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fecd2382 RP |
1 | /* atof_vax.c - turn a Flonum into a VAX floating point number |
2 | Copyright (C) 1987 Free Software Foundation, Inc. | |
a39116f1 RP |
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 | |
18 | the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA. */ | |
19 | ||
20 | /* JF added these two for md_atof() */ | |
fecd2382 RP |
21 | #include "as.h" |
22 | ||
23 | #include "flonum.h" | |
24 | ||
25 | ||
a39116f1 | 26 | /* Precision in LittleNums. */ |
fecd2382 RP |
27 | #define MAX_PRECISION (8) |
28 | #define H_PRECISION (8) | |
29 | #define G_PRECISION (4) | |
30 | #define D_PRECISION (4) | |
31 | #define F_PRECISION (2) | |
32 | ||
a39116f1 | 33 | /* Length in LittleNums of guard bits. */ |
fecd2382 RP |
34 | #define GUARD (2) |
35 | ||
36 | int /* Number of chars in flonum type 'letter'. */ | |
a39116f1 RP |
37 | atof_vax_sizeof (letter) |
38 | char letter; | |
fecd2382 | 39 | { |
a39116f1 RP |
40 | int return_value; |
41 | ||
42 | /* | |
43 | * Permitting uppercase letters is probably a bad idea. | |
44 | * Please use only lower-cased letters in case the upper-cased | |
45 | * ones become unsupported! | |
46 | */ | |
47 | switch (letter) | |
48 | { | |
49 | case 'f': | |
50 | case 'F': | |
51 | return_value = 4; | |
52 | break; | |
53 | ||
54 | case 'd': | |
55 | case 'D': | |
56 | case 'g': | |
57 | case 'G': | |
58 | return_value = 8; | |
59 | break; | |
60 | ||
61 | case 'h': | |
62 | case 'H': | |
63 | return_value = 16; | |
64 | break; | |
65 | ||
66 | default: | |
67 | return_value = 0; | |
68 | break; | |
69 | } | |
70 | return (return_value); | |
71 | } /* atof_vax_sizeof */ | |
fecd2382 RP |
72 | |
73 | static const long mask [] = { | |
a39116f1 RP |
74 | 0x00000000, |
75 | 0x00000001, | |
76 | 0x00000003, | |
77 | 0x00000007, | |
78 | 0x0000000f, | |
79 | 0x0000001f, | |
80 | 0x0000003f, | |
81 | 0x0000007f, | |
82 | 0x000000ff, | |
83 | 0x000001ff, | |
84 | 0x000003ff, | |
85 | 0x000007ff, | |
86 | 0x00000fff, | |
87 | 0x00001fff, | |
88 | 0x00003fff, | |
89 | 0x00007fff, | |
90 | 0x0000ffff, | |
91 | 0x0001ffff, | |
92 | 0x0003ffff, | |
93 | 0x0007ffff, | |
94 | 0x000fffff, | |
95 | 0x001fffff, | |
96 | 0x003fffff, | |
97 | 0x007fffff, | |
98 | 0x00ffffff, | |
99 | 0x01ffffff, | |
100 | 0x03ffffff, | |
101 | 0x07ffffff, | |
102 | 0x0fffffff, | |
103 | 0x1fffffff, | |
104 | 0x3fffffff, | |
105 | 0x7fffffff, | |
106 | 0xffffffff | |
107 | }; | |
fecd2382 RP |
108 | \f |
109 | ||
110 | /* Shared between flonum_gen2vax and next_bits */ | |
111 | static int bits_left_in_littlenum; | |
112 | static LITTLENUM_TYPE * littlenum_pointer; | |
113 | static LITTLENUM_TYPE * littlenum_end; | |
114 | ||
115 | static int | |
a39116f1 RP |
116 | next_bits (number_of_bits) |
117 | int number_of_bits; | |
fecd2382 | 118 | { |
a39116f1 RP |
119 | int return_value; |
120 | ||
121 | if(littlenum_pointer<littlenum_end) | |
122 | return 0; | |
123 | if (number_of_bits >= bits_left_in_littlenum) | |
124 | { | |
125 | return_value = mask [bits_left_in_littlenum] & * littlenum_pointer; | |
126 | number_of_bits -= bits_left_in_littlenum; | |
127 | return_value <<= number_of_bits; | |
128 | bits_left_in_littlenum = LITTLENUM_NUMBER_OF_BITS - number_of_bits; | |
129 | littlenum_pointer --; | |
