| 1 | /* Floating point routines for GDB, the GNU debugger. |
| 2 | Copyright 1986, 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995, 1996, |
| 3 | 1997, 1998, 1999, 2000, 2001 |
| 4 | Free Software Foundation, Inc. |
| 5 | |
| 6 | This file is part of GDB. |
| 7 | |
| 8 | This program is free software; you can redistribute it and/or modify |
| 9 | it under the terms of the GNU General Public License as published by |
| 10 | the Free Software Foundation; either version 2 of the License, or |
| 11 | (at your option) any later version. |
| 12 | |
| 13 | This program is distributed in the hope that it will be useful, |
| 14 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 15 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 16 | GNU General Public License for more details. |
| 17 | |
| 18 | You should have received a copy of the GNU General Public License |
| 19 | along with this program; if not, write to the Free Software |
| 20 | Foundation, Inc., 59 Temple Place - Suite 330, |
| 21 | Boston, MA 02111-1307, USA. */ |
| 22 | |
| 23 | /* Support for converting target fp numbers into host DOUBLEST format. */ |
| 24 | |
| 25 | /* XXX - This code should really be in libiberty/floatformat.c, |
| 26 | however configuration issues with libiberty made this very |
| 27 | difficult to do in the available time. */ |
| 28 | |
| 29 | #include "defs.h" |
| 30 | #include "doublest.h" |
| 31 | #include "floatformat.h" |
| 32 | #include "gdb_assert.h" |
| 33 | #include "gdb_string.h" |
| 34 | #include "gdbtypes.h" |
| 35 | #include <math.h> /* ldexp */ |
| 36 | |
| 37 | /* The odds that CHAR_BIT will be anything but 8 are low enough that I'm not |
| 38 | going to bother with trying to muck around with whether it is defined in |
| 39 | a system header, what we do if not, etc. */ |
| 40 | #define FLOATFORMAT_CHAR_BIT 8 |
| 41 | |
| 42 | static unsigned long get_field (unsigned char *, |
| 43 | enum floatformat_byteorders, |
| 44 | unsigned int, unsigned int, unsigned int); |
| 45 | |
| 46 | /* Extract a field which starts at START and is LEN bytes long. DATA and |
| 47 | TOTAL_LEN are the thing we are extracting it from, in byteorder ORDER. */ |
| 48 | static unsigned long |
| 49 | get_field (unsigned char *data, enum floatformat_byteorders order, |
| 50 | unsigned int total_len, unsigned int start, unsigned int len) |
| 51 | { |
| 52 | unsigned long result; |
| 53 | unsigned int cur_byte; |
| 54 | int cur_bitshift; |
| 55 | |
| 56 | /* Start at the least significant part of the field. */ |
| 57 | if (order == floatformat_little || order == floatformat_littlebyte_bigword) |
| 58 | { |
| 59 | /* We start counting from the other end (i.e, from the high bytes |
| 60 | rather than the low bytes). As such, we need to be concerned |
| 61 | with what happens if bit 0 doesn't start on a byte boundary. |
| 62 | I.e, we need to properly handle the case where total_len is |
| 63 | not evenly divisible by 8. So we compute ``excess'' which |
| 64 | represents the number of bits from the end of our starting |
| 65 | byte needed to get to bit 0. */ |
| 66 | int excess = FLOATFORMAT_CHAR_BIT - (total_len % FLOATFORMAT_CHAR_BIT); |
| 67 | cur_byte = (total_len / FLOATFORMAT_CHAR_BIT) |
| 68 | - ((start + len + excess) / FLOATFORMAT_CHAR_BIT); |
| 69 | cur_bitshift = ((start + len + excess) % FLOATFORMAT_CHAR_BIT) |
| 70 | - FLOATFORMAT_CHAR_BIT; |
| 71 | } |
| 72 | else |
| 73 | { |
| 74 | cur_byte = (start + len) / FLOATFORMAT_CHAR_BIT; |
| 75 | cur_bitshift = |
| 76 | ((start + len) % FLOATFORMAT_CHAR_BIT) - FLOATFORMAT_CHAR_BIT; |
| 77 | } |
| 78 | if (cur_bitshift > -FLOATFORMAT_CHAR_BIT) |
| 79 | result = *(data + cur_byte) >> (-cur_bitshift); |
