1 /*
2 * linux/arch/arm/vfp/vfpsingle.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/vfp.h>
38
39 #include "vfpinstr.h"
40 #include "vfp.h"
41
42 static struct vfp_single vfp_single_default_qnan = {
43 .exponent = 255,
44 .sign = 0,
45 .significand = VFP_SINGLE_SIGNIFICAND_QNAN,
46 };
47
vfp_single_dump(const char * str,struct vfp_single * s)48 static void vfp_single_dump(const char *str, struct vfp_single *s)
49 {
50 pr_debug("VFP: %s: sign=%d exponent=%d significand=%08x\n",
51 str, s->sign != 0, s->exponent, s->significand);
52 }
53
vfp_single_normalise_denormal(struct vfp_single * vs)54 static void vfp_single_normalise_denormal(struct vfp_single *vs)
55 {
56 int bits = 31 - fls(vs->significand);
57
58 vfp_single_dump("normalise_denormal: in", vs);
59
60 if (bits) {
61 vs->exponent -= bits - 1;
62 vs->significand <<= bits;
63 }
64
65 vfp_single_dump("normalise_denormal: out", vs);
66 }
67
68 #ifndef DEBUG
69 #define vfp_single_normaliseround(sd,vsd,fpscr,except,func) __vfp_single_normaliseround(sd,vsd,fpscr,except)
__vfp_single_normaliseround(int sd,struct vfp_single * vs,u32 fpscr,u32 exceptions)70 u32 __vfp_single_normaliseround(int sd, struct vfp_single *vs, u32 fpscr, u32 exceptions)
71 #else
72 u32 vfp_single_normaliseround(int sd, struct vfp_single *vs, u32 fpscr, u32 exceptions, const char *func)
73 #endif
74 {
75 u32 significand, incr, rmode;
76 int exponent, shift, underflow;
77
78 vfp_single_dump("pack: in", vs);
79
80 /*
81 * Infinities and NaNs are a special case.
82 */
83 if (vs->exponent == 255 && (vs->significand == 0 || exceptions))
84 goto pack;
85
86 /*
87 * Special-case zero.
88 */
89 if (vs->significand == 0) {
90 vs->exponent = 0;
91 goto pack;
92 }
93
94 exponent = vs->exponent;
95 significand = vs->significand;
96
97 /*
98 * Normalise first. Note that we shift the significand up to
99 * bit 31, so we have VFP_SINGLE_LOW_BITS + 1 below the least
100 * significant bit.
101 */
102 shift = 32 - fls(significand);
103 if (shift < 32 && shift) {
104 exponent -= shift;
105 significand <<= shift;
106 }
107
108 #ifdef DEBUG
109 vs->exponent = exponent;
110 vs->significand = significand;
111 vfp_single_dump("pack: normalised", vs);
112 #endif
113
114 /*
115 * Tiny number?
116 */
117 underflow = exponent < 0;
118 if (underflow) {
119 significand = vfp_shiftright32jamming(significand, -exponent);
120 exponent = 0;
121 #ifdef DEBUG
122 vs->exponent = exponent;
123 vs->significand = significand;
124 vfp_single_dump("pack: tiny number", vs);
125 #endif
126 if (!(significand & ((1 << (VFP_SINGLE_LOW_BITS + 1)) - 1)))
127 underflow = 0;
128 }
129
130 /*
131 * Select rounding increment.
132 */
133 incr = 0;
134 rmode = fpscr & FPSCR_RMODE_MASK;
135
136 if (rmode == FPSCR_ROUND_NEAREST) {
137 incr = 1 << VFP_SINGLE_LOW_BITS;
138 if ((significand & (1 << (VFP_SINGLE_LOW_BITS + 1))) == 0)
139 incr -= 1;
140 } else if (rmode == FPSCR_ROUND_TOZERO) {
141 incr = 0;
142 } else if ((rmode == FPSCR_ROUND_PLUSINF) ^ (vs->sign != 0))
143 incr = (1 << (VFP_SINGLE_LOW_BITS + 1)) - 1;
144
145 pr_debug("VFP: rounding increment = 0x%08x\n", incr);
146
147 /*
148 * Is our rounding going to overflow?
149 */
150 if ((significand + incr) < significand) {
151 exponent += 1;
152 significand = (significand >> 1) | (significand & 1);
153 incr >>= 1;
154 #ifdef DEBUG
155 vs->exponent = exponent;
156 vs->significand = significand;
157 vfp_single_dump("pack: overflow", vs);
158 #endif
159 }
160
161 /*
162 * If any of the low bits (which will be shifted out of the
163 * number) are non-zero, the result is inexact.
164 */
165 if (significand & ((1 << (VFP_SINGLE_LOW_BITS + 1)) - 1))
166 exceptions |= FPSCR_IXC;
167
168 /*
169 * Do our rounding.
170 */
171 significand += incr;
172
173 /*
174 * Infinity?
175 */
176 if (exponent >= 254) {
177 exceptions |= FPSCR_OFC | FPSCR_IXC;
178 if (incr == 0) {
179 vs->exponent = 253;
180 vs->significand = 0x7fffffff;
181 } else {
182 vs->exponent = 255; /* infinity */
183 vs->significand = 0;
184 }
185 } else {
186 if (significand >> (VFP_SINGLE_LOW_BITS + 1) == 0)
187 exponent = 0;
188 if (exponent || significand > 0x80000000)
189 underflow = 0;
190 if (underflow)
191 exceptions |= FPSCR_UFC;
192 vs->exponent = exponent;
193 vs->significand = significand >> 1;
194 }
195
196 pack:
197 vfp_single_dump("pack: final", vs);
198 {
199 s32 d = vfp_single_pack(vs);
200 #ifdef DEBUG
201 pr_debug("VFP: %s: d(s%d)=%08x exceptions=%08x\n", func,
202 sd, d, exceptions);
203 #endif
204 vfp_put_float(d, sd);
205 }
206
207 return exceptions;
208 }
209
210 /*
211 * Propagate the NaN, setting exceptions if it is signalling.
