meson: convert hw/vfio
[qemu.git] / libdecnumber / dpd / decimal32.c
1 /* Decimal 32-bit format module for the decNumber C Library.
2 Copyright (C) 2005, 2007 Free Software Foundation, Inc.
3 Contributed by IBM Corporation. Author Mike Cowlishaw.
4
5 This file is part of GCC.
6
7 GCC is free software; you can redistribute it and/or modify it under
8 the terms of the GNU General Public License as published by the Free
9 Software Foundation; either version 2, or (at your option) any later
10 version.
11
12 In addition to the permissions in the GNU General Public License,
13 the Free Software Foundation gives you unlimited permission to link
14 the compiled version of this file into combinations with other
15 programs, and to distribute those combinations without any
16 restriction coming from the use of this file. (The General Public
17 License restrictions do apply in other respects; for example, they
18 cover modification of the file, and distribution when not linked
19 into a combine executable.)
20
21 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
22 WARRANTY; without even the implied warranty of MERCHANTABILITY or
23 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
24 for more details.
25
26 You should have received a copy of the GNU General Public License
27 along with GCC; see the file COPYING. If not, write to the Free
28 Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA
29 02110-1301, USA. */
30
31 /* ------------------------------------------------------------------ */
32 /* Decimal 32-bit format module */
33 /* ------------------------------------------------------------------ */
34 /* This module comprises the routines for decimal32 format numbers. */
35 /* Conversions are supplied to and from decNumber and String. */
36 /* */
37 /* This is used when decNumber provides operations, either for all */
38 /* operations or as a proxy between decNumber and decSingle. */
39 /* */
40 /* Error handling is the same as decNumber (qv.). */
41 /* ------------------------------------------------------------------ */
42 #include "qemu/osdep.h"
43
44 #include "libdecnumber/dconfig.h"
45 #define DECNUMDIGITS 7 /* make decNumbers with space for 7 */
46 #include "libdecnumber/decNumber.h"
47 #include "libdecnumber/decNumberLocal.h"
48 #include "libdecnumber/dpd/decimal32.h"
49
50 /* Utility tables and routines [in decimal64.c] */
51 extern const uInt COMBEXP[32], COMBMSD[32];
52 extern const uByte BIN2CHAR[4001];
53
54 extern void decDigitsToDPD(const decNumber *, uInt *, Int);
55 extern void decDigitsFromDPD(decNumber *, const uInt *, Int);
56
57 #if DECTRACE || DECCHECK
58 void decimal32Show(const decimal32 *); /* for debug */
59 extern void decNumberShow(const decNumber *); /* .. */
60 #endif
61
62 /* Useful macro */
63 /* Clear a structure (e.g., a decNumber) */
64 #define DEC_clear(d) memset(d, 0, sizeof(*d))
65
66 /* ------------------------------------------------------------------ */
67 /* decimal32FromNumber -- convert decNumber to decimal32 */
68 /* */
69 /* ds is the target decimal32 */
70 /* dn is the source number (assumed valid) */
71 /* set is the context, used only for reporting errors */
72 /* */
73 /* The set argument is used only for status reporting and for the */
74 /* rounding mode (used if the coefficient is more than DECIMAL32_Pmax */
75 /* digits or an overflow is detected). If the exponent is out of the */
76 /* valid range then Overflow or Underflow will be raised. */
77 /* After Underflow a subnormal result is possible. */
78 /* */
79 /* DEC_Clamped is set if the number has to be 'folded down' to fit, */
80 /* by reducing its exponent and multiplying the coefficient by a */
81 /* power of ten, or if the exponent on a zero had to be clamped. */
82 /* ------------------------------------------------------------------ */
