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 * 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 * 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 * 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 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 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 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 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) 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