| 80 | else |
| 81 | result = 0; |
| 82 | cur_bitshift += FLOATFORMAT_CHAR_BIT; |
| 83 | if (order == floatformat_little || order == floatformat_littlebyte_bigword) |
| 84 | ++cur_byte; |
| 85 | else |
| 86 | --cur_byte; |
| 87 | |
| 88 | /* Move towards the most significant part of the field. */ |
| 89 | while (cur_bitshift < len) |
| 90 | { |
| 91 | result |= (unsigned long)*(data + cur_byte) << cur_bitshift; |
| 92 | cur_bitshift += FLOATFORMAT_CHAR_BIT; |
| 93 | if (order == floatformat_little || order == floatformat_littlebyte_bigword) |
| 94 | ++cur_byte; |
| 95 | else |
| 96 | --cur_byte; |
| 97 | } |
| 98 | if (len < sizeof(result) * FLOATFORMAT_CHAR_BIT) |
| 99 | /* Mask out bits which are not part of the field */ |
| 100 | result &= ((1UL << len) - 1); |
| 101 | return result; |
| 102 | } |
| 103 | |
| 104 | /* Convert from FMT to a DOUBLEST. |
| 105 | FROM is the address of the extended float. |
| 106 | Store the DOUBLEST in *TO. */ |
| 107 | |
| 108 | static void |
| 109 | convert_floatformat_to_doublest (const struct floatformat *fmt, |
| 110 | const void *from, |
| 111 | DOUBLEST *to) |
| 112 | { |
| 113 | unsigned char *ufrom = (unsigned char *) from; |
| 114 | DOUBLEST dto; |
| 115 | long exponent; |
| 116 | unsigned long mant; |
| 117 | unsigned int mant_bits, mant_off; |
| 118 | int mant_bits_left; |
| 119 | int special_exponent; /* It's a NaN, denorm or zero */ |
| 120 | |
| 121 | /* If the mantissa bits are not contiguous from one end of the |
| 122 | mantissa to the other, we need to make a private copy of the |
| 123 | source bytes that is in the right order since the unpacking |
| 124 | algorithm assumes that the bits are contiguous. |
| 125 | |
| 126 | Swap the bytes individually rather than accessing them through |
| 127 | "long *" since we have no guarantee that they start on a long |
| 128 | alignment, and also sizeof(long) for the host could be different |
| 129 | than sizeof(long) for the target. FIXME: Assumes sizeof(long) |
| 130 | for the target is 4. */ |
| 131 | |
| 132 | if (fmt->byteorder == floatformat_littlebyte_bigword) |
| 133 | { |
| 134 | static unsigned char *newfrom; |
| 135 | unsigned char *swapin, *swapout; |
| 136 | int longswaps; |
| 137 | |
| 138 | longswaps = fmt->totalsize / FLOATFORMAT_CHAR_BIT; |
| 139 | longswaps >>= 3; |
| 140 | |
| 141 | if (newfrom == NULL) |
| 142 | { |
| 143 | newfrom = (unsigned char *) xmalloc (fmt->totalsize); |
| 144 | } |
| 145 | swapout = newfrom; |
| 146 | swapin = ufrom; |
| 147 | ufrom = newfrom; |
| 148 | while (longswaps-- > 0) |
| 149 | { |
| 150 | /* This is ugly, but efficient */ |
| 151 | *swapout++ = swapin[4]; |
| 152 | *swapout++ = swapin[5]; |
| 153 | *swapout++ = swapin[6]; |
| 154 | *swapout++ = swapin[7]; |
| 155 | *swapout++ = swapin[0]; |
| 156 | *swapout++ = swapin[1]; |
| 157 | *swapout++ = swapin[2]; |
| 158 | *swapout++ = swapin[3]; |
| 159 | swapin += 8; |
| 160 | } |
| 161 | } |
| 162 | |
| 163 | exponent = get_field (ufrom, fmt->byteorder, fmt->totalsize, |
| 164 | fmt->exp_start, fmt->exp_len); |
| 165 | /* Note that if exponent indicates a NaN, we can't really do anything useful |
| 166 | (not knowing if the host has NaN's, or how to build one). So it will |
| 167 | end up as an infinity or something close; that is OK. */ |
| 168 | |
| 169 | mant_bits_left = fmt->man_len; |
| 170 | mant_off = fmt->man_start; |
| 171 | dto = 0.0; |
| 172 | |
| 173 | special_exponent = exponent == 0 || exponent == fmt->exp_nan; |
| 174 | |
| 175 | /* Don't bias NaNs. Use minimum exponent for denorms. For simplicity, |
| 176 | we don't check for zero as the exponent doesn't matter. */ |
| 177 | if (!special_exponent) |
