| 1 | /* Floating point routines for GDB, the GNU debugger. |
| 2 | |
| 3 | Copyright 1986, 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995, |
| 4 | 1996, 1997, 1998, 1999, 2000, 2001, 2003 Free Software Foundation, |
| 5 | Inc. |
| 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 |
| 21 | Foundation, Inc., 59 Temple Place - Suite 330, |
| 22 | Boston, MA 02111-1307, USA. */ |
| 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" |
| 35 | #include "gdbtypes.h" |
| 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 | |
| 43 | static unsigned long get_field (unsigned char *, |
| 44 | enum floatformat_byteorders, |
| 45 | unsigned int, unsigned int, unsigned int); |
| 46 | |
| 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 |
| 50 | get_field (unsigned char *data, enum floatformat_byteorders order, |
| 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 | |
| 57 | /* Start at the least significant part of the field. */ |
| 58 | if (order == floatformat_little || order == floatformat_littlebyte_bigword) |
| 59 | { |
| 60 | /* We start counting from the other end (i.e, from the high bytes |
| 61 | rather than the low bytes). As such, we need to be concerned |
| 62 | with what happens if bit 0 doesn't start on a byte boundary. |
| 63 | I.e, we need to properly handle the case where total_len is |
| 64 | not evenly divisible by 8. So we compute ``excess'' which |
| 65 | represents the number of bits from the end of our starting |
| 66 | byte needed to get to bit 0. */ |
| 67 | int excess = FLOATFORMAT_CHAR_BIT - (total_len % FLOATFORMAT_CHAR_BIT); |
| 68 | cur_byte = (total_len / FLOATFORMAT_CHAR_BIT) |
| 69 | - ((start + len + excess) / FLOATFORMAT_CHAR_BIT); |
| 70 | cur_bitshift = ((start + len + excess) % FLOATFORMAT_CHAR_BIT) |
| 71 | - FLOATFORMAT_CHAR_BIT; |
| 72 | } |
| 73 | else |
| 74 | { |
| 75 | cur_byte = (start + len) / FLOATFORMAT_CHAR_BIT; |
| 76 | cur_bitshift = |
| 77 | ((start + len) % FLOATFORMAT_CHAR_BIT) - FLOATFORMAT_CHAR_BIT; |
| 78 | } |
| 79 | if (cur_bitshift > -FLOATFORMAT_CHAR_BIT) |
| 80 | result = *(data + cur_byte) >> (-cur_bitshift); |
| 81 | else |
| 82 | result = 0; |
| 83 | cur_bitshift += FLOATFORMAT_CHAR_BIT; |
| 84 | if (order == floatformat_little || order == floatformat_littlebyte_bigword) |
| 85 | ++cur_byte; |
| 86 | else |
| 87 | --cur_byte; |
| 88 | |
| 89 | /* Move towards the most significant part of the field. */ |
| 90 | while (cur_bitshift < len) |
| 91 | { |
| 92 | result |= (unsigned long)*(data + cur_byte) << cur_bitshift; |
| 93 | cur_bitshift += FLOATFORMAT_CHAR_BIT; |
| 94 | if (order == floatformat_little || order == floatformat_littlebyte_bigword) |
| 95 | ++cur_byte; |
| 96 | else |
| 97 | --cur_byte; |
| 98 | } |
| 99 | if (len < sizeof(result) * FLOATFORMAT_CHAR_BIT) |
| 100 | /* Mask out bits which are not part of the field */ |
| 101 | result &= ((1UL << len) - 1); |
| 102 | return result; |
| 103 | } |
| 104 | |
| 105 | /* Convert from FMT to a DOUBLEST. |
| 106 | FROM is the address of the extended float. |
| 107 | Store the DOUBLEST in *TO. */ |
| 108 | |
| 109 | static void |
| 110 | convert_floatformat_to_doublest (const struct floatformat *fmt, |
| 111 | const void *from, |
| 112 | DOUBLEST *to) |
| 113 | { |
| 114 | unsigned char *ufrom = (unsigned char *) from; |
| 115 | DOUBLEST dto; |
| 116 | long exponent; |
| 117 | unsigned long mant; |
| 118 | unsigned int mant_bits, mant_off; |
| 119 | int mant_bits_left; |
| 120 | int special_exponent; /* It's a NaN, denorm or zero */ |
| 121 | |
| 122 | /* If the mantissa bits are not contiguous from one end of the |
| 123 | mantissa to the other, we need to make a private copy of the |