130 | if(littlenum_pointer>=littlenum_end) | |
131 | return_value |= ( (* littlenum_pointer) >> (bits_left_in_littlenum) ) & mask [number_of_bits]; | |
132 | } | |
133 | else | |
134 | { | |
135 | bits_left_in_littlenum -= number_of_bits; | |
136 | return_value = mask [number_of_bits] & ( (* littlenum_pointer) >> bits_left_in_littlenum); | |
137 | } | |
138 | return (return_value); | |
fecd2382 RP |
139 | } |
140 | ||
141 | static void | |
a39116f1 RP |
142 | make_invalid_floating_point_number (words) |
143 | LITTLENUM_TYPE * words; | |
fecd2382 | 144 | { |
a39116f1 | 145 | * words = 0x8000; /* Floating Reserved Operand Code */ |
fecd2382 RP |
146 | } |
147 | \f | |
148 | static int /* 0 means letter is OK. */ | |
a39116f1 RP |
149 | what_kind_of_float (letter, precisionP, exponent_bitsP) |
150 | char letter; /* In: lowercase please. What kind of float? */ | |
151 | int * precisionP; /* Number of 16-bit words in the float. */ | |
152 | long * exponent_bitsP; /* Number of exponent bits. */ | |
fecd2382 | 153 | { |
a39116f1 RP |
154 | int retval; /* 0: OK. */ |
155 | ||
156 | retval = 0; | |
157 | switch (letter) | |
158 | { | |
159 | case 'f': | |
160 | * precisionP = F_PRECISION; | |
161 | * exponent_bitsP = 8; | |
162 | break; | |
163 | ||
164 | case 'd': | |
165 | * precisionP = D_PRECISION; | |
166 | * exponent_bitsP = 8; | |
167 | break; | |
168 | ||
169 | case 'g': | |
170 | * precisionP = G_PRECISION; | |
171 | * exponent_bitsP = 11; | |
172 | break; | |
173 | ||
174 | case 'h': | |
175 | * precisionP = H_PRECISION; | |
176 | * exponent_bitsP = 15; | |
177 | break; | |
178 | ||
179 | default: | |
180 | retval = 69; | |
181 | break; | |
182 | } | |
183 | return (retval); | |
fecd2382 RP |
184 | } |
185 | \f | |
186 | /***********************************************************************\ | |
a39116f1 RP |
187 | * * |
188 | * Warning: this returns 16-bit LITTLENUMs, because that is * | |
189 | * what the VAX thinks in. It is up to the caller to figure * | |
190 | * out any alignment problems and to conspire for the bytes/word * | |
191 | * to be emitted in the right order. Bigendians beware! * | |
192 | * * | |
193 | \***********************************************************************/ | |
fecd2382 RP |
194 | |
195 | char * /* Return pointer past text consumed. */ | |
a39116f1 RP |
196 | atof_vax (str, what_kind, words) |
197 | char * str; /* Text to convert to binary. */ | |
198 | char what_kind; /* 'd', 'f', 'g', 'h' */ | |
199 | LITTLENUM_TYPE * words; /* Build the binary here. */ | |
fecd2382 | 200 | { |
a39116f1 RP |
201 | FLONUM_TYPE f; |
202 | LITTLENUM_TYPE bits [MAX_PRECISION + MAX_PRECISION + GUARD]; | |
203 | /* Extra bits for zeroed low-order bits. */ | |
204 | /* The 1st MAX_PRECISION are zeroed, */ | |
205 | /* the last contain flonum bits. */ | |
206 | char * return_value; | |
207 | int precision; /* Number of 16-bit words in the format. */ | |
208 | long exponent_bits; | |
209 | ||
210 | return_value = str; | |
211 | f . low = bits + MAX_PRECISION; | |
212 | f . high = NULL; | |
213 | f . leader = NULL; | |
214 | f . exponent = NULL; | |
215 | f . sign = '\0'; | |
216 | ||
217 | if (what_kind_of_float (what_kind, & precision, & exponent_bits)) | |
218 | { | |
219 | return_value = NULL; /* We lost. */ | |