| 178 | exponent -= fmt->exp_bias; |
| 179 | else if (exponent == 0) |
| 180 | exponent = 1 - fmt->exp_bias; |
| 181 | |
| 182 | /* Build the result algebraically. Might go infinite, underflow, etc; |
| 183 | who cares. */ |
| 184 | |
| 185 | /* If this format uses a hidden bit, explicitly add it in now. Otherwise, |
| 186 | increment the exponent by one to account for the integer bit. */ |
| 187 | |
| 188 | if (!special_exponent) |
| 189 | { |
| 190 | if (fmt->intbit == floatformat_intbit_no) |
| 191 | dto = ldexp (1.0, exponent); |
| 192 | else |
| 193 | exponent++; |
| 194 | } |
| 195 | |
| 196 | while (mant_bits_left > 0) |
| 197 | { |
| 198 | mant_bits = min (mant_bits_left, 32); |
| 199 | |
| 200 | mant = get_field (ufrom, fmt->byteorder, fmt->totalsize, |
| 201 | mant_off, mant_bits); |
| 202 | |
| 203 | dto += ldexp ((double) mant, exponent - mant_bits); |
| 204 | exponent -= mant_bits; |
| 205 | mant_off += mant_bits; |
| 206 | mant_bits_left -= mant_bits; |
| 207 | } |
| 208 | |
| 209 | /* Negate it if negative. */ |
| 210 | if (get_field (ufrom, fmt->byteorder, fmt->totalsize, fmt->sign_start, 1)) |
| 211 | dto = -dto; |
| 212 | *to = dto; |
| 213 | } |
| 214 | \f |
| 215 | static void put_field (unsigned char *, enum floatformat_byteorders, |
| 216 | unsigned int, |
| 217 | unsigned int, unsigned int, unsigned long); |
| 218 | |
| 219 | /* Set a field which starts at START and is LEN bytes long. DATA and |
| 220 | TOTAL_LEN are the thing we are extracting it from, in byteorder ORDER. */ |
| 221 | static void |
| 222 | put_field (unsigned char *data, enum floatformat_byteorders order, |
| 223 | unsigned int total_len, unsigned int start, unsigned int len, |
| 224 | unsigned long stuff_to_put) |
| 225 | { |
| 226 | unsigned int cur_byte; |
| 227 | int cur_bitshift; |
| 228 | |
| 229 | /* Start at the least significant part of the field. */ |
| 230 | if (order == floatformat_little || order == floatformat_littlebyte_bigword) |
| 231 | { |
| 232 | int excess = FLOATFORMAT_CHAR_BIT - (total_len % FLOATFORMAT_CHAR_BIT); |
| 233 | cur_byte = (total_len / FLOATFORMAT_CHAR_BIT) |
| 234 | - ((start + len + excess) / FLOATFORMAT_CHAR_BIT); |
| 235 | cur_bitshift = ((start + len + excess) % FLOATFORMAT_CHAR_BIT) |
| 236 | - FLOATFORMAT_CHAR_BIT; |
| 237 | } |
| 238 | else |
| 239 | { |
| 240 | cur_byte = (start + len) / FLOATFORMAT_CHAR_BIT; |
| 241 | cur_bitshift = |
| 242 | ((start + len) % FLOATFORMAT_CHAR_BIT) - FLOATFORMAT_CHAR_BIT; |
| 243 | } |
| 244 | if (cur_bitshift > -FLOATFORMAT_CHAR_BIT) |
| 245 | { |
| 246 | *(data + cur_byte) &= |
| 247 | ~(((1 << ((start + len) % FLOATFORMAT_CHAR_BIT)) - 1) |
| 248 | << (-cur_bitshift)); |
| 249 | *(data + cur_byte) |= |
| 250 | (stuff_to_put & ((1 << FLOATFORMAT_CHAR_BIT) - 1)) << (-cur_bitshift); |
| 251 | } |
| 252 | cur_bitshift += FLOATFORMAT_CHAR_BIT; |
| 253 | if (order == floatformat_little || order == floatformat_littlebyte_bigword) |
| 254 | ++cur_byte; |
| 255 | else |
| 256 | --cur_byte; |
| 257 | |
| 258 | /* Move towards the most significant part of the field. */ |
| 259 | while (cur_bitshift < len) |
| 260 | { |
| 261 | if (len - cur_bitshift < FLOATFORMAT_CHAR_BIT) |
| 262 | { |
| 263 | /* This is the last byte. */ |
| 264 | *(data + cur_byte) &= |
| 265 | ~((1 << (len - cur_bitshift)) - 1); |
| 266 | *(data + cur_byte) |= (stuff_to_put >> cur_bitshift); |
| 267 | } |
| 268 | else |
| 269 | *(data + cur_byte) = ((stuff_to_put >> cur_bitshift) |
| 270 | & ((1 << FLOATFORMAT_CHAR_BIT) - 1)); |
| 271 | cur_bitshift += FLOATFORMAT_CHAR_BIT; |
| 272 | if (order == floatformat_little || order == floatformat_littlebyte_bigword) |
| 273 | ++cur_byte; |
