| 1 | /* atof_vax.c - turn a Flonum into a VAX floating point number |
| 2 | Copyright (C) 1987, 1992, 93, 95, 1997, 1998 Free Software Foundation, Inc. |
| 3 | |
| 4 | This file is part of GAS, the GNU Assembler. |
| 5 | |
| 6 | GAS is free software; you can redistribute it and/or modify |
| 7 | it under the terms of the GNU General Public License as published by |
| 8 | the Free Software Foundation; either version 2, or (at your option) |
| 9 | any later version. |
| 10 | |
| 11 | GAS is distributed in the hope that it will be useful, |
| 12 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 13 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 14 | GNU General Public License for more details. |
| 15 | |
| 16 | You should have received a copy of the GNU General Public License |
| 17 | along with GAS; see the file COPYING. If not, write to the Free |
| 18 | Software Foundation, 59 Temple Place - Suite 330, Boston, MA |
| 19 | 02111-1307, USA. */ |
| 20 | |
| 21 | #include "as.h" |
| 22 | |
| 23 | static int atof_vax_sizeof PARAMS ((int)); |
| 24 | static int next_bits PARAMS ((int)); |
| 25 | static void make_invalid_floating_point_number PARAMS ((LITTLENUM_TYPE *)); |
| 26 | static int what_kind_of_float PARAMS ((int, int *, long *)); |
| 27 | static char *atof_vax PARAMS ((char *, int, LITTLENUM_TYPE *)); |
| 28 | |
| 29 | /* Precision in LittleNums. */ |
| 30 | #define MAX_PRECISION (8) |
| 31 | #define H_PRECISION (8) |
| 32 | #define G_PRECISION (4) |
| 33 | #define D_PRECISION (4) |
| 34 | #define F_PRECISION (2) |
| 35 | |
| 36 | /* Length in LittleNums of guard bits. */ |
| 37 | #define GUARD (2) |
| 38 | |
| 39 | int flonum_gen2vax PARAMS ((int format_letter, FLONUM_TYPE * f, |
| 40 | LITTLENUM_TYPE * words)); |
| 41 | |
| 42 | /* Number of chars in flonum type 'letter'. */ |
| 43 | static int |
| 44 | atof_vax_sizeof (letter) |
| 45 | int letter; |
| 46 | { |
| 47 | int return_value; |
| 48 | |
| 49 | /* |
| 50 | * Permitting uppercase letters is probably a bad idea. |
| 51 | * Please use only lower-cased letters in case the upper-cased |
| 52 | * ones become unsupported! |
| 53 | */ |
| 54 | switch (letter) |
| 55 | { |
| 56 | case 'f': |
| 57 | case 'F': |
| 58 | return_value = 4; |
| 59 | break; |
| 60 | |
| 61 | case 'd': |
| 62 | case 'D': |
| 63 | case 'g': |
| 64 | case 'G': |
| 65 | return_value = 8; |
| 66 | break; |
| 67 | |
| 68 | case 'h': |
| 69 | case 'H': |
| 70 | return_value = 16; |
| 71 | break; |
| 72 | |
| 73 | default: |
| 74 | return_value = 0; |
| 75 | break; |
| 76 | } |
| 77 | return (return_value); |
| 78 | } /* atof_vax_sizeof */ |
| 79 | |
| 80 | static const long mask[] = |
| 81 | { |
| 82 | 0x00000000, |
| 83 | 0x00000001, |
| 84 | 0x00000003, |
| 85 | 0x00000007, |
| 86 | 0x0000000f, |
| 87 | 0x0000001f, |
| 88 | 0x0000003f, |
| 89 | 0x0000007f, |
| 90 | 0x000000ff, |
| 91 | 0x000001ff, |
| 92 | 0x000003ff, |
| 93 | 0x000007ff, |
| 94 | 0x00000fff, |
| 95 | 0x00001fff, |
| 96 | 0x00003fff, |
| 97 | 0x00007fff, |
| 98 | 0x0000ffff, |
| 99 | 0x0001ffff, |
| 100 | 0x0003ffff, |
| 101 | 0x0007ffff, |
| 102 | 0x000fffff, |
| 103 | 0x001fffff, |
| 104 | 0x003fffff, |
| 105 | 0x007fffff, |
| 106 | 0x00ffffff, |
| 107 | 0x01ffffff, |
| 108 | 0x03ffffff, |
| 109 | 0x07ffffff, |
| 110 | 0x0fffffff, |
| 111 | 0x1fffffff, |
| 112 | 0x3fffffff, |
| 113 | 0x7fffffff, |
| 114 | 0xffffffff |
| 115 | }; |
