1 /*
2 * /src/NTP/ntp4-dev/libntp/ieee754io.c,v 4.12 2005/04/16 17:32:10 kardel RELEASE_20050508_A
3 *
4 * ieee754io.c,v 4.12 2005/04/16 17:32:10 kardel RELEASE_20050508_A
5 *
6 * $Created: Sun Jul 13 09:12:02 1997 $
7 *
8 * Copyright (c) 1997-2005 by Frank Kardel <kardel <AT> ntp.org>
9 *
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
12 * are met:
13 * 1. Redistributions of source code must retain the above copyright
14 * notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 * notice, this list of conditions and the following disclaimer in the
17 * documentation and/or other materials provided with the distribution.
18 * 3. Neither the name of the author nor the names of its contributors
19 * may be used to endorse or promote products derived from this software
20 * without specific prior written permission.
21 *
22 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
25 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32 * SUCH DAMAGE.
33 *
34 */
35
36 #ifdef HAVE_CONFIG_H
37 #include "config.h"
38 #endif
39
40 #include <stdio.h>
41 #include "l_stdlib.h"
42 #include "ntp_stdlib.h"
43 #include "ntp_fp.h"
44 #include "ieee754io.h"
45
46 static unsigned char get_byte (unsigned char *, offsets_t, int *);
47 #ifdef __not_yet__
48 static void put_byte (unsigned char *, offsets_t, int *, unsigned char);
49 #endif
50
51 #ifdef LIBDEBUG
52
53 #include "lib_strbuf.h"
54
55 static char *
fmt_blong(unsigned long val,int cnt)56 fmt_blong(
57 unsigned long val,
58 int cnt
59 )
60 {
61 char *buf, *s;
62 int i = cnt;
63
64 val <<= 32 - cnt;
65 LIB_GETBUF(buf);
66 s = buf;
67
68 while (i--)
69 {
70 if (val & 0x80000000)
71 {
72 *s++ = '1';
73 }
74 else
75 {
76 *s++ = '0';
77 }
78 val <<= 1;
79 }
80 *s = '\0';
81 return buf;
82 }
83
84 static char *
fmt_flt(unsigned int sign,unsigned long mh,unsigned long ml,unsigned long ch)85 fmt_flt(
86 unsigned int sign,
87 unsigned long mh,
88 unsigned long ml,
89 unsigned long ch
90 )
91 {
92 char *buf;
93
94 LIB_GETBUF(buf);
95 snprintf(buf, LIB_BUFLENGTH, "%c %s %s %s", sign ? '-' : '+',
96 fmt_blong(ch, 11),
97 fmt_blong(mh, 20),
98 fmt_blong(ml, 32));
99
100 return buf;
101 }
102
103 static char *
fmt_hex(unsigned char * bufp,int length)104 fmt_hex(
105 unsigned char *bufp,
106 int length
107 )
108 {
109 char * buf;
110 char hex[4];
111 int i;
112
113 LIB_GETBUF(buf);
114 buf[0] = '\0';
115 for (i = 0; i < length; i++) {
116 snprintf(hex, sizeof(hex), "%02x", bufp[i]);
117 strlcat(buf, hex, LIB_BUFLENGTH);
118 }
119
120 return buf;
121 }
122
123 #endif
124
125 static unsigned char
get_byte(unsigned char * bufp,offsets_t offset,int * fieldindex)126 get_byte(
127 unsigned char *bufp,
128 offsets_t offset,
129 int *fieldindex
130 )
131 {
132 unsigned char val;
133
134 val = *(bufp + offset[*fieldindex]);
135 #ifdef LIBDEBUG
136 if (debug > 4)
137 printf("fetchieee754: getbyte(0x%08x, %d) = 0x%02x\n", (unsigned int)(bufp)+offset[*fieldindex], *fieldindex, val);
138 #endif
139 (*fieldindex)++;
140 return val;
141 }
142
143 #ifdef __not_yet__
144 static void
put_byte(unsigned char * bufp,offsets_t offsets,int * fieldindex,unsigned char val)145 put_byte(
146 unsigned char *bufp,
147 offsets_t offsets,
148 int *fieldindex,
149 unsigned char val
150 )
151 {
152 *(bufp + offsets[*fieldindex]) = val;
153 (*fieldindex)++;
154 }
155 #endif
156
157 /*
158 * make conversions to and from external IEEE754 formats and internal
159 * NTP FP format.
