Commit | Line | Data |
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252b5132 | 1 | /* atof_ieee.c - turn a Flonum into an IEEE floating point number |
aef6203b | 2 | Copyright 1987, 1992, 1994, 1996, 1997, 1998, 1999, 2000, 2001, 2005 |
252b5132 RH |
3 | Free Software Foundation, Inc. |
4 | ||
5 | This file is part of GAS, the GNU Assembler. | |
6 | ||
7 | GAS is free software; you can redistribute it and/or modify | |
8 | it under the terms of the GNU General Public License as published by | |
9 | the Free Software Foundation; either version 2, or (at your option) | |
10 | any later version. | |
11 | ||
12 | GAS is distributed in the hope that it will be useful, | |
13 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
14 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
15 | GNU General Public License for more details. | |
16 | ||
17 | You should have received a copy of the GNU General Public License | |
18 | along with GAS; see the file COPYING. If not, write to the Free | |
4b4da160 NC |
19 | Software Foundation, 51 Franklin Street - Fifth Floor, Boston, MA |
20 | 02110-1301, USA. */ | |
252b5132 RH |
21 | |
22 | #include "as.h" | |
23 | ||
24 | /* Flonums returned here. */ | |
25 | extern FLONUM_TYPE generic_floating_point_number; | |
26 | ||
252b5132 | 27 | extern const char EXP_CHARS[]; |
2d484c7f | 28 | /* Precision in LittleNums. */ |
252b5132 | 29 | /* Don't count the gap in the m68k extended precision format. */ |
ea1562b3 NC |
30 | #define MAX_PRECISION 5 |
31 | #define F_PRECISION 2 | |
32 | #define D_PRECISION 4 | |
33 | #define X_PRECISION 5 | |
34 | #define P_PRECISION 5 | |
252b5132 | 35 | |
2d484c7f | 36 | /* Length in LittleNums of guard bits. */ |
ea1562b3 | 37 | #define GUARD 2 |
252b5132 | 38 | |
3a18fa4f | 39 | #ifndef TC_LARGEST_EXPONENT_IS_NORMAL |
580a832e | 40 | #define TC_LARGEST_EXPONENT_IS_NORMAL(PRECISION) 0 |
e103941e NC |
41 | #endif |
42 | ||
252b5132 RH |
43 | static const unsigned long mask[] = |
44 | { | |
45 | 0x00000000, | |
46 | 0x00000001, | |
47 | 0x00000003, | |
48 | 0x00000007, | |
49 | 0x0000000f, | |
50 | 0x0000001f, | |
51 | 0x0000003f, | |
52 | 0x0000007f, | |
53 | 0x000000ff, | |
54 | 0x000001ff, | |
55 | 0x000003ff, | |
56 | 0x000007ff, | |
57 | 0x00000fff, | |
58 | 0x00001fff, | |
59 | 0x00003fff, | |
60 | 0x00007fff, | |
61 | 0x0000ffff, | |
62 | 0x0001ffff, | |
63 | 0x0003ffff, | |
64 | 0x0007ffff, | |
65 | 0x000fffff, | |
66 | 0x001fffff, | |
67 | 0x003fffff, | |
68 | 0x007fffff, | |
69 | 0x00ffffff, | |
70 | 0x01ffffff, | |
71 | 0x03ffffff, | |
72 | 0x07ffffff, | |
73 | 0x0fffffff, | |
74 | 0x1fffffff, | |
75 | 0x3fffffff, | |
76 | 0x7fffffff, | |
77 | 0xffffffff, | |
78 | }; | |
79 | \f | |
252b5132 RH |
80 | static int bits_left_in_littlenum; |
81 | static int littlenums_left; | |
82 | static LITTLENUM_TYPE *littlenum_pointer; | |
83 | ||
84 | static int | |
ea1562b3 | 85 | next_bits (int number_of_bits) |
252b5132 RH |
86 | { |
87 | int return_value; | |
88 | ||
89 | if (!littlenums_left) | |
ea1562b3 NC |
90 | return 0; |
91 | ||
252b5132 RH |