| 116 | \f |
| 117 | |
| 118 | /* Shared between flonum_gen2vax and next_bits */ |
| 119 | static int bits_left_in_littlenum; |
| 120 | static LITTLENUM_TYPE *littlenum_pointer; |
| 121 | static LITTLENUM_TYPE *littlenum_end; |
| 122 | |
| 123 | static int |
| 124 | next_bits (number_of_bits) |
| 125 | int number_of_bits; |
| 126 | { |
| 127 | int return_value; |
| 128 | |
| 129 | if (littlenum_pointer < littlenum_end) |
| 130 | return 0; |
| 131 | if (number_of_bits >= bits_left_in_littlenum) |
| 132 | { |
| 133 | return_value = mask[bits_left_in_littlenum] & *littlenum_pointer; |
| 134 | number_of_bits -= bits_left_in_littlenum; |
| 135 | return_value <<= number_of_bits; |
| 136 | bits_left_in_littlenum = LITTLENUM_NUMBER_OF_BITS - number_of_bits; |
| 137 | littlenum_pointer--; |
| 138 | if (littlenum_pointer >= littlenum_end) |
| 139 | return_value |= ((*littlenum_pointer) >> (bits_left_in_littlenum)) & mask[number_of_bits]; |
| 140 | } |
| 141 | else |
| 142 | { |
| 143 | bits_left_in_littlenum -= number_of_bits; |
| 144 | return_value = mask[number_of_bits] & ((*littlenum_pointer) >> bits_left_in_littlenum); |
| 145 | } |
| 146 | return (return_value); |
| 147 | } |
| 148 | |
| 149 | static void |
| 150 | make_invalid_floating_point_number (words) |
| 151 | LITTLENUM_TYPE *words; |
| 152 | { |
| 153 | *words = 0x8000; /* Floating Reserved Operand Code */ |
| 154 | } |
| 155 | \f |
| 156 | static int /* 0 means letter is OK. */ |
| 157 | what_kind_of_float (letter, precisionP, exponent_bitsP) |
| 158 | int letter; /* In: lowercase please. What kind of float? */ |
| 159 | int *precisionP; /* Number of 16-bit words in the float. */ |
| 160 | long *exponent_bitsP; /* Number of exponent bits. */ |
| 161 | { |
| 162 | int retval; /* 0: OK. */ |
| 163 | |
| 164 | retval = 0; |
| 165 | switch (letter) |
| 166 | { |
| 167 | case 'f': |
| 168 | *precisionP = F_PRECISION; |
| 169 | *exponent_bitsP = 8; |
| 170 | break; |
| 171 | |
| 172 | case 'd': |
| 173 | *precisionP = D_PRECISION; |
| 174 | *exponent_bitsP = 8; |
| 175 | break; |
| 176 | |
| 177 | case 'g': |
| 178 | *precisionP = G_PRECISION; |
| 179 | *exponent_bitsP = 11; |
| 180 | break; |
| 181 | |
| 182 | case 'h': |
| 183 | *precisionP = H_PRECISION; |
| 184 | *exponent_bitsP = 15; |
| 185 | break; |
| 186 | |
| 187 | default: |
| 188 | retval = 69; |
| 189 | break; |
| 190 | } |
| 191 | return (retval); |
| 192 | } |
| 193 | \f |
| 194 | /***********************************************************************\ |
| 195 | * * |
| 196 | * Warning: this returns 16-bit LITTLENUMs, because that is * |
| 197 | * what the VAX thinks in. It is up to the caller to figure * |
| 198 | * out any alignment problems and to conspire for the bytes/word * |
| 199 | * to be emitted in the right order. Bigendians beware! * |
| 200 | * * |
| 201 | \***********************************************************************/ |
| 202 | |
| 203 | static char * /* Return pointer past text consumed. */ |
| 204 | atof_vax (str, what_kind, words) |
| 205 | char *str; /* Text to convert to binary. */ |
| 206 | int what_kind; /* 'd', 'f', 'g', 'h' */ |
| 207 | LITTLENUM_TYPE *words; /* Build the binary here. */ |
| 208 | { |
| 209 | FLONUM_TYPE f; |
| 210 | LITTLENUM_TYPE bits[MAX_PRECISION + MAX_PRECISION + GUARD]; |
| 211 | /* Extra bits for zeroed low-order bits. */ |
| 212 | /* The 1st MAX_PRECISION are zeroed, */ |
