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 | |
11 | the Free Software Foundation; either version 2 of the License, or | |
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 | |
20 | along with this program; if not, write to the Free Software | |
197e01b6 EZ |
21 | Foundation, Inc., 51 Franklin Street, Fifth Floor, |
22 | Boston, MA 02110-1301, USA. */ | |
d16aafd8 AC |
23 | |
24 | /* Support for converting target fp numbers into host DOUBLEST format. */ | |
25 | ||
26 | /* XXX - This code should really be in libiberty/floatformat.c, | |
27 | however configuration issues with libiberty made this very | |
28 | difficult to do in the available time. */ | |
29 | ||
30 | #include "defs.h" | |
31 | #include "doublest.h" | |
32 | #include "floatformat.h" | |
33 | #include "gdb_assert.h" | |
34 | #include "gdb_string.h" | |
96d2f608 | 35 | #include "gdbtypes.h" |
d16aafd8 AC |
36 | #include <math.h> /* ldexp */ |
37 | ||
38 | /* The odds that CHAR_BIT will be anything but 8 are low enough that I'm not | |
39 | going to bother with trying to muck around with whether it is defined in | |
40 | a system header, what we do if not, etc. */ | |
41 | #define FLOATFORMAT_CHAR_BIT 8 | |
42 | ||
fcab3fb5 RE |
43 | /* The number of bytes that the largest floating-point type that we |
44 | can convert to doublest will need. */ | |
45 | #define FLOATFORMAT_LARGEST_BYTES 16 | |
46 | ||
d16aafd8 AC |
47 | /* Extract a field which starts at START and is LEN bytes long. DATA and |
48 | TOTAL_LEN are the thing we are extracting it from, in byteorder ORDER. */ | |
49 | static unsigned long | |
108d6ead | 50 | get_field (const bfd_byte *data, enum floatformat_byteorders order, |
d16aafd8 AC |
51 | unsigned int total_len, unsigned int start, unsigned int len) |
52 | { | |
53 | unsigned long result; | |
54 | unsigned int cur_byte; | |
55 | int cur_bitshift; | |
56 | ||
fcab3fb5 RE |
57 | /* Caller must byte-swap words before calling this routine. */ |
58 | gdb_assert (order == floatformat_little || order == floatformat_big); | |
59 | ||
d16aafd8 | 60 | /* Start at the least significant part of the field. */ |
fcab3fb5 | 61 | if (order == floatformat_little) |
d16aafd8 AC |
62 | { |
63 | /* We start counting from the other end (i.e, from the high bytes | |
64 | rather than the low bytes). As such, we need to be concerned | |
65 | with what happens if bit 0 doesn't start on a byte boundary. | |
66 | I.e, we need to properly handle the case where total_len is | |
67 | not evenly divisible by 8. So we compute ``excess'' which | |
68 | represents the number of bits from the end of our starting | |
69 | byte needed to get to bit 0. */ | |
70 | int excess = FLOATFORMAT_CHAR_BIT - (total_len % FLOATFORMAT_CHAR_BIT); | |
71 | cur_byte = (total_len / FLOATFORMAT_CHAR_BIT) | |
72 | - ((start + len + excess) / FLOATFORMAT_CHAR_BIT); | |
73 | cur_bitshift = ((start + len + excess) % FLOATFORMAT_CHAR_BIT) | |
74 | - FLOATFORMAT_CHAR_BIT; | |
75 | } | |
76 | else | |
77 | { | |
78 | cur_byte = (start + len) / FLOATFORMAT_CHAR_BIT; | |
79 | cur_bitshift = | |
80 | ((start + len) % FLOATFORMAT_CHAR_BIT) - FLOATFORMAT_CHAR_BIT; | |
81 | } | |
82 | if (cur_bitshift > -FLOATFORMAT_CHAR_BIT) | |
83 | result = *(data + cur_byte) >> (-cur_bitshift); | |
84 | else | |
85 | result = 0; | |
86 | cur_bitshift += FLOATFORMAT_CHAR_BIT; | |
fcab3fb5 | 87 | if (order == floatformat_little) |
d16aafd8 AC |
88 | ++cur_byte; |
89 | else | |
90 | --cur_byte; | |
91 | ||
92 | /* Move towards the most significant part of the field. */ | |
93 | while (cur_bitshift < len) | |
94 | { | |
95 | result |= (unsigned long)*(data + cur_byte) << cur_bitshift; | |
96 | cur_bitshift += FLOATFORMAT_CHAR_BIT; | |
c35f4ffc AC |
97 | switch (order) |
98 | { | |
99 | case floatformat_little: | |
100 | ++cur_byte; | |
101 | break; | |
102 | case floatformat_big: | |
103 | --cur_byte; | |
104 | break; | |
c35f4ffc | 105 | } |
d16aafd8 AC |
106 | } |
107 | if (len < sizeof(result) * FLOATFORMAT_CHAR_BIT) | |
108 | /* Mask out bits which are not part of the field */ | |
109 | result &= ((1UL << len) - 1); | |
110 | return result; | |
111 | } | |
112 | ||
0a3e99f6 MK |
113 | /* Normalize the byte order of FROM into TO. If no normalization is |
114 | needed then FMT->byteorder is returned and TO is not changed; | |
115 | otherwise the format of the normalized form in TO is returned. */ | |
116 | ||
fcab3fb5 RE |
117 | static enum floatformat_byteorders |
118 | floatformat_normalize_byteorder (const struct floatformat *fmt, | |
119 | const void *from, void *to) | |
120 | { | |