| 124 | source bytes that is in the right order since the unpacking |
| 125 | algorithm assumes that the bits are contiguous. |
| 126 | |
| 127 | Swap the bytes individually rather than accessing them through |
| 128 | "long *" since we have no guarantee that they start on a long |
| 129 | alignment, and also sizeof(long) for the host could be different |
| 130 | than sizeof(long) for the target. FIXME: Assumes sizeof(long) |
| 131 | for the target is 4. */ |
| 132 | |
| 133 | if (fmt->byteorder == floatformat_littlebyte_bigword) |
| 134 | { |
| 135 | static unsigned char *newfrom; |
| 136 | unsigned char *swapin, *swapout; |
| 137 | int longswaps; |
| 138 | |
| 139 | longswaps = fmt->totalsize / FLOATFORMAT_CHAR_BIT; |
| 140 | longswaps >>= 3; |
| 141 | |
| 142 | if (newfrom == NULL) |
| 143 | { |
| 144 | newfrom = (unsigned char *) xmalloc (fmt->totalsize); |
| 145 | } |
| 146 | swapout = newfrom; |
| 147 | swapin = ufrom; |
| 148 | ufrom = newfrom; |
| 149 | while (longswaps-- > 0) |
| 150 | { |
| 151 | /* This is ugly, but efficient */ |
| 152 | *swapout++ = swapin[4]; |
| 153 | *swapout++ = swapin[5]; |
| 154 | *swapout++ = swapin[6]; |
| 155 | *swapout++ = swapin[7]; |
| 156 | *swapout++ = swapin[0]; |
| 157 | *swapout++ = swapin[1]; |
| 158 | *swapout++ = swapin[2]; |
| 159 | *swapout++ = swapin[3]; |
| 160 | swapin += 8; |
| 161 | } |
| 162 | } |
| 163 | |
| 164 | exponent = get_field (ufrom, fmt->byteorder, fmt->totalsize, |
| 165 | fmt->exp_start, fmt->exp_len); |
| 166 | /* Note that if exponent indicates a NaN, we can't really do anything useful |
| 167 | (not knowing if the host has NaN's, or how to build one). So it will |
| 168 | end up as an infinity or something close; that is OK. */ |
| 169 | |
| 170 | mant_bits_left = fmt->man_len; |
| 171 | mant_off = fmt->man_start; |
| 172 | dto = 0.0; |
| 173 | |
| 174 | special_exponent = exponent == 0 || exponent == fmt->exp_nan; |
| 175 | |
| 176 | /* Don't bias NaNs. Use minimum exponent for denorms. For simplicity, |
| 177 | we don't check for zero as the exponent doesn't matter. Note the cast |
| 178 | to int; exp_bias is unsigned, so it's important to make sure the |
| 179 | operation is done in signed arithmetic. */ |
| 180 | if (!special_exponent) |
| 181 | exponent -= fmt->exp_bias; |
| 182 | else if (exponent == 0) |
| 183 | exponent = 1 - fmt->exp_bias; |
| 184 | |
| 185 | /* Build the result algebraically. Might go infinite, underflow, etc; |
| 186 | who cares. */ |
| 187 | |
| 188 | /* If this format uses a hidden bit, explicitly add it in now. Otherwise, |
| 189 | increment the exponent by one to account for the integer bit. */ |
| 190 | |
| 191 | if (!special_exponent) |
| 192 | { |
| 193 | if (fmt->intbit == floatformat_intbit_no) |
| 194 | dto = ldexp (1.0, exponent); |
| 195 | else |
| 196 | exponent++; |
| 197 | } |
| 198 | |
| 199 | while (mant_bits_left > 0) |
| 200 | { |
| 201 | mant_bits = min (mant_bits_left, 32); |
| 202 | |
| 203 | mant = get_field (ufrom, fmt->byteorder, fmt->totalsize, |
| 204 | mant_off, mant_bits); |
| 205 | |
| 206 | dto += ldexp ((double) mant, exponent - mant_bits); |
| 207 | exponent -= mant_bits; |
| 208 | mant_off += mant_bits; |
| 209 | mant_bits_left -= mant_bits; |
| 210 | } |
| 211 | |
| 212 | /* Negate it if negative. */ |
| 213 | if (get_field (ufrom, fmt->byteorder, fmt->totalsize, fmt->sign_start, 1)) |
| 214 | dto = -dto; |
| 215 | *to = dto; |
| 216 | } |
| 217 | \f |
| 218 | static void put_field (unsigned char *, enum floatformat_byteorders, |
| 219 | unsigned int, |
| 220 | unsigned int, unsigned int, unsigned long); |
| 221 | |
| 222 | /* Set a field which starts at START and is LEN bytes long. DATA and |