92 | if (number_of_bits >= bits_left_in_littlenum) |
93 | { | |
94 | return_value = mask[bits_left_in_littlenum] & *littlenum_pointer; | |
95 | number_of_bits -= bits_left_in_littlenum; | |
96 | return_value <<= number_of_bits; | |
97 | ||
98 | if (--littlenums_left) | |
99 | { | |
100 | bits_left_in_littlenum = LITTLENUM_NUMBER_OF_BITS - number_of_bits; | |
101 | --littlenum_pointer; | |
2d484c7f KH |
102 | return_value |= |
103 | (*littlenum_pointer >> bits_left_in_littlenum) | |
104 | & mask[number_of_bits]; | |
252b5132 RH |
105 | } |
106 | } | |
107 | else | |
108 | { | |
109 | bits_left_in_littlenum -= number_of_bits; | |
2d484c7f KH |
110 | return_value = |
111 | mask[number_of_bits] & (*littlenum_pointer >> bits_left_in_littlenum); | |
252b5132 | 112 | } |
2d484c7f | 113 | return return_value; |
252b5132 RH |
114 | } |
115 | ||
2d484c7f KH |
116 | /* Num had better be less than LITTLENUM_NUMBER_OF_BITS. */ |
117 | ||
252b5132 | 118 | static void |
ea1562b3 | 119 | unget_bits (int num) |
252b5132 RH |
120 | { |
121 | if (!littlenums_left) | |
122 | { | |
123 | ++littlenum_pointer; | |
124 | ++littlenums_left; | |
125 | bits_left_in_littlenum = num; | |
126 | } | |
127 | else if (bits_left_in_littlenum + num > LITTLENUM_NUMBER_OF_BITS) | |
128 | { | |
2d484c7f KH |
129 | bits_left_in_littlenum = |
130 | num - (LITTLENUM_NUMBER_OF_BITS - bits_left_in_littlenum); | |
252b5132 RH |
131 | ++littlenum_pointer; |
132 | ++littlenums_left; | |
133 | } | |
134 | else | |
135 | bits_left_in_littlenum += num; | |
136 | } | |
137 | ||
138 | static void | |
ea1562b3 | 139 | make_invalid_floating_point_number (LITTLENUM_TYPE *words) |
252b5132 RH |
140 | { |
141 | as_bad (_("cannot create floating-point number")); | |
2d484c7f KH |
142 | /* Zero the leftmost bit. */ |
143 | words[0] = (LITTLENUM_TYPE) ((unsigned) -1) >> 1; | |
252b5132 RH |
144 | words[1] = (LITTLENUM_TYPE) -1; |
145 | words[2] = (LITTLENUM_TYPE) -1; | |
146 | words[3] = (LITTLENUM_TYPE) -1; | |
147 | words[4] = (LITTLENUM_TYPE) -1; | |
148 | words[5] = (LITTLENUM_TYPE) -1; | |
149 | } | |
150 | \f | |
2d484c7f KH |
151 | /* Warning: This returns 16-bit LITTLENUMs. It is up to the caller to |
152 | figure out any alignment problems and to conspire for the | |
153 | bytes/word to be emitted in the right order. Bigendians beware! */ | |
252b5132 RH |
154 | |
155 | /* Note that atof-ieee always has X and P precisions enabled. it is up | |
156 | to md_atof to filter them out if the target machine does not support | |
157 | them. */ | |
158 | ||
2d484c7f KH |
159 | /* Returns pointer past text consumed. */ |
160 | ||
252b5132 | 161 | char * |
ea1562b3 NC |
162 | atof_ieee (char *str, /* Text to convert to binary. */ |
163 | int what_kind, /* 'd', 'f', 'g', 'h'. */ | |
164 | LITTLENUM_TYPE *words) /* Build the binary here. */ | |
252b5132 | 165 | { |
2d484c7f KH |
166 | /* Extra bits for zeroed low-order bits. |
167 | The 1st MAX_PRECISION are zeroed, the last contain flonum bits. */ | |
252b5132 RH |
168 | static LITTLENUM_TYPE bits[MAX_PRECISION + MAX_PRECISION + GUARD]; |