| 213 | /* the last contain flonum bits. */ |
| 214 | char *return_value; |
| 215 | int precision; /* Number of 16-bit words in the format. */ |
| 216 | long exponent_bits; |
| 217 | |
| 218 | return_value = str; |
| 219 | f.low = bits + MAX_PRECISION; |
| 220 | f.high = NULL; |
| 221 | f.leader = NULL; |
| 222 | f.exponent = 0; |
| 223 | f.sign = '\0'; |
| 224 | |
| 225 | if (what_kind_of_float (what_kind, &precision, &exponent_bits)) |
| 226 | { |
| 227 | return_value = NULL; /* We lost. */ |
| 228 | make_invalid_floating_point_number (words); |
| 229 | } |
| 230 | |
| 231 | if (return_value) |
| 232 | { |
| 233 | memset (bits, '\0', sizeof (LITTLENUM_TYPE) * MAX_PRECISION); |
| 234 | |
| 235 | /* Use more LittleNums than seems */ |
| 236 | /* necessary: the highest flonum may have */ |
| 237 | /* 15 leading 0 bits, so could be useless. */ |
| 238 | f.high = f.low + precision - 1 + GUARD; |
| 239 | |
| 240 | if (atof_generic (&return_value, ".", "eE", &f)) |
| 241 | { |
| 242 | make_invalid_floating_point_number (words); |
| 243 | return_value = NULL; /* we lost */ |
| 244 | } |
| 245 | else |
| 246 | { |
| 247 | if (flonum_gen2vax (what_kind, &f, words)) |
| 248 | { |
| 249 | return_value = NULL; |
| 250 | } |
| 251 | } |
| 252 | } |
| 253 | return (return_value); |
| 254 | } /* atof_vax() */ |
| 255 | \f |
| 256 | /* |
| 257 | * In: a flonum, a vax floating point format. |
| 258 | * Out: a vax floating-point bit pattern. |
| 259 | */ |
| 260 | |
| 261 | int /* 0: OK. */ |
| 262 | flonum_gen2vax (format_letter, f, words) |
| 263 | char format_letter; /* One of 'd' 'f' 'g' 'h'. */ |
| 264 | FLONUM_TYPE *f; |
| 265 | LITTLENUM_TYPE *words; /* Deliver answer here. */ |
| 266 | { |
| 267 | LITTLENUM_TYPE *lp; |
| 268 | int precision; |
| 269 | long exponent_bits; |
| 270 | int return_value; /* 0 == OK. */ |
| 271 | |
| 272 | return_value = what_kind_of_float (format_letter, &precision, &exponent_bits); |
| 273 | |
| 274 | if (return_value != 0) |
| 275 | { |
| 276 | make_invalid_floating_point_number (words); |
| 277 | } |
| 278 | else |
| 279 | { |
| 280 | if (f->low > f->leader) |
| 281 | { |
| 282 | /* 0.0e0 seen. */ |
| 283 | memset (words, '\0', sizeof (LITTLENUM_TYPE) * precision); |
| 284 | } |
| 285 | else |
| 286 | { |
| 287 | long exponent_1; |
| 288 | long exponent_2; |
| 289 | long exponent_3; |
| 290 | long exponent_4; |
| 291 | int exponent_skippage; |
| 292 | LITTLENUM_TYPE word1; |
| 293 | |
| 294 | /* JF: Deal with new Nan, +Inf and -Inf codes */ |
| 295 | if (f->sign != '-' && f->sign != '+') |
| 296 | { |
| 297 | make_invalid_floating_point_number (words); |
| 298 | return return_value; |
| 299 | } |
| 300 | /* |
| 301 | * All vaxen floating_point formats (so far) have: |
| 302 | * Bit 15 is sign bit. |
| 303 | * Bits 14:n are excess-whatever exponent. |
| 304 | * Bits n-1:0 (if any) are most significant bits of fraction. |
| 305 | * Bits 15:0 of the next word are the next most significant bits. |
| 306 | * And so on for each other word. |
| 307 | * |
| 308 | * All this to be compatible with a KF11?? (Which is still faster |
| 309 | * than lots of vaxen I can think of, but it also has higher |
| 310 | * maintenance costs ... sigh). |
| 311 | * |
| 312 | * So we need: number of bits of exponent, number of bits of |
| 313 | * mantissa. |
| 314 | */ |
| 315 | |
| 316 | #ifdef NEVER /******* This zeroing seems redundant - Dean 3may86 **********/ |