| 223 | TOTAL_LEN are the thing we are extracting it from, in byteorder ORDER. */ |
| 224 | static void |
| 225 | put_field (unsigned char *data, enum floatformat_byteorders order, |
| 226 | unsigned int total_len, unsigned int start, unsigned int len, |
| 227 | unsigned long stuff_to_put) |
| 228 | { |
| 229 | unsigned int cur_byte; |
| 230 | int cur_bitshift; |
| 231 | |
| 232 | /* Start at the least significant part of the field. */ |
| 233 | if (order == floatformat_little || order == floatformat_littlebyte_bigword) |
| 234 | { |
| 235 | int excess = FLOATFORMAT_CHAR_BIT - (total_len % FLOATFORMAT_CHAR_BIT); |
| 236 | cur_byte = (total_len / FLOATFORMAT_CHAR_BIT) |
| 237 | - ((start + len + excess) / FLOATFORMAT_CHAR_BIT); |
| 238 | cur_bitshift = ((start + len + excess) % FLOATFORMAT_CHAR_BIT) |
| 239 | - FLOATFORMAT_CHAR_BIT; |
| 240 | } |
| 241 | else |
| 242 | { |
| 243 | cur_byte = (start + len) / FLOATFORMAT_CHAR_BIT; |
| 244 | cur_bitshift = |
| 245 | ((start + len) % FLOATFORMAT_CHAR_BIT) - FLOATFORMAT_CHAR_BIT; |
| 246 | } |
| 247 | if (cur_bitshift > -FLOATFORMAT_CHAR_BIT) |
| 248 | { |
| 249 | *(data + cur_byte) &= |
| 250 | ~(((1 << ((start + len) % FLOATFORMAT_CHAR_BIT)) - 1) |
| 251 | << (-cur_bitshift)); |
| 252 | *(data + cur_byte) |= |
| 253 | (stuff_to_put & ((1 << FLOATFORMAT_CHAR_BIT) - 1)) << (-cur_bitshift); |
| 254 | } |
| 255 | cur_bitshift += FLOATFORMAT_CHAR_BIT; |
| 256 | if (order == floatformat_little || order == floatformat_littlebyte_bigword) |
| 257 | ++cur_byte; |
| 258 | else |
| 259 | --cur_byte; |
| 260 | |
| 261 | /* Move towards the most significant part of the field. */ |
| 262 | while (cur_bitshift < len) |
| 263 | { |
| 264 | if (len - cur_bitshift < FLOATFORMAT_CHAR_BIT) |
| 265 | { |
| 266 | /* This is the last byte. */ |
| 267 | *(data + cur_byte) &= |
| 268 | ~((1 << (len - cur_bitshift)) - 1); |
| 269 | *(data + cur_byte) |= (stuff_to_put >> cur_bitshift); |
| 270 | } |
| 271 | else |
| 272 | *(data + cur_byte) = ((stuff_to_put >> cur_bitshift) |
| 273 | & ((1 << FLOATFORMAT_CHAR_BIT) - 1)); |
| 274 | cur_bitshift += FLOATFORMAT_CHAR_BIT; |
| 275 | if (order == floatformat_little || order == floatformat_littlebyte_bigword) |
| 276 | ++cur_byte; |
| 277 | else |
| 278 | --cur_byte; |
| 279 | } |
| 280 | } |
| 281 | |
| 282 | #ifdef HAVE_LONG_DOUBLE |
| 283 | /* Return the fractional part of VALUE, and put the exponent of VALUE in *EPTR. |
| 284 | The range of the returned value is >= 0.5 and < 1.0. This is equivalent to |
| 285 | frexp, but operates on the long double data type. */ |
| 286 | |
| 287 | static long double ldfrexp (long double value, int *eptr); |
| 288 | |
| 289 | static long double |
| 290 | ldfrexp (long double value, int *eptr) |
| 291 | { |
| 292 | long double tmp; |
| 293 | int exp; |
| 294 | |
| 295 | /* Unfortunately, there are no portable functions for extracting the exponent |
| 296 | of a long double, so we have to do it iteratively by multiplying or dividing |
| 297 | by two until the fraction is between 0.5 and 1.0. */ |
| 298 | |
| 299 | if (value < 0.0l) |
| 300 | value = -value; |
| 301 | |
| 302 | tmp = 1.0l; |
| 303 | exp = 0; |
| 304 | |
| 305 | if (value >= tmp) /* Value >= 1.0 */ |
| 306 | while (value >= tmp) |
| 307 | { |
| 308 | tmp *= 2.0l; |
| 309 | exp++; |
| 310 | } |
| 311 | else if (value != 0.0l) /* Value < 1.0 and > 0.0 */ |
| 312 | { |
| 313 | while (value < tmp) |
| 314 | { |
| 315 | tmp /= 2.0l; |
| 316 | exp--; |
| 317 | } |
| 318 | tmp *= 2.0l; |
| 319 | exp++; |
| 320 | } |
| 321 | |
| 322 | *eptr = exp; |
| 323 | return value / tmp; |
| 324 | } |
| 325 | #endif /* HAVE_LONG_DOUBLE */ |
| 326 | |
| 327 | |
| 328 | /* The converse: convert the DOUBLEST *FROM to an extended float |