| 274 | else |
| 275 | --cur_byte; |
| 276 | } |
| 277 | } |
| 278 | |
| 279 | #ifdef HAVE_LONG_DOUBLE |
| 280 | /* Return the fractional part of VALUE, and put the exponent of VALUE in *EPTR. |
| 281 | The range of the returned value is >= 0.5 and < 1.0. This is equivalent to |
| 282 | frexp, but operates on the long double data type. */ |
| 283 | |
| 284 | static long double ldfrexp (long double value, int *eptr); |
| 285 | |
| 286 | static long double |
| 287 | ldfrexp (long double value, int *eptr) |
| 288 | { |
| 289 | long double tmp; |
| 290 | int exp; |
| 291 | |
| 292 | /* Unfortunately, there are no portable functions for extracting the exponent |
| 293 | of a long double, so we have to do it iteratively by multiplying or dividing |
| 294 | by two until the fraction is between 0.5 and 1.0. */ |
| 295 | |
| 296 | if (value < 0.0l) |
| 297 | value = -value; |
| 298 | |
| 299 | tmp = 1.0l; |
| 300 | exp = 0; |
| 301 | |
| 302 | if (value >= tmp) /* Value >= 1.0 */ |
| 303 | while (value >= tmp) |
| 304 | { |
| 305 | tmp *= 2.0l; |
| 306 | exp++; |
| 307 | } |
| 308 | else if (value != 0.0l) /* Value < 1.0 and > 0.0 */ |
| 309 | { |
| 310 | while (value < tmp) |
| 311 | { |
| 312 | tmp /= 2.0l; |
| 313 | exp--; |
| 314 | } |
| 315 | tmp *= 2.0l; |
| 316 | exp++; |
| 317 | } |
| 318 | |
| 319 | *eptr = exp; |
| 320 | return value / tmp; |
| 321 | } |
| 322 | #endif /* HAVE_LONG_DOUBLE */ |
| 323 | |
| 324 | |
| 325 | /* The converse: convert the DOUBLEST *FROM to an extended float |
| 326 | and store where TO points. Neither FROM nor TO have any alignment |
| 327 | restrictions. */ |
| 328 | |
| 329 | static void |
| 330 | convert_doublest_to_floatformat (CONST struct floatformat *fmt, |
| 331 | const DOUBLEST *from, |
| 332 | void *to) |
| 333 | { |
| 334 | DOUBLEST dfrom; |
| 335 | int exponent; |
| 336 | DOUBLEST mant; |
| 337 | unsigned int mant_bits, mant_off; |
| 338 | int mant_bits_left; |
| 339 | unsigned char *uto = (unsigned char *) to; |
| 340 | |
| 341 | memcpy (&dfrom, from, sizeof (dfrom)); |
| 342 | memset (uto, 0, (fmt->totalsize + FLOATFORMAT_CHAR_BIT - 1) |
| 343 | / FLOATFORMAT_CHAR_BIT); |
| 344 | if (dfrom == 0) |
| 345 | return; /* Result is zero */ |
| 346 | if (dfrom != dfrom) /* Result is NaN */ |
| 347 | { |
| 348 | /* From is NaN */ |
| 349 | put_field (uto, fmt->byteorder, fmt->totalsize, fmt->exp_start, |
| 350 | fmt->exp_len, fmt->exp_nan); |
| 351 | /* Be sure it's not infinity, but NaN value is irrel */ |
| 352 | put_field (uto, fmt->byteorder, fmt->totalsize, fmt->man_start, |
| 353 | 32, 1); |
| 354 | return; |
| 355 | } |
| 356 | |
| 357 | /* If negative, set the sign bit. */ |
| 358 | if (dfrom < 0) |
| 359 | { |
| 360 | put_field (uto, fmt->byteorder, fmt->totalsize, fmt->sign_start, 1, 1); |
| 361 | dfrom = -dfrom; |
| 362 | } |
| 363 | |
| 364 | if (dfrom + dfrom == dfrom && dfrom != 0.0) /* Result is Infinity */ |
| 365 | { |
| 366 | /* Infinity exponent is same as NaN's. */ |
| 367 | put_field (uto, fmt->byteorder, fmt->totalsize, fmt->exp_start, |
| 368 | fmt->exp_len, fmt->exp_nan); |
| 369 | /* Infinity mantissa is all zeroes. */ |
| 370 | put_field (uto, fmt->byteorder, fmt->totalsize, fmt->man_start, |
| 371 | fmt->man_len, 0); |
| 372 | return; |
| 373 | } |
| 374 | |
| 375 | #ifdef HAVE_LONG_DOUBLE |
| 376 | mant = ldfrexp (dfrom, &exponent); |
| 377 | #else |
| 378 | mant = frexp (dfrom, &exponent); |
| 379 | #endif |
| 380 | |
| 381 | put_field (uto, fmt->byteorder, fmt->totalsize, fmt->exp_start, fmt->exp_len, |
| 382 | exponent + fmt->exp_bias - 1); |
| 383 | |
| 384 | mant_bits_left = fmt->man_len; |
| 385 | mant_off = fmt->man_start; |
| 386 | while (mant_bits_left > 0) |