169 | char *return_value; | |
2d484c7f | 170 | /* Number of 16-bit words in the format. */ |
252b5132 RH |
171 | int precision; |
172 | long exponent_bits; | |
173 | FLONUM_TYPE save_gen_flonum; | |
174 | ||
175 | /* We have to save the generic_floating_point_number because it | |
176 | contains storage allocation about the array of LITTLENUMs where | |
177 | the value is actually stored. We will allocate our own array of | |
178 | littlenums below, but have to restore the global one on exit. */ | |
179 | save_gen_flonum = generic_floating_point_number; | |
180 | ||
181 | return_value = str; | |
182 | generic_floating_point_number.low = bits + MAX_PRECISION; | |
183 | generic_floating_point_number.high = NULL; | |
184 | generic_floating_point_number.leader = NULL; | |
185 | generic_floating_point_number.exponent = 0; | |
186 | generic_floating_point_number.sign = '\0'; | |
187 | ||
188 | /* Use more LittleNums than seems necessary: the highest flonum may | |
2d484c7f | 189 | have 15 leading 0 bits, so could be useless. */ |
252b5132 RH |
190 | |
191 | memset (bits, '\0', sizeof (LITTLENUM_TYPE) * MAX_PRECISION); | |
192 | ||
193 | switch (what_kind) | |
194 | { | |
195 | case 'f': | |
196 | case 'F': | |
197 | case 's': | |
198 | case 'S': | |
199 | precision = F_PRECISION; | |
200 | exponent_bits = 8; | |
201 | break; | |
202 | ||
203 | case 'd': | |
204 | case 'D': | |
205 | case 'r': | |
206 | case 'R': | |
207 | precision = D_PRECISION; | |
208 | exponent_bits = 11; | |
209 | break; | |
210 | ||
211 | case 'x': | |
212 | case 'X': | |
213 | case 'e': | |
214 | case 'E': | |
215 | precision = X_PRECISION; | |
216 | exponent_bits = 15; | |
217 | break; | |
218 | ||
219 | case 'p': | |
220 | case 'P': | |
221 | ||
222 | precision = P_PRECISION; | |
223 | exponent_bits = -1; | |
224 | break; | |
225 | ||
226 | default: | |
227 | make_invalid_floating_point_number (words); | |
228 | return (NULL); | |
229 | } | |
230 | ||
231 | generic_floating_point_number.high | |
232 | = generic_floating_point_number.low + precision - 1 + GUARD; | |
233 | ||
234 | if (atof_generic (&return_value, ".", EXP_CHARS, | |
235 | &generic_floating_point_number)) | |
236 | { | |
237 | make_invalid_floating_point_number (words); | |
ea1562b3 | 238 | return NULL; |
252b5132 RH |
239 | } |
240 | gen_to_words (words, precision, exponent_bits); | |
241 | ||
242 | /* Restore the generic_floating_point_number's storage alloc (and | |
243 | everything else). */ | |
244 | generic_floating_point_number = save_gen_flonum; | |
245 | ||
246 | return return_value; | |
247 | } | |
248 | ||
249 | /* Turn generic_floating_point_number into a real float/double/extended. */ | |
2d484c7f | 250 | |
252b5132 | 251 | int |
ea1562b3 | 252 | gen_to_words (LITTLENUM_TYPE *words, int precision, long exponent_bits) |
252b5132 RH |
253 | { |
254 | int return_value = 0; | |
255 | ||
256 | long exponent_1; | |
257 | long exponent_2; | |
258 | long exponent_3; | |
259 | long exponent_4; | |
260 | int exponent_skippage; | |
261 | LITTLENUM_TYPE word1; | |
262 | LITTLENUM_TYPE *lp; | |
