xref: /openbmc/qemu/target/m68k/fpu_helper.c (revision dc5bd18f) 
1 /*
2  *  m68k FPU helpers
3  *
4  *  Copyright (c) 2006-2007 CodeSourcery
5  *  Written by Paul Brook
6  *
7  * This library is free software; you can redistribute it and/or
8  * modify it under the terms of the GNU Lesser General Public
9  * License as published by the Free Software Foundation; either
10  * version 2 of the License, or (at your option) any later version.
11  *
12  * This library is distributed in the hope that it will be useful,
13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
15  * General Public License for more details.
16  *
17  * You should have received a copy of the GNU Lesser General Public
18  * License along with this library; if not, see <http://www.gnu.org/licenses/>.
19  */
20 
21 #include "qemu/osdep.h"
22 #include "cpu.h"
23 #include "exec/helper-proto.h"
24 #include "exec/exec-all.h"
25 #include "exec/cpu_ldst.h"
26 #include "softfloat.h"
27 
28 /* Undefined offsets may be different on various FPU.
29  * On 68040 they return 0.0 (floatx80_zero)
30  */
31 
32 static const floatx80 fpu_rom[128] = {
33     [0x00] = make_floatx80_init(0x4000, 0xc90fdaa22168c235ULL),  /* Pi       */
34     [0x0b] = make_floatx80_init(0x3ffd, 0x9a209a84fbcff798ULL),  /* Log10(2) */
35     [0x0c] = make_floatx80_init(0x4000, 0xadf85458a2bb4a9aULL),  /* e        */
36     [0x0d] = make_floatx80_init(0x3fff, 0xb8aa3b295c17f0bcULL),  /* Log2(e)  */
37     [0x0e] = make_floatx80_init(0x3ffd, 0xde5bd8a937287195ULL),  /* Log10(e) */
38     [0x0f] = make_floatx80_init(0x0000, 0x0000000000000000ULL),  /* Zero     */
39     [0x30] = make_floatx80_init(0x3ffe, 0xb17217f7d1cf79acULL),  /* ln(2)    */
40     [0x31] = make_floatx80_init(0x4000, 0x935d8dddaaa8ac17ULL),  /* ln(10)   */
41     [0x32] = make_floatx80_init(0x3fff, 0x8000000000000000ULL),  /* 10^0     */
42     [0x33] = make_floatx80_init(0x4002, 0xa000000000000000ULL),  /* 10^1     */
43     [0x34] = make_floatx80_init(0x4005, 0xc800000000000000ULL),  /* 10^2     */
44     [0x35] = make_floatx80_init(0x400c, 0x9c40000000000000ULL),  /* 10^4     */
45     [0x36] = make_floatx80_init(0x4019, 0xbebc200000000000ULL),  /* 10^8     */
46     [0x37] = make_floatx80_init(0x4034, 0x8e1bc9bf04000000ULL),  /* 10^16    */
47     [0x38] = make_floatx80_init(0x4069, 0x9dc5ada82b70b59eULL),  /* 10^32    */
48     [0x39] = make_floatx80_init(0x40d3, 0xc2781f49ffcfa6d5ULL),  /* 10^64    */
49     [0x3a] = make_floatx80_init(0x41a8, 0x93ba47c980e98ce0ULL),  /* 10^128   */
50     [0x3b] = make_floatx80_init(0x4351, 0xaa7eebfb9df9de8eULL),  /* 10^256   */
51     [0x3c] = make_floatx80_init(0x46a3, 0xe319a0aea60e91c7ULL),  /* 10^512   */
52     [0x3d] = make_floatx80_init(0x4d48, 0xc976758681750c17ULL),  /* 10^1024  */
53     [0x3e] = make_floatx80_init(0x5a92, 0x9e8b3b5dc53d5de5ULL),  /* 10^2048  */
54     [0x3f] = make_floatx80_init(0x7525, 0xc46052028a20979bULL),  /* 10^4096  */
55 };
56 
57 int32_t HELPER(reds32)(CPUM68KState *env, FPReg *val)
58 {
59     return floatx80_to_int32(val->d, &env->fp_status);