212 * 'n' is always a NaN. 'm' may be a number, NaN or infinity.
213 */
214 static u32
vfp_propagate_nan(struct vfp_single * vsd,struct vfp_single * vsn,struct vfp_single * vsm,u32 fpscr)215 vfp_propagate_nan(struct vfp_single *vsd, struct vfp_single *vsn,
216 struct vfp_single *vsm, u32 fpscr)
217 {
218 struct vfp_single *nan;
219 int tn, tm = 0;
220
221 tn = vfp_single_type(vsn);
222
223 if (vsm)
224 tm = vfp_single_type(vsm);
225
226 if (fpscr & FPSCR_DEFAULT_NAN)
227 /*
228 * Default NaN mode - always returns a quiet NaN
229 */
230 nan = &vfp_single_default_qnan;
231 else {
232 /*
233 * Contemporary mode - select the first signalling
234 * NAN, or if neither are signalling, the first
235 * quiet NAN.
236 */
237 if (tn == VFP_SNAN || (tm != VFP_SNAN && tn == VFP_QNAN))
238 nan = vsn;
239 else
240 nan = vsm;
241 /*
242 * Make the NaN quiet.
243 */
244 nan->significand |= VFP_SINGLE_SIGNIFICAND_QNAN;
245 }
246
247 *vsd = *nan;
248
249 /*
250 * If one was a signalling NAN, raise invalid operation.
251 */
252 return tn == VFP_SNAN || tm == VFP_SNAN ? FPSCR_IOC : VFP_NAN_FLAG;
253 }
254
255
256 /*
257 * Extended operations
258 */
vfp_single_fabs(int sd,int unused,s32 m,u32 fpscr)259 static u32 vfp_single_fabs(int sd, int unused, s32 m, u32 fpscr)
260 {
261 vfp_put_float(vfp_single_packed_abs(m), sd);
262 return 0;
263 }
264
vfp_single_fcpy(int sd,int unused,s32 m,u32 fpscr)265 static u32 vfp_single_fcpy(int sd, int unused, s32 m, u32 fpscr)
266 {
267 vfp_put_float(m, sd);
268 return 0;
269 }
270
vfp_single_fneg(int sd,int unused,s32 m,u32 fpscr)271 static u32 vfp_single_fneg(int sd, int unused, s32 m, u32 fpscr)
272 {
273 vfp_put_float(vfp_single_packed_negate(m), sd);
274 return 0;
275 }
276
277 static const u16 sqrt_oddadjust[] = {
278 0x0004, 0x0022, 0x005d, 0x00b1, 0x011d, 0x019f, 0x0236, 0x02e0,
279 0x039c, 0x0468, 0x0545, 0x0631, 0x072b, 0x0832, 0x0946, 0x0a67
280 };
281
282 static const u16 sqrt_evenadjust[] = {
283 0x0a2d, 0x08af, 0x075a, 0x0629, 0x051a, 0x0429, 0x0356, 0x029e,
284 0x0200, 0x0179, 0x0109, 0x00af, 0x0068, 0x0034, 0x0012, 0x0002
285 };
286
vfp_estimate_sqrt_significand(u32 exponent,u32 significand)287 u32 vfp_estimate_sqrt_significand(u32 exponent, u32 significand)
288 {
289 int index;
290 u32 z, a;
291
292 if ((significand & 0xc0000000) != 0x40000000) {
293 pr_warn("VFP: estimate_sqrt: invalid significand\n");
294 }
295
296 a = significand << 1;
297 index = (a >> 27) & 15;
298 if (exponent & 1) {
299 z = 0x4000 + (a >> 17) - sqrt_oddadjust[index];
300 z = ((a / z) << 14) + (z << 15);
301 a >>= 1;
302 } else {
303 z = 0x8000 + (a >> 17) - sqrt_evenadjust[index];
304 z = a / z + z;
305 z = (z >= 0x20000) ? 0xffff8000 : (z << 15);
306 if (z <= a)
307 return (s32)a >> 1;
308 }
309 {
310 u64 v = (u64)a << 31;
311 do_div(v, z);
312 return v + (z >> 1);
313 }
314 }
315
vfp_single_fsqrt(int sd,int unused,s32 m,u32 fpscr)316 static u32 vfp_single_fsqrt(int sd, int unused, s32 m, u32 fpscr)
317 {
318 struct vfp_single vsm, vsd;
319 int ret, tm;
320
321 vfp_single_unpack(&vsm, m);
322 tm = vfp_single_type(&vsm);
323 if (tm & (VFP_NAN|VFP_INFINITY)) {
324 struct vfp_single *vsp = &vsd;
325
326 if (tm & VFP_NAN)
327 ret = vfp_propagate_nan(vsp, &vsm, NULL, fpscr);
328 else if (vsm.sign == 0) {
329 sqrt_copy:
330 vsp = &vsm;
331 ret = 0;
332 } else {
333 sqrt_invalid:
334 vsp = &vfp_single_default_qnan;
335 ret = FPSCR_IOC;
336 }
337 vfp_put_float(vfp_single_pack(vsp), sd);
338 return ret;
339 }
340
341 /*
342 * sqrt(+/- 0) == +/- 0
343 */
344 if (tm & VFP_ZERO)
345 goto sqrt_copy;
346
347 /*
348 * Normalise a denormalised number
349 */
350 if (tm & VFP_DENORMAL)
351 vfp_single_normalise_denormal(&vsm);
352
353 /*
354 * sqrt(<0) = invalid
355 */
356 if (vsm.sign)
357 goto sqrt_invalid;
358
359 vfp_single_dump("sqrt", &vsm);
360
361 /*
362 * Estimate the square root.
363 */
364 vsd.sign = 0;
365 vsd.exponent = ((vsm.exponent - 127) >> 1) + 127;
366 vsd.significand = vfp_estimate_sqrt_significand(vsm.exponent, vsm.significand) + 2;
367
368 vfp_single_dump("sqrt estimate", &vsd);
369
370 /*
371 * And now adjust.
