xref: /netbsd-src/sys/arch/sparc/fpu/fpu.c (revision 8c2f80f160efd6e997c0f045f56c727c8ad9d256)
1 /*	$NetBSD: fpu.c,v 1.29 2019/03/01 11:06:55 pgoyette Exp $ */
2 
3 /*
4  * Copyright (c) 1992, 1993
5  *	The Regents of the University of California.  All rights reserved.
6  *
7  * This software was developed by the Computer Systems Engineering group
8  * at Lawrence Berkeley Laboratory under DARPA contract BG 91-66 and
9  * contributed to Berkeley.
10  *
11  * All advertising materials mentioning features or use of this software
12  * must display the following acknowledgement:
13  *	This product includes software developed by the University of
14  *	California, Lawrence Berkeley Laboratory.
15  *
16  * Redistribution and use in source and binary forms, with or without
17  * modification, are permitted provided that the following conditions
18  * are met:
19  * 1. Redistributions of source code must retain the above copyright
20  *    notice, this list of conditions and the following disclaimer.
21  * 2. Redistributions in binary form must reproduce the above copyright
22  *    notice, this list of conditions and the following disclaimer in the
23  *    documentation and/or other materials provided with the distribution.
24  * 3. Neither the name of the University nor the names of its contributors
25  *    may be used to endorse or promote products derived from this software
26  *    without specific prior written permission.
27  *
28  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
29  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
30  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
31  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
32  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
33  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
34  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
35  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
36  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
37  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
38  * SUCH DAMAGE.
39  *
40  *	@(#)fpu.c	8.1 (Berkeley) 6/11/93
41  */
42 
43 #include <sys/cdefs.h>
44 __KERNEL_RCSID(0, "$NetBSD: fpu.c,v 1.29 2019/03/01 11:06:55 pgoyette Exp $");
45 
46 #include <sys/param.h>
47 #include <sys/proc.h>
48 #include <sys/signal.h>
49 #include <sys/systm.h>
50 #include <sys/syslog.h>
51 #include <sys/signalvar.h>
52 #include <sys/compat_stub.h>
53 
54 #include <machine/instr.h>
55 #include <machine/reg.h>
56 
57 #include <sparc/fpu/fpu_emu.h>
58 #include <sparc/fpu/fpu_extern.h>
59 
60 int fpe_debug = 0;
61 
62 #ifdef DEBUG
63 /*
64  * Dump a `fpn' structure.
65  */
66 void
fpu_dumpfpn(struct fpn * fp)67 fpu_dumpfpn(struct fpn *fp)
68 {
69 	static const char *class[] = {
70 		"SNAN", "QNAN", "ZERO", "NUM", "INF"
71 	};
72 
73 	printf("%s %c.%x %x %x %xE%d", class[fp->fp_class + 2],
74 		fp->fp_sign ? '-' : ' ',
75 		fp->fp_mant[0],	fp->fp_mant[1],
76 		fp->fp_mant[2], fp->fp_mant[3],
77 		fp->fp_exp);
78 }
79 #endif
80 
81 /*
82  * fpu_execute returns the following error numbers (0 = no error):
83  */
84 #define	FPE		1	/* take a floating point exception */
85 #define	NOTFPU		2	/* not an FPU instruction */
86 
87 /*
88  * Translate current exceptions into `first' exception.  The
89  * bits go the wrong way for ffs() (0x10 is most important, etc).
90  * There are only 5, so do it the obvious way.
91  */
92 #define	X1(x) x
93 #define	X2(x) x,x
94 #define	X4(x) x,x,x,x
95 #define	X8(x) X4(x),X4(x)
96 #define	X16(x) X8(x),X8(x)
97 
98 static char cx_to_trapx[] = {
99 	X1(FSR_NX),
100 	X2(FSR_DZ),
101 	X4(FSR_UF),
102 	X8(FSR_OF),
103 	X16(FSR_NV)
104 };
105 static u_char fpu_codes_native[] = {
106 	X1(FPE_FLTRES),
107 	X2(FPE_FLTDIV),
108 	X4(FPE_FLTUND),
109 	X8(FPE_FLTOVF),
110 	X16(FPE_FLTINV)
111 };
112 static u_char fpu_codes_sunos[] = {
113 	X1(FPE_FLTINEX_TRAP),
114 	X2(FPE_FLTDIV_TRAP),
115 	X4(FPE_FLTUND_TRAP),
116 	X8(FPE_FLTOVF_TRAP),
117 	X16(FPE_FLTOPERR_TRAP)
118 };
119 
120 /* Note: SVR4(Solaris) FPE_* codes happen to be compatible with ours */
121 
122 /*
123  * The FPU gave us an exception.  Clean up the mess.  Note that the
124  * fp queue can only have FPops in it, never load/store FP registers
125  * nor FBfcc instructions.  Experiments with `crashme' prove that
126  * unknown FPops do enter the queue, however.