| 329 | and store where TO points. Neither FROM nor TO have any alignment |
| 330 | restrictions. */ |
| 331 | |
| 332 | static void |
| 333 | convert_doublest_to_floatformat (CONST struct floatformat *fmt, |
| 334 | const DOUBLEST *from, |
| 335 | void *to) |
| 336 | { |
| 337 | DOUBLEST dfrom; |
| 338 | int exponent; |
| 339 | DOUBLEST mant; |
| 340 | unsigned int mant_bits, mant_off; |
| 341 | int mant_bits_left; |
| 342 | unsigned char *uto = (unsigned char *) to; |
| 343 | |
| 344 | memcpy (&dfrom, from, sizeof (dfrom)); |
| 345 | memset (uto, 0, (fmt->totalsize + FLOATFORMAT_CHAR_BIT - 1) |
| 346 | / FLOATFORMAT_CHAR_BIT); |
| 347 | if (dfrom == 0) |
| 348 | return; /* Result is zero */ |
| 349 | if (dfrom != dfrom) /* Result is NaN */ |
| 350 | { |
| 351 | /* From is NaN */ |
| 352 | put_field (uto, fmt->byteorder, fmt->totalsize, fmt->exp_start, |
| 353 | fmt->exp_len, fmt->exp_nan); |
| 354 | /* Be sure it's not infinity, but NaN value is irrel */ |
| 355 | put_field (uto, fmt->byteorder, fmt->totalsize, fmt->man_start, |
| 356 | 32, 1); |
| 357 | return; |
| 358 | } |
| 359 | |
| 360 | /* If negative, set the sign bit. */ |
| 361 | if (dfrom < 0) |
| 362 | { |
| 363 | put_field (uto, fmt->byteorder, fmt->totalsize, fmt->sign_start, 1, 1); |
| 364 | dfrom = -dfrom; |
| 365 | } |
| 366 | |
| 367 | if (dfrom + dfrom == dfrom && dfrom != 0.0) /* Result is Infinity */ |
| 368 | { |
| 369 | /* Infinity exponent is same as NaN's. */ |
| 370 | put_field (uto, fmt->byteorder, fmt->totalsize, fmt->exp_start, |
| 371 | fmt->exp_len, fmt->exp_nan); |
| 372 | /* Infinity mantissa is all zeroes. */ |
| 373 | put_field (uto, fmt->byteorder, fmt->totalsize, fmt->man_start, |
| 374 | fmt->man_len, 0); |
| 375 | return; |
| 376 | } |
| 377 | |
| 378 | #ifdef HAVE_LONG_DOUBLE |
| 379 | mant = ldfrexp (dfrom, &exponent); |
| 380 | #else |
| 381 | mant = frexp (dfrom, &exponent); |
| 382 | #endif |
| 383 | |
| 384 | put_field (uto, fmt->byteorder, fmt->totalsize, fmt->exp_start, fmt->exp_len, |
| 385 | exponent + fmt->exp_bias - 1); |
| 386 | |
| 387 | mant_bits_left = fmt->man_len; |
| 388 | mant_off = fmt->man_start; |
| 389 | while (mant_bits_left > 0) |
| 390 | { |
| 391 | unsigned long mant_long; |
| 392 | mant_bits = mant_bits_left < 32 ? mant_bits_left : 32; |
| 393 | |
| 394 | mant *= 4294967296.0; |
| 395 | mant_long = ((unsigned long) mant) & 0xffffffffL; |
| 396 | mant -= mant_long; |
| 397 | |
| 398 | /* If the integer bit is implicit, then we need to discard it. |
| 399 | If we are discarding a zero, we should be (but are not) creating |
| 400 | a denormalized number which means adjusting the exponent |
| 401 | (I think). */ |
| 402 | if (mant_bits_left == fmt->man_len |
| 403 | && fmt->intbit == floatformat_intbit_no) |
| 404 | { |
| 405 | mant_long <<= 1; |
| 406 | mant_long &= 0xffffffffL; |
| 407 | /* If we are processing the top 32 mantissa bits of a doublest |
| 408 | so as to convert to a float value with implied integer bit, |
| 409 | we will only be putting 31 of those 32 bits into the |
| 410 | final value due to the discarding of the top bit. In the |
| 411 | case of a small float value where the number of mantissa |
| 412 | bits is less than 32, discarding the top bit does not alter |
| 413 | the number of bits we will be adding to the result. */ |
| 414 | if (mant_bits == 32) |
| 415 | mant_bits -= 1; |
| 416 | } |
| 417 | |
| 418 | if (mant_bits < 32) |
| 419 | { |
| 420 | /* The bits we want are in the most significant MANT_BITS bits of |
| 421 | mant_long. Move them to the least significant. */ |
| 422 | mant_long >>= 32 - mant_bits; |
| 423 | } |
| 424 | |
| 425 | put_field (uto, fmt->byteorder, fmt->totalsize, |