121 | const unsigned char *swapin; | |
122 | unsigned char *swapout; | |
123 | int words; | |
124 | ||
125 | if (fmt->byteorder == floatformat_little | |
126 | || fmt->byteorder == floatformat_big) | |
127 | return fmt->byteorder; | |
128 | ||
fcab3fb5 RE |
129 | words = fmt->totalsize / FLOATFORMAT_CHAR_BIT; |
130 | words >>= 2; | |
131 | ||
132 | swapout = (unsigned char *)to; | |
133 | swapin = (const unsigned char *)from; | |
134 | ||
0a3e99f6 MK |
135 | if (fmt->byteorder == floatformat_vax) |
136 | { | |
137 | while (words-- > 0) | |
138 | { | |
139 | *swapout++ = swapin[1]; | |
140 | *swapout++ = swapin[0]; | |
141 | *swapout++ = swapin[3]; | |
142 | *swapout++ = swapin[2]; | |
143 | swapin += 4; | |
144 | } | |
145 | /* This may look weird, since VAX is little-endian, but it is | |
146 | easier to translate to big-endian than to little-endian. */ | |
147 | return floatformat_big; | |
148 | } | |
149 | else | |
fcab3fb5 | 150 | { |
0a3e99f6 MK |
151 | gdb_assert (fmt->byteorder == floatformat_littlebyte_bigword); |
152 | ||
153 | while (words-- > 0) | |
154 | { | |
155 | *swapout++ = swapin[3]; | |
156 | *swapout++ = swapin[2]; | |
157 | *swapout++ = swapin[1]; | |
158 | *swapout++ = swapin[0]; | |
159 | swapin += 4; | |
160 | } | |
161 | return floatformat_big; | |
fcab3fb5 | 162 | } |
fcab3fb5 RE |
163 | } |
164 | ||
d16aafd8 AC |
165 | /* Convert from FMT to a DOUBLEST. |
166 | FROM is the address of the extended float. | |
167 | Store the DOUBLEST in *TO. */ | |
168 | ||
c422e771 AC |
169 | static void |
170 | convert_floatformat_to_doublest (const struct floatformat *fmt, | |
171 | const void *from, | |
172 | DOUBLEST *to) | |
d16aafd8 AC |
173 | { |
174 | unsigned char *ufrom = (unsigned char *) from; | |
175 | DOUBLEST dto; | |
176 | long exponent; | |
177 | unsigned long mant; | |
178 | unsigned int mant_bits, mant_off; | |
179 | int mant_bits_left; | |
180 | int special_exponent; /* It's a NaN, denorm or zero */ | |
fcab3fb5 RE |
181 | enum floatformat_byteorders order; |
182 | unsigned char newfrom[FLOATFORMAT_LARGEST_BYTES]; | |
20389057 | 183 | enum float_kind kind; |
fcab3fb5 RE |
184 | |
185 | gdb_assert (fmt->totalsize | |
186 | <= FLOATFORMAT_LARGEST_BYTES * FLOATFORMAT_CHAR_BIT); | |
d16aafd8 | 187 | |
20389057 DJ |
188 | /* For non-numbers, reuse libiberty's logic to find the correct |
189 | format. We do not lose any precision in this case by passing | |
190 | through a double. */ | |
191 | kind = floatformat_classify (fmt, from); | |
192 | if (kind == float_infinite || kind == float_nan) | |
193 | { | |
194 | double dto; | |
195 | floatformat_to_double (fmt, from, &dto); | |
196 | *to = (DOUBLEST) dto; | |
197 | return; | |
198 | } | |
199 | ||
fcab3fb5 | 200 | order = floatformat_normalize_byteorder (fmt, ufrom, newfrom); |
d16aafd8 | 201 | |
fcab3fb5 RE |
202 | if (order != fmt->byteorder) |
203 | ufrom = newfrom; | |
d16aafd8 | 204 | |
fcab3fb5 RE |
205 | exponent = get_field (ufrom, order, fmt->totalsize, fmt->exp_start, |
206 | fmt->exp_len); | |
d16aafd8 AC |
207 | /* Note that if exponent indicates a NaN, we can't really do anything useful |
208 | (not knowing if the host has NaN's, or how to build one). So it will | |
209 | end up as an infinity or something close; that is OK. */ | |
210 | ||
211 | mant_bits_left = fmt->man_len; | |
212 | mant_off = fmt->man_start; | |
213 | dto = 0.0; | |
214 | ||
215 | special_exponent = exponent == 0 || exponent == fmt->exp_nan; | |
216 | ||
38c52d5a DJ |
217 | /* Don't bias NaNs. Use minimum exponent for denorms. For simplicity, |
218 | we don't check for zero as the exponent doesn't matter. Note the cast | |
219 | to int; exp_bias is unsigned, so it's important to make sure the | |
220 | operation is done in signed arithmetic. */ | |
d16aafd8 AC |
221 | if (!special_exponent) |
222 | exponent -= fmt->exp_bias; | |
223 | else if (exponent == 0) | |
1c704f11 | 224 | exponent = 1 - fmt->exp_bias; |
d16aafd8 AC |
225 | |
226 | /* Build the result algebraically. Might go infinite, underflow, etc; | |
227 | who cares. */ | |
228 | ||
229 | /* If this format uses a hidden bit, explicitly add it in now. Otherwise, | |
230 | increment the exponent by one to account for the integer bit. */ | |
231 | ||
232 | if (!special_exponent) | |
233 | { | |
234 | if (fmt->intbit == floatformat_intbit_no) | |
235 | dto = ldexp (1.0, exponent); | |
236 | else | |
237 | exponent++; | |
238 | } | |
239 | ||
240 | while (mant_bits_left > 0) | |
241 | { | |
242 | mant_bits = min (mant_bits_left, 32); | |
243 | ||
fcab3fb5 | 244 | mant = get_field (ufrom, order, fmt->totalsize, mant_off, mant_bits); |