220 | make_invalid_floating_point_number (words); | |
221 | } | |
222 | if (return_value) | |
fecd2382 | 223 | { |
a39116f1 RP |
224 | bzero (bits, sizeof(LITTLENUM_TYPE) * MAX_PRECISION); |
225 | ||
226 | /* Use more LittleNums than seems */ | |
227 | /* necessary: the highest flonum may have */ | |
228 | /* 15 leading 0 bits, so could be useless. */ | |
229 | f . high = f . low + precision - 1 + GUARD; | |
230 | ||
231 | if (atof_generic (& return_value, ".", "eE", & f)) | |
232 | { | |
233 | make_invalid_floating_point_number (words); | |
234 | return_value = NULL; /* we lost */ | |
235 | } | |
236 | else | |
237 | { | |
238 | if (flonum_gen2vax (what_kind, & f, words)) | |
239 | { | |
240 | return_value = NULL; | |
241 | } | |
242 | } | |
fecd2382 | 243 | } |
a39116f1 | 244 | return (return_value); |
fecd2382 RP |
245 | } |
246 | \f | |
247 | /* | |
248 | * In: a flonum, a vax floating point format. | |
249 | * Out: a vax floating-point bit pattern. | |
250 | */ | |
251 | ||
252 | int /* 0: OK. */ | |
a39116f1 RP |
253 | flonum_gen2vax (format_letter, f, words) |
254 | char format_letter; /* One of 'd' 'f' 'g' 'h'. */ | |
255 | FLONUM_TYPE * f; | |
256 | LITTLENUM_TYPE * words; /* Deliver answer here. */ | |
fecd2382 | 257 | { |
a39116f1 RP |
258 | LITTLENUM_TYPE * lp; |
259 | int precision; | |
260 | long exponent_bits; | |
261 | int return_value; /* 0 == OK. */ | |
262 | ||
263 | return_value = what_kind_of_float (format_letter, & precision, & exponent_bits); | |
264 | if (return_value != 0) | |
fecd2382 | 265 | { |
a39116f1 | 266 | make_invalid_floating_point_number (words); |
fecd2382 | 267 | } |
a39116f1 | 268 | else |
fecd2382 | 269 | { |
a39116f1 RP |
270 | if (f -> low > f -> leader) |
271 | { | |
272 | /* 0.0e0 seen. */ | |
273 | bzero (words, sizeof(LITTLENUM_TYPE) * precision); | |
274 | } | |
275 | else | |
276 | { | |
277 | long exponent_1; | |
278 | long exponent_2; | |
279 | long exponent_3; | |
280 | long exponent_4; | |
281 | int exponent_skippage; | |
282 | LITTLENUM_TYPE word1; | |
283 | ||
284 | /* JF: Deal with new Nan, +Inf and -Inf codes */ | |
285 | if(f->sign!='-' && f->sign!='+') { | |
286 | make_invalid_floating_point_number(words); | |
287 | return return_value; | |
288 | } | |
289 | /* | |
290 | * All vaxen floating_point formats (so far) have: | |
291 | * Bit 15 is sign bit. | |
292 | * Bits 14:n are excess-whatever exponent. | |
293 | * Bits n-1:0 (if any) are most significant bits of fraction. | |
294 | * Bits 15:0 of the next word are the next most significant bits. | |
295 | * And so on for each other word. | |
296 | * | |
297 | * All this to be compatible with a KF11?? (Which is still faster | |
298 | * than lots of vaxen I can think of, but it also has higher | |
299 | * maintenance costs ... sigh). | |
300 | * | |
301 | * So we need: number of bits of exponent, number of bits of | |
302 | * mantissa. | |
303 | */ | |
304 | ||
305 | #ifdef NEVER /******* This zeroing seems redundant - Dean 3may86 **********/ | |
306 | /* | |
307 | * No matter how few bits we got back from the atof() | |
308 | * routine, add enough zero littlenums so the rest of the | |
309 | * code won't run out of "significant" bits in the mantissa. | |
310 | */ | |
311 | { | |
312 | LITTLENUM_TYPE * ltp; | |
313 | for (ltp = f -> leader + 1; | |
