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[ARM] 3789/4: Fix VFP emulation to ignore VECITR for scalar instruction
[deliverable/linux.git] / arch / arm / vfp / vfpdouble.c
1 /*
2 * linux/arch/arm/vfp/vfpdouble.c
3 *
4 * This code is derived in part from John R. Housers softfloat library, which
5 * carries the following notice:
6 *
7 * ===========================================================================
8 * This C source file is part of the SoftFloat IEC/IEEE Floating-point
9 * Arithmetic Package, Release 2.
10 *
11 * Written by John R. Hauser. This work was made possible in part by the
12 * International Computer Science Institute, located at Suite 600, 1947 Center
13 * Street, Berkeley, California 94704. Funding was partially provided by the
14 * National Science Foundation under grant MIP-9311980. The original version
15 * of this code was written as part of a project to build a fixed-point vector
16 * processor in collaboration with the University of California at Berkeley,
17 * overseen by Profs. Nelson Morgan and John Wawrzynek. More information
18 * is available through the web page `http://HTTP.CS.Berkeley.EDU/~jhauser/
19 * arithmetic/softfloat.html'.
20 *
21 * THIS SOFTWARE IS DISTRIBUTED AS IS, FOR FREE. Although reasonable effort
22 * has been made to avoid it, THIS SOFTWARE MAY CONTAIN FAULTS THAT WILL AT
23 * TIMES RESULT IN INCORRECT BEHAVIOR. USE OF THIS SOFTWARE IS RESTRICTED TO
24 * PERSONS AND ORGANIZATIONS WHO CAN AND WILL TAKE FULL RESPONSIBILITY FOR ANY
25 * AND ALL LOSSES, COSTS, OR OTHER PROBLEMS ARISING FROM ITS USE.
26 *
27 * Derivative works are acceptable, even for commercial purposes, so long as
28 * (1) they include prominent notice that the work is derivative, and (2) they
29 * include prominent notice akin to these three paragraphs for those parts of
30 * this code that are retained.
31 * ===========================================================================
32 */
33 #include <linux/kernel.h>
34 #include <linux/bitops.h>
35
36 #include <asm/div64.h>
37 #include <asm/ptrace.h>
38 #include <asm/vfp.h>
39
40 #include "vfpinstr.h"
41 #include "vfp.h"
42
43 static struct vfp_double vfp_double_default_qnan = {
44 .exponent = 2047,
45 .sign = 0,
46 .significand = VFP_DOUBLE_SIGNIFICAND_QNAN,
47 };
48
49 static void vfp_double_dump(const char *str, struct vfp_double *d)
50 {
51 pr_debug("VFP: %s: sign=%d exponent=%d significand=%016llx\n",
52 str, d->sign != 0, d->exponent, d->significand);
53 }
54
55 static void vfp_double_normalise_denormal(struct vfp_double *vd)
56 {
57 int bits = 31 - fls(vd->significand >> 32);
58 if (bits == 31)
59 bits = 62 - fls(vd->significand);
60
61 vfp_double_dump("normalise_denormal: in", vd);
62
63 if (bits) {
64 vd->exponent -= bits - 1;
65 vd->significand <<= bits;
66 }
67
68 vfp_double_dump("normalise_denormal: out", vd);
69 }
70
71 u32 vfp_double_normaliseround(int dd, struct vfp_double *vd, u32 fpscr, u32 exceptions, const char *func)
72 {
73 u64 significand, incr;
74 int exponent, shift, underflow;
75 u32 rmode;
76
77 vfp_double_dump("pack: in", vd);
78
79 /*
80 * Infinities and NaNs are a special case.
81 */
82 if (vd->exponent == 2047 && (vd->significand == 0 || exceptions))
83 goto pack;
84
85 /*
86 * Special-case zero.
87 */
88 if (vd->significand == 0) {
89 vd->exponent = 0;
90 goto pack;
91 }
92
93 exponent = vd->exponent;
94 significand = vd->significand;
95
96 shift = 32 - fls(significand >> 32);
97 if (shift == 32)
98 shift = 64 - fls(significand);
99 if (shift) {
100 exponent -= shift;
101 significand <<= shift;
102 }
103
104 #ifdef DEBUG
105 vd->exponent = exponent;
106 vd->significand = significand;
107 vfp_double_dump("pack: normalised", vd);
108 #endif
109
110 /*
111 * Tiny number?
112 */
113 underflow = exponent < 0;
114 if (underflow) {
115 significand = vfp_shiftright64jamming(significand, -exponent);
116 exponent = 0;
117 #ifdef DEBUG
118 vd->exponent = exponent;
119 vd->significand = significand;
120 vfp_double_dump("pack: tiny number", vd);
121 #endif
122 if (!(significand & ((1ULL << (VFP_DOUBLE_LOW_BITS + 1)) - 1)))
123 underflow = 0;
124 }
125
126 /*
127 * Select rounding increment.
128 */
129 incr = 0;
130 rmode = fpscr & FPSCR_RMODE_MASK;
131
132 if (rmode == FPSCR_ROUND_NEAREST) {
133 incr = 1ULL << VFP_DOUBLE_LOW_BITS;
134 if ((significand & (1ULL << (VFP_DOUBLE_LOW_BITS + 1))) == 0)
135 incr -= 1;
136 } else if (rmode == FPSCR_ROUND_TOZERO) {
137 incr = 0;
138 } else if ((rmode == FPSCR_ROUND_PLUSINF) ^ (vd->sign != 0))
139 incr = (1ULL << (VFP_DOUBLE_LOW_BITS + 1)) - 1;
140
141 pr_debug("VFP: rounding increment = 0x%08llx\n", incr);
142
143 /*
144 * Is our rounding going to overflow?