d16aafd8 AC |
245 | |
246 | dto += ldexp ((double) mant, exponent - mant_bits); | |
247 | exponent -= mant_bits; | |
248 | mant_off += mant_bits; | |
249 | mant_bits_left -= mant_bits; | |
250 | } | |
251 | ||
252 | /* Negate it if negative. */ | |
fcab3fb5 | 253 | if (get_field (ufrom, order, fmt->totalsize, fmt->sign_start, 1)) |
d16aafd8 AC |
254 | dto = -dto; |
255 | *to = dto; | |
256 | } | |
257 | \f | |
258 | static void put_field (unsigned char *, enum floatformat_byteorders, | |
259 | unsigned int, | |
260 | unsigned int, unsigned int, unsigned long); | |
261 | ||
262 | /* Set a field which starts at START and is LEN bytes long. DATA and | |
263 | TOTAL_LEN are the thing we are extracting it from, in byteorder ORDER. */ | |
264 | static void | |
265 | put_field (unsigned char *data, enum floatformat_byteorders order, | |
266 | unsigned int total_len, unsigned int start, unsigned int len, | |
267 | unsigned long stuff_to_put) | |
268 | { | |
269 | unsigned int cur_byte; | |
270 | int cur_bitshift; | |
271 | ||
fcab3fb5 RE |
272 | /* Caller must byte-swap words before calling this routine. */ |
273 | gdb_assert (order == floatformat_little || order == floatformat_big); | |
274 | ||
d16aafd8 | 275 | /* Start at the least significant part of the field. */ |
fcab3fb5 | 276 | if (order == floatformat_little) |
d16aafd8 AC |
277 | { |
278 | int excess = FLOATFORMAT_CHAR_BIT - (total_len % FLOATFORMAT_CHAR_BIT); | |
279 | cur_byte = (total_len / FLOATFORMAT_CHAR_BIT) | |
280 | - ((start + len + excess) / FLOATFORMAT_CHAR_BIT); | |
281 | cur_bitshift = ((start + len + excess) % FLOATFORMAT_CHAR_BIT) | |
282 | - FLOATFORMAT_CHAR_BIT; | |
283 | } | |
284 | else | |
285 | { | |
286 | cur_byte = (start + len) / FLOATFORMAT_CHAR_BIT; | |
287 | cur_bitshift = | |
288 | ((start + len) % FLOATFORMAT_CHAR_BIT) - FLOATFORMAT_CHAR_BIT; | |
289 | } | |
290 | if (cur_bitshift > -FLOATFORMAT_CHAR_BIT) | |
291 | { | |
292 | *(data + cur_byte) &= | |
293 | ~(((1 << ((start + len) % FLOATFORMAT_CHAR_BIT)) - 1) | |
294 | << (-cur_bitshift)); | |
295 | *(data + cur_byte) |= | |
296 | (stuff_to_put & ((1 << FLOATFORMAT_CHAR_BIT) - 1)) << (-cur_bitshift); | |
297 | } | |
298 | cur_bitshift += FLOATFORMAT_CHAR_BIT; | |
fcab3fb5 | 299 | if (order == floatformat_little) |
d16aafd8 AC |
300 | ++cur_byte; |
301 | else | |
302 | --cur_byte; | |
303 | ||
304 | /* Move towards the most significant part of the field. */ | |
305 | while (cur_bitshift < len) | |
306 | { | |
307 | if (len - cur_bitshift < FLOATFORMAT_CHAR_BIT) | |
308 | { | |
309 | /* This is the last byte. */ | |
310 | *(data + cur_byte) &= | |
311 | ~((1 << (len - cur_bitshift)) - 1); | |
312 | *(data + cur_byte) |= (stuff_to_put >> cur_bitshift); | |
313 | } | |
314 | else | |
315 | *(data + cur_byte) = ((stuff_to_put >> cur_bitshift) | |
316 | & ((1 << FLOATFORMAT_CHAR_BIT) - 1)); | |
317 | cur_bitshift += FLOATFORMAT_CHAR_BIT; | |
fcab3fb5 | 318 | if (order == floatformat_little) |
d16aafd8 AC |
319 | ++cur_byte; |
320 | else | |
321 | --cur_byte; | |
322 | } | |
323 | } | |
324 | ||
325 | #ifdef HAVE_LONG_DOUBLE | |
326 | /* Return the fractional part of VALUE, and put the exponent of VALUE in *EPTR. | |
327 | The range of the returned value is >= 0.5 and < 1.0. This is equivalent to | |
328 | frexp, but operates on the long double data type. */ | |
329 | ||
330 | static long double ldfrexp (long double value, int *eptr); | |
331 | ||
332 | static long double | |
333 | ldfrexp (long double value, int *eptr) | |
334 | { | |
335 | long double tmp; | |
336 | int exp; | |
337 | ||
338 | /* Unfortunately, there are no portable functions for extracting the exponent | |
339 | of a long double, so we have to do it iteratively by multiplying or dividing | |
340 | by two until the fraction is between 0.5 and 1.0. */ | |
341 | ||
342 | if (value < 0.0l) | |
343 | value = -value; | |
344 | ||
345 | tmp = 1.0l; | |
346 | exp = 0; | |
347 | ||
348 | if (value >= tmp) /* Value >= 1.0 */ | |
349 | while (value >= tmp) | |
350 | { | |
351 | tmp *= 2.0l; | |
352 | exp++; | |
353 | } | |
354 | else if (value != 0.0l) /* Value < 1.0 and > 0.0 */ | |
355 | { | |
356 | while (value < tmp) | |
357 | { | |
358 | tmp /= 2.0l; | |
359 | exp--; | |
360 | } | |
361 | tmp *= 2.0l; | |
362 | exp++; | |
363 | } | |
364 | ||
365 | *eptr = exp; | |
366 | return value / tmp; | |
367 | } | |
368 | #endif /* HAVE_LONG_DOUBLE */ | |
369 | ||
370 | ||
0a3e99f6 MK |
371 | /* The converse: convert the DOUBLEST *FROM to an extended float and |
372 | store where TO points. Neither FROM nor TO have any alignment | |