| 387 | { |
| 388 | unsigned long mant_long; |
| 389 | mant_bits = mant_bits_left < 32 ? mant_bits_left : 32; |
| 390 | |
| 391 | mant *= 4294967296.0; |
| 392 | mant_long = ((unsigned long) mant) & 0xffffffffL; |
| 393 | mant -= mant_long; |
| 394 | |
| 395 | /* If the integer bit is implicit, then we need to discard it. |
| 396 | If we are discarding a zero, we should be (but are not) creating |
| 397 | a denormalized number which means adjusting the exponent |
| 398 | (I think). */ |
| 399 | if (mant_bits_left == fmt->man_len |
| 400 | && fmt->intbit == floatformat_intbit_no) |
| 401 | { |
| 402 | mant_long <<= 1; |
| 403 | mant_long &= 0xffffffffL; |
| 404 | mant_bits -= 1; |
| 405 | } |
| 406 | |
| 407 | if (mant_bits < 32) |
| 408 | { |
| 409 | /* The bits we want are in the most significant MANT_BITS bits of |
| 410 | mant_long. Move them to the least significant. */ |
| 411 | mant_long >>= 32 - mant_bits; |
| 412 | } |
| 413 | |
| 414 | put_field (uto, fmt->byteorder, fmt->totalsize, |
| 415 | mant_off, mant_bits, mant_long); |
| 416 | mant_off += mant_bits; |
| 417 | mant_bits_left -= mant_bits; |
| 418 | } |
| 419 | if (fmt->byteorder == floatformat_littlebyte_bigword) |
| 420 | { |
| 421 | int count; |
| 422 | unsigned char *swaplow = uto; |
| 423 | unsigned char *swaphigh = uto + 4; |
| 424 | unsigned char tmp; |
| 425 | |
| 426 | for (count = 0; count < 4; count++) |
| 427 | { |
| 428 | tmp = *swaplow; |
| 429 | *swaplow++ = *swaphigh; |
| 430 | *swaphigh++ = tmp; |
| 431 | } |
| 432 | } |
| 433 | } |
| 434 | |
| 435 | /* Check if VAL (which is assumed to be a floating point number whose |
| 436 | format is described by FMT) is negative. */ |
| 437 | |
| 438 | int |
| 439 | floatformat_is_negative (const struct floatformat *fmt, char *val) |
| 440 | { |
| 441 | unsigned char *uval = (unsigned char *) val; |
| 442 | gdb_assert (fmt != NULL); |
| 443 | return get_field (uval, fmt->byteorder, fmt->totalsize, fmt->sign_start, 1); |
| 444 | } |
| 445 | |
| 446 | /* Check if VAL is "not a number" (NaN) for FMT. */ |
| 447 | |
| 448 | int |
| 449 | floatformat_is_nan (const struct floatformat *fmt, char *val) |
| 450 | { |
| 451 | unsigned char *uval = (unsigned char *) val; |
| 452 | long exponent; |
| 453 | unsigned long mant; |
| 454 | unsigned int mant_bits, mant_off; |
| 455 | int mant_bits_left; |
| 456 | |
| 457 | gdb_assert (fmt != NULL); |
| 458 | |
| 459 | if (! fmt->exp_nan) |
| 460 | return 0; |
| 461 | |
| 462 | exponent = get_field (uval, fmt->byteorder, fmt->totalsize, |
| 463 | fmt->exp_start, fmt->exp_len); |
| 464 | |
| 465 | if (exponent != fmt->exp_nan) |
| 466 | return 0; |
| 467 | |
| 468 | mant_bits_left = fmt->man_len; |
| 469 | mant_off = fmt->man_start; |
| 470 | |
| 471 | while (mant_bits_left > 0) |
| 472 | { |
| 473 | mant_bits = min (mant_bits_left, 32); |
| 474 | |
| 475 | mant = get_field (uval, fmt->byteorder, fmt->totalsize, |
| 476 | mant_off, mant_bits); |
| 477 | |
| 478 | /* If there is an explicit integer bit, mask it off. */ |
| 479 | if (mant_off == fmt->man_start |
| 480 | && fmt->intbit == floatformat_intbit_yes) |
| 481 | mant &= ~(1 << (mant_bits - 1)); |
| 482 | |
| 483 | if (mant) |
| 484 | return 1; |
| 485 | |
| 486 | mant_off += mant_bits; |
| 487 | mant_bits_left -= mant_bits; |
| 488 | } |
| 489 | |
| 490 | return 0; |
| 491 | } |
| 492 | |
| 493 | /* Convert the mantissa of VAL (which is assumed to be a floating |
| 494 | point number whose format is described by FMT) into a hexadecimal |
| 495 | and store it in a static string. Return a pointer to that string. */ |
| 496 | |
| 497 | char * |
| 498 | floatformat_mantissa (const struct floatformat *fmt, char *val) |