145 */
146 if ((significand + incr) < significand) {
147 exponent += 1;
148 significand = (significand >> 1) | (significand & 1);
149 incr >>= 1;
150 #ifdef DEBUG
151 vd->exponent = exponent;
152 vd->significand = significand;
153 vfp_double_dump("pack: overflow", vd);
154 #endif
155 }
156
157 /*
158 * If any of the low bits (which will be shifted out of the
159 * number) are non-zero, the result is inexact.
160 */
161 if (significand & ((1 << (VFP_DOUBLE_LOW_BITS + 1)) - 1))
162 exceptions |= FPSCR_IXC;
163
164 /*
165 * Do our rounding.
166 */
167 significand += incr;
168
169 /*
170 * Infinity?
171 */
172 if (exponent >= 2046) {
173 exceptions |= FPSCR_OFC | FPSCR_IXC;
174 if (incr == 0) {
175 vd->exponent = 2045;
176 vd->significand = 0x7fffffffffffffffULL;
177 } else {
178 vd->exponent = 2047; /* infinity */
179 vd->significand = 0;
180 }
181 } else {
182 if (significand >> (VFP_DOUBLE_LOW_BITS + 1) == 0)
183 exponent = 0;
184 if (exponent || significand > 0x8000000000000000ULL)
185 underflow = 0;
186 if (underflow)
187 exceptions |= FPSCR_UFC;
188 vd->exponent = exponent;
189 vd->significand = significand >> 1;
190 }
191
192 pack:
193 vfp_double_dump("pack: final", vd);
194 {
195 s64 d = vfp_double_pack(vd);
196 pr_debug("VFP: %s: d(d%d)=%016llx exceptions=%08x\n", func,
197 dd, d, exceptions);
198 vfp_put_double(d, dd);
199 }
200 return exceptions;
201 }
202
203 /*
204 * Propagate the NaN, setting exceptions if it is signalling.
205 * 'n' is always a NaN. 'm' may be a number, NaN or infinity.
206 */
207 static u32
208 vfp_propagate_nan(struct vfp_double *vdd, struct vfp_double *vdn,
209 struct vfp_double *vdm, u32 fpscr)
210 {
211 struct vfp_double *nan;
212 int tn, tm = 0;
213
214 tn = vfp_double_type(vdn);
215
216 if (vdm)
217 tm = vfp_double_type(vdm);
218
219 if (fpscr & FPSCR_DEFAULT_NAN)
220 /*
221 * Default NaN mode - always returns a quiet NaN
222 */
223 nan = &vfp_double_default_qnan;
224 else {
225 /*
226 * Contemporary mode - select the first signalling
227 * NAN, or if neither are signalling, the first
228 * quiet NAN.
229 */
230 if (tn == VFP_SNAN || (tm != VFP_SNAN && tn == VFP_QNAN))
231 nan = vdn;
232 else
233 nan = vdm;
234 /*
235 * Make the NaN quiet.
236 */
237 nan->significand |= VFP_DOUBLE_SIGNIFICAND_QNAN;
238 }
239
240 *vdd = *nan;
241
242 /*
243 * If one was a signalling NAN, raise invalid operation.
244 */
245 return tn == VFP_SNAN || tm == VFP_SNAN ? FPSCR_IOC : VFP_NAN_FLAG;
246 }
247
248 /*
249 * Extended operations
250 */
251 static u32 vfp_double_fabs(int dd, int unused, int dm, u32 fpscr)
252 {
253 vfp_put_double(vfp_double_packed_abs(vfp_get_double(dm)), dd);
254 return 0;
255 }
256
257 static u32 vfp_double_fcpy(int dd, int unused, int dm, u32 fpscr)
258 {
259 vfp_put_double(vfp_get_double(dm), dd);
260 return 0;
261 }
262
263 static u32 vfp_double_fneg(int dd, int unused, int dm, u32 fpscr)
264 {
265 vfp_put_double(vfp_double_packed_negate(vfp_get_double(dm)), dd);
266 return 0;
267 }
268
269 static u32 vfp_double_fsqrt(int dd, int unused, int dm, u32 fpscr)
270 {
271 struct vfp_double vdm, vdd;
272 int ret, tm;
273
274 vfp_double_unpack(&vdm, vfp_get_double(dm));
275 tm = vfp_double_type(&vdm);
276 if (tm & (VFP_NAN|VFP_INFINITY)) {
277 struct vfp_double *vdp = &vdd;
278
279 if (tm & VFP_NAN)
280 ret = vfp_propagate_nan(vdp, &vdm, NULL, fpscr);
281 else if (vdm.sign == 0) {
282 sqrt_copy:
283 vdp = &vdm;
284 ret = 0;
285 } else {
286 sqrt_invalid:
287 vdp = &vfp_double_default_qnan;
288 ret = FPSCR_IOC;
289 }
290 vfp_put_double(vfp_double_pack(vdp), dd);
291 return ret;
292 }
293
294 /*
295 * sqrt(+/- 0) == +/- 0
296 */
297 if (tm & VFP_ZERO)
298 goto sqrt_copy;
299
300 /*
301 * Normalise a denormalised number
302 */
303 if (tm & VFP_DENORMAL)
304 vfp_double_normalise_denormal(&vdm);
305
306 /*
307 * sqrt(<0) = invalid
308 */
309 if (vdm.sign)
310 goto sqrt_invalid;
311
312 vfp_double_dump("sqrt", &vdm);
313
314 /*
315 * Estimate the square root.
316 */
317 vdd.sign = 0;
318 vdd.exponent = ((vdm.exponent - 1023) >> 1) + 1023;
319 vdd.significand = (u64)vfp_estimate_sqrt_significand(vdm.exponent, vdm.significand >> 32) << 31;
320
321 vfp_double_dump("sqrt estimate1", &vdd);
322
323 vdm.significand >>= 1 + (vdm.exponent & 1);
324 vdd.significand += 2 + vfp_estimate_div128to64(vdm.significand, 0, vdd.significand);
325
326 vfp_double_dump("sqrt estimate2", &vdd);
327
328 /*
329 * And now adjust.