d16aafd8 AC |
373 | restrictions. */ |
374 | ||
c422e771 AC |
375 | static void |
376 | convert_doublest_to_floatformat (CONST struct floatformat *fmt, | |
0a3e99f6 | 377 | const DOUBLEST *from, void *to) |
d16aafd8 AC |
378 | { |
379 | DOUBLEST dfrom; | |
380 | int exponent; | |
381 | DOUBLEST mant; | |
382 | unsigned int mant_bits, mant_off; | |
383 | int mant_bits_left; | |
384 | unsigned char *uto = (unsigned char *) to; | |
fcab3fb5 | 385 | enum floatformat_byteorders order = fmt->byteorder; |
0a3e99f6 | 386 | unsigned char newto[FLOATFORMAT_LARGEST_BYTES]; |
fcab3fb5 | 387 | |
0a3e99f6 | 388 | if (order != floatformat_little) |
fcab3fb5 | 389 | order = floatformat_big; |
d16aafd8 | 390 | |
0a3e99f6 MK |
391 | if (order != fmt->byteorder) |
392 | uto = newto; | |
393 | ||
d16aafd8 AC |
394 | memcpy (&dfrom, from, sizeof (dfrom)); |
395 | memset (uto, 0, (fmt->totalsize + FLOATFORMAT_CHAR_BIT - 1) | |
396 | / FLOATFORMAT_CHAR_BIT); | |
397 | if (dfrom == 0) | |
398 | return; /* Result is zero */ | |
399 | if (dfrom != dfrom) /* Result is NaN */ | |
400 | { | |
401 | /* From is NaN */ | |
fcab3fb5 | 402 | put_field (uto, order, fmt->totalsize, fmt->exp_start, |
d16aafd8 AC |
403 | fmt->exp_len, fmt->exp_nan); |
404 | /* Be sure it's not infinity, but NaN value is irrel */ | |
fcab3fb5 | 405 | put_field (uto, order, fmt->totalsize, fmt->man_start, |
d16aafd8 | 406 | 32, 1); |
fcab3fb5 | 407 | goto finalize_byteorder; |
d16aafd8 AC |
408 | } |
409 | ||
410 | /* If negative, set the sign bit. */ | |
411 | if (dfrom < 0) | |
412 | { | |
fcab3fb5 | 413 | put_field (uto, order, fmt->totalsize, fmt->sign_start, 1, 1); |
d16aafd8 AC |
414 | dfrom = -dfrom; |
415 | } | |
416 | ||
417 | if (dfrom + dfrom == dfrom && dfrom != 0.0) /* Result is Infinity */ | |
418 | { | |
419 | /* Infinity exponent is same as NaN's. */ | |
fcab3fb5 | 420 | put_field (uto, order, fmt->totalsize, fmt->exp_start, |
d16aafd8 AC |
421 | fmt->exp_len, fmt->exp_nan); |
422 | /* Infinity mantissa is all zeroes. */ | |
fcab3fb5 | 423 | put_field (uto, order, fmt->totalsize, fmt->man_start, |
d16aafd8 | 424 | fmt->man_len, 0); |
fcab3fb5 | 425 | goto finalize_byteorder; |
d16aafd8 AC |
426 | } |
427 | ||
428 | #ifdef HAVE_LONG_DOUBLE | |
429 | mant = ldfrexp (dfrom, &exponent); | |
430 | #else | |
431 | mant = frexp (dfrom, &exponent); | |
432 | #endif | |
433 | ||
fcab3fb5 | 434 | put_field (uto, order, fmt->totalsize, fmt->exp_start, fmt->exp_len, |
d16aafd8 AC |
435 | exponent + fmt->exp_bias - 1); |
436 | ||
437 | mant_bits_left = fmt->man_len; | |
438 | mant_off = fmt->man_start; | |
439 | while (mant_bits_left > 0) | |
440 | { | |
441 | unsigned long mant_long; | |
442 | mant_bits = mant_bits_left < 32 ? mant_bits_left : 32; | |
443 | ||
444 | mant *= 4294967296.0; | |
445 | mant_long = ((unsigned long) mant) & 0xffffffffL; | |
446 | mant -= mant_long; | |
447 | ||
448 | /* If the integer bit is implicit, then we need to discard it. | |
449 | If we are discarding a zero, we should be (but are not) creating | |
450 | a denormalized number which means adjusting the exponent | |
451 | (I think). */ | |
452 | if (mant_bits_left == fmt->man_len | |
453 | && fmt->intbit == floatformat_intbit_no) | |
454 | { | |
455 | mant_long <<= 1; | |
456 | mant_long &= 0xffffffffL; | |
06194148 JJ |
457 | /* If we are processing the top 32 mantissa bits of a doublest |
458 | so as to convert to a float value with implied integer bit, | |
459 | we will only be putting 31 of those 32 bits into the | |
460 | final value due to the discarding of the top bit. In the | |
461 | case of a small float value where the number of mantissa | |
462 | bits is less than 32, discarding the top bit does not alter | |
463 | the number of bits we will be adding to the result. */ | |
464 | if (mant_bits == 32) | |
465 | mant_bits -= 1; | |
d16aafd8 AC |
466 | } |
467 | ||
468 | if (mant_bits < 32) | |
469 | { | |
470 | /* The bits we want are in the most significant MANT_BITS bits of | |
471 | mant_long. Move them to the least significant. */ | |
472 | mant_long >>= 32 - mant_bits; | |
473 | } | |
474 | ||
fcab3fb5 | 475 | put_field (uto, order, fmt->totalsize, |
d16aafd8 AC |
476 | mant_off, mant_bits, mant_long); |
477 | mant_off += mant_bits; | |
478 | mant_bits_left -= mant_bits; | |
479 | } | |
fcab3fb5 RE |
480 | |
481 | finalize_byteorder: | |
482 | /* Do we need to byte-swap the words in the result? */ | |
483 | if (order != fmt->byteorder) | |
0a3e99f6 | 484 | floatformat_normalize_byteorder (fmt, newto, to); |
d16aafd8 AC |
485 | } |