60 }
61 
62 float32 HELPER(redf32)(CPUM68KState *env, FPReg *val)
63 {
64     return floatx80_to_float32(val->d, &env->fp_status);
65 }
66 
67 void HELPER(exts32)(CPUM68KState *env, FPReg *res, int32_t val)
68 {
69     res->d = int32_to_floatx80(val, &env->fp_status);
70 }
71 
72 void HELPER(extf32)(CPUM68KState *env, FPReg *res, float32 val)
73 {
74     res->d = float32_to_floatx80(val, &env->fp_status);
75 }
76 
77 void HELPER(extf64)(CPUM68KState *env, FPReg *res, float64 val)
78 {
79     res->d = float64_to_floatx80(val, &env->fp_status);
80 }
81 
82 float64 HELPER(redf64)(CPUM68KState *env, FPReg *val)
83 {
84     return floatx80_to_float64(val->d, &env->fp_status);
85 }
86 
87 void HELPER(firound)(CPUM68KState *env, FPReg *res, FPReg *val)
88 {
89     res->d = floatx80_round_to_int(val->d, &env->fp_status);
90 }
91 
92 static void m68k_restore_precision_mode(CPUM68KState *env)
93 {
94     switch (env->fpcr & FPCR_PREC_MASK) {
95     case FPCR_PREC_X: /* extended */
96         set_floatx80_rounding_precision(80, &env->fp_status);
97         break;
98     case FPCR_PREC_S: /* single */
99         set_floatx80_rounding_precision(32, &env->fp_status);
100         break;
101     case FPCR_PREC_D: /* double */
102         set_floatx80_rounding_precision(64, &env->fp_status);
103         break;
104     case FPCR_PREC_U: /* undefined */
105     default:
106         break;
107     }
108 }
109 
110 static void cf_restore_precision_mode(CPUM68KState *env)
111 {
112     if (env->fpcr & FPCR_PREC_S) { /* single */
113         set_floatx80_rounding_precision(32, &env->fp_status);
114     } else { /* double */
115         set_floatx80_rounding_precision(64, &env->fp_status);
116     }
117 }
118 
119 static void restore_rounding_mode(CPUM68KState *env)
120 {
121     switch (env->fpcr & FPCR_RND_MASK) {
122     case FPCR_RND_N: /* round to nearest */
123         set_float_rounding_mode(float_round_nearest_even, &env->fp_status);
124         break;
125     case FPCR_RND_Z: /* round to zero */
126         set_float_rounding_mode(float_round_to_zero, &env->fp_status);
127         break;
128     case FPCR_RND_M: /* round toward minus infinity */
129         set_float_rounding_mode(float_round_down, &env->fp_status);
130         break;
131     case FPCR_RND_P: /* round toward positive infinity */
132         set_float_rounding_mode(float_round_up, &env->fp_status);
133         break;
134     }
135 }
136 
137 void cpu_m68k_set_fpcr(CPUM68KState *env, uint32_t val)
138 {
139     env->fpcr = val & 0xffff;
140 
141     if (m68k_feature(env, M68K_FEATURE_CF_FPU)) {
142         cf_restore_precision_mode(env);
143     } else {
144         m68k_restore_precision_mode(env);
145     }
146     restore_rounding_mode(env);
147 }
148 
149 void HELPER(fitrunc)(CPUM68KState *env, FPReg *res, FPReg *val)
150 {
151     int rounding_mode = get_float_rounding_mode(&env->fp_status);
152     set_float_rounding_mode(float_round_to_zero, &env->fp_status);
153     res->d = floatx80_round_to_int(val->d, &env->fp_status);
154     set_float_rounding_mode(rounding_mode, &env->fp_status);
