | gdb_assert (TYPE_CODE (type) == TYPE_CODE_FLT); | |
755 | if (TYPE_FLOATFORMAT (type) != NULL) | |
0d20ae72 | 756 | return TYPE_FLOATFORMAT (type)[gdbarch_byte_order (current_gdbarch)]; |
c2f05ac9 AC |
757 | else |
758 | return floatformat_from_length (TYPE_LENGTH (type)); | |
759 | } | |
760 | ||
87ffba60 MK |
761 | /* If the host doesn't define NAN, use zero instead. */ |
762 | #ifndef NAN | |
763 | #define NAN 0.0 | |
764 | #endif | |
765 | ||
766 | /* Extract a floating-point number of length LEN from a target-order | |
767 | byte-stream at ADDR. Returns the value as type DOUBLEST. */ | |
768 | ||
f1908289 AC |
769 | static DOUBLEST |
770 | extract_floating_by_length (const void *addr, int len) | |
87ffba60 MK |
771 | { |
772 | const struct floatformat *fmt = floatformat_from_length (len); | |
773 | DOUBLEST val; | |
774 | ||
87ffba60 MK |
775 | floatformat_to_doublest (fmt, addr, &val); |
776 | return val; | |
d16aafd8 AC |
777 | } |
778 | ||
f1908289 AC |
779 | DOUBLEST |
780 | deprecated_extract_floating (const void *addr, int len) | |
781 | { | |
782 | return extract_floating_by_length (addr, len); | |
783 | } | |
784 | ||
87ffba60 MK |
785 | /* Store VAL as a floating-point number of length LEN to a |
786 | target-order byte-stream at ADDR. */ | |
787 | ||
f1908289 AC |
788 | static void |
789 | store_floating_by_length (void *addr, int len, DOUBLEST val) | |
d16aafd8 | 790 | { |
87ffba60 MK |
791 | const struct floatformat *fmt = floatformat_from_length (len); |
792 | ||
87ffba60 | 793 | floatformat_from_doublest (fmt, &val, addr); |
d16aafd8 | 794 | } |
96d2f608 | 795 | |
f1908289 AC |
796 | void |
797 | deprecated_store_floating (void *addr, int len, DOUBLEST val) | |
798 | { | |
799 | store_floating_by_length (addr, len, val); | |
800 | } | |
801 | ||
87ffba60 MK |
802 | /* Extract a floating-point number of type TYPE from a target-order |
803 | byte-stream at ADDR. Returns the value as type DOUBLEST. */ | |
96d2f608 AC |
804 | |
805 | DOUBLEST | |
806 | extract_typed_floating (const void *addr, const struct type *type) | |
807 | { | |
808 | DOUBLEST retval; | |
87ffba60 | 809 | |
96d2f608 | 810 | gdb_assert (TYPE_CODE (type) == TYPE_CODE_FLT); |
87ffba60 | 811 | |
96d2f608 | 812 | if (TYPE_FLOATFORMAT (type) == NULL) |
f1908289 AC |
813 | /* Not all code remembers to set the FLOATFORMAT (language |
814 | specific code? stabs?) so handle that here as a special case. */ | |
815 | return extract_floating_by_length (addr, TYPE_LENGTH (type)); | |
87ffba60 | 816 | |
0d20ae72 UW |
817 | floatformat_to_doublest |
818 | (TYPE_FLOATFORMAT (type)[gdbarch_byte_order (current_gdbarch)], | |
8da61cc4 | 819 | addr, &retval); |
96d2f608 AC |
820 | return retval; |
821 | } | |
822 | ||
87ffba60 MK |
823 | /* Store VAL as a floating-point number of type TYPE to a target-order |
824 | byte-stream at ADDR. */ | |
825 | ||
96d2f608 AC |
826 | void |
827 | store_typed_floating (void *addr, const struct type *type, DOUBLEST val) | |
828 | { | |
829 | gdb_assert (TYPE_CODE (type) == TYPE_CODE_FLT); | |
87ffba60 MK |
830 | |
831 | /* FIXME: kettenis/2001-10-28: It is debatable whether we should | |
832 | zero out any remaining bytes in the target buffer when TYPE is | |
833 | longer than the actual underlying floating-point format. Perhaps | |
834 | we should store a fixed bitpattern in those remaining bytes, | |
835 | instead of zero, or perhaps we shouldn't touch those remaining | |
836 | bytes at all. | |
837 | ||
838 | NOTE: cagney/2001-10-28: With the way things currently work, it | |
839 | isn't a good idea to leave the end bits undefined. This is | |
840 | because GDB writes out the entire sizeof(<floating>) bits of the | |
841 | floating-point type even though the value might only be stored | |
842 | in, and the target processor may only refer to, the first N < | |
843 | TYPE_LENGTH (type) bits. If the end of the buffer wasn't | |
844 | initialized, GDB would write undefined data to the target. An | |
845 | errant program, refering to that undefined data, would then | |
43686d64 MK |
846 | become non-deterministic. |
847 | ||
848 | See also the function convert_typed_floating below. */ | |
96d2f608 | 849 | memset (addr, 0, TYPE_LENGTH (type)); |
87ffba60 | 850 | |
96d2f608 | 851 | if (TYPE_FLOATFORMAT (type) == NULL) |
f1908289 AC |