| 499 | { |
| 500 | unsigned char *uval = (unsigned char *) val; |
| 501 | unsigned long mant; |
| 502 | unsigned int mant_bits, mant_off; |
| 503 | int mant_bits_left; |
| 504 | static char res[50]; |
| 505 | char buf[9]; |
| 506 | |
| 507 | /* Make sure we have enough room to store the mantissa. */ |
| 508 | gdb_assert (fmt != NULL); |
| 509 | gdb_assert (sizeof res > ((fmt->man_len + 7) / 8) * 2); |
| 510 | |
| 511 | mant_off = fmt->man_start; |
| 512 | mant_bits_left = fmt->man_len; |
| 513 | mant_bits = (mant_bits_left % 32) > 0 ? mant_bits_left % 32 : 32; |
| 514 | |
| 515 | mant = get_field (uval, fmt->byteorder, fmt->totalsize, |
| 516 | mant_off, mant_bits); |
| 517 | |
| 518 | sprintf (res, "%lx", mant); |
| 519 | |
| 520 | mant_off += mant_bits; |
| 521 | mant_bits_left -= mant_bits; |
| 522 | |
| 523 | while (mant_bits_left > 0) |
| 524 | { |
| 525 | mant = get_field (uval, fmt->byteorder, fmt->totalsize, |
| 526 | mant_off, 32); |
| 527 | |
| 528 | sprintf (buf, "%08lx", mant); |
| 529 | strcat (res, buf); |
| 530 | |
| 531 | mant_off += 32; |
| 532 | mant_bits_left -= 32; |
| 533 | } |
| 534 | |
| 535 | return res; |
| 536 | } |
| 537 | |
| 538 | \f |
| 539 | /* Convert TO/FROM target to the hosts DOUBLEST floating-point format. |
| 540 | |
| 541 | If the host and target formats agree, we just copy the raw data |
| 542 | into the appropriate type of variable and return, letting the host |
| 543 | increase precision as necessary. Otherwise, we call the conversion |
| 544 | routine and let it do the dirty work. */ |
| 545 | |
| 546 | #ifndef HOST_FLOAT_FORMAT |
| 547 | #define HOST_FLOAT_FORMAT 0 |
| 548 | #endif |
| 549 | #ifndef HOST_DOUBLE_FORMAT |
| 550 | #define HOST_DOUBLE_FORMAT 0 |
| 551 | #endif |
| 552 | #ifndef HOST_LONG_DOUBLE_FORMAT |
| 553 | #define HOST_LONG_DOUBLE_FORMAT 0 |
| 554 | #endif |
| 555 | |
| 556 | static const struct floatformat *host_float_format = HOST_FLOAT_FORMAT; |
| 557 | static const struct floatformat *host_double_format = HOST_DOUBLE_FORMAT; |
| 558 | static const struct floatformat *host_long_double_format = HOST_LONG_DOUBLE_FORMAT; |
| 559 | |
| 560 | void |
| 561 | floatformat_to_doublest (const struct floatformat *fmt, |
| 562 | const void *in, DOUBLEST *out) |
| 563 | { |
| 564 | gdb_assert (fmt != NULL); |
| 565 | if (fmt == host_float_format) |
| 566 | { |
| 567 | float val; |
| 568 | memcpy (&val, in, sizeof (val)); |
| 569 | *out = val; |
| 570 | } |
| 571 | else if (fmt == host_double_format) |
| 572 | { |
| 573 | double val; |
| 574 | memcpy (&val, in, sizeof (val)); |
| 575 | *out = val; |
| 576 | } |
| 577 | else if (fmt == host_long_double_format) |
| 578 | { |
| 579 | long double val; |
| 580 | memcpy (&val, in, sizeof (val)); |
| 581 | *out = val; |
| 582 | } |
| 583 | else |
| 584 | convert_floatformat_to_doublest (fmt, in, out); |
| 585 | } |
| 586 | |
| 587 | void |
| 588 | floatformat_from_doublest (const struct floatformat *fmt, |
| 589 | const DOUBLEST *in, void *out) |
| 590 | { |
| 591 | gdb_assert (fmt != NULL); |
| 592 | if (fmt == host_float_format) |
| 593 | { |
| 594 | float val = *in; |
| 595 | memcpy (out, &val, sizeof (val)); |
| 596 | } |
| 597 | else if (fmt == host_double_format) |
| 598 | { |
| 599 | double val = *in; |
| 600 | memcpy (out, &val, sizeof (val)); |
| 601 | } |
| 602 | else if (fmt == host_long_double_format) |
| 603 | { |
| 604 | long double val = *in; |
| 605 | memcpy (out, &val, sizeof (val)); |
| 606 | } |
| 607 | else |
| 608 | convert_doublest_to_floatformat (fmt, in, out); |
| 609 | } |
| 610 | |
| 611 | \f |
| 612 | /* Return a floating-point format for a floating-point variable of |