372 */
373 if ((vsd.significand & VFP_SINGLE_LOW_BITS_MASK) <= 5) {
374 if (vsd.significand < 2) {
375 vsd.significand = 0xffffffff;
376 } else {
377 u64 term;
378 s64 rem;
379 vsm.significand <<= !(vsm.exponent & 1);
380 term = (u64)vsd.significand * vsd.significand;
381 rem = ((u64)vsm.significand << 32) - term;
382
383 pr_debug("VFP: term=%016llx rem=%016llx\n", term, rem);
384
385 while (rem < 0) {
386 vsd.significand -= 1;
387 rem += ((u64)vsd.significand << 1) | 1;
388 }
389 vsd.significand |= rem != 0;
390 }
391 }
392 vsd.significand = vfp_shiftright32jamming(vsd.significand, 1);
393
394 return vfp_single_normaliseround(sd, &vsd, fpscr, 0, "fsqrt");
395 }
396
397 /*
398 * Equal := ZC
399 * Less than := N
400 * Greater than := C
401 * Unordered := CV
402 */
vfp_compare(int sd,int signal_on_qnan,s32 m,u32 fpscr)403 static u32 vfp_compare(int sd, int signal_on_qnan, s32 m, u32 fpscr)
404 {
405 s32 d;
406 u32 ret = 0;
407
408 d = vfp_get_float(sd);
409 if (vfp_single_packed_exponent(m) == 255 && vfp_single_packed_mantissa(m)) {
410 ret |= FPSCR_C | FPSCR_V;
411 if (signal_on_qnan || !(vfp_single_packed_mantissa(m) & (1 << (VFP_SINGLE_MANTISSA_BITS - 1))))
412 /*
413 * Signalling NaN, or signalling on quiet NaN
414 */
415 ret |= FPSCR_IOC;
416 }
417
418 if (vfp_single_packed_exponent(d) == 255 && vfp_single_packed_mantissa(d)) {
419 ret |= FPSCR_C | FPSCR_V;
420 if (signal_on_qnan || !(vfp_single_packed_mantissa(d) & (1 << (VFP_SINGLE_MANTISSA_BITS - 1))))
421 /*
422 * Signalling NaN, or signalling on quiet NaN
423 */
424 ret |= FPSCR_IOC;
425 }
426
427 if (ret == 0) {
428 if (d == m || vfp_single_packed_abs(d | m) == 0) {
429 /*
430 * equal
431 */
432 ret |= FPSCR_Z | FPSCR_C;
433 } else if (vfp_single_packed_sign(d ^ m)) {
434 /*
435 * different signs
436 */
437 if (vfp_single_packed_sign(d))
438 /*
439 * d is negative, so d < m
440 */
441 ret |= FPSCR_N;
442 else
443 /*
444 * d is positive, so d > m
445 */
446 ret |= FPSCR_C;
447 } else if ((vfp_single_packed_sign(d) != 0) ^ (d < m)) {
448 /*
449 * d < m
450 */
451 ret |= FPSCR_N;
452 } else if ((vfp_single_packed_sign(d) != 0) ^ (d > m)) {
453 /*
454 * d > m
455 */
456 ret |= FPSCR_C;
457 }
458 }
459 return ret;
460 }
461
vfp_single_fcmp(int sd,int unused,s32 m,u32 fpscr)462 static u32 vfp_single_fcmp(int sd, int unused, s32 m, u32 fpscr)
463 {
464 return vfp_compare(sd, 0, m, fpscr);
465 }
466
vfp_single_fcmpe(int sd,int unused,s32 m,u32 fpscr)467 static u32 vfp_single_fcmpe(int sd, int unused, s32 m, u32 fpscr)
468 {
469 return vfp_compare(sd, 1, m, fpscr);
470 }
471
vfp_single_fcmpz(int sd,int unused,s32 m,u32 fpscr)472 static u32 vfp_single_fcmpz(int sd, int unused, s32 m, u32 fpscr)
473 {
474 return vfp_compare(sd, 0, 0, fpscr);
475 }
476
vfp_single_fcmpez(int sd,int unused,s32 m,u32 fpscr)477 static u32 vfp_single_fcmpez(int sd, int unused, s32 m, u32 fpscr)
478 {
479 return vfp_compare(sd, 1, 0, fpscr);
480 }
481
vfp_single_fcvtd(int dd,int unused,s32 m,u32 fpscr)482 static u32 vfp_single_fcvtd(int dd, int unused, s32 m, u32 fpscr)
483 {
484 struct vfp_single vsm;
485 struct vfp_double vdd;
486 int tm;
487 u32 exceptions = 0;
488
489 vfp_single_unpack(&vsm, m);
490
491 tm = vfp_single_type(&vsm);
492
493 /*
494 * If we have a signalling NaN, signal invalid operation.
495 */
496 if (tm == VFP_SNAN)
497 exceptions = FPSCR_IOC;
498
499 if (tm & VFP_DENORMAL)
500 vfp_single_normalise_denormal(&vsm);
501
502 vdd.sign = vsm.sign;
503 vdd.significand = (u64)vsm.significand << 32;
504
505 /*
506 * If we have an infinity or NaN, the exponent must be 2047.