486 | ||
487 | /* Check if VAL (which is assumed to be a floating point number whose | |
488 | format is described by FMT) is negative. */ | |
489 | ||
490 | int | |
108d6ead AC |
491 | floatformat_is_negative (const struct floatformat *fmt, |
492 | const bfd_byte *uval) | |
d16aafd8 | 493 | { |
fcab3fb5 RE |
494 | enum floatformat_byteorders order; |
495 | unsigned char newfrom[FLOATFORMAT_LARGEST_BYTES]; | |
496 | ||
069e84fd | 497 | gdb_assert (fmt != NULL); |
fcab3fb5 RE |
498 | gdb_assert (fmt->totalsize |
499 | <= FLOATFORMAT_LARGEST_BYTES * FLOATFORMAT_CHAR_BIT); | |
500 | ||
501 | order = floatformat_normalize_byteorder (fmt, uval, newfrom); | |
502 | ||
503 | if (order != fmt->byteorder) | |
504 | uval = newfrom; | |
505 | ||
506 | return get_field (uval, order, fmt->totalsize, fmt->sign_start, 1); | |
d16aafd8 AC |
507 | } |
508 | ||
509 | /* Check if VAL is "not a number" (NaN) for FMT. */ | |
510 | ||
20389057 DJ |
511 | enum float_kind |
512 | floatformat_classify (const struct floatformat *fmt, | |
513 | const bfd_byte *uval) | |
d16aafd8 | 514 | { |
d16aafd8 AC |
515 | long exponent; |
516 | unsigned long mant; | |
517 | unsigned int mant_bits, mant_off; | |
518 | int mant_bits_left; | |
fcab3fb5 RE |
519 | enum floatformat_byteorders order; |
520 | unsigned char newfrom[FLOATFORMAT_LARGEST_BYTES]; | |
20389057 | 521 | int mant_zero; |
fcab3fb5 | 522 | |
069e84fd | 523 | gdb_assert (fmt != NULL); |
fcab3fb5 RE |
524 | gdb_assert (fmt->totalsize |
525 | <= FLOATFORMAT_LARGEST_BYTES * FLOATFORMAT_CHAR_BIT); | |
526 | ||
527 | order = floatformat_normalize_byteorder (fmt, uval, newfrom); | |
528 | ||
529 | if (order != fmt->byteorder) | |
530 | uval = newfrom; | |
069e84fd | 531 | |
fcab3fb5 RE |
532 | exponent = get_field (uval, order, fmt->totalsize, fmt->exp_start, |
533 | fmt->exp_len); | |
d16aafd8 | 534 | |
d16aafd8 AC |
535 | mant_bits_left = fmt->man_len; |
536 | mant_off = fmt->man_start; | |
537 | ||
20389057 | 538 | mant_zero = 1; |
d16aafd8 AC |
539 | while (mant_bits_left > 0) |
540 | { | |
541 | mant_bits = min (mant_bits_left, 32); | |
542 | ||
fcab3fb5 | 543 | mant = get_field (uval, order, fmt->totalsize, mant_off, mant_bits); |
d16aafd8 AC |
544 | |
545 | /* If there is an explicit integer bit, mask it off. */ | |
546 | if (mant_off == fmt->man_start | |
547 | && fmt->intbit == floatformat_intbit_yes) | |
548 | mant &= ~(1 << (mant_bits - 1)); | |
549 | ||
550 | if (mant) | |
20389057 DJ |
551 | { |
552 | mant_zero = 0; | |
553 | break; | |
554 | } | |
d16aafd8 AC |
555 | |
556 | mant_off += mant_bits; | |
557 | mant_bits_left -= mant_bits; | |
558 | } | |
559 | ||
20389057 DJ |
560 | /* If exp_nan is not set, assume that inf, NaN, and subnormals are not |
561 | supported. */ | |
562 | if (! fmt->exp_nan) | |
563 | { | |
564 | if (mant_zero) | |
565 | return float_zero; | |
566 | else | |
567 | return float_normal; | |
568 | } | |
569 | ||
570 | if (exponent == 0 && !mant_zero) | |
571 | return float_subnormal; | |
572 | ||
573 | if (exponent == fmt->exp_nan) | |
574 | { | |
575 | if (mant_zero) | |
576 | return float_infinite; | |
577 | else | |
578 | return float_nan; | |
579 | } | |
580 | ||
581 | if (mant_zero) | |
582 | return float_zero; | |
583 | ||
584 | return float_normal; | |
d16aafd8 AC |
585 | } |
586 | ||
587 | /* Convert the mantissa of VAL (which is assumed to be a floating | |
588 | point number whose format is described by FMT) into a hexadecimal | |
589 | and store it in a static string. Return a pointer to that string. */ | |
590 | ||
108d6ead AC |
591 | const char * |
592 | floatformat_mantissa (const struct floatformat *fmt, | |
593 | const bfd_byte *val) | |
d16aafd8 AC |
594 | { |
595 | unsigned char *uval = (unsigned char *) val; | |
596 | unsigned long mant; | |
597 | unsigned int mant_bits, mant_off; | |
598 | int mant_bits_left; | |
599 | static char res[50]; | |
600 | char buf[9]; | |
27df76f3 | 601 | int len; |
fcab3fb5 RE |
602 | enum floatformat_byteorders order; |
603 | unsigned char newfrom[FLOATFORMAT_LARGEST_BYTES]; | |
604 | ||
605 | gdb_assert (fmt != NULL); | |
606 | gdb_assert (fmt->totalsize | |
607 | <= FLOATFORMAT_LARGEST_BYTES * FLOATFORMAT_CHAR_BIT); | |
608 | ||
609 | order = floatformat_normalize_byteorder (fmt, uval, newfrom); | |
610 | ||
611 | if (order != fmt->byteorder) | |
612 | uval = newfrom; | |
613 | ||
614 | if (! fmt->exp_nan) | |
615 | return 0; | |
d16aafd8 AC |
616 | |
617 | /* Make sure we have enough room to store the mantissa. */ | |
618 | gdb_assert (sizeof res > ((fmt->man_len + 7) / 8) * 2); | |
619 | ||