| 426 | mant_off, mant_bits, mant_long); |
| 427 | mant_off += mant_bits; |
| 428 | mant_bits_left -= mant_bits; |
| 429 | } |
| 430 | if (fmt->byteorder == floatformat_littlebyte_bigword) |
| 431 | { |
| 432 | int count; |
| 433 | unsigned char *swaplow = uto; |
| 434 | unsigned char *swaphigh = uto + 4; |
| 435 | unsigned char tmp; |
| 436 | |
| 437 | for (count = 0; count < 4; count++) |
| 438 | { |
| 439 | tmp = *swaplow; |
| 440 | *swaplow++ = *swaphigh; |
| 441 | *swaphigh++ = tmp; |
| 442 | } |
| 443 | } |
| 444 | } |
| 445 | |
| 446 | /* Check if VAL (which is assumed to be a floating point number whose |
| 447 | format is described by FMT) is negative. */ |
| 448 | |
| 449 | int |
| 450 | floatformat_is_negative (const struct floatformat *fmt, char *val) |
| 451 | { |
| 452 | unsigned char *uval = (unsigned char *) val; |
| 453 | gdb_assert (fmt != NULL); |
| 454 | return get_field (uval, fmt->byteorder, fmt->totalsize, fmt->sign_start, 1); |
| 455 | } |
| 456 | |
| 457 | /* Check if VAL is "not a number" (NaN) for FMT. */ |
| 458 | |
| 459 | int |
| 460 | floatformat_is_nan (const struct floatformat *fmt, char *val) |
| 461 | { |
| 462 | unsigned char *uval = (unsigned char *) val; |
| 463 | long exponent; |
| 464 | unsigned long mant; |
| 465 | unsigned int mant_bits, mant_off; |
| 466 | int mant_bits_left; |
| 467 | |
| 468 | gdb_assert (fmt != NULL); |
| 469 | |
| 470 | if (! fmt->exp_nan) |
| 471 | return 0; |
| 472 | |
| 473 | exponent = get_field (uval, fmt->byteorder, fmt->totalsize, |
| 474 | fmt->exp_start, fmt->exp_len); |
| 475 | |
| 476 | if (exponent != fmt->exp_nan) |
| 477 | return 0; |
| 478 | |
| 479 | mant_bits_left = fmt->man_len; |
| 480 | mant_off = fmt->man_start; |
| 481 | |
| 482 | while (mant_bits_left > 0) |
| 483 | { |
| 484 | mant_bits = min (mant_bits_left, 32); |
| 485 | |
| 486 | mant = get_field (uval, fmt->byteorder, fmt->totalsize, |
| 487 | mant_off, mant_bits); |
| 488 | |
| 489 | /* If there is an explicit integer bit, mask it off. */ |
| 490 | if (mant_off == fmt->man_start |
| 491 | && fmt->intbit == floatformat_intbit_yes) |
| 492 | mant &= ~(1 << (mant_bits - 1)); |
| 493 | |
| 494 | if (mant) |
| 495 | return 1; |
| 496 | |
| 497 | mant_off += mant_bits; |
| 498 | mant_bits_left -= mant_bits; |
| 499 | } |
| 500 | |
| 501 | return 0; |
| 502 | } |
| 503 | |
| 504 | /* Convert the mantissa of VAL (which is assumed to be a floating |
| 505 | point number whose format is described by FMT) into a hexadecimal |
| 506 | and store it in a static string. Return a pointer to that string. */ |
| 507 | |
| 508 | char * |
| 509 | floatformat_mantissa (const struct floatformat *fmt, char *val) |
| 510 | { |
| 511 | unsigned char *uval = (unsigned char *) val; |
| 512 | unsigned long mant; |
| 513 | unsigned int mant_bits, mant_off; |
| 514 | int mant_bits_left; |
| 515 | static char res[50]; |
| 516 | char buf[9]; |
| 517 | |
| 518 | /* Make sure we have enough room to store the mantissa. */ |
| 519 | gdb_assert (fmt != NULL); |
| 520 | gdb_assert (sizeof res > ((fmt->man_len + 7) / 8) * 2); |
| 521 | |
| 522 | mant_off = fmt->man_start; |
| 523 | mant_bits_left = fmt->man_len; |
| 524 | mant_bits = (mant_bits_left % 32) > 0 ? mant_bits_left % 32 : 32; |
| 525 | |
| 526 | mant = get_field (uval, fmt->byteorder, fmt->totalsize, |
| 527 | mant_off, mant_bits); |
| 528 | |
| 529 | sprintf (res, "%lx", mant); |
| 530 | |
| 531 | mant_off += mant_bits; |
| 532 | mant_bits_left -= mant_bits; |
| 533 | |
| 534 | while (mant_bits_left > 0) |
| 535 | { |
| 536 | mant = get_field (uval, fmt->byteorder, fmt->totalsize, |
| 537 | mant_off, 32); |
| 538 | |
| 539 | sprintf (buf, "%08lx", mant); |