507 */
508 if (tm & (VFP_INFINITY|VFP_NAN)) {
509 vdd.exponent = 2047;
510 if (tm == VFP_QNAN)
511 vdd.significand |= VFP_DOUBLE_SIGNIFICAND_QNAN;
512 goto pack_nan;
513 } else if (tm & VFP_ZERO)
514 vdd.exponent = 0;
515 else
516 vdd.exponent = vsm.exponent + (1023 - 127);
517
518 return vfp_double_normaliseround(dd, &vdd, fpscr, exceptions, "fcvtd");
519
520 pack_nan:
521 vfp_put_double(vfp_double_pack(&vdd), dd);
522 return exceptions;
523 }
524
vfp_single_fuito(int sd,int unused,s32 m,u32 fpscr)525 static u32 vfp_single_fuito(int sd, int unused, s32 m, u32 fpscr)
526 {
527 struct vfp_single vs;
528
529 vs.sign = 0;
530 vs.exponent = 127 + 31 - 1;
531 vs.significand = (u32)m;
532
533 return vfp_single_normaliseround(sd, &vs, fpscr, 0, "fuito");
534 }
535
vfp_single_fsito(int sd,int unused,s32 m,u32 fpscr)536 static u32 vfp_single_fsito(int sd, int unused, s32 m, u32 fpscr)
537 {
538 struct vfp_single vs;
539
540 vs.sign = (m & 0x80000000) >> 16;
541 vs.exponent = 127 + 31 - 1;
542 vs.significand = vs.sign ? -m : m;
543
544 return vfp_single_normaliseround(sd, &vs, fpscr, 0, "fsito");
545 }
546
vfp_single_ftoui(int sd,int unused,s32 m,u32 fpscr)547 static u32 vfp_single_ftoui(int sd, int unused, s32 m, u32 fpscr)
548 {
549 struct vfp_single vsm;
550 u32 d, exceptions = 0;
551 int rmode = fpscr & FPSCR_RMODE_MASK;
552 int tm;
553
554 vfp_single_unpack(&vsm, m);
555 vfp_single_dump("VSM", &vsm);
556
557 /*
558 * Do we have a denormalised number?
559 */
560 tm = vfp_single_type(&vsm);
561 if (tm & VFP_DENORMAL)
562 exceptions |= FPSCR_IDC;
563
564 if (tm & VFP_NAN)
565 vsm.sign = 0;
566
567 if (vsm.exponent >= 127 + 32) {
568 d = vsm.sign ? 0 : 0xffffffff;
569 exceptions = FPSCR_IOC;
570 } else if (vsm.exponent >= 127 - 1) {
571 int shift = 127 + 31 - vsm.exponent;
572 u32 rem, incr = 0;
573
574 /*
575 * 2^0 <= m < 2^32-2^8
576 */
577 d = (vsm.significand << 1) >> shift;
578 rem = vsm.significand << (33 - shift);
579
580 if (rmode == FPSCR_ROUND_NEAREST) {
581 incr = 0x80000000;
582 if ((d & 1) == 0)
583 incr -= 1;
584 } else if (rmode == FPSCR_ROUND_TOZERO) {
585 incr = 0;
586 } else if ((rmode == FPSCR_ROUND_PLUSINF) ^ (vsm.sign != 0)) {
587 incr = ~0;
588 }
589
590 if ((rem + incr) < rem) {
591 if (d < 0xffffffff)
592 d += 1;
593 else
594 exceptions |= FPSCR_IOC;
595 }
596
597 if (d && vsm.sign) {
598 d = 0;
599 exceptions |= FPSCR_IOC;
600 } else if (rem)
601 exceptions |= FPSCR_IXC;
602 } else {
603 d = 0;
604 if (vsm.exponent | vsm.significand) {
605 exceptions |= FPSCR_IXC;
606 if (rmode == FPSCR_ROUND_PLUSINF && vsm.sign == 0)
607 d = 1;
608 else if (rmode == FPSCR_ROUND_MINUSINF && vsm.sign) {
609 d = 0;
610 exceptions |= FPSCR_IOC;
611 }
612 }
613 }
614
615 pr_debug("VFP: ftoui: d(s%d)=%08x exceptions=%08x\n", sd, d, exceptions);
616
617 vfp_put_float(d, sd);
618
619 return exceptions;
620 }
621
vfp_single_ftouiz(int sd,int unused,s32 m,u32 fpscr)622 static u32 vfp_single_ftouiz(int sd, int unused, s32 m, u32 fpscr)
623 {
624 return vfp_single_ftoui(sd, unused, m, FPSCR_ROUND_TOZERO);
625 }
626
vfp_single_ftosi(int sd,int unused,s32 m,u32 fpscr)627 static u32 vfp_single_ftosi(int sd, int unused, s32 m, u32 fpscr)
628 {
629 struct vfp_single vsm;
630 u32 d, exceptions = 0;
631 int rmode = fpscr & FPSCR_RMODE_MASK;
632 int tm;
633
634 vfp_single_unpack(&vsm, m);
635 vfp_single_dump("VSM", &vsm);
636
637 /*
638 * Do we have a denormalised number?
639 */
640 tm = vfp_single_type(&vsm);
641 if (vfp_single_type(&vsm) & VFP_DENORMAL)
642 exceptions |= FPSCR_IDC;
643
644 if (tm & VFP_NAN) {
645 d = 0;
646 exceptions |= FPSCR_IOC;
647 } else if (vsm.exponent >= 127 + 32) {
648 /*
649 * m >= 2^31-2^7: invalid
650 */
651 d = 0x7fffffff;
652 if (vsm.sign)
653 d = ~d;
654 exceptions |= FPSCR_IOC;
655 } else if (vsm.exponent >= 127 - 1) {
656 int shift = 127 + 31 - vsm.exponent;
657 u32 rem, incr = 0;
658
659 /* 2^0 <= m <= 2^31-2^7 */
660 d = (vsm.significand << 1) >> shift;
661 rem = vsm.significand << (33 - shift);
662
663 if (rmode == FPSCR_ROUND_NEAREST) {
664 incr = 0x80000000;
665 if ((d & 1) == 0)
666 incr -= 1;
667 } else if (rmode == FPSCR_ROUND_TOZERO) {
668 incr = 0;
669 } else if ((rmode == FPSCR_ROUND_PLUSINF) ^ (vsm.sign != 0)) {
670 incr = ~0;