330 */
331 if ((vdd.significand & VFP_DOUBLE_LOW_BITS_MASK) <= 5) {
332 if (vdd.significand < 2) {
333 vdd.significand = ~0ULL;
334 } else {
335 u64 termh, terml, remh, reml;
336 vdm.significand <<= 2;
337 mul64to128(&termh, &terml, vdd.significand, vdd.significand);
338 sub128(&remh, &reml, vdm.significand, 0, termh, terml);
339 while ((s64)remh < 0) {
340 vdd.significand -= 1;
341 shift64left(&termh, &terml, vdd.significand);
342 terml |= 1;
343 add128(&remh, &reml, remh, reml, termh, terml);
344 }
345 vdd.significand |= (remh | reml) != 0;
346 }
347 }
348 vdd.significand = vfp_shiftright64jamming(vdd.significand, 1);
349
350 return vfp_double_normaliseround(dd, &vdd, fpscr, 0, "fsqrt");
351 }
352
353 /*
354 * Equal := ZC
355 * Less than := N
356 * Greater than := C
357 * Unordered := CV
358 */
359 static u32 vfp_compare(int dd, int signal_on_qnan, int dm, u32 fpscr)
360 {
361 s64 d, m;
362 u32 ret = 0;
363
364 m = vfp_get_double(dm);
365 if (vfp_double_packed_exponent(m) == 2047 && vfp_double_packed_mantissa(m)) {
366 ret |= FPSCR_C | FPSCR_V;
367 if (signal_on_qnan || !(vfp_double_packed_mantissa(m) & (1ULL << (VFP_DOUBLE_MANTISSA_BITS - 1))))
368 /*
369 * Signalling NaN, or signalling on quiet NaN
370 */
371 ret |= FPSCR_IOC;
372 }
373
374 d = vfp_get_double(dd);
375 if (vfp_double_packed_exponent(d) == 2047 && vfp_double_packed_mantissa(d)) {
376 ret |= FPSCR_C | FPSCR_V;
377 if (signal_on_qnan || !(vfp_double_packed_mantissa(d) & (1ULL << (VFP_DOUBLE_MANTISSA_BITS - 1))))
378 /*
379 * Signalling NaN, or signalling on quiet NaN
380 */
381 ret |= FPSCR_IOC;
382 }
383
384 if (ret == 0) {
385 if (d == m || vfp_double_packed_abs(d | m) == 0) {
386 /*
387 * equal
388 */
389 ret |= FPSCR_Z | FPSCR_C;
390 } else if (vfp_double_packed_sign(d ^ m)) {
391 /*
392 * different signs
393 */
394 if (vfp_double_packed_sign(d))
395 /*
396 * d is negative, so d < m
397 */
398 ret |= FPSCR_N;
399 else
400 /*
401 * d is positive, so d > m
402 */
403 ret |= FPSCR_C;
404 } else if ((vfp_double_packed_sign(d) != 0) ^ (d < m)) {
405 /*
406 * d < m
407 */
408 ret |= FPSCR_N;
409 } else if ((vfp_double_packed_sign(d) != 0) ^ (d > m)) {
410 /*
411 * d > m
412 */
413 ret |= FPSCR_C;
414 }
415 }
416
417 return ret;
418 }
419
420 static u32 vfp_double_fcmp(int dd, int unused, int dm, u32 fpscr)
421 {
422 return vfp_compare(dd, 0, dm, fpscr);
423 }
424
425 static u32 vfp_double_fcmpe(int dd, int unused, int dm, u32 fpscr)
426 {
427 return vfp_compare(dd, 1, dm, fpscr);
428 }
429
430 static u32 vfp_double_fcmpz(int dd, int unused, int dm, u32 fpscr)
431 {
432 return vfp_compare(dd, 0, VFP_REG_ZERO, fpscr);
433 }
434
435 static u32 vfp_double_fcmpez(int dd, int unused, int dm, u32 fpscr)
436 {
437 return vfp_compare(dd, 1, VFP_REG_ZERO, fpscr);
438 }
439
440 static u32 vfp_double_fcvts(int sd, int unused, int dm, u32 fpscr)
441 {
442 struct vfp_double vdm;
443 struct vfp_single vsd;
444 int tm;
445 u32 exceptions = 0;
446
447 vfp_double_unpack(&vdm, vfp_get_double(dm));
448
449 tm = vfp_double_type(&vdm);
450
451 /*
452 * If we have a signalling NaN, signal invalid operation.