263 | LITTLENUM_TYPE *words_end; | |
264 | ||
265 | words_end = words + precision; | |
266 | #ifdef TC_M68K | |
267 | if (precision == X_PRECISION) | |
268 | /* On the m68k the extended precision format has a gap of 16 bits | |
269 | between the exponent and the mantissa. */ | |
270 | words_end++; | |
271 | #endif | |
272 | ||
273 | if (generic_floating_point_number.low > generic_floating_point_number.leader) | |
274 | { | |
2d484c7f | 275 | /* 0.0e0 seen. */ |
252b5132 RH |
276 | if (generic_floating_point_number.sign == '+') |
277 | words[0] = 0x0000; | |
278 | else | |
279 | words[0] = 0x8000; | |
280 | memset (&words[1], '\0', | |
281 | (words_end - words - 1) * sizeof (LITTLENUM_TYPE)); | |
2d484c7f | 282 | return return_value; |
252b5132 RH |
283 | } |
284 | ||
2d484c7f | 285 | /* NaN: Do the right thing. */ |
252b5132 RH |
286 | if (generic_floating_point_number.sign == 0) |
287 | { | |
580a832e | 288 | if (TC_LARGEST_EXPONENT_IS_NORMAL (precision)) |
e103941e | 289 | as_warn ("NaNs are not supported by this target\n"); |
252b5132 RH |
290 | if (precision == F_PRECISION) |
291 | { | |
292 | words[0] = 0x7fff; | |
293 | words[1] = 0xffff; | |
294 | } | |
295 | else if (precision == X_PRECISION) | |
296 | { | |
297 | #ifdef TC_M68K | |
298 | words[0] = 0x7fff; | |
299 | words[1] = 0; | |
300 | words[2] = 0xffff; | |
301 | words[3] = 0xffff; | |
302 | words[4] = 0xffff; | |
303 | words[5] = 0xffff; | |
2d484c7f | 304 | #else /* ! TC_M68K */ |
252b5132 RH |
305 | #ifdef TC_I386 |
306 | words[0] = 0xffff; | |
307 | words[1] = 0xc000; | |
308 | words[2] = 0; | |
309 | words[3] = 0; | |
310 | words[4] = 0; | |
2d484c7f | 311 | #else /* ! TC_I386 */ |
252b5132 | 312 | abort (); |
2d484c7f KH |
313 | #endif /* ! TC_I386 */ |
314 | #endif /* ! TC_M68K */ | |
252b5132 RH |
315 | } |
316 | else | |
317 | { | |
318 | words[0] = 0x7fff; | |
319 | words[1] = 0xffff; | |
320 | words[2] = 0xffff; | |
321 | words[3] = 0xffff; | |
322 | } | |
323 | return return_value; | |
324 | } | |
325 | else if (generic_floating_point_number.sign == 'P') | |
326 | { | |
580a832e | 327 | if (TC_LARGEST_EXPONENT_IS_NORMAL (precision)) |
e103941e NC |
328 | as_warn ("Infinities are not supported by this target\n"); |
329 | ||
2d484c7f | 330 | /* +INF: Do the right thing. */ |
252b5132 RH |
331 | if (precision == F_PRECISION) |
332 | { | |
333 | words[0] = 0x7f80; | |
334 | words[1] = 0; | |
335 | } | |
336 | else if (precision == X_PRECISION) | |
337 | { | |
338 | #ifdef TC_M68K | |
339 | words[0] = 0x7fff; | |
340 | words[1] = 0; | |
341 | words[2] = 0; | |
342 | words[3] = 0; | |
343 | words[4] = 0; | |
344 | words[5] = 0; | |
2d484c7f | 345 | #else /* ! TC_M68K */ |
252b5132 RH |
346 | #ifdef TC_I386 |
347 | words[0] = 0x7fff; | |
348 | words[1] = 0x8000; | |
349 | words[2] = 0; | |
350 | words[3] = 0; | |
351 | words[4] = 0; | |
2d484c7f | 352 | #else /* ! TC_I386 */ |
252b5132 | 353 | abort (); |
2d484c7f KH |
354 | #endif /* ! TC_I386 */ |
355 | #endif /* ! TC_M68K */ | |
252b5132 RH |
356 | } |
357 | else | |
358 | { | |
359 | words[0] = 0x7ff0; | |