671 }
672
673 if ((rem + incr) < rem && d < 0xffffffff)
674 d += 1;
675 if (d > 0x7fffffff + (vsm.sign != 0)) {
676 d = 0x7fffffff + (vsm.sign != 0);
677 exceptions |= FPSCR_IOC;
678 } else if (rem)
679 exceptions |= FPSCR_IXC;
680
681 if (vsm.sign)
682 d = -d;
683 } else {
684 d = 0;
685 if (vsm.exponent | vsm.significand) {
686 exceptions |= FPSCR_IXC;
687 if (rmode == FPSCR_ROUND_PLUSINF && vsm.sign == 0)
688 d = 1;
689 else if (rmode == FPSCR_ROUND_MINUSINF && vsm.sign)
690 d = -1;
691 }
692 }
693
694 pr_debug("VFP: ftosi: d(s%d)=%08x exceptions=%08x\n", sd, d, exceptions);
695
696 vfp_put_float((s32)d, sd);
697
698 return exceptions;
699 }
700
vfp_single_ftosiz(int sd,int unused,s32 m,u32 fpscr)701 static u32 vfp_single_ftosiz(int sd, int unused, s32 m, u32 fpscr)
702 {
703 return vfp_single_ftosi(sd, unused, m, FPSCR_ROUND_TOZERO);
704 }
705
706 static struct op fops_ext[32] = {
707 [FEXT_TO_IDX(FEXT_FCPY)] = { vfp_single_fcpy, 0 },
708 [FEXT_TO_IDX(FEXT_FABS)] = { vfp_single_fabs, 0 },
709 [FEXT_TO_IDX(FEXT_FNEG)] = { vfp_single_fneg, 0 },
710 [FEXT_TO_IDX(FEXT_FSQRT)] = { vfp_single_fsqrt, 0 },
711 [FEXT_TO_IDX(FEXT_FCMP)] = { vfp_single_fcmp, OP_SCALAR },
712 [FEXT_TO_IDX(FEXT_FCMPE)] = { vfp_single_fcmpe, OP_SCALAR },
713 [FEXT_TO_IDX(FEXT_FCMPZ)] = { vfp_single_fcmpz, OP_SCALAR },
714 [FEXT_TO_IDX(FEXT_FCMPEZ)] = { vfp_single_fcmpez, OP_SCALAR },
715 [FEXT_TO_IDX(FEXT_FCVT)] = { vfp_single_fcvtd, OP_SCALAR|OP_DD },
716 [FEXT_TO_IDX(FEXT_FUITO)] = { vfp_single_fuito, OP_SCALAR },
717 [FEXT_TO_IDX(FEXT_FSITO)] = { vfp_single_fsito, OP_SCALAR },
718 [FEXT_TO_IDX(FEXT_FTOUI)] = { vfp_single_ftoui, OP_SCALAR },
719 [FEXT_TO_IDX(FEXT_FTOUIZ)] = { vfp_single_ftouiz, OP_SCALAR },
720 [FEXT_TO_IDX(FEXT_FTOSI)] = { vfp_single_ftosi, OP_SCALAR },
721 [FEXT_TO_IDX(FEXT_FTOSIZ)] = { vfp_single_ftosiz, OP_SCALAR },
722 };
723
724
725
726
727
728 static u32
vfp_single_fadd_nonnumber(struct vfp_single * vsd,struct vfp_single * vsn,struct vfp_single * vsm,u32 fpscr)729 vfp_single_fadd_nonnumber(struct vfp_single *vsd, struct vfp_single *vsn,
730 struct vfp_single *vsm, u32 fpscr)
731 {
732 struct vfp_single *vsp;
733 u32 exceptions = 0;
734 int tn, tm;
735
736 tn = vfp_single_type(vsn);
737 tm = vfp_single_type(vsm);
738
739 if (tn & tm & VFP_INFINITY) {
740 /*
741 * Two infinities. Are they different signs?
742 */
743 if (vsn->sign ^ vsm->sign) {
744 /*
745 * different signs -> invalid
746 */
747 exceptions = FPSCR_IOC;
748 vsp = &vfp_single_default_qnan;
749 } else {
750 /*
751 * same signs -> valid
752 */
753 vsp = vsn;
754 }
755 } else if (tn & VFP_INFINITY && tm & VFP_NUMBER) {
756 /*
757 * One infinity and one number -> infinity
758 */
759 vsp = vsn;
760 } else {
761 /*
762 * 'n' is a NaN of some type
763 */
764 return vfp_propagate_nan(vsd, vsn, vsm, fpscr);
765 }
766 *vsd = *vsp;
767 return exceptions;
768 }
769
770 static u32
vfp_single_add(struct vfp_single * vsd,struct vfp_single * vsn,struct vfp_single * vsm,u32 fpscr)771 vfp_single_add(struct vfp_single *vsd, struct vfp_single *vsn,
772 struct vfp_single *vsm, u32 fpscr)
773 {
774 u32 exp_diff, m_sig;
775
776 if (vsn->significand & 0x80000000 ||
777 vsm->significand & 0x80000000) {
778 pr_info("VFP: bad FP values in %s\n", __func__);
779 vfp_single_dump("VSN", vsn);
780 vfp_single_dump("VSM", vsm);
781 }
782
783 /*
784 * Ensure that 'n' is the largest magnitude number. Note that
785 * if 'n' and 'm' have equal exponents, we do not swap them.
786 * This ensures that NaN propagation works correctly.
787 */
788 if (vsn->exponent < vsm->exponent) {
789 struct vfp_single *t = vsn;
790 vsn = vsm;
791 vsm = t;
792 }
793
794 /*
795 * Is 'n' an infinity or a NaN? Note that 'm' may be a number,
796 * infinity or a NaN here.
797 */
798 if (vsn->exponent == 255)
799 return vfp_single_fadd_nonnumber(vsd, vsn, vsm, fpscr);
800
801 /*
802 * We have two proper numbers, where 'vsn' is the larger magnitude.
803 *
804 * Copy 'n' to 'd' before doing the arithmetic.
805 */
806 *vsd = *vsn;
807
808 /*
809 * Align both numbers.
810 */
811 exp_diff = vsn->exponent - vsm->exponent;
812 m_sig = vfp_shiftright32jamming(vsm->significand, exp_diff);
813
814 /*
815 * If the signs are different, we are really subtracting.