453 */
454 if (tm == VFP_SNAN)
455 exceptions = FPSCR_IOC;
456
457 if (tm & VFP_DENORMAL)
458 vfp_double_normalise_denormal(&vdm);
459
460 vsd.sign = vdm.sign;
461 vsd.significand = vfp_hi64to32jamming(vdm.significand);
462
463 /*
464 * If we have an infinity or a NaN, the exponent must be 255
465 */
466 if (tm & (VFP_INFINITY|VFP_NAN)) {
467 vsd.exponent = 255;
468 if (tm == VFP_QNAN)
469 vsd.significand |= VFP_SINGLE_SIGNIFICAND_QNAN;
470 goto pack_nan;
471 } else if (tm & VFP_ZERO)
472 vsd.exponent = 0;
473 else
474 vsd.exponent = vdm.exponent - (1023 - 127);
475
476 return vfp_single_normaliseround(sd, &vsd, fpscr, exceptions, "fcvts");
477
478 pack_nan:
479 vfp_put_float(vfp_single_pack(&vsd), sd);
480 return exceptions;
481 }
482
483 static u32 vfp_double_fuito(int dd, int unused, int dm, u32 fpscr)
484 {
485 struct vfp_double vdm;
486 u32 m = vfp_get_float(dm);
487
488 vdm.sign = 0;
489 vdm.exponent = 1023 + 63 - 1;
490 vdm.significand = (u64)m;
491
492 return vfp_double_normaliseround(dd, &vdm, fpscr, 0, "fuito");
493 }
494
495 static u32 vfp_double_fsito(int dd, int unused, int dm, u32 fpscr)
496 {
497 struct vfp_double vdm;
498 u32 m = vfp_get_float(dm);
499
500 vdm.sign = (m & 0x80000000) >> 16;
501 vdm.exponent = 1023 + 63 - 1;
502 vdm.significand = vdm.sign ? -m : m;
503
504 return vfp_double_normaliseround(dd, &vdm, fpscr, 0, "fsito");
505 }
506
507 static u32 vfp_double_ftoui(int sd, int unused, int dm, u32 fpscr)
508 {
509 struct vfp_double vdm;
510 u32 d, exceptions = 0;
511 int rmode = fpscr & FPSCR_RMODE_MASK;
512 int tm;
513
514 vfp_double_unpack(&vdm, vfp_get_double(dm));
515
516 /*
517 * Do we have a denormalised number?
518 */
519 tm = vfp_double_type(&vdm);
520 if (tm & VFP_DENORMAL)
521 exceptions |= FPSCR_IDC;
522
523 if (tm & VFP_NAN)
524 vdm.sign = 0;
525
526 if (vdm.exponent >= 1023 + 32) {
527 d = vdm.sign ? 0 : 0xffffffff;
528 exceptions = FPSCR_IOC;
529 } else if (vdm.exponent >= 1023 - 1) {
530 int shift = 1023 + 63 - vdm.exponent;
531 u64 rem, incr = 0;
532
533 /*
534 * 2^0 <= m < 2^32-2^8
535 */
536 d = (vdm.significand << 1) >> shift;
537 rem = vdm.significand << (65 - shift);
538
539 if (rmode == FPSCR_ROUND_NEAREST) {
540 incr = 0x8000000000000000ULL;
541 if ((d & 1) == 0)
542 incr -= 1;
543 } else if (rmode == FPSCR_ROUND_TOZERO) {
544 incr = 0;
545 } else if ((rmode == FPSCR_ROUND_PLUSINF) ^ (vdm.sign != 0)) {
546 incr = ~0ULL;
547 }
548
549 if ((rem + incr) < rem) {
550 if (d < 0xffffffff)
551 d += 1;
552 else
553 exceptions |= FPSCR_IOC;
554 }
555
556 if (d && vdm.sign) {
557 d = 0;
558 exceptions |= FPSCR_IOC;
559 } else if (rem)
560 exceptions |= FPSCR_IXC;
561 } else {
562 d = 0;
563 if (vdm.exponent | vdm.significand) {
564 exceptions |= FPSCR_IXC;
565 if (rmode == FPSCR_ROUND_PLUSINF && vdm.sign == 0)
566 d = 1;
567 else if (rmode == FPSCR_ROUND_MINUSINF && vdm.sign) {
568 d = 0;
569 exceptions |= FPSCR_IOC;
570 }
571 }
572 }
573
574 pr_debug("VFP: ftoui: d(s%d)=%08x exceptions=%08x\n", sd, d, exceptions);
575
576 vfp_put_float(d, sd);
577
578 return exceptions;
579 }
580
581 static u32 vfp_double_ftouiz(int sd, int unused, int dm, u32 fpscr)
582 {
583 return vfp_double_ftoui(sd, unused, dm, FPSCR_ROUND_TOZERO);
584 }
585
586 static u32 vfp_double_ftosi(int sd, int unused, int dm, u32 fpscr)
587 {
588 struct vfp_double vdm;
589 u32 d, exceptions = 0;
590 int rmode = fpscr & FPSCR_RMODE_MASK;
591 int tm;
592
593 vfp_double_unpack(&vdm, vfp_get_double(dm));
594 vfp_double_dump("VDM", &vdm);
595
596 /*
597 * Do we have denormalised number?