360 | words[1] = 0; | |
361 | words[2] = 0; | |
362 | words[3] = 0; | |
363 | } | |
2d484c7f | 364 | return return_value; |
252b5132 RH |
365 | } |
366 | else if (generic_floating_point_number.sign == 'N') | |
367 | { | |
580a832e | 368 | if (TC_LARGEST_EXPONENT_IS_NORMAL (precision)) |
e103941e NC |
369 | as_warn ("Infinities are not supported by this target\n"); |
370 | ||
2d484c7f | 371 | /* Negative INF. */ |
252b5132 RH |
372 | if (precision == F_PRECISION) |
373 | { | |
374 | words[0] = 0xff80; | |
375 | words[1] = 0x0; | |
376 | } | |
377 | else if (precision == X_PRECISION) | |
378 | { | |
379 | #ifdef TC_M68K | |
380 | words[0] = 0xffff; | |
381 | words[1] = 0; | |
382 | words[2] = 0; | |
383 | words[3] = 0; | |
384 | words[4] = 0; | |
385 | words[5] = 0; | |
2d484c7f | 386 | #else /* ! TC_M68K */ |
252b5132 RH |
387 | #ifdef TC_I386 |
388 | words[0] = 0xffff; | |
389 | words[1] = 0x8000; | |
390 | words[2] = 0; | |
391 | words[3] = 0; | |
392 | words[4] = 0; | |
2d484c7f | 393 | #else /* ! TC_I386 */ |
252b5132 | 394 | abort (); |
2d484c7f KH |
395 | #endif /* ! TC_I386 */ |
396 | #endif /* ! TC_M68K */ | |
252b5132 RH |
397 | } |
398 | else | |
399 | { | |
400 | words[0] = 0xfff0; | |
401 | words[1] = 0x0; | |
402 | words[2] = 0x0; | |
403 | words[3] = 0x0; | |
404 | } | |
2d484c7f | 405 | return return_value; |
252b5132 | 406 | } |
2d484c7f KH |
407 | |
408 | /* The floating point formats we support have: | |
409 | Bit 15 is sign bit. | |
410 | Bits 14:n are excess-whatever exponent. | |
411 | Bits n-1:0 (if any) are most significant bits of fraction. | |
412 | Bits 15:0 of the next word(s) are the next most significant bits. | |
413 | ||
414 | So we need: number of bits of exponent, number of bits of | |
415 | mantissa. */ | |
252b5132 RH |
416 | bits_left_in_littlenum = LITTLENUM_NUMBER_OF_BITS; |
417 | littlenum_pointer = generic_floating_point_number.leader; | |
418 | littlenums_left = (1 | |
419 | + generic_floating_point_number.leader | |
420 | - generic_floating_point_number.low); | |
2d484c7f KH |
421 | |
422 | /* Seek (and forget) 1st significant bit. */ | |
252b5132 RH |
423 | for (exponent_skippage = 0; !next_bits (1); ++exponent_skippage);; |
424 | exponent_1 = (generic_floating_point_number.exponent | |
425 | + generic_floating_point_number.leader | |
426 | + 1 | |
427 | - generic_floating_point_number.low); | |
2d484c7f | 428 | |
252b5132 | 429 | /* Radix LITTLENUM_RADIX, point just higher than |
2d484c7f | 430 | generic_floating_point_number.leader. */ |
252b5132 | 431 | exponent_2 = exponent_1 * LITTLENUM_NUMBER_OF_BITS; |
2d484c7f KH |
432 | |
433 | /* Radix 2. */ | |
252b5132 | 434 | exponent_3 = exponent_2 - exponent_skippage; |
2d484c7f KH |
435 | |
436 | /* Forget leading zeros, forget 1st bit. */ | |
252b5132 | 437 | exponent_4 = exponent_3 + ((1 << (exponent_bits - 1)) - 2); |
252b5132 | 438 | |
2d484c7f | 439 | /* Offset exponent. */ |
252b5132 RH |
440 | lp = words; |
441 | ||
2d484c7f | 442 | /* Word 1. Sign, exponent and perhaps high bits. */ |
252b5132 RH |
443 | word1 = ((generic_floating_point_number.sign == '+') |