| 317 | /* |
| 318 | * No matter how few bits we got back from the atof() |
| 319 | * routine, add enough zero littlenums so the rest of the |
| 320 | * code won't run out of "significant" bits in the mantissa. |
| 321 | */ |
| 322 | { |
| 323 | LITTLENUM_TYPE *ltp; |
| 324 | for (ltp = f->leader + 1; |
| 325 | ltp <= f->low + precision; |
| 326 | ltp++) |
| 327 | { |
| 328 | *ltp = 0; |
| 329 | } |
| 330 | } |
| 331 | #endif |
| 332 | |
| 333 | bits_left_in_littlenum = LITTLENUM_NUMBER_OF_BITS; |
| 334 | littlenum_pointer = f->leader; |
| 335 | littlenum_end = f->low; |
| 336 | /* Seek (and forget) 1st significant bit */ |
| 337 | for (exponent_skippage = 0; |
| 338 | !next_bits (1); |
| 339 | exponent_skippage++);; |
| 340 | |
| 341 | exponent_1 = f->exponent + f->leader + 1 - f->low; |
| 342 | /* Radix LITTLENUM_RADIX, point just higher than f->leader. */ |
| 343 | exponent_2 = exponent_1 * LITTLENUM_NUMBER_OF_BITS; |
| 344 | /* Radix 2. */ |
| 345 | exponent_3 = exponent_2 - exponent_skippage; |
| 346 | /* Forget leading zeros, forget 1st bit. */ |
| 347 | exponent_4 = exponent_3 + (1 << (exponent_bits - 1)); |
| 348 | /* Offset exponent. */ |
| 349 | |
| 350 | if (exponent_4 & ~mask[exponent_bits]) |
| 351 | { |
| 352 | /* |
| 353 | * Exponent overflow. Lose immediately. |
| 354 | */ |
| 355 | |
| 356 | make_invalid_floating_point_number (words); |
| 357 | |
| 358 | /* |
| 359 | * We leave return_value alone: admit we read the |
| 360 | * number, but return a floating exception |
| 361 | * because we can't encode the number. |
| 362 | */ |
| 363 | } |
| 364 | else |
| 365 | { |
| 366 | lp = words; |
| 367 | |
| 368 | /* Word 1. Sign, exponent and perhaps high bits. */ |
| 369 | /* Assume 2's complement integers. */ |
| 370 | word1 = (((exponent_4 & mask[exponent_bits]) << (15 - exponent_bits)) |
| 371 | | ((f->sign == '+') ? 0 : 0x8000) |
| 372 | | next_bits (15 - exponent_bits)); |
| 373 | *lp++ = word1; |
| 374 | |
| 375 | /* The rest of the words are just mantissa bits. */ |
| 376 | for (; lp < words + precision; lp++) |
| 377 | { |
| 378 | *lp = next_bits (LITTLENUM_NUMBER_OF_BITS); |
| 379 | } |
| 380 | |
| 381 | if (next_bits (1)) |
| 382 | { |
| 383 | /* |
| 384 | * Since the NEXT bit is a 1, round UP the mantissa. |
| 385 | * The cunning design of these hidden-1 floats permits |
| 386 | * us to let the mantissa overflow into the exponent, and |
| 387 | * it 'does the right thing'. However, we lose if the |
| 388 | * highest-order bit of the lowest-order word flips. |
| 389 | * Is that clear? |
| 390 | */ |
| 391 | |
| 392 | unsigned long carry; |
| 393 | |
| 394 | /* |
| 395 | #if (sizeof(carry)) < ((sizeof(bits[0]) * BITS_PER_CHAR) + 2) |
| 396 | Please allow at least 1 more bit in carry than is in a LITTLENUM. |
| 397 | We need that extra bit to hold a carry during a LITTLENUM carry |
| 398 | propagation. Another extra bit (kept 0) will assure us that we |
| 399 | don't get a sticky sign bit after shifting right, and that |
| 400 | permits us to propagate the carry without any masking of bits. |
| 401 | #endif |
| 402 | */ |
| 403 | for (carry = 1, lp--; |
| 404 | carry && (lp >= words); |
| 405 | lp--) |
| 406 | { |
| 407 | carry = *lp + carry; |
| 408 | *lp = carry; |
| 409 | carry >>= LITTLENUM_NUMBER_OF_BITS; |
| 410 | } |
| 411 | |
| 412 | if ((word1 ^ *words) & (1 << (LITTLENUM_NUMBER_OF_BITS - 1))) |