598 */
599 tm = vfp_double_type(&vdm);
600 if (tm & VFP_DENORMAL)
601 exceptions |= FPSCR_IDC;
602
603 if (tm & VFP_NAN) {
604 d = 0;
605 exceptions |= FPSCR_IOC;
606 } else if (vdm.exponent >= 1023 + 32) {
607 d = 0x7fffffff;
608 if (vdm.sign)
609 d = ~d;
610 exceptions |= FPSCR_IOC;
611 } else if (vdm.exponent >= 1023 - 1) {
612 int shift = 1023 + 63 - vdm.exponent; /* 58 */
613 u64 rem, incr = 0;
614
615 d = (vdm.significand << 1) >> shift;
616 rem = vdm.significand << (65 - shift);
617
618 if (rmode == FPSCR_ROUND_NEAREST) {
619 incr = 0x8000000000000000ULL;
620 if ((d & 1) == 0)
621 incr -= 1;
622 } else if (rmode == FPSCR_ROUND_TOZERO) {
623 incr = 0;
624 } else if ((rmode == FPSCR_ROUND_PLUSINF) ^ (vdm.sign != 0)) {
625 incr = ~0ULL;
626 }
627
628 if ((rem + incr) < rem && d < 0xffffffff)
629 d += 1;
630 if (d > 0x7fffffff + (vdm.sign != 0)) {
631 d = 0x7fffffff + (vdm.sign != 0);
632 exceptions |= FPSCR_IOC;
633 } else if (rem)
634 exceptions |= FPSCR_IXC;
635
636 if (vdm.sign)
637 d = -d;
638 } else {
639 d = 0;
640 if (vdm.exponent | vdm.significand) {
641 exceptions |= FPSCR_IXC;
642 if (rmode == FPSCR_ROUND_PLUSINF && vdm.sign == 0)
643 d = 1;
644 else if (rmode == FPSCR_ROUND_MINUSINF && vdm.sign)
645 d = -1;
646 }
647 }
648
649 pr_debug("VFP: ftosi: d(s%d)=%08x exceptions=%08x\n", sd, d, exceptions);
650
651 vfp_put_float((s32)d, sd);
652
653 return exceptions;
654 }
655
656 static u32 vfp_double_ftosiz(int dd, int unused, int dm, u32 fpscr)
657 {
658 return vfp_double_ftosi(dd, unused, dm, FPSCR_ROUND_TOZERO);
659 }
660
661
662 static struct op fops_ext[32] = {
663 [FEXT_TO_IDX(FEXT_FCPY)] = {vfp_double_fcpy, 0},
664 [FEXT_TO_IDX(FEXT_FABS)] = {vfp_double_fabs, 0},
665 [FEXT_TO_IDX(FEXT_FNEG)] = {vfp_double_fneg, 0},
666 [FEXT_TO_IDX(FEXT_FSQRT)] = {vfp_double_fsqrt, 0},
667 [FEXT_TO_IDX(FEXT_FCMP)] = {vfp_double_fcmp, OP_SCALAR},
668 [FEXT_TO_IDX(FEXT_FCMPE)] = {vfp_double_fcmpe, OP_SCALAR},
669 [FEXT_TO_IDX(FEXT_FCMPZ)] = {vfp_double_fcmpz, OP_SCALAR},
670 [FEXT_TO_IDX(FEXT_FCMPEZ)] = {vfp_double_fcmpez, OP_SCALAR},
671 [FEXT_TO_IDX(FEXT_FCVT)] = {vfp_double_fcvts, (OP_SD|OP_SCALAR)},
672 [FEXT_TO_IDX(FEXT_FUITO)] = {vfp_double_fuito, OP_SCALAR},
673 [FEXT_TO_IDX(FEXT_FSITO)] = {vfp_double_fsito, OP_SCALAR},
674 [FEXT_TO_IDX(FEXT_FTOUI)] = {vfp_double_ftoui, (OP_SD|OP_SCALAR)},
675 [FEXT_TO_IDX(FEXT_FTOUIZ)] = {vfp_double_ftouiz, (OP_SD|OP_SCALAR)},
676 [FEXT_TO_IDX(FEXT_FTOSI)] = {vfp_double_ftosi, (OP_SD|OP_SCALAR)},
677 [FEXT_TO_IDX(FEXT_FTOSIZ)] = {vfp_double_ftosiz, (OP_SD|OP_SCALAR)},
678 };
679
680
681
682
683 static u32
684 vfp_double_fadd_nonnumber(struct vfp_double *vdd, struct vfp_double *vdn,
685 struct vfp_double *vdm, u32 fpscr)
686 {
687 struct vfp_double *vdp;
688 u32 exceptions = 0;
689 int tn, tm;
690
691 tn = vfp_double_type(vdn);
692 tm = vfp_double_type(vdm);
693
694 if (tn & tm & VFP_INFINITY) {
695 /*
696 * Two infinities. Are they different signs?
697 */
698 if (vdn->sign ^ vdm->sign) {
699 /*
700 * different signs -> invalid
701 */
702 exceptions = FPSCR_IOC;
703 vdp = &vfp_double_default_qnan;
704 } else {
705 /*
706 * same signs -> valid
707 */
708 vdp = vdn;
709 }
710 } else if (tn & VFP_INFINITY && tm & VFP_NUMBER) {
711 /*
712 * One infinity and one number -> infinity
713 */
714 vdp = vdn;
715 } else {
716 /*
717 * 'n' is a NaN of some type
718 */
719 return vfp_propagate_nan(vdd, vdn, vdm, fpscr);
720 }
721 *vdd = *vdp;
722 return exceptions;
723 }
724
725 static u32
726 vfp_double_add(struct vfp_double *vdd, struct vfp_double *vdn,
727 struct vfp_double *vdm, u32 fpscr)
728 {
729 u32 exp_diff;
730 u64 m_sig;
731
732 if (vdn->significand & (1ULL << 63) ||
733 vdm->significand & (1ULL << 63)) {
734 pr_info("VFP: bad FP values in %s\n", __func__);
735 vfp_double_dump("VDN", vdn);
736 vfp_double_dump("VDM", vdm);
737 }
738
739 /*
740 * Ensure that 'n' is the largest magnitude number. Note that
741 * if 'n' and 'm' have equal exponents, we do not swap them.
742 * This ensures that NaN propagation works correctly.
743 */
744 if (vdn->exponent < vdm->exponent) {
745 struct vfp_double *t = vdn;
746 vdn = vdm;
747 vdm = t;
748 }
749
750 /*
751 * Is 'n' an infinity or a NaN? Note that 'm' may be a number,
752 * infinity or a NaN here.
753 */
754 if (vdn->exponent == 2047)
755 return vfp_double_fadd_nonnumber(vdd, vdn, vdm, fpscr);
756
757 /*
758 * We have two proper numbers, where 'vdn' is the larger magnitude.
759 *
760 * Copy 'n' to 'd' before doing the arithmetic.
761 */
762 *vdd = *vdn;
763
764 /*
765 * Align 'm' with the result.
766 */
767 exp_diff = vdn->exponent - vdm->exponent;
768 m_sig = vfp_shiftright64jamming(vdm->significand, exp_diff);
769
770 /*
771 * If the signs are different, we are really subtracting.