155 }
156 
157 void HELPER(set_fpcr)(CPUM68KState *env, uint32_t val)
158 {
159     cpu_m68k_set_fpcr(env, val);
160 }
161 
162 #define PREC_BEGIN(prec)                                        \
163     do {                                                        \
164         int old;                                                \
165         old = get_floatx80_rounding_precision(&env->fp_status); \
166         set_floatx80_rounding_precision(prec, &env->fp_status)  \
167 
168 #define PREC_END()                                              \
169         set_floatx80_rounding_precision(old, &env->fp_status);  \
170     } while (0)
171 
172 void HELPER(fsround)(CPUM68KState *env, FPReg *res, FPReg *val)
173 {
174     PREC_BEGIN(32);
175     res->d = floatx80_round(val->d, &env->fp_status);
176     PREC_END();
177 }
178 
179 void HELPER(fdround)(CPUM68KState *env, FPReg *res, FPReg *val)
180 {
181     PREC_BEGIN(64);
182     res->d = floatx80_round(val->d, &env->fp_status);
183     PREC_END();
184 }
185 
186 void HELPER(fsqrt)(CPUM68KState *env, FPReg *res, FPReg *val)
187 {
188     res->d = floatx80_sqrt(val->d, &env->fp_status);
189 }
190 
191 void HELPER(fssqrt)(CPUM68KState *env, FPReg *res, FPReg *val)
192 {
193     PREC_BEGIN(32);
194     res->d = floatx80_sqrt(val->d, &env->fp_status);
195     PREC_END();
196 }
197 
198 void HELPER(fdsqrt)(CPUM68KState *env, FPReg *res, FPReg *val)
199 {
200     PREC_BEGIN(64);
201     res->d = floatx80_sqrt(val->d, &env->fp_status);
202     PREC_END();
203 }
204 
205 void HELPER(fabs)(CPUM68KState *env, FPReg *res, FPReg *val)
206 {
207     res->d = floatx80_round(floatx80_abs(val->d), &env->fp_status);
208 }
209 
210 void HELPER(fsabs)(CPUM68KState *env, FPReg *res, FPReg *val)
211 {
212     PREC_BEGIN(32);
213     res->d = floatx80_round(floatx80_abs(val->d), &env->fp_status);
214     PREC_END();
215 }
216 
217 void HELPER(fdabs)(CPUM68KState *env, FPReg *res, FPReg *val)
218 {
219     PREC_BEGIN(64);
220     res->d = floatx80_round(floatx80_abs(val->d), &env->fp_status);
221     PREC_END();
222 }
223 
224 void HELPER(fneg)(CPUM68KState *env, FPReg *res, FPReg *val)
225 {
226     res->d = floatx80_round(floatx80_chs(val->d), &env->fp_status);
227 }
228 
229 void HELPER(fsneg)(CPUM68KState *env, FPReg *res, FPReg *val)
230 {
231     PREC_BEGIN(32);
232     res->d = floatx80_round(floatx80_chs(val->d), &env->fp_status);
233     PREC_END();
234 }
235 
236 void HELPER(fdneg)(CPUM68KState *env, FPReg *res, FPReg *val)
237 {
238     PREC_BEGIN(64);
239     res->d = floatx80_round(floatx80_chs(val->d), &env->fp_status);
240     PREC_END();
241 }
242 
243 void HELPER(fadd)(CPUM68KState *env, FPReg *res, FPReg *val0, FPReg *val1)
244 {
245     res->d = floatx80_add(val0->d, val1->d, &env->fp_status);
246 }
247 
248 void HELPER(fsadd)(CPUM68KState *env, FPReg *res, FPReg *val0, FPReg *val1)
249 {
250     PREC_BEGIN(32);
251     res->d = floatx80_add(val0->d, val1->d, &env->fp_status);
252     PREC_END();
253 }
254 
255 void HELPER(fdadd)(CPUM68KState *env, FPReg *res, FPReg *val0, FPReg *val1)