83 decimal32 * decimal32FromNumber(decimal32 *d32, const decNumber *dn,
84 decContext *set) {
85 uInt status=0; /* status accumulator */
86 Int ae; /* adjusted exponent */
87 decNumber dw; /* work */
88 decContext dc; /* .. */
89 uInt *pu; /* .. */
90 uInt comb, exp; /* .. */
91 uInt targ=0; /* target 32-bit */
92
93 /* If the number has too many digits, or the exponent could be */
94 /* out of range then reduce the number under the appropriate */
95 /* constraints. This could push the number to Infinity or zero, */
96 /* so this check and rounding must be done before generating the */
97 /* decimal32] */
98 ae=dn->exponent+dn->digits-1; /* [0 if special] */
99 if (dn->digits>DECIMAL32_Pmax /* too many digits */
100 || ae>DECIMAL32_Emax /* likely overflow */
101 || ae<DECIMAL32_Emin) { /* likely underflow */
102 decContextDefault(&dc, DEC_INIT_DECIMAL32); /* [no traps] */
103 dc.round=set->round; /* use supplied rounding */
104 decNumberPlus(&dw, dn, &dc); /* (round and check) */
105 /* [this changes -0 to 0, so enforce the sign...] */
106 dw.bits|=dn->bits&DECNEG;
107 status=dc.status; /* save status */
108 dn=&dw; /* use the work number */
109 } /* maybe out of range */
110
111 if (dn->bits&DECSPECIAL) { /* a special value */
112 if (dn->bits&DECINF) targ=DECIMAL_Inf<<24;
113 else { /* sNaN or qNaN */
114 if ((*dn->lsu!=0 || dn->digits>1) /* non-zero coefficient */
115 && (dn->digits<DECIMAL32_Pmax)) { /* coefficient fits */
116 decDigitsToDPD(dn, &targ, 0);
117 }
118 if (dn->bits&DECNAN) targ|=DECIMAL_NaN<<24;
119 else targ|=DECIMAL_sNaN<<24;
120 } /* a NaN */
121 } /* special */
122
123 else { /* is finite */
124 if (decNumberIsZero(dn)) { /* is a zero */
125 /* set and clamp exponent */
126 if (dn->exponent<-DECIMAL32_Bias) {
127 exp=0; /* low clamp */
128 status|=DEC_Clamped;
129 }
130 else {
131 exp=dn->exponent+DECIMAL32_Bias; /* bias exponent */
132 if (exp>DECIMAL32_Ehigh) { /* top clamp */
133 exp=DECIMAL32_Ehigh;
134 status|=DEC_Clamped;
135 }
136 }
137 comb=(exp>>3) & 0x18; /* msd=0, exp top 2 bits .. */
138 }
139 else { /* non-zero finite number */
140 uInt msd; /* work */
141 Int pad=0; /* coefficient pad digits */
142
143 /* the dn is known to fit, but it may need to be padded */
144 exp=(uInt)(dn->exponent+DECIMAL32_Bias); /* bias exponent */
145 if (exp>DECIMAL32_Ehigh) { /* fold-down case */
146 pad=exp-DECIMAL32_Ehigh;
147 exp=DECIMAL32_Ehigh; /* [to maximum] */
148 status|=DEC_Clamped;
149 }
150
151 /* fastpath common case */
152 if (DECDPUN==3 && pad==0) {
153 targ=BIN2DPD[dn->lsu[0]];
154 if (dn->digits>3) targ|=(uInt)(BIN2DPD[dn->lsu[1]])<<10;
155 msd=(dn->digits==7 ? dn->lsu[2] : 0);
156 }
157 else { /* general case */
158 decDigitsToDPD(dn, &targ, pad);
159 /* save and clear the top digit */
160 msd=targ>>20;
161 targ&=0x000fffff;
162 }
163
164 /* create the combination field */
165 if (msd>=8) comb=0x18 | ((exp>>5) & 0x06) | (msd & 0x01);
166 else comb=((exp>>3) & 0x18) | msd;
167 }
168 targ|=comb<<26; /* add combination field .. */
169 targ|=(exp&0x3f)<<20; /* .. and exponent continuation */
170 } /* finite */
171
172 if (dn->bits&DECNEG) targ|=0x80000000; /* add sign bit */
173
174 /* now write to storage; this is endian */
175 pu=(uInt *)d32->bytes; /* overlay */
176 *pu=targ; /* directly store the int */
177
178 if (status!=0) decContextSetStatus(set, status); /* pass on status */
179 /* decimal32Show(d32); */
180 return d32;
181 } /* decimal32FromNumber */
182
183 /* ------------------------------------------------------------------ */
184 /* decimal32ToNumber -- convert decimal32 to decNumber */
185 /* d32 is the source decimal32 */
186 /* dn is the target number, with appropriate space */
187 /* No error is possible. */
188 /* ------------------------------------------------------------------ */