772 */
773 if (vdn->sign ^ vdm->sign) {
774 m_sig = vdn->significand - m_sig;
775 if ((s64)m_sig < 0) {
776 vdd->sign = vfp_sign_negate(vdd->sign);
777 m_sig = -m_sig;
778 } else if (m_sig == 0) {
779 vdd->sign = (fpscr & FPSCR_RMODE_MASK) ==
780 FPSCR_ROUND_MINUSINF ? 0x8000 : 0;
781 }
782 } else {
783 m_sig += vdn->significand;
784 }
785 vdd->significand = m_sig;
786
787 return 0;
788 }
789
790 static u32
791 vfp_double_multiply(struct vfp_double *vdd, struct vfp_double *vdn,
792 struct vfp_double *vdm, u32 fpscr)
793 {
794 vfp_double_dump("VDN", vdn);
795 vfp_double_dump("VDM", vdm);
796
797 /*
798 * Ensure that 'n' is the largest magnitude number. Note that
799 * if 'n' and 'm' have equal exponents, we do not swap them.
800 * This ensures that NaN propagation works correctly.
801 */
802 if (vdn->exponent < vdm->exponent) {
803 struct vfp_double *t = vdn;
804 vdn = vdm;
805 vdm = t;
806 pr_debug("VFP: swapping M <-> N\n");
807 }
808
809 vdd->sign = vdn->sign ^ vdm->sign;
810
811 /*
812 * If 'n' is an infinity or NaN, handle it. 'm' may be anything.
813 */
814 if (vdn->exponent == 2047) {
815 if (vdn->significand || (vdm->exponent == 2047 && vdm->significand))
816 return vfp_propagate_nan(vdd, vdn, vdm, fpscr);
817 if ((vdm->exponent | vdm->significand) == 0) {
818 *vdd = vfp_double_default_qnan;
819 return FPSCR_IOC;
820 }
821 vdd->exponent = vdn->exponent;
822 vdd->significand = 0;
823 return 0;
824 }
825
826 /*
827 * If 'm' is zero, the result is always zero. In this case,
828 * 'n' may be zero or a number, but it doesn't matter which.
829 */
830 if ((vdm->exponent | vdm->significand) == 0) {
831 vdd->exponent = 0;
832 vdd->significand = 0;
833 return 0;
834 }
835
836 /*
837 * We add 2 to the destination exponent for the same reason
838 * as the addition case - though this time we have +1 from
839 * each input operand.
840 */
841 vdd->exponent = vdn->exponent + vdm->exponent - 1023 + 2;
842 vdd->significand = vfp_hi64multiply64(vdn->significand, vdm->significand);
843
844 vfp_double_dump("VDD", vdd);
845 return 0;
846 }
847
848 #define NEG_MULTIPLY (1 << 0)
849 #define NEG_SUBTRACT (1 << 1)
850
851 static u32
852 vfp_double_multiply_accumulate(int dd, int dn, int dm, u32 fpscr, u32 negate, char *func)
853 {
854 struct vfp_double vdd, vdp, vdn, vdm;
855 u32 exceptions;
856
857 vfp_double_unpack(&vdn, vfp_get_double(dn));
858 if (vdn.exponent == 0 && vdn.significand)
859 vfp_double_normalise_denormal(&vdn);
860
861 vfp_double_unpack(&vdm, vfp_get_double(dm));
862 if (vdm.exponent == 0 && vdm.significand)
863 vfp_double_normalise_denormal(&vdm);
864
865 exceptions = vfp_double_multiply(&vdp, &vdn, &vdm, fpscr);
866 if (negate & NEG_MULTIPLY)
867 vdp.sign = vfp_sign_negate(vdp.sign);
868
869 vfp_double_unpack(&vdn, vfp_get_double(dd));
870 if (negate & NEG_SUBTRACT)
871 vdn.sign = vfp_sign_negate(vdn.sign);
872
873 exceptions |= vfp_double_add(&vdd, &vdn, &vdp, fpscr);
874
875 return vfp_double_normaliseround(dd, &vdd, fpscr, exceptions, func);
876 }
877
878 /*
879 * Standard operations
880 */
881
882 /*
883 * sd = sd + (sn * sm)
884 */
885 static u32 vfp_double_fmac(int dd, int dn, int dm, u32 fpscr)
886 {
887 return vfp_double_multiply_accumulate(dd, dn, dm, fpscr, 0, "fmac");
888 }
889
890 /*
891 * sd = sd - (sn * sm)
892 */
893 static u32 vfp_double_fnmac(int dd, int dn, int dm, u32 fpscr)
894 {
895 return vfp_double_multiply_accumulate(dd, dn, dm, fpscr, NEG_MULTIPLY, "fnmac");
896 }
897
898 /*
899 * sd = -sd + (sn * sm)
900 */
901 static u32 vfp_double_fmsc(int dd, int dn, int dm, u32 fpscr)
902 {
903 return vfp_double_multiply_accumulate(dd, dn, dm, fpscr, NEG_SUBTRACT, "fmsc");
904 }
905
906 /*
907 * sd = -sd - (sn * sm)
908 */
909 static u32 vfp_double_fnmsc(int dd, int dn, int dm, u32 fpscr)
910 {
911 return vfp_double_multiply_accumulate(dd, dn, dm, fpscr, NEG_SUBTRACT | NEG_MULTIPLY, "fnmsc");
912 }
913