444 | ? 0 | |
445 | : (1 << (LITTLENUM_NUMBER_OF_BITS - 1))); | |
446 | ||
2d484c7f | 447 | /* Assume 2's complement integers. */ |
252b5132 RH |
448 | if (exponent_4 <= 0) |
449 | { | |
450 | int prec_bits; | |
451 | int num_bits; | |
452 | ||
453 | unget_bits (1); | |
454 | num_bits = -exponent_4; | |
2d484c7f KH |
455 | prec_bits = |
456 | LITTLENUM_NUMBER_OF_BITS * precision - (exponent_bits + 1 + num_bits); | |
252b5132 RH |
457 | #ifdef TC_I386 |
458 | if (precision == X_PRECISION && exponent_bits == 15) | |
459 | { | |
460 | /* On the i386 a denormalized extended precision float is | |
461 | shifted down by one, effectively decreasing the exponent | |
462 | bias by one. */ | |
463 | prec_bits -= 1; | |
464 | num_bits += 1; | |
465 | } | |
466 | #endif | |
467 | ||
468 | if (num_bits >= LITTLENUM_NUMBER_OF_BITS - exponent_bits) | |
469 | { | |
2d484c7f | 470 | /* Bigger than one littlenum. */ |
252b5132 RH |
471 | num_bits -= (LITTLENUM_NUMBER_OF_BITS - 1) - exponent_bits; |
472 | *lp++ = word1; | |
2d484c7f KH |
473 | if (num_bits + exponent_bits + 1 |
474 | > precision * LITTLENUM_NUMBER_OF_BITS) | |
252b5132 | 475 | { |
2d484c7f | 476 | /* Exponent overflow. */ |
252b5132 | 477 | make_invalid_floating_point_number (words); |
2d484c7f | 478 | return return_value; |
252b5132 RH |
479 | } |
480 | #ifdef TC_M68K | |
481 | if (precision == X_PRECISION && exponent_bits == 15) | |
482 | *lp++ = 0; | |
483 | #endif | |
484 | while (num_bits >= LITTLENUM_NUMBER_OF_BITS) | |
485 | { | |
486 | num_bits -= LITTLENUM_NUMBER_OF_BITS; | |
487 | *lp++ = 0; | |
488 | } | |
489 | if (num_bits) | |
490 | *lp++ = next_bits (LITTLENUM_NUMBER_OF_BITS - (num_bits)); | |
491 | } | |
492 | else | |
493 | { | |
494 | if (precision == X_PRECISION && exponent_bits == 15) | |
495 | { | |
496 | *lp++ = word1; | |
497 | #ifdef TC_M68K | |
498 | *lp++ = 0; | |
499 | #endif | |
500 | *lp++ = next_bits (LITTLENUM_NUMBER_OF_BITS - num_bits); | |
501 | } | |
502 | else | |
503 | { | |
2d484c7f KH |
504 | word1 |= next_bits ((LITTLENUM_NUMBER_OF_BITS - 1) |
505 | - (exponent_bits + num_bits)); | |
252b5132 RH |
506 | *lp++ = word1; |
507 | } | |
508 | } | |
509 | while (lp < words_end) | |
510 | *lp++ = next_bits (LITTLENUM_NUMBER_OF_BITS); | |
511 | ||
2d484c7f | 512 | /* Round the mantissa up, but don't change the number. */ |
252b5132 RH |
513 | if (next_bits (1)) |
514 | { | |
515 | --lp; | |
19b34177 | 516 | if (prec_bits >= LITTLENUM_NUMBER_OF_BITS) |
252b5132 RH |
517 | { |
518 | int n = 0; | |
519 | int tmp_bits; | |
520 | ||
521 | n = 0; | |
522 | tmp_bits = prec_bits; | |
523 | while (tmp_bits > LITTLENUM_NUMBER_OF_BITS) | |
524 | { | |
525 | if (lp[n] != (LITTLENUM_TYPE) - 1) | |
526 | break; | |
527 | --n; | |
528 | tmp_bits -= LITTLENUM_NUMBER_OF_BITS; | |
529 | } | |
19b34177 AS |
530 | if (tmp_bits > LITTLENUM_NUMBER_OF_BITS |
531 | || (lp[n] & mask[tmp_bits]) != mask[tmp_bits] | |
532 | || (prec_bits != (precision * LITTLENUM_NUMBER_OF_BITS | |
533 | - exponent_bits - 1) | |
534 | #ifdef TC_I386 | |