189 decNumber * decimal32ToNumber(const decimal32 *d32, decNumber *dn) {
190 uInt msd; /* coefficient MSD */
191 uInt exp; /* exponent top two bits */
192 uInt comb; /* combination field */
193 uInt sour; /* source 32-bit */
194 const uInt *pu; /* work */
195
196 /* load source from storage; this is endian */
197 pu=(const uInt *)d32->bytes; /* overlay */
198 sour=*pu; /* directly load the int */
199
200 comb=(sour>>26)&0x1f; /* combination field */
201
202 decNumberZero(dn); /* clean number */
203 if (sour&0x80000000) dn->bits=DECNEG; /* set sign if negative */
204
205 msd=COMBMSD[comb]; /* decode the combination field */
206 exp=COMBEXP[comb]; /* .. */
207
208 if (exp==3) { /* is a special */
209 if (msd==0) {
210 dn->bits|=DECINF;
211 return dn; /* no coefficient needed */
212 }
213 else if (sour&0x02000000) dn->bits|=DECSNAN;
214 else dn->bits|=DECNAN;
215 msd=0; /* no top digit */
216 }
217 else { /* is a finite number */
218 dn->exponent=(exp<<6)+((sour>>20)&0x3f)-DECIMAL32_Bias; /* unbiased */
219 }
220
221 /* get the coefficient */
222 sour&=0x000fffff; /* clean coefficient continuation */
223 if (msd) { /* non-zero msd */
224 sour|=msd<<20; /* prefix to coefficient */
225 decDigitsFromDPD(dn, &sour, 3); /* process 3 declets */
226 return dn;
227 }
228 /* msd=0 */
229 if (!sour) return dn; /* easy: coefficient is 0 */
230 if (sour&0x000ffc00) /* need 2 declets? */
231 decDigitsFromDPD(dn, &sour, 2); /* process 2 declets */
232 else
233 decDigitsFromDPD(dn, &sour, 1); /* process 1 declet */
234 return dn;
235 } /* decimal32ToNumber */
236
237 /* ------------------------------------------------------------------ */
238 /* to-scientific-string -- conversion to numeric string */
239 /* to-engineering-string -- conversion to numeric string */
240 /* */
241 /* decimal32ToString(d32, string); */
242 /* decimal32ToEngString(d32, string); */
243 /* */
244 /* d32 is the decimal32 format number to convert */
245 /* string is the string where the result will be laid out */
246 /* */
247 /* string must be at least 24 characters */
248 /* */
249 /* No error is possible, and no status can be set. */
250 /* ------------------------------------------------------------------ */
251 char * decimal32ToEngString(const decimal32 *d32, char *string){
252 decNumber dn; /* work */
253 decimal32ToNumber(d32, &dn);
254 decNumberToEngString(&dn, string);
255 return string;
256 } /* decimal32ToEngString */
257
258 char * decimal32ToString(const decimal32 *d32, char *string){
259 uInt msd; /* coefficient MSD */
260 Int exp; /* exponent top two bits or full */
261 uInt comb; /* combination field */
262 char *cstart; /* coefficient start */
263 char *c; /* output pointer in string */
264 const uInt *pu; /* work */
265 const uByte *u; /* .. */
266 char *s, *t; /* .. (source, target) */
267 Int dpd; /* .. */
268 Int pre, e; /* .. */
269 uInt sour; /* source 32-bit */
270
271 /* load source from storage; this is endian */
272 pu=(const uInt *)d32->bytes; /* overlay */
273 sour=*pu; /* directly load the int */
274
275 c=string; /* where result will go */
276 if (((Int)sour)<0) *c++='-'; /* handle sign */
277
278 comb=(sour>>26)&0x1f; /* combination field */
279 msd=COMBMSD[comb]; /* decode the combination field */
280 exp=COMBEXP[comb]; /* .. */
281
282 if (exp==3) {
283 if (msd==0) { /* infinity */
284 strcpy(c, "Inf");
285 strcpy(c+3, "inity");
286 return string; /* easy */
287 }
288 if (sour&0x02000000) *c++='s'; /* sNaN */
289 strcpy(c, "NaN"); /* complete word */
290 c+=3; /* step past */
291 if ((sour&0x000fffff)==0) return string; /* zero payload */
292 /* otherwise drop through to add integer; set correct exp */
293 exp=0; msd=0; /* setup for following code */
294 }
295 else exp=(exp<<6)+((sour>>20)&0x3f)-DECIMAL32_Bias; /* unbiased */
296
297 /* convert 7 digits of significand to characters */