620 | mant_off = fmt->man_start; | |
621 | mant_bits_left = fmt->man_len; | |
622 | mant_bits = (mant_bits_left % 32) > 0 ? mant_bits_left % 32 : 32; | |
623 | ||
fcab3fb5 | 624 | mant = get_field (uval, order, fmt->totalsize, mant_off, mant_bits); |
d16aafd8 | 625 | |
27df76f3 | 626 | len = xsnprintf (res, sizeof res, "%lx", mant); |
d16aafd8 AC |
627 | |
628 | mant_off += mant_bits; | |
629 | mant_bits_left -= mant_bits; | |
27df76f3 | 630 | |
d16aafd8 AC |
631 | while (mant_bits_left > 0) |
632 | { | |
fcab3fb5 | 633 | mant = get_field (uval, order, fmt->totalsize, mant_off, 32); |
d16aafd8 | 634 | |
27df76f3 MK |
635 | xsnprintf (buf, sizeof buf, "%08lx", mant); |
636 | gdb_assert (len + strlen (buf) <= sizeof res); | |
d16aafd8 AC |
637 | strcat (res, buf); |
638 | ||
639 | mant_off += 32; | |
640 | mant_bits_left -= 32; | |
641 | } | |
642 | ||
643 | return res; | |
644 | } | |
645 | ||
d16aafd8 | 646 | \f |
c422e771 AC |
647 | /* Convert TO/FROM target to the hosts DOUBLEST floating-point format. |
648 | ||
649 | If the host and target formats agree, we just copy the raw data | |
650 | into the appropriate type of variable and return, letting the host | |
651 | increase precision as necessary. Otherwise, we call the conversion | |
652 | routine and let it do the dirty work. */ | |
653 | ||
c35f4ffc AC |
654 | static const struct floatformat *host_float_format = GDB_HOST_FLOAT_FORMAT; |
655 | static const struct floatformat *host_double_format = GDB_HOST_DOUBLE_FORMAT; | |
656 | static const struct floatformat *host_long_double_format = GDB_HOST_LONG_DOUBLE_FORMAT; | |
c422e771 AC |
657 | |
658 | void | |
659 | floatformat_to_doublest (const struct floatformat *fmt, | |
660 | const void *in, DOUBLEST *out) | |
661 | { | |
662 | gdb_assert (fmt != NULL); | |
663 | if (fmt == host_float_format) | |
664 | { | |
665 | float val; | |
666 | memcpy (&val, in, sizeof (val)); | |
667 | *out = val; | |
668 | } | |
669 | else if (fmt == host_double_format) | |
670 | { | |
671 | double val; | |
672 | memcpy (&val, in, sizeof (val)); | |
673 | *out = val; | |
674 | } | |
675 | else if (fmt == host_long_double_format) | |
676 | { | |
677 | long double val; | |
678 | memcpy (&val, in, sizeof (val)); | |
679 | *out = val; | |
680 | } | |
681 | else | |
682 | convert_floatformat_to_doublest (fmt, in, out); | |
683 | } | |
684 | ||
685 | void | |
686 | floatformat_from_doublest (const struct floatformat *fmt, | |
687 | const DOUBLEST *in, void *out) | |
688 | { | |
689 | gdb_assert (fmt != NULL); | |
690 | if (fmt == host_float_format) | |
691 | { | |
692 | float val = *in; | |
693 | memcpy (out, &val, sizeof (val)); | |
694 | } | |
695 | else if (fmt == host_double_format) | |
696 | { | |
697 | double val = *in; | |
698 | memcpy (out, &val, sizeof (val)); | |
699 | } | |
700 | else if (fmt == host_long_double_format) | |
701 | { | |
702 | long double val = *in; | |
703 | memcpy (out, &val, sizeof (val)); | |
704 | } | |
705 | else | |
706 | convert_doublest_to_floatformat (fmt, in, out); | |
707 | } | |
d16aafd8 | 708 | |
c422e771 | 709 | \f |
87ffba60 | 710 | /* Return a floating-point format for a floating-point variable of |
47b3f456 AC |
711 | length LEN. If no suitable floating-point format is found, an |
712 | error is thrown. | |
d16aafd8 | 713 | |
87ffba60 MK |
714 | We need this functionality since information about the |
715 | floating-point format of a type is not always available to GDB; the | |
716 | debug information typically only tells us the size of a | |
717 | floating-point type. | |
718 | ||
719 | FIXME: kettenis/2001-10-28: In many places, particularly in | |
720 | target-dependent code, the format of floating-point types is known, | |
721 | but not passed on by GDB. This should be fixed. */ | |
722 | ||
b9362cc7 | 723 | static const struct floatformat * |
87ffba60 | 724 | floatformat_from_length (int len) |
d16aafd8 | 725 | { |
47b3f456 | 726 | const struct floatformat *format; |
d16aafd8 | 727 | if (len * TARGET_CHAR_BIT == TARGET_FLOAT_BIT) |
8da61cc4 | 728 | format = TARGET_FLOAT_FORMAT[TARGET_BYTE_ORDER]; |
d16aafd8 | 729 | else if (len * TARGET_CHAR_BIT == TARGET_DOUBLE_BIT) |
8da61cc4 | 730 | format = TARGET_DOUBLE_FORMAT[TARGET_BYTE_ORDER]; |
d16aafd8 | 731 | else if (len * TARGET_CHAR_BIT == TARGET_LONG_DOUBLE_BIT) |
8da61cc4 | 732 | format = TARGET_LONG_DOUBLE_FORMAT[TARGET_BYTE_ORDER]; |
ddbfdd06 PM |
733 | /* On i386 the 'long double' type takes 96 bits, |
734 | while the real number of used bits is only 80, | |
735 | both in processor and in memory. | |
736 | The code below accepts the real bit size. */ | |