256 {
257     PREC_BEGIN(64);
258     res->d = floatx80_add(val0->d, val1->d, &env->fp_status);
259     PREC_END();
260 }
261 
262 void HELPER(fsub)(CPUM68KState *env, FPReg *res, FPReg *val0, FPReg *val1)
263 {
264     res->d = floatx80_sub(val1->d, val0->d, &env->fp_status);
265 }
266 
267 void HELPER(fssub)(CPUM68KState *env, FPReg *res, FPReg *val0, FPReg *val1)
268 {
269     PREC_BEGIN(32);
270     res->d = floatx80_sub(val1->d, val0->d, &env->fp_status);
271     PREC_END();
272 }
273 
274 void HELPER(fdsub)(CPUM68KState *env, FPReg *res, FPReg *val0, FPReg *val1)
275 {
276     PREC_BEGIN(64);
277     res->d = floatx80_sub(val1->d, val0->d, &env->fp_status);
278     PREC_END();
279 }
280 
281 void HELPER(fmul)(CPUM68KState *env, FPReg *res, FPReg *val0, FPReg *val1)
282 {
283     res->d = floatx80_mul(val0->d, val1->d, &env->fp_status);
284 }
285 
286 void HELPER(fsmul)(CPUM68KState *env, FPReg *res, FPReg *val0, FPReg *val1)
287 {
288     PREC_BEGIN(32);
289     res->d = floatx80_mul(val0->d, val1->d, &env->fp_status);
290     PREC_END();
291 }
292 
293 void HELPER(fdmul)(CPUM68KState *env, FPReg *res, FPReg *val0, FPReg *val1)
294 {
295     PREC_BEGIN(64);
296     res->d = floatx80_mul(val0->d, val1->d, &env->fp_status);
297     PREC_END();
298 }
299 
300 void HELPER(fsglmul)(CPUM68KState *env, FPReg *res, FPReg *val0, FPReg *val1)
301 {
302     int rounding_mode = get_float_rounding_mode(&env->fp_status);
303     floatx80 a, b;
304 
305     PREC_BEGIN(32);
306     set_float_rounding_mode(float_round_to_zero, &env->fp_status);
307     a = floatx80_round(val0->d, &env->fp_status);
308     b = floatx80_round(val1->d, &env->fp_status);
309     set_float_rounding_mode(rounding_mode, &env->fp_status);
310     res->d = floatx80_mul(a, b, &env->fp_status);
311     PREC_END();
312 }
313 
314 void HELPER(fdiv)(CPUM68KState *env, FPReg *res, FPReg *val0, FPReg *val1)
315 {
316     res->d = floatx80_div(val1->d, val0->d, &env->fp_status);
317 }
318 
319 void HELPER(fsdiv)(CPUM68KState *env, FPReg *res, FPReg *val0, FPReg *val1)
320 {
321     PREC_BEGIN(32);
322     res->d = floatx80_div(val1->d, val0->d, &env->fp_status);
323     PREC_END();
324 }
325 
326 void HELPER(fddiv)(CPUM68KState *env, FPReg *res, FPReg *val0, FPReg *val1)
327 {
328     PREC_BEGIN(64);
329     res->d = floatx80_div(val1->d, val0->d, &env->fp_status);
330     PREC_END();
331 }
332 
333 void HELPER(fsgldiv)(CPUM68KState *env, FPReg *res, FPReg *val0, FPReg *val1)
334 {
335     int rounding_mode = get_float_rounding_mode(&env->fp_status);
336     floatx80 a, b;
337 
338     PREC_BEGIN(32);
339     set_float_rounding_mode(float_round_to_zero, &env->fp_status);
340     a = floatx80_round(val1->d, &env->fp_status);
341     b = floatx80_round(val0->d, &env->fp_status);
342     set_float_rounding_mode(rounding_mode, &env->fp_status);
343     res->d = floatx80_div(a, b, &env->fp_status);
344     PREC_END();
345 }
346 
347 static int float_comp_to_cc(int float_compare)
348 {
349     switch (float_compare) {
350     case float_relation_equal:
351         return FPSR_CC_Z;
352     case float_relation_less:
353         return FPSR_CC_N;
354     case float_relation_unordered:
355         return FPSR_CC_A;
356     case float_relation_greater:
357         return 0;
358     default:
359         g_assert_not_reached();
360     }
361 }
362 
363 void HELPER(fcmp)(CPUM68KState *env, FPReg *val0, FPReg *val1)
364 {
365     int float_compare;
366 
367     float_compare = floatx80_compare(val1->d, val0->d, &env->fp_status);
368     env->fpsr = (env->fpsr & ~FPSR_CC_MASK) | float_comp_to_cc(float_compare);
369 }
370 
371 void HELPER(ftst)(CPUM68KState *env, FPReg *val)
372 {
373     uint32_t cc = 0;
374 
375     if (floatx80_is_neg(val->d)) {
376         cc |= FPSR_CC_N;
377     }
378 
379     if (floatx80_is_any_nan(val->d)) {
380         cc |= FPSR_CC_A;
381     } else if (floatx80_is_infinity(val->d)) {
382         cc |= FPSR_CC_I;
383     } else if (floatx80_is_zero(val->d)) {
384         cc |= FPSR_CC_Z;
385     }
386     env->fpsr = (env->fpsr & ~FPSR_CC_MASK) | cc;
387 }
388 
389 void HELPER(fconst)(CPUM68KState *env, FPReg *val, uint32_t offset)
390 {
391     val->d = fpu_rom[offset];
392 }
393 
394 typedef int (*float_access)(CPUM68KState *env, uint32_t addr, FPReg *fp,
395                             uintptr_t ra);
396 
397 static uint32_t fmovem_predec(CPUM68KState *env, uint32_t addr, uint32_t mask,
398                                float_access access)
399 {
400     uintptr_t ra = GETPC();
401     int i, size;
402 
403     for (i = 7; i >= 0; i--, mask <<= 1) {
404         if (mask & 0x80) {
405             size = access(env, addr, &env->fregs[i], ra);
406             if ((mask & 0xff) != 0x80) {
407                 addr -= size;
408             }
409         }
410     }
411 
412     return addr;
413 }
414 
415 static uint32_t fmovem_postinc(CPUM68KState *env, uint32_t addr, uint32_t mask,
416                                float_access access)
417 {
418     uintptr_t ra = GETPC();
419     int i, size;
420 
421     for (i = 0; i < 8; i++, mask <<= 1) {
422         if (mask & 0x80) {
423             size = access(env, addr, &env->fregs[i], ra);
424             addr += size;
425         }
426     }
427 
428     return addr;
429 }
430 
431 static int cpu_ld_floatx80_ra(CPUM68KState *env, uint32_t addr, FPReg *fp,
432                               uintptr_t ra)
433 {
434     uint32_t high;
435     uint64_t low;
436 
437     high = cpu_ldl_data_ra(env, addr, ra);
438     low = cpu_ldq_data_ra(env, addr + 4, ra);
439 
440     fp->l.upper = high >> 16;
441     fp->l.lower = low;
442 
443     return 12;
444 }
445 
446 static int cpu_st_floatx80_ra(CPUM68KState *env, uint32_t addr, FPReg *fp,
447                                uintptr_t ra)
448 {
449     cpu_stl_data_ra(env, addr, fp->l.upper << 16, ra);
450     cpu_stq_data_ra(env, addr + 4, fp->l.lower, ra);
451 
452     return 12;
453 }
454 
455 static int cpu_ld_float64_ra(CPUM68KState *env, uint32_t addr, FPReg *fp,
456                              uintptr_t ra)
457 {
458     uint64_t val;
459 