314 | ltp <= f -> low + precision; | |
315 | ltp ++) | |
316 | { | |
317 | * ltp = 0; | |
318 | } | |
319 | } | |
320 | #endif | |
321 | ||
322 | bits_left_in_littlenum = LITTLENUM_NUMBER_OF_BITS; | |
323 | littlenum_pointer = f -> leader; | |
324 | littlenum_end = f->low; | |
325 | /* Seek (and forget) 1st significant bit */ | |
326 | for (exponent_skippage = 0; | |
327 | ! next_bits(1); | |
328 | exponent_skippage ++) | |
329 | { | |
330 | } | |
331 | exponent_1 = f -> exponent + f -> leader + 1 - f -> low; | |
332 | /* Radix LITTLENUM_RADIX, point just higher than f -> leader. */ | |
333 | exponent_2 = exponent_1 * LITTLENUM_NUMBER_OF_BITS; | |
334 | /* Radix 2. */ | |
335 | exponent_3 = exponent_2 - exponent_skippage; | |
336 | /* Forget leading zeros, forget 1st bit. */ | |
337 | exponent_4 = exponent_3 + (1 << (exponent_bits - 1)); | |
338 | /* Offset exponent. */ | |
339 | ||
340 | if (exponent_4 & ~ mask [exponent_bits]) | |
341 | { | |
342 | /* | |
343 | * Exponent overflow. Lose immediately. | |
344 | */ | |
345 | ||
346 | make_invalid_floating_point_number (words); | |
347 | ||
348 | /* | |
349 | * We leave return_value alone: admit we read the | |
350 | * number, but return a floating exception | |
351 | * because we can't encode the number. | |
352 | */ | |
353 | } | |
354 | else | |
355 | { | |
356 | lp = words; | |
357 | ||
358 | /* Word 1. Sign, exponent and perhaps high bits. */ | |
359 | /* Assume 2's complement integers. */ | |
360 | word1 = ((exponent_4 & mask [exponent_bits]) << (15 - exponent_bits)) | |
361 | | ((f -> sign == '+') ? 0 : 0x8000) | |
362 | | next_bits (15 - exponent_bits); | |
363 | * lp ++ = word1; | |
364 | ||
365 | /* The rest of the words are just mantissa bits. */ | |
366 | for (; lp < words + precision; lp++) | |
367 | { | |
368 | * lp = next_bits (LITTLENUM_NUMBER_OF_BITS); | |
369 | } | |
370 | ||
371 | if (next_bits (1)) | |
372 | { | |
373 | /* | |
374 | * Since the NEXT bit is a 1, round UP the mantissa. | |
375 | * The cunning design of these hidden-1 floats permits | |
376 | * us to let the mantissa overflow into the exponent, and | |
377 | * it 'does the right thing'. However, we lose if the | |
378 | * highest-order bit of the lowest-order word flips. | |
379 | * Is that clear? | |
380 | */ | |
381 | ||
382 | unsigned long carry; | |
383 | ||
384 | /* | |
385 | #if (sizeof(carry)) < ((sizeof(bits[0]) * BITS_PER_CHAR) + 2) | |
386 | Please allow at least 1 more bit in carry than is in a LITTLENUM. | |
387 | We need that extra bit to hold a carry during a LITTLENUM carry | |
388 | propagation. Another extra bit (kept 0) will assure us that we | |
389 | don't get a sticky sign bit after shifting right, and that | |
390 | permits us to propagate the carry without any masking of bits. | |
391 | #endif | |
392 | */ | |
393 | for (carry = 1, lp --; | |
394 | carry && (lp >= words); | |
395 | lp --) | |
396 | { | |
397 | carry = * lp + carry; | |
398 | * lp = carry; | |
399 | carry >>= LITTLENUM_NUMBER_OF_BITS; | |
400 | } | |
401 | ||
402 | if ( (word1 ^ *words) & (1 << (LITTLENUM_NUMBER_OF_BITS - 1)) ) | |
403 | { | |
404 | make_invalid_floating_point_number (words); | |
405 | /* | |
406 | * We leave return_value alone: admit we read the | |
407 | * number, but return a floating exception | |