816 */
817 if (vsn->sign ^ vsm->sign) {
818 m_sig = vsn->significand - m_sig;
819 if ((s32)m_sig < 0) {
820 vsd->sign = vfp_sign_negate(vsd->sign);
821 m_sig = -m_sig;
822 } else if (m_sig == 0) {
823 vsd->sign = (fpscr & FPSCR_RMODE_MASK) ==
824 FPSCR_ROUND_MINUSINF ? 0x8000 : 0;
825 }
826 } else {
827 m_sig = vsn->significand + m_sig;
828 }
829 vsd->significand = m_sig;
830
831 return 0;
832 }
833
834 static u32
vfp_single_multiply(struct vfp_single * vsd,struct vfp_single * vsn,struct vfp_single * vsm,u32 fpscr)835 vfp_single_multiply(struct vfp_single *vsd, struct vfp_single *vsn, struct vfp_single *vsm, u32 fpscr)
836 {
837 vfp_single_dump("VSN", vsn);
838 vfp_single_dump("VSM", vsm);
839
840 /*
841 * Ensure that 'n' is the largest magnitude number. Note that
842 * if 'n' and 'm' have equal exponents, we do not swap them.
843 * This ensures that NaN propagation works correctly.
844 */
845 if (vsn->exponent < vsm->exponent) {
846 struct vfp_single *t = vsn;
847 vsn = vsm;
848 vsm = t;
849 pr_debug("VFP: swapping M <-> N\n");
850 }
851
852 vsd->sign = vsn->sign ^ vsm->sign;
853
854 /*
855 * If 'n' is an infinity or NaN, handle it. 'm' may be anything.
856 */
857 if (vsn->exponent == 255) {
858 if (vsn->significand || (vsm->exponent == 255 && vsm->significand))
859 return vfp_propagate_nan(vsd, vsn, vsm, fpscr);
860 if ((vsm->exponent | vsm->significand) == 0) {
861 *vsd = vfp_single_default_qnan;
862 return FPSCR_IOC;
863 }
864 vsd->exponent = vsn->exponent;
865 vsd->significand = 0;
866 return 0;
867 }
868
869 /*
870 * If 'm' is zero, the result is always zero. In this case,
871 * 'n' may be zero or a number, but it doesn't matter which.
872 */
873 if ((vsm->exponent | vsm->significand) == 0) {
874 vsd->exponent = 0;
875 vsd->significand = 0;
876 return 0;
877 }
878
879 /*
880 * We add 2 to the destination exponent for the same reason as
881 * the addition case - though this time we have +1 from each
882 * input operand.
883 */
884 vsd->exponent = vsn->exponent + vsm->exponent - 127 + 2;
885 vsd->significand = vfp_hi64to32jamming((u64)vsn->significand * vsm->significand);
886
887 vfp_single_dump("VSD", vsd);
888 return 0;
889 }
890
891 #define NEG_MULTIPLY (1 << 0)
892 #define NEG_SUBTRACT (1 << 1)
893
894 static u32
vfp_single_multiply_accumulate(int sd,int sn,s32 m,u32 fpscr,u32 negate,char * func)895 vfp_single_multiply_accumulate(int sd, int sn, s32 m, u32 fpscr, u32 negate, char *func)
896 {
897 struct vfp_single vsd, vsp, vsn, vsm;
898 u32 exceptions;
899 s32 v;
900
901 v = vfp_get_float(sn);
902 pr_debug("VFP: s%u = %08x\n", sn, v);
903 vfp_single_unpack(&vsn, v);
904 if (vsn.exponent == 0 && vsn.significand)
905 vfp_single_normalise_denormal(&vsn);
906
907 vfp_single_unpack(&vsm, m);
908 if (vsm.exponent == 0 && vsm.significand)
909 vfp_single_normalise_denormal(&vsm);
910
911 exceptions = vfp_single_multiply(&vsp, &vsn, &vsm, fpscr);
912 if (negate & NEG_MULTIPLY)
913 vsp.sign = vfp_sign_negate(vsp.sign);
914
915 v = vfp_get_float(sd);
916 pr_debug("VFP: s%u = %08x\n", sd, v);
917 vfp_single_unpack(&vsn, v);
918 if (vsn.exponent == 0 && vsn.significand)
919 vfp_single_normalise_denormal(&vsn);
920 if (negate & NEG_SUBTRACT)
921 vsn.sign = vfp_sign_negate(vsn.sign);
922
923 exceptions |= vfp_single_add(&vsd, &vsn, &vsp, fpscr);
924
925 return vfp_single_normaliseround(sd, &vsd, fpscr, exceptions, func);
926 }
927
928 /*
929 * Standard operations
930 */
931
932 /*
933 * sd = sd + (sn * sm)
934 */
vfp_single_fmac(int sd,int sn,s32 m,u32 fpscr)935 static u32 vfp_single_fmac(int sd, int sn, s32 m, u32 fpscr)
936 {
937 return vfp_single_multiply_accumulate(sd, sn, m, fpscr, 0, "fmac");
938 }
939
940 /*
941 * sd = sd - (sn * sm)
942 */
vfp_single_fnmac(int sd,int sn,s32 m,u32 fpscr)943 static u32 vfp_single_fnmac(int sd, int sn, s32 m, u32 fpscr)
944 {
945 return vfp_single_multiply_accumulate(sd, sn, m, fpscr, NEG_MULTIPLY, "fnmac");
946 }
947
948 /*
949 * sd = -sd + (sn * sm)
950 */
vfp_single_fmsc(int sd,int sn,s32 m,u32 fpscr)951 static u32 vfp_single_fmsc(int sd, int sn, s32 m, u32 fpscr)
952 {
953 return vfp_single_multiply_accumulate(sd, sn, m, fpscr, NEG_SUBTRACT, "fmsc");
954 }
955
956 /*