535 | /* An extended precision float with only the integer | |
536 | bit set would be invalid. That must be converted | |
537 | to the smallest normalized number. */ | |
538 | && !(precision == X_PRECISION | |
539 | && prec_bits == (precision * LITTLENUM_NUMBER_OF_BITS | |
540 | - exponent_bits - 2)) | |
541 | #endif | |
542 | )) | |
252b5132 RH |
543 | { |
544 | unsigned long carry; | |
545 | ||
546 | for (carry = 1; carry && (lp >= words); lp--) | |
547 | { | |
548 | carry = *lp + carry; | |
549 | *lp = carry; | |
550 | carry >>= LITTLENUM_NUMBER_OF_BITS; | |
551 | } | |
552 | } | |
553 | else | |
554 | { | |
555 | /* This is an overflow of the denormal numbers. We | |
556 | need to forget what we have produced, and instead | |
557 | generate the smallest normalized number. */ | |
558 | lp = words; | |
559 | word1 = ((generic_floating_point_number.sign == '+') | |
560 | ? 0 | |
561 | : (1 << (LITTLENUM_NUMBER_OF_BITS - 1))); | |
562 | word1 |= (1 | |
563 | << ((LITTLENUM_NUMBER_OF_BITS - 1) | |
564 | - exponent_bits)); | |
565 | *lp++ = word1; | |
19b34177 AS |
566 | #ifdef TC_I386 |
567 | /* Set the integer bit in the extended precision format. | |
568 | This cannot happen on the m68k where the mantissa | |
569 | just overflows into the integer bit above. */ | |
570 | if (precision == X_PRECISION) | |
571 | *lp++ = 1 << (LITTLENUM_NUMBER_OF_BITS - 1); | |
572 | #endif | |
252b5132 RH |
573 | while (lp < words_end) |
574 | *lp++ = 0; | |
575 | } | |
576 | } | |
19b34177 | 577 | else |
252b5132 RH |
578 | *lp += 1; |
579 | } | |
580 | ||
581 | return return_value; | |
582 | } | |
e103941e | 583 | else if ((unsigned long) exponent_4 > mask[exponent_bits] |
580a832e | 584 | || (! TC_LARGEST_EXPONENT_IS_NORMAL (precision) |
e103941e | 585 | && (unsigned long) exponent_4 == mask[exponent_bits])) |
252b5132 | 586 | { |
2d484c7f KH |
587 | /* Exponent overflow. Lose immediately. */ |
588 | ||
589 | /* We leave return_value alone: admit we read the | |
590 | number, but return a floating exception | |
591 | because we can't encode the number. */ | |
252b5132 RH |
592 | make_invalid_floating_point_number (words); |
593 | return return_value; | |
594 | } | |
595 | else | |
596 | { | |
597 | word1 |= (exponent_4 << ((LITTLENUM_NUMBER_OF_BITS - 1) - exponent_bits)) | |
598 | | next_bits ((LITTLENUM_NUMBER_OF_BITS - 1) - exponent_bits); | |
599 | } | |
600 | ||
601 | *lp++ = word1; | |
602 | ||
603 | /* X_PRECISION is special: on the 68k, it has 16 bits of zero in the | |
2d484c7f | 604 | middle. Either way, it is then followed by a 1 bit. */ |
252b5132 RH |
605 | if (exponent_bits == 15 && precision == X_PRECISION) |
606 | { | |
607 | #ifdef TC_M68K | |
608 | *lp++ = 0; | |
609 | #endif | |
610 | *lp++ = (1 << (LITTLENUM_NUMBER_OF_BITS - 1) | |
611 | | next_bits (LITTLENUM_NUMBER_OF_BITS - 1)); | |
612 | } | |
613 | ||
2d484c7f | 614 | /* The rest of the words are just mantissa bits. */ |
252b5132 RH |
615 | while (lp < words_end) |
616 | *lp++ = next_bits (LITTLENUM_NUMBER_OF_BITS); | |
617 | ||
618 | if (next_bits (1)) | |
619 | { | |
620 | unsigned long carry; | |