| 413 | { |
| 414 | make_invalid_floating_point_number (words); |
| 415 | /* |
| 416 | * We leave return_value alone: admit we read the |
| 417 | * number, but return a floating exception |
| 418 | * because we can't encode the number. |
| 419 | */ |
| 420 | } |
| 421 | } /* if (we needed to round up) */ |
| 422 | } /* if (exponent overflow) */ |
| 423 | } /* if (0.0e0) */ |
| 424 | } /* if (float_type was OK) */ |
| 425 | return (return_value); |
| 426 | } /* flonum_gen2vax() */ |
| 427 | |
| 428 | |
| 429 | /* JF this used to be in vax.c but this looks like a better place for it */ |
| 430 | |
| 431 | /* |
| 432 | * md_atof() |
| 433 | * |
| 434 | * In: input_line_pointer->the 1st character of a floating-point |
| 435 | * number. |
| 436 | * 1 letter denoting the type of statement that wants a |
| 437 | * binary floating point number returned. |
| 438 | * Address of where to build floating point literal. |
| 439 | * Assumed to be 'big enough'. |
| 440 | * Address of where to return size of literal (in chars). |
| 441 | * |
| 442 | * Out: Input_line_pointer->of next char after floating number. |
| 443 | * Error message, or 0. |
| 444 | * Floating point literal. |
| 445 | * Number of chars we used for the literal. |
| 446 | */ |
| 447 | |
| 448 | #define MAXIMUM_NUMBER_OF_LITTLENUMS (8) /* For .hfloats. */ |
| 449 | |
| 450 | char * |
| 451 | md_atof (what_statement_type, literalP, sizeP) |
| 452 | int what_statement_type; |
| 453 | char *literalP; |
| 454 | int *sizeP; |
| 455 | { |
| 456 | LITTLENUM_TYPE words[MAXIMUM_NUMBER_OF_LITTLENUMS]; |
| 457 | register char kind_of_float; |
| 458 | register int number_of_chars; |
| 459 | register LITTLENUM_TYPE *littlenumP; |
| 460 | |
| 461 | switch (what_statement_type) |
| 462 | { |
| 463 | case 'F': /* .float */ |
| 464 | case 'f': /* .ffloat */ |
| 465 | kind_of_float = 'f'; |
| 466 | break; |
| 467 | |
| 468 | case 'D': /* .double */ |
| 469 | case 'd': /* .dfloat */ |
| 470 | kind_of_float = 'd'; |
| 471 | break; |
| 472 | |
| 473 | case 'g': /* .gfloat */ |
| 474 | kind_of_float = 'g'; |
| 475 | break; |
| 476 | |
| 477 | case 'h': /* .hfloat */ |
| 478 | kind_of_float = 'h'; |
| 479 | break; |
| 480 | |
| 481 | default: |
| 482 | kind_of_float = 0; |
| 483 | break; |
| 484 | }; |
| 485 | |
| 486 | if (kind_of_float) |
| 487 | { |
| 488 | register LITTLENUM_TYPE *limit; |
| 489 | |
| 490 | input_line_pointer = atof_vax (input_line_pointer, |
| 491 | kind_of_float, |
| 492 | words); |
| 493 | /* |
| 494 | * The atof_vax() builds up 16-bit numbers. |
| 495 | * Since the assembler may not be running on |
| 496 | * a little-endian machine, be very careful about |
| 497 | * converting words to chars. |
| 498 | */ |
| 499 | number_of_chars = atof_vax_sizeof (kind_of_float); |
| 500 | know (number_of_chars <= MAXIMUM_NUMBER_OF_LITTLENUMS * sizeof (LITTLENUM_TYPE)); |
| 501 | limit = words + (number_of_chars / sizeof (LITTLENUM_TYPE)); |
| 502 | for (littlenumP = words; littlenumP < limit; littlenumP++) |
| 503 | { |
| 504 | md_number_to_chars (literalP, *littlenumP, sizeof (LITTLENUM_TYPE)); |
| 505 | literalP += sizeof (LITTLENUM_TYPE); |
| 506 | }; |
| 507 | } |
| 508 | else |
| 509 | { |
| 510 | number_of_chars = 0; |
| 511 | }; |
| 512 | |
| 513 | *sizeP = number_of_chars; |
| 514 | return kind_of_float ? 0 : _("Bad call to md_atof()"); |
| 515 | } |
| 516 | |
| 517 | /* end of atof-vax.c */ |