914 /*
915 * sd = sn * sm
916 */
917 static u32 vfp_double_fmul(int dd, int dn, int dm, u32 fpscr)
918 {
919 struct vfp_double vdd, vdn, vdm;
920 u32 exceptions;
921
922 vfp_double_unpack(&vdn, vfp_get_double(dn));
923 if (vdn.exponent == 0 && vdn.significand)
924 vfp_double_normalise_denormal(&vdn);
925
926 vfp_double_unpack(&vdm, vfp_get_double(dm));
927 if (vdm.exponent == 0 && vdm.significand)
928 vfp_double_normalise_denormal(&vdm);
929
930 exceptions = vfp_double_multiply(&vdd, &vdn, &vdm, fpscr);
931 return vfp_double_normaliseround(dd, &vdd, fpscr, exceptions, "fmul");
932 }
933
934 /*
935 * sd = -(sn * sm)
936 */
937 static u32 vfp_double_fnmul(int dd, int dn, int dm, u32 fpscr)
938 {
939 struct vfp_double vdd, vdn, vdm;
940 u32 exceptions;
941
942 vfp_double_unpack(&vdn, vfp_get_double(dn));
943 if (vdn.exponent == 0 && vdn.significand)
944 vfp_double_normalise_denormal(&vdn);
945
946 vfp_double_unpack(&vdm, vfp_get_double(dm));
947 if (vdm.exponent == 0 && vdm.significand)
948 vfp_double_normalise_denormal(&vdm);
949
950 exceptions = vfp_double_multiply(&vdd, &vdn, &vdm, fpscr);
951 vdd.sign = vfp_sign_negate(vdd.sign);
952
953 return vfp_double_normaliseround(dd, &vdd, fpscr, exceptions, "fnmul");
954 }
955
956 /*
957 * sd = sn + sm
958 */
959 static u32 vfp_double_fadd(int dd, int dn, int dm, u32 fpscr)
960 {
961 struct vfp_double vdd, vdn, vdm;
962 u32 exceptions;
963
964 vfp_double_unpack(&vdn, vfp_get_double(dn));
965 if (vdn.exponent == 0 && vdn.significand)
966 vfp_double_normalise_denormal(&vdn);
967
968 vfp_double_unpack(&vdm, vfp_get_double(dm));
969 if (vdm.exponent == 0 && vdm.significand)
970 vfp_double_normalise_denormal(&vdm);
971
972 exceptions = vfp_double_add(&vdd, &vdn, &vdm, fpscr);
973
974 return vfp_double_normaliseround(dd, &vdd, fpscr, exceptions, "fadd");
975 }
976
977 /*
978 * sd = sn - sm
979 */
980 static u32 vfp_double_fsub(int dd, int dn, int dm, u32 fpscr)
981 {
982 struct vfp_double vdd, vdn, vdm;
983 u32 exceptions;
984
985 vfp_double_unpack(&vdn, vfp_get_double(dn));
986 if (vdn.exponent == 0 && vdn.significand)
987 vfp_double_normalise_denormal(&vdn);
988
989 vfp_double_unpack(&vdm, vfp_get_double(dm));
990 if (vdm.exponent == 0 && vdm.significand)
991 vfp_double_normalise_denormal(&vdm);
992
993 /*
994 * Subtraction is like addition, but with a negated operand.
995 */
996 vdm.sign = vfp_sign_negate(vdm.sign);
997
998 exceptions = vfp_double_add(&vdd, &vdn, &vdm, fpscr);
999
1000 return vfp_double_normaliseround(dd, &vdd, fpscr, exceptions, "fsub");
1001 }
1002
1003 /*
1004 * sd = sn / sm
1005 */
1006 static u32 vfp_double_fdiv(int dd, int dn, int dm, u32 fpscr)
1007 {
1008 struct vfp_double vdd, vdn, vdm;
1009 u32 exceptions = 0;
1010 int tm, tn;
1011
1012 vfp_double_unpack(&vdn, vfp_get_double(dn));
1013 vfp_double_unpack(&vdm, vfp_get_double(dm));
1014
1015 vdd.sign = vdn.sign ^ vdm.sign;
1016
1017 tn = vfp_double_type(&vdn);
1018 tm = vfp_double_type(&vdm);
1019
1020 /*
1021 * Is n a NAN?
1022 */
1023 if (tn & VFP_NAN)
1024 goto vdn_nan;
1025
1026 /*
1027 * Is m a NAN?
1028 */
1029 if (tm & VFP_NAN)
1030 goto vdm_nan;
1031
1032 /*
1033 * If n and m are infinity, the result is invalid
1034 * If n and m are zero, the result is invalid
1035 */
1036 if (tm & tn & (VFP_INFINITY|VFP_ZERO))
1037 goto invalid;
1038
1039 /*
1040 * If n is infinity, the result is infinity
1041 */
1042 if (tn & VFP_INFINITY)
1043 goto infinity;
1044
1045 /*
1046 * If m is zero, raise div0 exceptions
1047 */
1048 if (tm & VFP_ZERO)
1049 goto divzero;
1050
1051 /*
1052 * If m is infinity, or n is zero, the result is zero
1053 */
1054 if (tm & VFP_INFINITY || tn & VFP_ZERO)
1055 goto zero;
1056
1057 if (tn & VFP_DENORMAL)
1058 vfp_double_normalise_denormal(&vdn);
1059 if (tm & VFP_DENORMAL)
1060 vfp_double_normalise_denormal(&vdm);
1061
1062 /*
1063 * Ok, we have two numbers, we can perform division.