460     val = cpu_ldq_data_ra(env, addr, ra);
461     fp->d = float64_to_floatx80(*(float64 *)&val, &env->fp_status);
462 
463     return 8;
464 }
465 
466 static int cpu_st_float64_ra(CPUM68KState *env, uint32_t addr, FPReg *fp,
467                              uintptr_t ra)
468 {
469     float64 val;
470 
471     val = floatx80_to_float64(fp->d, &env->fp_status);
472     cpu_stq_data_ra(env, addr, *(uint64_t *)&val, ra);
473 
474     return 8;
475 }
476 
477 uint32_t HELPER(fmovemx_st_predec)(CPUM68KState *env, uint32_t addr,
478                                    uint32_t mask)
479 {
480     return fmovem_predec(env, addr, mask, cpu_st_floatx80_ra);
481 }
482 
483 uint32_t HELPER(fmovemx_st_postinc)(CPUM68KState *env, uint32_t addr,
484                                     uint32_t mask)
485 {
486     return fmovem_postinc(env, addr, mask, cpu_st_floatx80_ra);
487 }
488 
489 uint32_t HELPER(fmovemx_ld_postinc)(CPUM68KState *env, uint32_t addr,
490                                     uint32_t mask)
491 {
492     return fmovem_postinc(env, addr, mask, cpu_ld_floatx80_ra);
493 }
494 
495 uint32_t HELPER(fmovemd_st_predec)(CPUM68KState *env, uint32_t addr,
496                                    uint32_t mask)
497 {
498     return fmovem_predec(env, addr, mask, cpu_st_float64_ra);
499 }
500 
501 uint32_t HELPER(fmovemd_st_postinc)(CPUM68KState *env, uint32_t addr,
502                                     uint32_t mask)
503 {
504     return fmovem_postinc(env, addr, mask, cpu_st_float64_ra);
505 }
506 
507 uint32_t HELPER(fmovemd_ld_postinc)(CPUM68KState *env, uint32_t addr,
508                                     uint32_t mask)
509 {
510     return fmovem_postinc(env, addr, mask, cpu_ld_float64_ra);
511 }
512 
513 static void make_quotient(CPUM68KState *env, floatx80 val)
514 {
515     int32_t quotient;
516     int sign;
517 
518     if (floatx80_is_any_nan(val)) {
519         return;
520     }
521 
522     quotient = floatx80_to_int32(val, &env->fp_status);
523     sign = quotient < 0;
524     if (sign) {
525         quotient = -quotient;
526     }
527 
528     quotient = (sign << 7) | (quotient & 0x7f);
529     env->fpsr = (env->fpsr & ~FPSR_QT_MASK) | (quotient << FPSR_QT_SHIFT);
530 }
531 
532 void HELPER(fmod)(CPUM68KState *env, FPReg *res, FPReg *val0, FPReg *val1)
533 {
534     res->d = floatx80_mod(val1->d, val0->d, &env->fp_status);
535 
536     make_quotient(env, res->d);
537 }
538 
539 void HELPER(frem)(CPUM68KState *env, FPReg *res, FPReg *val0, FPReg *val1)
540 {
541     res->d = floatx80_rem(val1->d, val0->d, &env->fp_status);
542 
543     make_quotient(env, res->d);
544 }
545 
546 void HELPER(fgetexp)(CPUM68KState *env, FPReg *res, FPReg *val)
547 {
548     res->d = floatx80_getexp(val->d, &env->fp_status);
549 }
550 
551 void HELPER(fgetman)(CPUM68KState *env, FPReg *res, FPReg *val)
552 {
553     res->d = floatx80_getman(val->d, &env->fp_status);
554 }
555 
556 void HELPER(fscale)(CPUM68KState *env, FPReg *res, FPReg *val0, FPReg *val1)
557 {
558     res->d = floatx80_scale(val1->d, val0->d, &env->fp_status);
559 }
560