737 | else if ((TARGET_LONG_DOUBLE_FORMAT != NULL) | |
738 | && (len * TARGET_CHAR_BIT == | |
8da61cc4 DJ |
739 | TARGET_LONG_DOUBLE_FORMAT[0]->totalsize)) |
740 | format = TARGET_LONG_DOUBLE_FORMAT[TARGET_BYTE_ORDER]; | |
47b3f456 AC |
741 | else |
742 | format = NULL; | |
743 | if (format == NULL) | |
8a3fe4f8 | 744 | error (_("Unrecognized %d-bit floating-point type."), |
9b0dea39 | 745 | len * TARGET_CHAR_BIT); |
47b3f456 | 746 | return format; |
87ffba60 MK |
747 | } |
748 | ||
c2f05ac9 AC |
749 | const struct floatformat * |
750 | floatformat_from_type (const struct type *type) | |
751 | { | |
752 | gdb_assert (TYPE_CODE (type) == TYPE_CODE_FLT); | |
753 | if (TYPE_FLOATFORMAT (type) != NULL) | |
8da61cc4 | 754 | return TYPE_FLOATFORMAT (type)[TARGET_BYTE_ORDER]; |
c2f05ac9 AC |
755 | else |
756 | return floatformat_from_length (TYPE_LENGTH (type)); | |
757 | } | |
758 | ||
87ffba60 MK |
759 | /* If the host doesn't define NAN, use zero instead. */ |
760 | #ifndef NAN | |
761 | #define NAN 0.0 | |
762 | #endif | |
763 | ||
764 | /* Extract a floating-point number of length LEN from a target-order | |
765 | byte-stream at ADDR. Returns the value as type DOUBLEST. */ | |
766 | ||
f1908289 AC |
767 | static DOUBLEST |
768 | extract_floating_by_length (const void *addr, int len) | |
87ffba60 MK |
769 | { |
770 | const struct floatformat *fmt = floatformat_from_length (len); | |
771 | DOUBLEST val; | |
772 | ||
87ffba60 MK |
773 | floatformat_to_doublest (fmt, addr, &val); |
774 | return val; | |
d16aafd8 AC |
775 | } |
776 | ||
f1908289 AC |
777 | DOUBLEST |
778 | deprecated_extract_floating (const void *addr, int len) | |
779 | { | |
780 | return extract_floating_by_length (addr, len); | |
781 | } | |
782 | ||
87ffba60 MK |
783 | /* Store VAL as a floating-point number of length LEN to a |
784 | target-order byte-stream at ADDR. */ | |
785 | ||
f1908289 AC |
786 | static void |
787 | store_floating_by_length (void *addr, int len, DOUBLEST val) | |
d16aafd8 | 788 | { |
87ffba60 MK |
789 | const struct floatformat *fmt = floatformat_from_length (len); |
790 | ||
87ffba60 | 791 | floatformat_from_doublest (fmt, &val, addr); |
d16aafd8 | 792 | } |
96d2f608 | 793 | |
f1908289 AC |
794 | void |
795 | deprecated_store_floating (void *addr, int len, DOUBLEST val) | |
796 | { | |
797 | store_floating_by_length (addr, len, val); | |
798 | } | |
799 | ||
87ffba60 MK |
800 | /* Extract a floating-point number of type TYPE from a target-order |
801 | byte-stream at ADDR. Returns the value as type DOUBLEST. */ | |
96d2f608 AC |
802 | |
803 | DOUBLEST | |
804 | extract_typed_floating (const void *addr, const struct type *type) | |
805 | { | |
806 | DOUBLEST retval; | |
87ffba60 | 807 | |
96d2f608 | 808 | gdb_assert (TYPE_CODE (type) == TYPE_CODE_FLT); |
87ffba60 | 809 | |
96d2f608 | 810 | if (TYPE_FLOATFORMAT (type) == NULL) |
f1908289 AC |
811 | /* Not all code remembers to set the FLOATFORMAT (language |
812 | specific code? stabs?) so handle that here as a special case. */ | |
813 | return extract_floating_by_length (addr, TYPE_LENGTH (type)); | |
87ffba60 | 814 | |
8da61cc4 DJ |
815 | floatformat_to_doublest (TYPE_FLOATFORMAT (type)[TARGET_BYTE_ORDER], |
816 | addr, &retval); | |
96d2f608 AC |
817 | return retval; |
818 | } | |
819 | ||
87ffba60 MK |
820 | /* Store VAL as a floating-point number of type TYPE to a target-order |
821 | byte-stream at ADDR. */ | |
822 | ||
96d2f608 AC |
823 | void |
824 | store_typed_floating (void *addr, const struct type *type, DOUBLEST val) | |
825 | { | |
826 | gdb_assert (TYPE_CODE (type) == TYPE_CODE_FLT); | |
87ffba60 MK |
827 | |
828 | /* FIXME: kettenis/2001-10-28: It is debatable whether we should | |
829 | zero out any remaining bytes in the target buffer when TYPE is | |
830 | longer than the actual underlying floating-point format. Perhaps | |
831 | we should store a fixed bitpattern in those remaining bytes, | |
832 | instead of zero, or perhaps we shouldn't touch those remaining | |
833 | bytes at all. | |
834 | ||
835 | NOTE: cagney/2001-10-28: With the way things currently work, it | |
836 | isn't a good idea to leave the end bits undefined. This is | |
837 | because GDB writes out the entire sizeof(<floating>) bits of the | |
838 | floating-point type even though the value might only be stored | |
839 | in, and the target processor may only refer to, the first N < | |
840 | TYPE_LENGTH (type) bits. If the end of the buffer wasn't | |
841 | initialized, GDB would write undefined data to the target. An | |
842 | errant program, refering to that undefined data, would then | |