298 cstart=c; /* save start of coefficient */
299 if (msd) *c++='0'+(char)msd; /* non-zero most significant digit */
300
301 /* Now decode the declets. After extracting each one, it is */
302 /* decoded to binary and then to a 4-char sequence by table lookup; */
303 /* the 4-chars are a 1-char length (significant digits, except 000 */
304 /* has length 0). This allows us to left-align the first declet */
305 /* with non-zero content, then remaining ones are full 3-char */
306 /* length. We use fixed-length memcpys because variable-length */
307 /* causes a subroutine call in GCC. (These are length 4 for speed */
308 /* and are safe because the array has an extra terminator byte.) */
309 #define dpd2char u=&BIN2CHAR[DPD2BIN[dpd]*4]; \
310 if (c!=cstart) {memcpy(c, u+1, 4); c+=3;} \
311 else if (*u) {memcpy(c, u+4-*u, 4); c+=*u;}
312
313 dpd=(sour>>10)&0x3ff; /* declet 1 */
314 dpd2char;
315 dpd=(sour)&0x3ff; /* declet 2 */
316 dpd2char;
317
318 if (c==cstart) *c++='0'; /* all zeros -- make 0 */
319
320 if (exp==0) { /* integer or NaN case -- easy */
321 *c='\0'; /* terminate */
322 return string;
323 }
324
325 /* non-0 exponent */
326 e=0; /* assume no E */
327 pre=c-cstart+exp;
328 /* [here, pre-exp is the digits count (==1 for zero)] */
329 if (exp>0 || pre<-5) { /* need exponential form */
330 e=pre-1; /* calculate E value */
331 pre=1; /* assume one digit before '.' */
332 } /* exponential form */
333
334 /* modify the coefficient, adding 0s, '.', and E+nn as needed */
335 s=c-1; /* source (LSD) */
336 if (pre>0) { /* ddd.ddd (plain), perhaps with E */
337 char *dotat=cstart+pre;
338 if (dotat<c) { /* if embedded dot needed... */
339 t=c; /* target */
340 for (; s>=dotat; s--, t--) *t=*s; /* open the gap; leave t at gap */
341 *t='.'; /* insert the dot */
342 c++; /* length increased by one */
343 }
344
345 /* finally add the E-part, if needed; it will never be 0, and has */
346 /* a maximum length of 3 digits (E-101 case) */
347 if (e!=0) {
348 *c++='E'; /* starts with E */
349 *c++='+'; /* assume positive */
350 if (e<0) {
351 *(c-1)='-'; /* oops, need '-' */
352 e=-e; /* uInt, please */
353 }
354 u=&BIN2CHAR[e*4]; /* -> length byte */
355 memcpy(c, u+4-*u, 4); /* copy fixed 4 characters [is safe] */
356 c+=*u; /* bump pointer appropriately */
357 }
358 *c='\0'; /* add terminator */
359 /*printf("res %s\n", string); */
360 return string;
361 } /* pre>0 */
362
363 /* -5<=pre<=0: here for plain 0.ddd or 0.000ddd forms (can never have E) */
364 t=c+1-pre;
365 *(t+1)='\0'; /* can add terminator now */
366 for (; s>=cstart; s--, t--) *t=*s; /* shift whole coefficient right */
367 c=cstart;
368 *c++='0'; /* always starts with 0. */
369 *c++='.';
370 for (; pre<0; pre++) *c++='0'; /* add any 0's after '.' */
371 /*printf("res %s\n", string); */
372 return string;
373 } /* decimal32ToString */
374
375 /* ------------------------------------------------------------------ */
376 /* to-number -- conversion from numeric string */
377 /* */
378 /* decimal32FromString(result, string, set); */
379 /* */
380 /* result is the decimal32 format number which gets the result of */
381 /* the conversion */
382 /* *string is the character string which should contain a valid */
383 /* number (which may be a special value) */
384 /* set is the context */
385 /* */
386 /* The context is supplied to this routine is used for error handling */
387 /* (setting of status and traps) and for the rounding mode, only. */
388 /* If an error occurs, the result will be a valid decimal32 NaN. */
389 /* ------------------------------------------------------------------ */
390 decimal32 * decimal32FromString(decimal32 *result, const char *string,
391 decContext *set) {
392 decContext dc; /* work */
393 decNumber dn; /* .. */
394
395 decContextDefault(&dc, DEC_INIT_DECIMAL32); /* no traps, please */