| 540 | strcat (res, buf); |
| 541 | |
| 542 | mant_off += 32; |
| 543 | mant_bits_left -= 32; |
| 544 | } |
| 545 | |
| 546 | return res; |
| 547 | } |
| 548 | |
| 549 | \f |
| 550 | /* Convert TO/FROM target to the hosts DOUBLEST floating-point format. |
| 551 | |
| 552 | If the host and target formats agree, we just copy the raw data |
| 553 | into the appropriate type of variable and return, letting the host |
| 554 | increase precision as necessary. Otherwise, we call the conversion |
| 555 | routine and let it do the dirty work. */ |
| 556 | |
| 557 | #ifndef HOST_FLOAT_FORMAT |
| 558 | #define HOST_FLOAT_FORMAT 0 |
| 559 | #endif |
| 560 | #ifndef HOST_DOUBLE_FORMAT |
| 561 | #define HOST_DOUBLE_FORMAT 0 |
| 562 | #endif |
| 563 | #ifndef HOST_LONG_DOUBLE_FORMAT |
| 564 | #define HOST_LONG_DOUBLE_FORMAT 0 |
| 565 | #endif |
| 566 | |
| 567 | static const struct floatformat *host_float_format = HOST_FLOAT_FORMAT; |
| 568 | static const struct floatformat *host_double_format = HOST_DOUBLE_FORMAT; |
| 569 | static const struct floatformat *host_long_double_format = HOST_LONG_DOUBLE_FORMAT; |
| 570 | |
| 571 | void |
| 572 | floatformat_to_doublest (const struct floatformat *fmt, |
| 573 | const void *in, DOUBLEST *out) |
| 574 | { |
| 575 | gdb_assert (fmt != NULL); |
| 576 | if (fmt == host_float_format) |
| 577 | { |
| 578 | float val; |
| 579 | memcpy (&val, in, sizeof (val)); |
| 580 | *out = val; |
| 581 | } |
| 582 | else if (fmt == host_double_format) |
| 583 | { |
| 584 | double val; |
| 585 | memcpy (&val, in, sizeof (val)); |
| 586 | *out = val; |
| 587 | } |
| 588 | else if (fmt == host_long_double_format) |
| 589 | { |
| 590 | long double val; |
| 591 | memcpy (&val, in, sizeof (val)); |
| 592 | *out = val; |
| 593 | } |
| 594 | else |
| 595 | convert_floatformat_to_doublest (fmt, in, out); |
| 596 | } |
| 597 | |
| 598 | void |
| 599 | floatformat_from_doublest (const struct floatformat *fmt, |
| 600 | const DOUBLEST *in, void *out) |
| 601 | { |
| 602 | gdb_assert (fmt != NULL); |
| 603 | if (fmt == host_float_format) |
| 604 | { |
| 605 | float val = *in; |
| 606 | memcpy (out, &val, sizeof (val)); |
| 607 | } |
| 608 | else if (fmt == host_double_format) |
| 609 | { |
| 610 | double val = *in; |
| 611 | memcpy (out, &val, sizeof (val)); |
| 612 | } |
| 613 | else if (fmt == host_long_double_format) |
| 614 | { |
| 615 | long double val = *in; |
| 616 | memcpy (out, &val, sizeof (val)); |
| 617 | } |
| 618 | else |
| 619 | convert_doublest_to_floatformat (fmt, in, out); |
| 620 | } |
| 621 | |
| 622 | \f |
| 623 | /* Return a floating-point format for a floating-point variable of |
| 624 | length LEN. Return NULL, if no suitable floating-point format |
| 625 | could be found. |
| 626 | |
| 627 | We need this functionality since information about the |
| 628 | floating-point format of a type is not always available to GDB; the |
| 629 | debug information typically only tells us the size of a |
| 630 | floating-point type. |
| 631 | |
| 632 | FIXME: kettenis/2001-10-28: In many places, particularly in |
| 633 | target-dependent code, the format of floating-point types is known, |
| 634 | but not passed on by GDB. This should be fixed. */ |
| 635 | |
| 636 | static const struct floatformat * |
| 637 | floatformat_from_length (int len) |
| 638 | { |
| 639 | if (len * TARGET_CHAR_BIT == TARGET_FLOAT_BIT) |
| 640 | return TARGET_FLOAT_FORMAT; |
| 641 | else if (len * TARGET_CHAR_BIT == TARGET_DOUBLE_BIT) |
| 642 | return TARGET_DOUBLE_FORMAT; |
| 643 | else if (len * TARGET_CHAR_BIT == TARGET_LONG_DOUBLE_BIT) |
| 644 | return TARGET_LONG_DOUBLE_FORMAT; |
| 645 | /* On i386 the 'long double' type takes 96 bits, |