957 * sd = -sd - (sn * sm)
958 */
vfp_single_fnmsc(int sd,int sn,s32 m,u32 fpscr)959 static u32 vfp_single_fnmsc(int sd, int sn, s32 m, u32 fpscr)
960 {
961 return vfp_single_multiply_accumulate(sd, sn, m, fpscr, NEG_SUBTRACT | NEG_MULTIPLY, "fnmsc");
962 }
963
964 /*
965 * sd = sn * sm
966 */
vfp_single_fmul(int sd,int sn,s32 m,u32 fpscr)967 static u32 vfp_single_fmul(int sd, int sn, s32 m, u32 fpscr)
968 {
969 struct vfp_single vsd, vsn, vsm;
970 u32 exceptions;
971 s32 n = vfp_get_float(sn);
972
973 pr_debug("VFP: s%u = %08x\n", sn, n);
974
975 vfp_single_unpack(&vsn, n);
976 if (vsn.exponent == 0 && vsn.significand)
977 vfp_single_normalise_denormal(&vsn);
978
979 vfp_single_unpack(&vsm, m);
980 if (vsm.exponent == 0 && vsm.significand)
981 vfp_single_normalise_denormal(&vsm);
982
983 exceptions = vfp_single_multiply(&vsd, &vsn, &vsm, fpscr);
984 return vfp_single_normaliseround(sd, &vsd, fpscr, exceptions, "fmul");
985 }
986
987 /*
988 * sd = -(sn * sm)
989 */
vfp_single_fnmul(int sd,int sn,s32 m,u32 fpscr)990 static u32 vfp_single_fnmul(int sd, int sn, s32 m, u32 fpscr)
991 {
992 struct vfp_single vsd, vsn, vsm;
993 u32 exceptions;
994 s32 n = vfp_get_float(sn);
995
996 pr_debug("VFP: s%u = %08x\n", sn, n);
997
998 vfp_single_unpack(&vsn, n);
999 if (vsn.exponent == 0 && vsn.significand)
1000 vfp_single_normalise_denormal(&vsn);
1001
1002 vfp_single_unpack(&vsm, m);
1003 if (vsm.exponent == 0 && vsm.significand)
1004 vfp_single_normalise_denormal(&vsm);
1005
1006 exceptions = vfp_single_multiply(&vsd, &vsn, &vsm, fpscr);
1007 vsd.sign = vfp_sign_negate(vsd.sign);
1008 return vfp_single_normaliseround(sd, &vsd, fpscr, exceptions, "fnmul");
1009 }
1010
1011 /*
1012 * sd = sn + sm
1013 */
vfp_single_fadd(int sd,int sn,s32 m,u32 fpscr)1014 static u32 vfp_single_fadd(int sd, int sn, s32 m, u32 fpscr)
1015 {
1016 struct vfp_single vsd, vsn, vsm;
1017 u32 exceptions;
1018 s32 n = vfp_get_float(sn);
1019
1020 pr_debug("VFP: s%u = %08x\n", sn, n);
1021
1022 /*
1023 * Unpack and normalise denormals.
1024 */
1025 vfp_single_unpack(&vsn, n);
1026 if (vsn.exponent == 0 && vsn.significand)
1027 vfp_single_normalise_denormal(&vsn);
1028
1029 vfp_single_unpack(&vsm, m);
1030 if (vsm.exponent == 0 && vsm.significand)
1031 vfp_single_normalise_denormal(&vsm);
1032
1033 exceptions = vfp_single_add(&vsd, &vsn, &vsm, fpscr);
1034
1035 return vfp_single_normaliseround(sd, &vsd, fpscr, exceptions, "fadd");
1036 }
1037
1038 /*
1039 * sd = sn - sm
1040 */
vfp_single_fsub(int sd,int sn,s32 m,u32 fpscr)1041 static u32 vfp_single_fsub(int sd, int sn, s32 m, u32 fpscr)
1042 {
1043 /*
1044 * Subtraction is addition with one sign inverted.
1045 */
1046 return vfp_single_fadd(sd, sn, vfp_single_packed_negate(m), fpscr);
1047 }
1048
1049 /*
1050 * sd = sn / sm
1051 */
vfp_single_fdiv(int sd,int sn,s32 m,u32 fpscr)1052 static u32 vfp_single_fdiv(int sd, int sn, s32 m, u32 fpscr)
1053 {
1054 struct vfp_single vsd, vsn, vsm;
1055 u32 exceptions = 0;
1056 s32 n = vfp_get_float(sn);
1057 int tm, tn;
1058
1059 pr_debug("VFP: s%u = %08x\n", sn, n);
1060
1061 vfp_single_unpack(&vsn, n);
1062 vfp_single_unpack(&vsm, m);
1063
1064 vsd.sign = vsn.sign ^ vsm.sign;
1065
1066 tn = vfp_single_type(&vsn);
1067 tm = vfp_single_type(&vsm);
1068
1069 /*
1070 * Is n a NAN?
1071 */
1072 if (tn & VFP_NAN)
1073 goto vsn_nan;
1074
1075 /*
1076 * Is m a NAN?
1077 */
1078 if (tm & VFP_NAN)
1079 goto vsm_nan;
1080
1081 /*
1082 * If n and m are infinity, the result is invalid
1083 * If n and m are zero, the result is invalid
1084 */
1085 if (tm & tn & (VFP_INFINITY|VFP_ZERO))
1086 goto invalid;
1087
1088 /*
1089 * If n is infinity, the result is infinity
1090 */
1091 if (tn & VFP_INFINITY)
1092 goto infinity;
1093
1094 /*
1095 * If m is zero, raise div0 exception
1096 */
1097 if (tm & VFP_ZERO)
1098 goto divzero;
1099
1100 /*
1101 * If m is infinity, or n is zero, the result is zero
1102 */
1103 if (tm & VFP_INFINITY || tn & VFP_ZERO)
1104 goto zero;
1105
1106 if (tn & VFP_DENORMAL)
1107 vfp_single_normalise_denormal(&vsn);
1108 if (tm & VFP_DENORMAL)
1109 vfp_single_normalise_denormal(&vsm);
1110
1111 /*
1112 * Ok, we have two numbers, we can perform division.