396 dc.round=set->round; /* use supplied rounding */
397
398 decNumberFromString(&dn, string, &dc); /* will round if needed */
399 decimal32FromNumber(result, &dn, &dc);
400 if (dc.status!=0) { /* something happened */
401 decContextSetStatus(set, dc.status); /* .. pass it on */
402 }
403 return result;
404 } /* decimal32FromString */
405
406 /* ------------------------------------------------------------------ */
407 /* decimal32IsCanonical -- test whether encoding is canonical */
408 /* d32 is the source decimal32 */
409 /* returns 1 if the encoding of d32 is canonical, 0 otherwise */
410 /* No error is possible. */
411 /* ------------------------------------------------------------------ */
412 uint32_t decimal32IsCanonical(const decimal32 *d32) {
413 decNumber dn; /* work */
414 decimal32 canon; /* .. */
415 decContext dc; /* .. */
416 decContextDefault(&dc, DEC_INIT_DECIMAL32);
417 decimal32ToNumber(d32, &dn);
418 decimal32FromNumber(&canon, &dn, &dc);/* canon will now be canonical */
419 return memcmp(d32, &canon, DECIMAL32_Bytes)==0;
420 } /* decimal32IsCanonical */
421
422 /* ------------------------------------------------------------------ */
423 /* decimal32Canonical -- copy an encoding, ensuring it is canonical */
424 /* d32 is the source decimal32 */
425 /* result is the target (may be the same decimal32) */
426 /* returns result */
427 /* No error is possible. */
428 /* ------------------------------------------------------------------ */
429 decimal32 * decimal32Canonical(decimal32 *result, const decimal32 *d32) {
430 decNumber dn; /* work */
431 decContext dc; /* .. */
432 decContextDefault(&dc, DEC_INIT_DECIMAL32);
433 decimal32ToNumber(d32, &dn);
434 decimal32FromNumber(result, &dn, &dc);/* result will now be canonical */
435 return result;
436 } /* decimal32Canonical */
437
438 #if DECTRACE || DECCHECK
439 /* Macros for accessing decimal32 fields. These assume the argument
440 is a reference (pointer) to the decimal32 structure, and the
441 decimal32 is in network byte order (big-endian) */
442 /* Get sign */
443 #define decimal32Sign(d) ((unsigned)(d)->bytes[0]>>7)
444
445 /* Get combination field */
446 #define decimal32Comb(d) (((d)->bytes[0] & 0x7c)>>2)
447
448 /* Get exponent continuation [does not remove bias] */
449 #define decimal32ExpCon(d) ((((d)->bytes[0] & 0x03)<<4) \
450 | ((unsigned)(d)->bytes[1]>>4))
451
452 /* Set sign [this assumes sign previously 0] */
453 #define decimal32SetSign(d, b) { \
454 (d)->bytes[0]|=((unsigned)(b)<<7);}
455
456 /* Set exponent continuation [does not apply bias] */
457 /* This assumes range has been checked and exponent previously 0; */
458 /* type of exponent must be unsigned */
459 #define decimal32SetExpCon(d, e) { \
460 (d)->bytes[0]|=(uint8_t)((e)>>4); \
461 (d)->bytes[1]|=(uint8_t)(((e)&0x0F)<<4);}
462
463 /* ------------------------------------------------------------------ */
464 /* decimal32Show -- display a decimal32 in hexadecimal [debug aid] */
465 /* d32 -- the number to show */
466 /* ------------------------------------------------------------------ */
467 /* Also shows sign/cob/expconfields extracted - valid bigendian only */
468 void decimal32Show(const decimal32 *d32) {
469 char buf[DECIMAL32_Bytes*2+1];
470 Int i, j=0;
471
472 if (DECLITEND) {
473 for (i=0; i<DECIMAL32_Bytes; i++, j+=2) {
474 sprintf(&buf[j], "%02x", d32->bytes[3-i]);
475 }
476 printf(" D32> %s [S:%d Cb:%02x Ec:%02x] LittleEndian\n", buf,
477 d32->bytes[3]>>7, (d32->bytes[3]>>2)&0x1f,
478 ((d32->bytes[3]&0x3)<<4)| (d32->bytes[2]>>4));
479 }
480 else {
481 for (i=0; i<DECIMAL32_Bytes; i++, j+=2) {
482 sprintf(&buf[j], "%02x", d32->bytes[i]);
483 }
484 printf(" D32> %s [S:%d Cb:%02x Ec:%02x] BigEndian\n", buf,
485 decimal32Sign(d32), decimal32Comb(d32), decimal32ExpCon(d32));
486 }
487 } /* decimal32Show */
488 #endif