| 646 | while the real number of used bits is only 80, |
| 647 | both in processor and in memory. |
| 648 | The code below accepts the real bit size. */ |
| 649 | else if ((TARGET_LONG_DOUBLE_FORMAT != NULL) |
| 650 | && (len * TARGET_CHAR_BIT == |
| 651 | TARGET_LONG_DOUBLE_FORMAT->totalsize)) |
| 652 | return TARGET_LONG_DOUBLE_FORMAT; |
| 653 | |
| 654 | return NULL; |
| 655 | } |
| 656 | |
| 657 | const struct floatformat * |
| 658 | floatformat_from_type (const struct type *type) |
| 659 | { |
| 660 | gdb_assert (TYPE_CODE (type) == TYPE_CODE_FLT); |
| 661 | if (TYPE_FLOATFORMAT (type) != NULL) |
| 662 | return TYPE_FLOATFORMAT (type); |
| 663 | else |
| 664 | return floatformat_from_length (TYPE_LENGTH (type)); |
| 665 | } |
| 666 | |
| 667 | /* If the host doesn't define NAN, use zero instead. */ |
| 668 | #ifndef NAN |
| 669 | #define NAN 0.0 |
| 670 | #endif |
| 671 | |
| 672 | /* Extract a floating-point number of length LEN from a target-order |
| 673 | byte-stream at ADDR. Returns the value as type DOUBLEST. */ |
| 674 | |
| 675 | static DOUBLEST |
| 676 | extract_floating_by_length (const void *addr, int len) |
| 677 | { |
| 678 | const struct floatformat *fmt = floatformat_from_length (len); |
| 679 | DOUBLEST val; |
| 680 | |
| 681 | if (fmt == NULL) |
| 682 | { |
| 683 | warning ("Can't extract a floating-point number of %d bytes.", len); |
| 684 | return NAN; |
| 685 | } |
| 686 | |
| 687 | floatformat_to_doublest (fmt, addr, &val); |
| 688 | return val; |
| 689 | } |
| 690 | |
| 691 | DOUBLEST |
| 692 | deprecated_extract_floating (const void *addr, int len) |
| 693 | { |
| 694 | return extract_floating_by_length (addr, len); |
| 695 | } |
| 696 | |
| 697 | /* Store VAL as a floating-point number of length LEN to a |
| 698 | target-order byte-stream at ADDR. */ |
| 699 | |
| 700 | static void |
| 701 | store_floating_by_length (void *addr, int len, DOUBLEST val) |
| 702 | { |
| 703 | const struct floatformat *fmt = floatformat_from_length (len); |
| 704 | |
| 705 | if (fmt == NULL) |
| 706 | { |
| 707 | warning ("Can't store a floating-point number of %d bytes.", len); |
| 708 | memset (addr, 0, len); |
| 709 | return; |
| 710 | } |
| 711 | |
| 712 | floatformat_from_doublest (fmt, &val, addr); |
| 713 | } |
| 714 | |
| 715 | void |
| 716 | deprecated_store_floating (void *addr, int len, DOUBLEST val) |
| 717 | { |
| 718 | store_floating_by_length (addr, len, val); |
| 719 | } |
| 720 | |
| 721 | /* Extract a floating-point number of type TYPE from a target-order |
| 722 | byte-stream at ADDR. Returns the value as type DOUBLEST. */ |
| 723 | |
| 724 | DOUBLEST |
| 725 | extract_typed_floating (const void *addr, const struct type *type) |
| 726 | { |
| 727 | DOUBLEST retval; |
| 728 | |
| 729 | gdb_assert (TYPE_CODE (type) == TYPE_CODE_FLT); |
| 730 | |
| 731 | if (TYPE_FLOATFORMAT (type) == NULL) |
| 732 | /* Not all code remembers to set the FLOATFORMAT (language |
| 733 | specific code? stabs?) so handle that here as a special case. */ |
| 734 | return extract_floating_by_length (addr, TYPE_LENGTH (type)); |
| 735 | |
| 736 | floatformat_to_doublest (TYPE_FLOATFORMAT (type), addr, &retval); |
| 737 | return retval; |
| 738 | } |
| 739 | |
| 740 | /* Store VAL as a floating-point number of type TYPE to a target-order |
| 741 | byte-stream at ADDR. */ |
| 742 | |
| 743 | void |
| 744 | store_typed_floating (void *addr, const struct type *type, DOUBLEST val) |
| 745 | { |
| 746 | gdb_assert (TYPE_CODE (type) == TYPE_CODE_FLT); |
| 747 | |
| 748 | /* FIXME: kettenis/2001-10-28: It is debatable whether we should |
| 749 | zero out any remaining bytes in the target buffer when TYPE is |
| 750 | longer than the actual underlying floating-point format. Perhaps |