852 | /* Not all code remembers to set the FLOATFORMAT (language |
853 | specific code? stabs?) so handle that here as a special case. */ | |
854 | store_floating_by_length (addr, TYPE_LENGTH (type), val); | |
0b87a11d | 855 | else |
0d20ae72 UW |
856 | floatformat_from_doublest |
857 | (TYPE_FLOATFORMAT (type)[gdbarch_byte_order (current_gdbarch)], | |
858 | &val, addr); | |
96d2f608 | 859 | } |
43686d64 MK |
860 | |
861 | /* Convert a floating-point number of type FROM_TYPE from a | |
862 | target-order byte-stream at FROM to a floating-point number of type | |
863 | TO_TYPE, and store it to a target-order byte-stream at TO. */ | |
864 | ||
865 | void | |
866 | convert_typed_floating (const void *from, const struct type *from_type, | |
867 | void *to, const struct type *to_type) | |
868 | { | |
c2f05ac9 AC |
869 | const struct floatformat *from_fmt = floatformat_from_type (from_type); |
870 | const struct floatformat *to_fmt = floatformat_from_type (to_type); | |
43686d64 MK |
871 | |
872 | gdb_assert (TYPE_CODE (from_type) == TYPE_CODE_FLT); | |
873 | gdb_assert (TYPE_CODE (to_type) == TYPE_CODE_FLT); | |
874 | ||
43686d64 MK |
875 | if (from_fmt == NULL || to_fmt == NULL) |
876 | { | |
877 | /* If we don't know the floating-point format of FROM_TYPE or | |
878 | TO_TYPE, there's not much we can do. We might make the | |
879 | assumption that if the length of FROM_TYPE and TO_TYPE match, | |
880 | their floating-point format would match too, but that | |
881 | assumption might be wrong on targets that support | |
882 | floating-point types that only differ in endianness for | |
883 | example. So we warn instead, and zero out the target buffer. */ | |
8a3fe4f8 | 884 | warning (_("Can't convert floating-point number to desired type.")); |
43686d64 MK |
885 | memset (to, 0, TYPE_LENGTH (to_type)); |
886 | } | |
887 | else if (from_fmt == to_fmt) | |
888 | { | |
889 | /* We're in business. The floating-point format of FROM_TYPE | |
890 | and TO_TYPE match. However, even though the floating-point | |
891 | format matches, the length of the type might still be | |
892 | different. Make sure we don't overrun any buffers. See | |
893 | comment in store_typed_floating for a discussion about | |
894 | zeroing out remaining bytes in the target buffer. */ | |
895 | memset (to, 0, TYPE_LENGTH (to_type)); | |
896 | memcpy (to, from, min (TYPE_LENGTH (from_type), TYPE_LENGTH (to_type))); | |
897 | } | |
898 | else | |
899 | { | |
900 | /* The floating-point types don't match. The best we can do | |
901 | (aport from simulating the target FPU) is converting to the | |
902 | widest floating-point type supported by the host, and then | |
903 | again to the desired type. */ | |
904 | DOUBLEST d; | |
905 | ||
906 | floatformat_to_doublest (from_fmt, from, &d); | |
907 | floatformat_from_doublest (to_fmt, &d, to); | |
908 | } | |
909 | } | |
5ef2d0aa AC |
910 | |
911 | const struct floatformat *floatformat_ieee_single[BFD_ENDIAN_UNKNOWN]; | |
912 | const struct floatformat *floatformat_ieee_double[BFD_ENDIAN_UNKNOWN]; | |
49c54768 | 913 | const struct floatformat *floatformat_ieee_quad[BFD_ENDIAN_UNKNOWN]; |
5ef2d0aa AC |
914 | const struct floatformat *floatformat_arm_ext[BFD_ENDIAN_UNKNOWN]; |
915 | const struct floatformat *floatformat_ia64_spill[BFD_ENDIAN_UNKNOWN]; | |
5ef2d0aa AC |
916 | |
917 | extern void _initialize_doublest (void); | |
918 | ||
919 | extern void | |
920 | _initialize_doublest (void) | |
921 | { | |
922 | floatformat_ieee_single[BFD_ENDIAN_LITTLE] = &floatformat_ieee_single_little; | |
923 | floatformat_ieee_single[BFD_ENDIAN_BIG] = &floatformat_ieee_single_big; | |
924 | floatformat_ieee_double[BFD_ENDIAN_LITTLE] = &floatformat_ieee_double_little; | |
925 | floatformat_ieee_double[BFD_ENDIAN_BIG] = &floatformat_ieee_double_big; | |
926 | floatformat_arm_ext[BFD_ENDIAN_LITTLE] = &floatformat_arm_ext_littlebyte_bigword; | |
927 | floatformat_arm_ext[BFD_ENDIAN_BIG] = &floatformat_arm_ext_big; | |
928 | floatformat_ia64_spill[BFD_ENDIAN_LITTLE] = &floatformat_ia64_spill_little; | |
929 | floatformat_ia64_spill[BFD_ENDIAN_BIG] = &floatformat_ia64_spill_big; | |
49c54768 AC |
930 | floatformat_ieee_quad[BFD_ENDIAN_LITTLE] = &floatformat_ia64_quad_little; |
931 | floatformat_ieee_quad[BFD_ENDIAN_BIG] = &floatformat_ia64_quad_big; | |
5ef2d0aa | 932 | } |