408 | * because we can't encode the number. | |
409 | */ | |
410 | } | |
411 | } /* if (we needed to round up) */ | |
412 | } /* if (exponent overflow) */ | |
413 | } /* if (0.0e0) */ | |
414 | } /* if (float_type was OK) */ | |
415 | return (return_value); | |
fecd2382 RP |
416 | } |
417 | ||
418 | ||
419 | /* JF this used to be in vax.c but this looks like a better place for it */ | |
420 | ||
421 | /* | |
422 | * md_atof() | |
423 | * | |
424 | * In: input_line_pointer -> the 1st character of a floating-point | |
425 | * number. | |
426 | * 1 letter denoting the type of statement that wants a | |
427 | * binary floating point number returned. | |
428 | * Address of where to build floating point literal. | |
429 | * Assumed to be 'big enough'. | |
430 | * Address of where to return size of literal (in chars). | |
431 | * | |
432 | * Out: Input_line_pointer -> of next char after floating number. | |
433 | * Error message, or "". | |
434 | * Floating point literal. | |
435 | * Number of chars we used for the literal. | |
436 | */ | |
437 | ||
438 | #define MAXIMUM_NUMBER_OF_LITTLENUMS (8) /* For .hfloats. */ | |
439 | ||
440 | char * | |
a39116f1 RP |
441 | md_atof (what_statement_type, literalP, sizeP) |
442 | char what_statement_type; | |
443 | char * literalP; | |
444 | int * sizeP; | |
fecd2382 | 445 | { |
a39116f1 RP |
446 | LITTLENUM_TYPE words [MAXIMUM_NUMBER_OF_LITTLENUMS]; |
447 | register char kind_of_float; | |
448 | register int number_of_chars; | |
449 | register LITTLENUM_TYPE * littlenum_pointer; | |
450 | ||
451 | switch (what_statement_type) | |
452 | { | |
453 | case 'F': /* .float */ | |
454 | case 'f': /* .ffloat */ | |
455 | kind_of_float = 'f'; | |
456 | break; | |
457 | ||
458 | case 'D': /* .double */ | |
459 | case 'd': /* .dfloat */ | |
460 | kind_of_float = 'd'; | |
461 | break; | |
462 | ||
463 | case 'g': /* .gfloat */ | |
464 | kind_of_float = 'g'; | |
465 | break; | |
466 | ||
467 | case 'h': /* .hfloat */ | |
468 | kind_of_float = 'h'; | |
469 | break; | |
470 | ||
471 | default: | |
472 | kind_of_float = 0; | |
473 | break; | |
474 | }; | |
475 | ||
476 | if (kind_of_float) | |
477 | { | |
478 | register LITTLENUM_TYPE * limit; | |
479 | ||
480 | input_line_pointer = atof_vax (input_line_pointer, | |
481 | kind_of_float, | |
482 | words); | |
483 | /* | |
484 | * The atof_vax() builds up 16-bit numbers. | |
485 | * Since the assembler may not be running on | |
486 | * a little-endian machine, be very careful about | |
487 | * converting words to chars. | |
488 | */ | |
489 | number_of_chars = atof_vax_sizeof (kind_of_float); | |
490 | know( number_of_chars <= MAXIMUM_NUMBER_OF_LITTLENUMS * sizeof(LITTLENUM_TYPE) ); | |
491 | limit = words + (number_of_chars / sizeof(LITTLENUM_TYPE)); | |
492 | for (littlenum_pointer = words; | |
493 | littlenum_pointer < limit; | |
494 | littlenum_pointer ++) | |
495 | { | |
496 | md_number_to_chars (literalP, * littlenum_pointer, sizeof(LITTLENUM_TYPE)); | |
497 | literalP += sizeof(LITTLENUM_TYPE); | |
498 | }; | |
499 | } | |
500 | else | |
501 | { | |
502 | number_of_chars = 0; | |
503 | }; | |
504 | ||
505 | * sizeP = number_of_chars; | |
506 | return (kind_of_float ? "" : "Bad call to md_atof()"); | |
fecd2382 RP |
507 | } /* md_atof() */ |
508 | ||
8b228fe9 | 509 | /* end of atof-vax.c */ |