1064 */
1065 vdd.exponent = vdn.exponent - vdm.exponent + 1023 - 1;
1066 vdm.significand <<= 1;
1067 if (vdm.significand <= (2 * vdn.significand)) {
1068 vdn.significand >>= 1;
1069 vdd.exponent++;
1070 }
1071 vdd.significand = vfp_estimate_div128to64(vdn.significand, 0, vdm.significand);
1072 if ((vdd.significand & 0x1ff) <= 2) {
1073 u64 termh, terml, remh, reml;
1074 mul64to128(&termh, &terml, vdm.significand, vdd.significand);
1075 sub128(&remh, &reml, vdn.significand, 0, termh, terml);
1076 while ((s64)remh < 0) {
1077 vdd.significand -= 1;
1078 add128(&remh, &reml, remh, reml, 0, vdm.significand);
1079 }
1080 vdd.significand |= (reml != 0);
1081 }
1082 return vfp_double_normaliseround(dd, &vdd, fpscr, 0, "fdiv");
1083
1084 vdn_nan:
1085 exceptions = vfp_propagate_nan(&vdd, &vdn, &vdm, fpscr);
1086 pack:
1087 vfp_put_double(vfp_double_pack(&vdd), dd);
1088 return exceptions;
1089
1090 vdm_nan:
1091 exceptions = vfp_propagate_nan(&vdd, &vdm, &vdn, fpscr);
1092 goto pack;
1093
1094 zero:
1095 vdd.exponent = 0;
1096 vdd.significand = 0;
1097 goto pack;
1098
1099 divzero:
1100 exceptions = FPSCR_DZC;
1101 infinity:
1102 vdd.exponent = 2047;
1103 vdd.significand = 0;
1104 goto pack;
1105
1106 invalid:
1107 vfp_put_double(vfp_double_pack(&vfp_double_default_qnan), dd);
1108 return FPSCR_IOC;
1109 }
1110
1111 static struct op fops[16] = {
1112 [FOP_TO_IDX(FOP_FMAC)] = {vfp_double_fmac, 0},
1113 [FOP_TO_IDX(FOP_FNMAC)] = {vfp_double_fnmac, 0},
1114 [FOP_TO_IDX(FOP_FMSC)] = {vfp_double_fmsc, 0},
1115 [FOP_TO_IDX(FOP_FNMSC)] = {vfp_double_fnmsc, 0},
1116 [FOP_TO_IDX(FOP_FMUL)] = {vfp_double_fmul, 0},
1117 [FOP_TO_IDX(FOP_FNMUL)] = {vfp_double_fnmul, 0},
1118 [FOP_TO_IDX(FOP_FADD)] = {vfp_double_fadd, 0},
1119 [FOP_TO_IDX(FOP_FSUB)] = {vfp_double_fsub, 0},
1120 [FOP_TO_IDX(FOP_FDIV)] = {vfp_double_fdiv, 0},
1121 };
1122
1123 #define FREG_BANK(x) ((x) & 0x0c)
1124 #define FREG_IDX(x) ((x) & 3)
1125
1126 u32 vfp_double_cpdo(u32 inst, u32 fpscr)
1127 {
1128 u32 op = inst & FOP_MASK;
1129 u32 exceptions = 0;
1130 unsigned int dest;
1131 unsigned int dn = vfp_get_dn(inst);
1132 unsigned int dm = vfp_get_dm(inst);
1133 unsigned int vecitr, veclen, vecstride;
1134 struct op *fop;
1135
1136 vecstride = (1 + ((fpscr & FPSCR_STRIDE_MASK) == FPSCR_STRIDE_MASK)) * 2;
1137
1138 fop = (op == FOP_EXT) ? &fops_ext[FEXT_TO_IDX(inst)] : &fops[FOP_TO_IDX(op)];
1139 /*
1140 * fcvtds takes an sN register number as destination, not dN.
1141 * It also always operates on scalars.
1142 */
1143 if (fop->flags & OP_SD)
1144 dest = vfp_get_sd(inst);
1145 else
1146 dest = vfp_get_dd(inst);
1147
1148 /*
1149 * If destination bank is zero, vector length is always '1'.
1150 * ARM DDI0100F C5.1.3, C5.3.2.
1151 */
1152 if ((fop->flags & OP_SCALAR) || (FREG_BANK(dest) == 0))
1153 veclen = 0;
1154 else
1155 veclen = fpscr & FPSCR_LENGTH_MASK;
1156
1157 pr_debug("VFP: vecstride=%u veclen=%u\n", vecstride,
1158 (veclen >> FPSCR_LENGTH_BIT) + 1);
1159
1160 if (!fop->fn)
1161 goto invalid;
1162
1163 for (vecitr = 0; vecitr <= veclen; vecitr += 1 << FPSCR_LENGTH_BIT) {
1164 u32 except;
1165
1166 if (op == FOP_EXT && (fop->flags & OP_SD))
1167 pr_debug("VFP: itr%d (s%u) = op[%u] (d%u)\n",
1168 vecitr >> FPSCR_LENGTH_BIT,
1169 dest, dn, dm);
1170 else if (op == FOP_EXT)
1171 pr_debug("VFP: itr%d (d%u) = op[%u] (d%u)\n",
1172 vecitr >> FPSCR_LENGTH_BIT,
1173 dest, dn, dm);
1174 else
1175 pr_debug("VFP: itr%d (d%u) = (d%u) op[%u] (d%u)\n",
1176 vecitr >> FPSCR_LENGTH_BIT,
1177 dest, dn, FOP_TO_IDX(op), dm);
1178
1179 except = fop->fn(dest, dn, dm, fpscr);
1180 pr_debug("VFP: itr%d: exceptions=%08x\n",
1181 vecitr >> FPSCR_LENGTH_BIT, except);
1182
1183 exceptions |= except;
1184
1185 /*
1186 * This ensures that comparisons only operate on scalars;
1187 * comparisons always return with one FPSCR status bit set.
1188 */
1189 if (except & (FPSCR_N|FPSCR_Z|FPSCR_C|FPSCR_V))
1190 break;
1191
1192 /*
1193 * CHECK: It appears to be undefined whether we stop when
1194 * we encounter an exception. We continue.
1195 */
1196
1197 dest = FREG_BANK(dest) + ((FREG_IDX(dest) + vecstride) & 6);
1198 dn = FREG_BANK(dn) + ((FREG_IDX(dn) + vecstride) & 6);
1199 if (FREG_BANK(dm) != 0)
1200 dm = FREG_BANK(dm) + ((FREG_IDX(dm) + vecstride) & 6);
1201 }
1202 return exceptions;
1203
1204 invalid:
1205 return ~0;
1206 }
Linux kernel - Deliverables
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