| 613 | length LEN. Return NULL, if no suitable floating-point format |
| 614 | could be found. |
| 615 | |
| 616 | We need this functionality since information about the |
| 617 | floating-point format of a type is not always available to GDB; the |
| 618 | debug information typically only tells us the size of a |
| 619 | floating-point type. |
| 620 | |
| 621 | FIXME: kettenis/2001-10-28: In many places, particularly in |
| 622 | target-dependent code, the format of floating-point types is known, |
| 623 | but not passed on by GDB. This should be fixed. */ |
| 624 | |
| 625 | const struct floatformat * |
| 626 | floatformat_from_length (int len) |
| 627 | { |
| 628 | if (len * TARGET_CHAR_BIT == TARGET_FLOAT_BIT) |
| 629 | return TARGET_FLOAT_FORMAT; |
| 630 | else if (len * TARGET_CHAR_BIT == TARGET_DOUBLE_BIT) |
| 631 | return TARGET_DOUBLE_FORMAT; |
| 632 | else if (len * TARGET_CHAR_BIT == TARGET_LONG_DOUBLE_BIT) |
| 633 | return TARGET_LONG_DOUBLE_FORMAT; |
| 634 | |
| 635 | return NULL; |
| 636 | } |
| 637 | |
| 638 | const struct floatformat * |
| 639 | floatformat_from_type (const struct type *type) |
| 640 | { |
| 641 | gdb_assert (TYPE_CODE (type) == TYPE_CODE_FLT); |
| 642 | if (TYPE_FLOATFORMAT (type) != NULL) |
| 643 | return TYPE_FLOATFORMAT (type); |
| 644 | else |
| 645 | return floatformat_from_length (TYPE_LENGTH (type)); |
| 646 | } |
| 647 | |
| 648 | /* If the host doesn't define NAN, use zero instead. */ |
| 649 | #ifndef NAN |
| 650 | #define NAN 0.0 |
| 651 | #endif |
| 652 | |
| 653 | /* Extract a floating-point number of length LEN from a target-order |
| 654 | byte-stream at ADDR. Returns the value as type DOUBLEST. */ |
| 655 | |
| 656 | DOUBLEST |
| 657 | extract_floating (const void *addr, int len) |
| 658 | { |
| 659 | const struct floatformat *fmt = floatformat_from_length (len); |
| 660 | DOUBLEST val; |
| 661 | |
| 662 | if (fmt == NULL) |
| 663 | { |
| 664 | warning ("Can't store a floating-point number of %d bytes.", len); |
| 665 | return NAN; |
| 666 | } |
| 667 | |
| 668 | floatformat_to_doublest (fmt, addr, &val); |
| 669 | return val; |
| 670 | } |
| 671 | |
| 672 | /* Store VAL as a floating-point number of length LEN to a |
| 673 | target-order byte-stream at ADDR. */ |
| 674 | |
| 675 | void |
| 676 | store_floating (void *addr, int len, DOUBLEST val) |
| 677 | { |
| 678 | const struct floatformat *fmt = floatformat_from_length (len); |
| 679 | |
| 680 | if (fmt == NULL) |
| 681 | { |
| 682 | warning ("Can't store a floating-point number of %d bytes.", len); |
| 683 | memset (addr, 0, len); |
| 684 | return; |
| 685 | } |
| 686 | |
| 687 | floatformat_from_doublest (fmt, &val, addr); |
| 688 | } |
| 689 | |
| 690 | /* Extract a floating-point number of type TYPE from a target-order |
| 691 | byte-stream at ADDR. Returns the value as type DOUBLEST. */ |
| 692 | |
| 693 | DOUBLEST |
| 694 | extract_typed_floating (const void *addr, const struct type *type) |
| 695 | { |
| 696 | DOUBLEST retval; |
| 697 | |
| 698 | gdb_assert (TYPE_CODE (type) == TYPE_CODE_FLT); |
| 699 | |
| 700 | if (TYPE_FLOATFORMAT (type) == NULL) |
| 701 | return extract_floating (addr, TYPE_LENGTH (type)); |
| 702 | |
| 703 | floatformat_to_doublest (TYPE_FLOATFORMAT (type), addr, &retval); |
| 704 | return retval; |
| 705 | } |
| 706 | |
| 707 | /* Store VAL as a floating-point number of type TYPE to a target-order |
| 708 | byte-stream at ADDR. */ |
| 709 | |
| 710 | void |
| 711 | store_typed_floating (void *addr, const struct type *type, DOUBLEST val) |
| 712 | { |
| 713 | gdb_assert (TYPE_CODE (type) == TYPE_CODE_FLT); |
| 714 | |
| 715 | /* FIXME: kettenis/2001-10-28: It is debatable whether we should |