160 */
161 int
fetch_ieee754(unsigned char ** buffpp,int size,l_fp * lfpp,offsets_t offsets)162 fetch_ieee754(
163 unsigned char **buffpp,
164 int size,
165 l_fp *lfpp,
166 offsets_t offsets
167 )
168 {
169 unsigned char *bufp = *buffpp;
170 unsigned int sign;
171 unsigned int bias;
172 unsigned int maxexp;
173 int mbits;
174 u_long mantissa_low;
175 u_long mantissa_high;
176 u_long characteristic;
177 long exponent;
178 #ifdef LIBDEBUG
179 int length;
180 #endif
181 unsigned char val;
182 int fieldindex = 0;
183
184 switch (size)
185 {
186 case IEEE_DOUBLE:
187 #ifdef LIBDEBUG
188 length = 8;
189 #endif
190 mbits = 52;
191 bias = 1023;
192 maxexp = 2047;
193 break;
194
195 case IEEE_SINGLE:
196 #ifdef LIBDEBUG
197 length = 4;
198 #endif
199 mbits = 23;
200 bias = 127;
201 maxexp = 255;
202 break;
203
204 default:
205 return IEEE_BADCALL;
206 }
207
208 val = get_byte(bufp, offsets, &fieldindex); /* fetch sign byte & first part of characteristic */
209
210 sign = (val & 0x80) != 0;
211 characteristic = (val & 0x7F);
212
213 val = get_byte(bufp, offsets, &fieldindex); /* fetch rest of characteristic and start of mantissa */
214
215 switch (size)
216 {
217 case IEEE_SINGLE:
218 characteristic <<= 1;
219 characteristic |= (val & 0x80) != 0; /* grab last characteristic bit */
220
221 mantissa_high = 0;
222
223 mantissa_low = (val &0x7F) << 16;
224 mantissa_low |= (u_long)get_byte(bufp, offsets, &fieldindex) << 8;
225 mantissa_low |= get_byte(bufp, offsets, &fieldindex);
226 break;
227
228 case IEEE_DOUBLE:
229 characteristic <<= 4;
230 characteristic |= (val & 0xF0) >> 4; /* grab lower characteristic bits */
231
232 mantissa_high = (val & 0x0F) << 16;
233 mantissa_high |= (u_long)get_byte(bufp, offsets, &fieldindex) << 8;
234 mantissa_high |= get_byte(bufp, offsets, &fieldindex);
235
236 mantissa_low = (u_long)get_byte(bufp, offsets, &fieldindex) << 24;
237 mantissa_low |= (u_long)get_byte(bufp, offsets, &fieldindex) << 16;
238 mantissa_low |= (u_long)get_byte(bufp, offsets, &fieldindex) << 8;
239 mantissa_low |= get_byte(bufp, offsets, &fieldindex);
240 break;
241
242 default:
243 return IEEE_BADCALL;
244 }
245 #ifdef LIBDEBUG
246 if (debug > 4)
247 {
248 double d;
249 float f;
250
251 if (size == IEEE_SINGLE)
252 {
253 int i;
254
255 for (i = 0; i < length; i++)
256 {
257 *((unsigned char *)(&f)+i) = *(*buffpp + offsets[i]);
258 }
259 d = f;
260 }
261 else
262 {
263 int i;
264
265 for (i = 0; i < length; i++)
266 {
267 *((unsigned char *)(&d)+i) = *(*buffpp + offsets[i]);
268 }
269 }
270
271 printf("fetchieee754: FP: %s -> %s -> %e(=%s)\n", fmt_hex(*buffpp, length),
272 fmt_flt(sign, mantissa_high, mantissa_low, characteristic),
273 d, fmt_hex((unsigned char *)&d, length));
274 }
275 #endif
276
277 *buffpp += fieldindex;
278
279 /*
280 * detect funny numbers
281 */
282 if (characteristic == maxexp)
283 {
284 /*
285 * NaN or Infinity
286 */
287 if (mantissa_low || mantissa_high)
288 {
289 /*
290 * NaN
291 */
292 return IEEE_NAN;
293 }
294 else
295 {
296 /*
297 * +Inf or -Inf
298 */
299 return sign ? IEEE_NEGINFINITY : IEEE_POSINFINITY;
300 }
301 }
302 else
303 {
304 /*
305 * collect real numbers
306 */
307
308 L_CLR(lfpp);
309
310 /*
311 * check for overflows
312 */
313 exponent = characteristic - bias;
314