1113 */
1114 vsd.exponent = vsn.exponent - vsm.exponent + 127 - 1;
1115 vsm.significand <<= 1;
1116 if (vsm.significand <= (2 * vsn.significand)) {
1117 vsn.significand >>= 1;
1118 vsd.exponent++;
1119 }
1120 {
1121 u64 significand = (u64)vsn.significand << 32;
1122 do_div(significand, vsm.significand);
1123 vsd.significand = significand;
1124 }
1125 if ((vsd.significand & 0x3f) == 0)
1126 vsd.significand |= ((u64)vsm.significand * vsd.significand != (u64)vsn.significand << 32);
1127
1128 return vfp_single_normaliseround(sd, &vsd, fpscr, 0, "fdiv");
1129
1130 vsn_nan:
1131 exceptions = vfp_propagate_nan(&vsd, &vsn, &vsm, fpscr);
1132 pack:
1133 vfp_put_float(vfp_single_pack(&vsd), sd);
1134 return exceptions;
1135
1136 vsm_nan:
1137 exceptions = vfp_propagate_nan(&vsd, &vsm, &vsn, fpscr);
1138 goto pack;
1139
1140 zero:
1141 vsd.exponent = 0;
1142 vsd.significand = 0;
1143 goto pack;
1144
1145 divzero:
1146 exceptions = FPSCR_DZC;
1147 infinity:
1148 vsd.exponent = 255;
1149 vsd.significand = 0;
1150 goto pack;
1151
1152 invalid:
1153 vfp_put_float(vfp_single_pack(&vfp_single_default_qnan), sd);
1154 return FPSCR_IOC;
1155 }
1156
1157 static struct op fops[16] = {
1158 [FOP_TO_IDX(FOP_FMAC)] = { vfp_single_fmac, 0 },
1159 [FOP_TO_IDX(FOP_FNMAC)] = { vfp_single_fnmac, 0 },
1160 [FOP_TO_IDX(FOP_FMSC)] = { vfp_single_fmsc, 0 },
1161 [FOP_TO_IDX(FOP_FNMSC)] = { vfp_single_fnmsc, 0 },
1162 [FOP_TO_IDX(FOP_FMUL)] = { vfp_single_fmul, 0 },
1163 [FOP_TO_IDX(FOP_FNMUL)] = { vfp_single_fnmul, 0 },
1164 [FOP_TO_IDX(FOP_FADD)] = { vfp_single_fadd, 0 },
1165 [FOP_TO_IDX(FOP_FSUB)] = { vfp_single_fsub, 0 },
1166 [FOP_TO_IDX(FOP_FDIV)] = { vfp_single_fdiv, 0 },
1167 };
1168
1169 #define FREG_BANK(x) ((x) & 0x18)
1170 #define FREG_IDX(x) ((x) & 7)
1171
vfp_single_cpdo(u32 inst,u32 fpscr)1172 u32 vfp_single_cpdo(u32 inst, u32 fpscr)
1173 {
1174 u32 op = inst & FOP_MASK;
1175 u32 exceptions = 0;
1176 unsigned int dest;
1177 unsigned int sn = vfp_get_sn(inst);
1178 unsigned int sm = vfp_get_sm(inst);
1179 unsigned int vecitr, veclen, vecstride;
1180 struct op *fop;
1181
1182 vecstride = 1 + ((fpscr & FPSCR_STRIDE_MASK) == FPSCR_STRIDE_MASK);
1183
1184 fop = (op == FOP_EXT) ? &fops_ext[FEXT_TO_IDX(inst)] : &fops[FOP_TO_IDX(op)];
1185
1186 /*
1187 * fcvtsd takes a dN register number as destination, not sN.
1188 * Technically, if bit 0 of dd is set, this is an invalid
1189 * instruction. However, we ignore this for efficiency.
1190 * It also only operates on scalars.
1191 */
1192 if (fop->flags & OP_DD)
1193 dest = vfp_get_dd(inst);
1194 else
1195 dest = vfp_get_sd(inst);
1196
1197 /*
1198 * If destination bank is zero, vector length is always '1'.
1199 * ARM DDI0100F C5.1.3, C5.3.2.
1200 */
1201 if ((fop->flags & OP_SCALAR) || FREG_BANK(dest) == 0)
1202 veclen = 0;
1203 else
1204 veclen = fpscr & FPSCR_LENGTH_MASK;
1205
1206 pr_debug("VFP: vecstride=%u veclen=%u\n", vecstride,
1207 (veclen >> FPSCR_LENGTH_BIT) + 1);
1208
1209 if (!fop->fn)
1210 goto invalid;
1211
1212 for (vecitr = 0; vecitr <= veclen; vecitr += 1 << FPSCR_LENGTH_BIT) {
1213 s32 m = vfp_get_float(sm);
1214 u32 except;
1215 char type;
1216
1217 type = fop->flags & OP_DD ? 'd' : 's';
1218 if (op == FOP_EXT)
1219 pr_debug("VFP: itr%d (%c%u) = op[%u] (s%u=%08x)\n",
1220 vecitr >> FPSCR_LENGTH_BIT, type, dest, sn,
1221 sm, m);
1222 else
1223 pr_debug("VFP: itr%d (%c%u) = (s%u) op[%u] (s%u=%08x)\n",
1224 vecitr >> FPSCR_LENGTH_BIT, type, dest, sn,
1225 FOP_TO_IDX(op), sm, m);
1226
1227 except = fop->fn(dest, sn, m, fpscr);
1228 pr_debug("VFP: itr%d: exceptions=%08x\n",
1229 vecitr >> FPSCR_LENGTH_BIT, except);
1230
1231 exceptions |= except;
1232
1233 /*
1234 * CHECK: It appears to be undefined whether we stop when
1235 * we encounter an exception. We continue.
1236 */
1237 dest = FREG_BANK(dest) + ((FREG_IDX(dest) + vecstride) & 7);
1238 sn = FREG_BANK(sn) + ((FREG_IDX(sn) + vecstride) & 7);
1239 if (FREG_BANK(sm) != 0)
1240 sm = FREG_BANK(sm) + ((FREG_IDX(sm) + vecstride) & 7);
1241 }
1242 return exceptions;
1243
1244 invalid:
1245 return (u32)-1;
1246 }
1247