| 716 | zero out any remaining bytes in the target buffer when TYPE is |
| 717 | longer than the actual underlying floating-point format. Perhaps |
| 718 | we should store a fixed bitpattern in those remaining bytes, |
| 719 | instead of zero, or perhaps we shouldn't touch those remaining |
| 720 | bytes at all. |
| 721 | |
| 722 | NOTE: cagney/2001-10-28: With the way things currently work, it |
| 723 | isn't a good idea to leave the end bits undefined. This is |
| 724 | because GDB writes out the entire sizeof(<floating>) bits of the |
| 725 | floating-point type even though the value might only be stored |
| 726 | in, and the target processor may only refer to, the first N < |
| 727 | TYPE_LENGTH (type) bits. If the end of the buffer wasn't |
| 728 | initialized, GDB would write undefined data to the target. An |
| 729 | errant program, refering to that undefined data, would then |
| 730 | become non-deterministic. |
| 731 | |
| 732 | See also the function convert_typed_floating below. */ |
| 733 | memset (addr, 0, TYPE_LENGTH (type)); |
| 734 | |
| 735 | if (TYPE_FLOATFORMAT (type) == NULL) |
| 736 | store_floating (addr, TYPE_LENGTH (type), val); |
| 737 | else |
| 738 | floatformat_from_doublest (TYPE_FLOATFORMAT (type), &val, addr); |
| 739 | } |
| 740 | |
| 741 | /* Convert a floating-point number of type FROM_TYPE from a |
| 742 | target-order byte-stream at FROM to a floating-point number of type |
| 743 | TO_TYPE, and store it to a target-order byte-stream at TO. */ |
| 744 | |
| 745 | void |
| 746 | convert_typed_floating (const void *from, const struct type *from_type, |
| 747 | void *to, const struct type *to_type) |
| 748 | { |
| 749 | const struct floatformat *from_fmt = floatformat_from_type (from_type); |
| 750 | const struct floatformat *to_fmt = floatformat_from_type (to_type); |
| 751 | |
| 752 | gdb_assert (TYPE_CODE (from_type) == TYPE_CODE_FLT); |
| 753 | gdb_assert (TYPE_CODE (to_type) == TYPE_CODE_FLT); |
| 754 | |
| 755 | if (from_fmt == NULL || to_fmt == NULL) |
| 756 | { |
| 757 | /* If we don't know the floating-point format of FROM_TYPE or |
| 758 | TO_TYPE, there's not much we can do. We might make the |
| 759 | assumption that if the length of FROM_TYPE and TO_TYPE match, |
| 760 | their floating-point format would match too, but that |
| 761 | assumption might be wrong on targets that support |
| 762 | floating-point types that only differ in endianness for |
| 763 | example. So we warn instead, and zero out the target buffer. */ |
| 764 | warning ("Can't convert floating-point number to desired type."); |
| 765 | memset (to, 0, TYPE_LENGTH (to_type)); |
| 766 | } |
| 767 | else if (from_fmt == to_fmt) |
| 768 | { |
| 769 | /* We're in business. The floating-point format of FROM_TYPE |
| 770 | and TO_TYPE match. However, even though the floating-point |
| 771 | format matches, the length of the type might still be |
| 772 | different. Make sure we don't overrun any buffers. See |
| 773 | comment in store_typed_floating for a discussion about |
| 774 | zeroing out remaining bytes in the target buffer. */ |
| 775 | memset (to, 0, TYPE_LENGTH (to_type)); |
| 776 | memcpy (to, from, min (TYPE_LENGTH (from_type), TYPE_LENGTH (to_type))); |
| 777 | } |
| 778 | else |
| 779 | { |
| 780 | /* The floating-point types don't match. The best we can do |
| 781 | (aport from simulating the target FPU) is converting to the |
| 782 | widest floating-point type supported by the host, and then |
| 783 | again to the desired type. */ |
| 784 | DOUBLEST d; |
| 785 | |
| 786 | floatformat_to_doublest (from_fmt, from, &d); |
| 787 | floatformat_from_doublest (to_fmt, &d, to); |
| 788 | } |
| 789 | } |