315 if (exponent > 31) /* sorry - hardcoded */
316 {
317 /*
318 * overflow only in respect to NTP-FP representation
319 */
320 return sign ? IEEE_NEGOVERFLOW : IEEE_POSOVERFLOW;
321 }
322 else
323 {
324 int frac_offset; /* where the fraction starts */
325
326 frac_offset = mbits - exponent;
327
328 if (characteristic == 0)
329 {
330 /*
331 * de-normalized or tiny number - fits only as 0
332 */
333 return IEEE_OK;
334 }
335 else
336 {
337 /*
338 * adjust for implied 1
339 */
340 if (mbits > 31)
341 mantissa_high |= 1 << (mbits - 32);
342 else
343 mantissa_low |= 1 << mbits;
344
345 /*
346 * take mantissa apart - if only all machine would support
347 * 64 bit operations 8-(
348 */
349 if (frac_offset > mbits)
350 {
351 lfpp->l_ui = 0; /* only fractional number */
352 frac_offset -= mbits + 1; /* will now contain right shift count - 1*/
353 if (mbits > 31)
354 {
355 lfpp->l_uf = mantissa_high << (63 - mbits);
356 lfpp->l_uf |= mantissa_low >> (mbits - 33);
357 lfpp->l_uf >>= frac_offset;
358 }
359 else
360 {
361 lfpp->l_uf = mantissa_low >> frac_offset;
362 }
363 }
364 else
365 {
366 if (frac_offset > 32)
367 {
368 /*
369 * must split in high word
370 */
371 lfpp->l_ui = mantissa_high >> (frac_offset - 32);
372 lfpp->l_uf = (mantissa_high & ((1 << (frac_offset - 32)) - 1)) << (64 - frac_offset);
373 lfpp->l_uf |= mantissa_low >> (frac_offset - 32);
374 }
375 else
376 {
377 /*
378 * must split in low word
379 */
380 lfpp->l_ui = mantissa_high << (32 - frac_offset);
381 lfpp->l_ui |= (mantissa_low >> frac_offset) & ((1 << (32 - frac_offset)) - 1);
382 lfpp->l_uf = (mantissa_low & ((1 << frac_offset) - 1)) << (32 - frac_offset);
383 }
384 }
385
386 /*
387 * adjust for sign
388 */
389 if (sign)
390 {
391 L_NEG(lfpp);
392 }
393
394 return IEEE_OK;
395 }
396 }
397 }
398 }
399
400 int
put_ieee754(unsigned char ** bufpp,int size,l_fp * lfpp,offsets_t offsets)401 put_ieee754(
402 unsigned char **bufpp,
403 int size,
404 l_fp *lfpp,
405 offsets_t offsets
406 )
407 {
408 l_fp outlfp;
409 #ifdef LIBDEBUG
410 unsigned int sign;
411 unsigned int bias;
412 #endif
413 /*unsigned int maxexp;*/
414 int mbits;
415 int msb;
416 u_long mantissa_low = 0;
417 u_long mantissa_high = 0;
418 #ifdef LIBDEBUG
419 u_long characteristic = 0;
420 long exponent;
421 #endif
422 /*int length;*/
423 unsigned long mask;
424
425 outlfp = *lfpp;
426
427 switch (size)
428 {
429 case IEEE_DOUBLE:
430 /*length = 8;*/
431 mbits = 52;
432 #ifdef LIBDEBUG
433 bias = 1023;
434 #endif
435 /*maxexp = 2047;*/
436 break;
437
438 case IEEE_SINGLE:
439 /*length = 4;*/
440 mbits = 23;
441 #ifdef LIBDEBUG
442 bias = 127;
443 #endif
444 /*maxexp = 255;*/
445 break;
446
447 default:
448 return IEEE_BADCALL;
449 }
450
451 /*
452 * find sign
453 */
454 if (L_ISNEG(&outlfp))
455 {
456 L_NEG(&outlfp);
457 #ifdef LIBDEBUG
458 sign = 1;
459 #endif
460 }
461 else
462 {
463 #ifdef LIBDEBUG
464 sign = 0;
465 #endif
466 }
467
468 if (L_ISZERO(&outlfp))
469 {
470 #ifdef LIBDEBUG
471 exponent = mantissa_high = mantissa_low = 0; /* true zero */
472 #endif
473 }
474 else
475 {
476 /*
477 * find number of significant integer bits
478 */
479 mask = 0x80000000;
480 if (outlfp.l_ui)
481 {
482 msb = 63;
483 while (mask && ((outlfp.l_ui & mask) == 0))
484 {
485 mask >>= 1;
486 msb--;
487 }
488 }
489 else
490 {
491 msb = 31;