43686d64 MK |
843 | become non-deterministic. |
844 | ||
845 | See also the function convert_typed_floating below. */ | |
96d2f608 | 846 | memset (addr, 0, TYPE_LENGTH (type)); |
87ffba60 | 847 | |
96d2f608 | 848 | if (TYPE_FLOATFORMAT (type) == NULL) |
f1908289 AC |
849 | /* Not all code remembers to set the FLOATFORMAT (language |
850 | specific code? stabs?) so handle that here as a special case. */ | |
851 | store_floating_by_length (addr, TYPE_LENGTH (type), val); | |
0b87a11d | 852 | else |
8da61cc4 DJ |
853 | floatformat_from_doublest (TYPE_FLOATFORMAT (type)[TARGET_BYTE_ORDER], |
854 | &val, addr); | |
96d2f608 | 855 | } |
43686d64 MK |
856 | |
857 | /* Convert a floating-point number of type FROM_TYPE from a | |
858 | target-order byte-stream at FROM to a floating-point number of type | |
859 | TO_TYPE, and store it to a target-order byte-stream at TO. */ | |
860 | ||
861 | void | |
862 | convert_typed_floating (const void *from, const struct type *from_type, | |
863 | void *to, const struct type *to_type) | |
864 | { | |
c2f05ac9 AC |
865 | const struct floatformat *from_fmt = floatformat_from_type (from_type); |
866 | const struct floatformat *to_fmt = floatformat_from_type (to_type); | |
43686d64 MK |
867 | |
868 | gdb_assert (TYPE_CODE (from_type) == TYPE_CODE_FLT); | |
869 | gdb_assert (TYPE_CODE (to_type) == TYPE_CODE_FLT); | |
870 | ||
43686d64 MK |
871 | if (from_fmt == NULL || to_fmt == NULL) |
872 | { | |
873 | /* If we don't know the floating-point format of FROM_TYPE or | |
874 | TO_TYPE, there's not much we can do. We might make the | |
875 | assumption that if the length of FROM_TYPE and TO_TYPE match, | |
876 | their floating-point format would match too, but that | |
877 | assumption might be wrong on targets that support | |
878 | floating-point types that only differ in endianness for | |
879 | example. So we warn instead, and zero out the target buffer. */ | |
8a3fe4f8 | 880 | warning (_("Can't convert floating-point number to desired type.")); |
43686d64 MK |
881 | memset (to, 0, TYPE_LENGTH (to_type)); |
882 | } | |
883 | else if (from_fmt == to_fmt) | |
884 | { | |
885 | /* We're in business. The floating-point format of FROM_TYPE | |
886 | and TO_TYPE match. However, even though the floating-point | |
887 | format matches, the length of the type might still be | |
888 | different. Make sure we don't overrun any buffers. See | |
889 | comment in store_typed_floating for a discussion about | |
890 | zeroing out remaining bytes in the target buffer. */ | |
891 | memset (to, 0, TYPE_LENGTH (to_type)); | |
892 | memcpy (to, from, min (TYPE_LENGTH (from_type), TYPE_LENGTH (to_type))); | |
893 | } | |
894 | else | |
895 | { | |
896 | /* The floating-point types don't match. The best we can do | |
897 | (aport from simulating the target FPU) is converting to the | |
898 | widest floating-point type supported by the host, and then | |
899 | again to the desired type. */ | |
900 | DOUBLEST d; | |
901 | ||
902 | floatformat_to_doublest (from_fmt, from, &d); | |
903 | floatformat_from_doublest (to_fmt, &d, to); | |
904 | } | |
905 | } | |
5ef2d0aa AC |
906 | |
907 | const struct floatformat *floatformat_ieee_single[BFD_ENDIAN_UNKNOWN]; | |
908 | const struct floatformat *floatformat_ieee_double[BFD_ENDIAN_UNKNOWN]; | |
49c54768 | 909 | const struct floatformat *floatformat_ieee_quad[BFD_ENDIAN_UNKNOWN]; |
5ef2d0aa AC |
910 | const struct floatformat *floatformat_arm_ext[BFD_ENDIAN_UNKNOWN]; |
911 | const struct floatformat *floatformat_ia64_spill[BFD_ENDIAN_UNKNOWN]; | |
5ef2d0aa AC |
912 | |
913 | extern void _initialize_doublest (void); | |
914 | ||
915 | extern void | |
916 | _initialize_doublest (void) | |
917 | { | |
918 | floatformat_ieee_single[BFD_ENDIAN_LITTLE] = &floatformat_ieee_single_little; | |
919 | floatformat_ieee_single[BFD_ENDIAN_BIG] = &floatformat_ieee_single_big; | |
920 | floatformat_ieee_double[BFD_ENDIAN_LITTLE] = &floatformat_ieee_double_little; | |
921 | floatformat_ieee_double[BFD_ENDIAN_BIG] = &floatformat_ieee_double_big; | |
922 | floatformat_arm_ext[BFD_ENDIAN_LITTLE] = &floatformat_arm_ext_littlebyte_bigword; | |
923 | floatformat_arm_ext[BFD_ENDIAN_BIG] = &floatformat_arm_ext_big; | |
924 | floatformat_ia64_spill[BFD_ENDIAN_LITTLE] = &floatformat_ia64_spill_little; | |
925 | floatformat_ia64_spill[BFD_ENDIAN_BIG] = &floatformat_ia64_spill_big; | |
49c54768 AC |
926 | floatformat_ieee_quad[BFD_ENDIAN_LITTLE] = &floatformat_ia64_quad_little; |
927 | floatformat_ieee_quad[BFD_ENDIAN_BIG] = &floatformat_ia64_quad_big; | |
5ef2d0aa | 928 | } |