| 751 | we should store a fixed bitpattern in those remaining bytes, |
| 752 | instead of zero, or perhaps we shouldn't touch those remaining |
| 753 | bytes at all. |
| 754 | |
| 755 | NOTE: cagney/2001-10-28: With the way things currently work, it |
| 756 | isn't a good idea to leave the end bits undefined. This is |
| 757 | because GDB writes out the entire sizeof(<floating>) bits of the |
| 758 | floating-point type even though the value might only be stored |
| 759 | in, and the target processor may only refer to, the first N < |
| 760 | TYPE_LENGTH (type) bits. If the end of the buffer wasn't |
| 761 | initialized, GDB would write undefined data to the target. An |
| 762 | errant program, refering to that undefined data, would then |
| 763 | become non-deterministic. |
| 764 | |
| 765 | See also the function convert_typed_floating below. */ |
| 766 | memset (addr, 0, TYPE_LENGTH (type)); |
| 767 | |
| 768 | if (TYPE_FLOATFORMAT (type) == NULL) |
| 769 | /* Not all code remembers to set the FLOATFORMAT (language |
| 770 | specific code? stabs?) so handle that here as a special case. */ |
| 771 | store_floating_by_length (addr, TYPE_LENGTH (type), val); |
| 772 | else |
| 773 | floatformat_from_doublest (TYPE_FLOATFORMAT (type), &val, addr); |
| 774 | } |
| 775 | |
| 776 | /* Convert a floating-point number of type FROM_TYPE from a |
| 777 | target-order byte-stream at FROM to a floating-point number of type |
| 778 | TO_TYPE, and store it to a target-order byte-stream at TO. */ |
| 779 | |
| 780 | void |
| 781 | convert_typed_floating (const void *from, const struct type *from_type, |
| 782 | void *to, const struct type *to_type) |
| 783 | { |
| 784 | const struct floatformat *from_fmt = floatformat_from_type (from_type); |
| 785 | const struct floatformat *to_fmt = floatformat_from_type (to_type); |
| 786 | |
| 787 | gdb_assert (TYPE_CODE (from_type) == TYPE_CODE_FLT); |
| 788 | gdb_assert (TYPE_CODE (to_type) == TYPE_CODE_FLT); |
| 789 | |
| 790 | if (from_fmt == NULL || to_fmt == NULL) |
| 791 | { |
| 792 | /* If we don't know the floating-point format of FROM_TYPE or |
| 793 | TO_TYPE, there's not much we can do. We might make the |
| 794 | assumption that if the length of FROM_TYPE and TO_TYPE match, |
| 795 | their floating-point format would match too, but that |
| 796 | assumption might be wrong on targets that support |
| 797 | floating-point types that only differ in endianness for |
| 798 | example. So we warn instead, and zero out the target buffer. */ |
| 799 | warning ("Can't convert floating-point number to desired type."); |
| 800 | memset (to, 0, TYPE_LENGTH (to_type)); |
| 801 | } |
| 802 | else if (from_fmt == to_fmt) |
| 803 | { |
| 804 | /* We're in business. The floating-point format of FROM_TYPE |
| 805 | and TO_TYPE match. However, even though the floating-point |
| 806 | format matches, the length of the type might still be |
| 807 | different. Make sure we don't overrun any buffers. See |
| 808 | comment in store_typed_floating for a discussion about |
| 809 | zeroing out remaining bytes in the target buffer. */ |
| 810 | memset (to, 0, TYPE_LENGTH (to_type)); |
| 811 | memcpy (to, from, min (TYPE_LENGTH (from_type), TYPE_LENGTH (to_type))); |
| 812 | } |
| 813 | else |
| 814 | { |
| 815 | /* The floating-point types don't match. The best we can do |
| 816 | (aport from simulating the target FPU) is converting to the |
| 817 | widest floating-point type supported by the host, and then |
| 818 | again to the desired type. */ |
| 819 | DOUBLEST d; |
| 820 | |
| 821 | floatformat_to_doublest (from_fmt, from, &d); |
| 822 | floatformat_from_doublest (to_fmt, &d, to); |
| 823 | } |
| 824 | } |