492 while (mask && ((outlfp.l_uf & mask) == 0))
493 {
494 mask >>= 1;
495 msb--;
496 }
497 }
498
499 switch (size)
500 {
501 case IEEE_SINGLE:
502 mantissa_high = 0;
503 if (msb >= 32)
504 {
505 mantissa_low = (outlfp.l_ui & ((1 << (msb - 32)) - 1)) << (mbits - (msb - 32));
506 mantissa_low |= outlfp.l_uf >> (mbits - (msb - 32));
507 }
508 else
509 {
510 mantissa_low = (outlfp.l_uf << (mbits - msb)) & ((1 << mbits) - 1);
511 }
512 break;
513
514 case IEEE_DOUBLE:
515 if (msb >= 32)
516 {
517 mantissa_high = (outlfp.l_ui << (mbits - msb)) & ((1 << (mbits - 32)) - 1);
518 mantissa_high |= outlfp.l_uf >> (32 - (mbits - msb));
519 mantissa_low = (outlfp.l_ui & ((1 << (msb - mbits)) - 1)) << (32 - (msb - mbits));
520 mantissa_low |= outlfp.l_uf >> (msb - mbits);
521 }
522 else
523 {
524 mantissa_high = outlfp.l_uf << (mbits - 32 - msb);
525 mantissa_low = outlfp.l_uf << (mbits - 32);
526 }
527 }
528
529 #ifdef LIBDEBUG
530 exponent = msb - 32;
531 characteristic = exponent + bias;
532
533 if (debug > 4)
534 printf("FP: %s\n", fmt_flt(sign, mantissa_high, mantissa_low, characteristic));
535 #endif
536 }
537 return IEEE_OK;
538 }
539
540
541 #if defined(DEBUG) && defined(LIBDEBUG)
main(int argc,char ** argv)542 int main(
543 int argc,
544 char **argv
545 )
546 {
547 static offsets_t native_off = { 0, 1, 2, 3, 4, 5, 6, 7 };
548 double f = 1.0;
549 double *f_p = &f;
550 l_fp fp;
551
552 if (argc == 2)
553 {
554 if (sscanf(argv[1], "%lf", &f) != 1)
555 {
556 printf("cannot convert %s to a float\n", argv[1]);
557 return 1;
558 }
559 }
560
561 printf("double: %s %s\n", fmt_blong(*(unsigned long *)&f, 32), fmt_blong(*(unsigned long *)((char *)(&f)+4), 32));
562 printf("fetch from %f = %d\n", f, fetch_ieee754((void *)&f_p, IEEE_DOUBLE, &fp, native_off));
563 printf("fp [%s %s] = %s\n", fmt_blong(fp.l_ui, 32), fmt_blong(fp.l_uf, 32), mfptoa(fp.l_ui, fp.l_uf, 15));
564 f_p = &f;
565 put_ieee754((void *)&f_p, IEEE_DOUBLE, &fp, native_off);
566
567 return 0;
568 }
569
570 #endif
571 /*
572 * History:
573 *
574 * ieee754io.c,v
575 * Revision 4.12 2005/04/16 17:32:10 kardel
576 * update copyright
577 *
578 * Revision 4.11 2004/11/14 15:29:41 kardel
579 * support PPSAPI, upgrade Copyright to Berkeley style
580 *
581 * Revision 4.8 1999/02/21 12:17:36 kardel
582 * 4.91f reconcilation
583 *
584 * Revision 4.7 1999/02/21 11:26:03 kardel
585 * renamed index to fieldindex to avoid index() name clash
586 *
587 * Revision 4.6 1998/11/15 20:27:52 kardel
588 * Release 4.0.73e13 reconcilation
589 *
590 * Revision 4.5 1998/08/16 19:01:51 kardel
591 * debug information only compile for LIBDEBUG case
592 *
593 * Revision 4.4 1998/08/09 09:39:28 kardel
594 * Release 4.0.73e2 reconcilation
595 *
596 * Revision 4.3 1998/06/13 11:56:19 kardel
597 * disabled putbute() for the time being
598 *
599 * Revision 4.2 1998/06/12 15:16:58 kardel
600 * ansi2knr compatibility
601 *
602 * Revision 4.1 1998/05/24 07:59:56 kardel
603 * conditional debug support
604 *
605 * Revision 4.0 1998/04/10 19:46:29 kardel
606 * Start 4.0 release version numbering
607 *
608 * Revision 1.1 1998/04/10 19:27:46 kardel
609 * initial NTP VERSION 4 integration of PARSE with GPS166 binary support
610 *
611 * Revision 1.1 1997/10/06 21:05:45 kardel
612 * new parse structure
613 *
614 */
615