2d484c7f KH |
621 | /* Since the NEXT bit is a 1, round UP the mantissa. |
622 | The cunning design of these hidden-1 floats permits | |
623 | us to let the mantissa overflow into the exponent, and | |
624 | it 'does the right thing'. However, we lose if the | |
625 | highest-order bit of the lowest-order word flips. | |
626 | Is that clear? */ | |
252b5132 RH |
627 | |
628 | /* #if (sizeof(carry)) < ((sizeof(bits[0]) * BITS_PER_CHAR) + 2) | |
629 | Please allow at least 1 more bit in carry than is in a LITTLENUM. | |
630 | We need that extra bit to hold a carry during a LITTLENUM carry | |
631 | propagation. Another extra bit (kept 0) will assure us that we | |
632 | don't get a sticky sign bit after shifting right, and that | |
633 | permits us to propagate the carry without any masking of bits. | |
634 | #endif */ | |
44877466 | 635 | for (carry = 1, lp--; carry; lp--) |
252b5132 RH |
636 | { |
637 | carry = *lp + carry; | |
638 | *lp = carry; | |
639 | carry >>= LITTLENUM_NUMBER_OF_BITS; | |
44877466 ILT |
640 | if (lp == words) |
641 | break; | |
252b5132 RH |
642 | } |
643 | if (precision == X_PRECISION && exponent_bits == 15) | |
644 | { | |
645 | /* Extended precision numbers have an explicit integer bit | |
646 | that we may have to restore. */ | |
647 | if (lp == words) | |
648 | { | |
649 | #ifdef TC_M68K | |
650 | /* On the m68k there is a gap of 16 bits. We must | |
2d484c7f | 651 | explicitly propagate the carry into the exponent. */ |
252b5132 RH |
652 | words[0] += words[1]; |
653 | words[1] = 0; | |
654 | lp++; | |
655 | #endif | |
2d484c7f | 656 | /* Put back the integer bit. */ |
252b5132 RH |
657 | lp[1] |= 1 << (LITTLENUM_NUMBER_OF_BITS - 1); |
658 | } | |
2d484c7f | 659 | } |
252b5132 RH |
660 | if ((word1 ^ *words) & (1 << (LITTLENUM_NUMBER_OF_BITS - 1))) |
661 | { | |
2d484c7f KH |
662 | /* We leave return_value alone: admit we read the number, |
663 | but return a floating exception because we can't encode | |
664 | the number. */ | |
252b5132 | 665 | *words &= ~(1 << (LITTLENUM_NUMBER_OF_BITS - 1)); |
252b5132 RH |
666 | } |
667 | } | |
2d484c7f | 668 | return return_value; |
252b5132 RH |
669 | } |
670 | ||
252b5132 RH |
671 | #ifdef TEST |
672 | char * | |
673 | print_gen (gen) | |
674 | FLONUM_TYPE *gen; | |
675 | { | |
676 | FLONUM_TYPE f; | |
677 | LITTLENUM_TYPE arr[10]; | |
678 | double dv; | |
679 | float fv; | |
680 | static char sbuf[40]; | |
681 | ||
682 | if (gen) | |
683 | { | |
684 | f = generic_floating_point_number; | |
685 | generic_floating_point_number = *gen; | |
686 | } | |
687 | gen_to_words (&arr[0], 4, 11); | |
688 | memcpy (&dv, &arr[0], sizeof (double)); | |
689 | sprintf (sbuf, "%x %x %x %x %.14G ", arr[0], arr[1], arr[2], arr[3], dv); | |
690 | gen_to_words (&arr[0], 2, 8); | |
691 | memcpy (&fv, &arr[0], sizeof (float)); | |
692 | sprintf (sbuf + strlen (sbuf), "%x %x %.12g\n", arr[0], arr[1], fv); | |
693 | ||
694 | if (gen) | |
2d484c7f | 695 | generic_floating_point_number = f; |
252b5132 RH |
696 | |
697 | return (sbuf); | |
698 | } | |
699 | ||
700 | #endif |