127  */
128 int
fpu_cleanup(struct lwp * l,struct fpstate * fs)129 fpu_cleanup(
130 	struct lwp *l,
131 #ifndef SUN4U
132 	struct fpstate *fs
133 #else /* SUN4U */
134 	struct fpstate64 *fs
135 #endif /* SUN4U */
136 	)
137 {
138 	int i, fsr = fs->fs_fsr, error;
139 	struct proc *p = l->l_proc;
140 	union instr instr;
141 	struct fpemu fe;
142 	u_char *fpu_codes;
143 	int code = 0;
144 	int ret;
145 	const struct emul *sunos_emul;
146 
147 	MODULE_HOOK_CALL(get_emul_sunos_hook, (&sunos_emul), enosys(), ret);
148 
149 	if (ret == 0 && p->p_emul == sunos_emul)
150 		fpu_codes = fpu_codes_sunos;
151 	else
152 		fpu_codes = fpu_codes_native;
153 
154 	switch ((fsr >> FSR_FTT_SHIFT) & FSR_FTT_MASK) {
155 
156 	case FSR_TT_NONE:
157 		panic("fpu_cleanup: No fault");	/* ??? */
158 		break;
159 
160 	case FSR_TT_IEEE:
161 		DPRINTF(FPE_INSN, ("fpu_cleanup: FSR_TT_IEEE\n"));
162 		/* XXX missing trap address! */
163 		if ((i = fsr & FSR_CX) == 0)
164 			panic("fpu ieee trap, but no exception");
165 		code = fpu_codes[i - 1];
166 		break;		/* XXX should return, but queue remains */
167 
168 	case FSR_TT_UNFIN:
169 		DPRINTF(FPE_INSN, ("fpu_cleanup: FSR_TT_UNFIN\n"));
170 #ifdef SUN4U
171 		if (fs->fs_qsize == 0) {
172 			printf("fpu_cleanup: unfinished fpop");
173 			/* The book sez reexecute or emulate. */
174 			return (0);
175 		}
176 		break;
177 
178 #endif /* SUN4U */
179 	case FSR_TT_UNIMP:
180 		DPRINTF(FPE_INSN, ("fpu_cleanup: FSR_TT_UNIMP\n"));
181 		if (fs->fs_qsize == 0)
182 			panic("fpu_cleanup: unimplemented fpop");
183 		break;
184 
185 	case FSR_TT_SEQ:
186 		panic("fpu sequence error");
187 		/* NOTREACHED */
188 
189 	case FSR_TT_HWERR:
190 		DPRINTF(FPE_INSN, ("fpu_cleanup: FSR_TT_HWERR\n"));
191 		log(LOG_ERR, "fpu hardware error (%s[%d])\n",
192 		    p->p_comm, p->p_pid);
193 		uprintf("%s[%d]: fpu hardware error\n", p->p_comm, p->p_pid);
194 		code = SI_NOINFO;
195 		goto out;
196 
197 	default:
198 		printf("fsr=0x%x\n", fsr);
199 		panic("fpu error");
200 	}
201 
202 	/* emulate the instructions left in the queue */
203 	fe.fe_fpstate = fs;
204 	for (i = 0; i < fs->fs_qsize; i++) {
205 		instr.i_int = fs->fs_queue[i].fq_instr;
206 		if (instr.i_any.i_op != IOP_reg ||
207 		    (instr.i_op3.i_op3 != IOP3_FPop1 &&
208 		     instr.i_op3.i_op3 != IOP3_FPop2))
209 			panic("bogus fpu queue");
210 		error = fpu_execute(&fe, instr);
211 		if (error == 0)
212 			continue;
213 
214 		switch (error) {
215 		case FPE:
216 			code = fpu_codes[(fs->fs_fsr & FSR_CX) - 1];
217 			break;
218 
219 		case NOTFPU:
220 #ifdef SUN4U
221 #ifdef DEBUG
222 			printf("fpu_cleanup: not an FPU error -- sending SIGILL\n");
223 #endif
224 #endif /* SUN4U */
225 			code = SI_NOINFO;
226 			break;
227 
228 		default:
229 			panic("fpu_cleanup 3");
230 			/* NOTREACHED */
231 		}
232 		/* XXX should stop here, but queue remains */
233 	}
234 out:
235 	fs->fs_qsize = 0;
236 	return (code);
237 }
238 
239 #ifdef notyet
240 /*
241  * If we have no FPU at all (are there any machines like this out
242  * there!?) we have to emulate each instruction, and we need a pointer
243  * to the trapframe so that we can step over them and do FBfcc's.
244  * We know the `queue' is empty, though; we just want to emulate
245  * the instruction at tf->tf_pc.
246  */
247 fpu_emulate(l, tf, fs)
248 	struct lwp *l;
249 	struct trapframe *tf;
250 #ifndef SUN4U
251 	struct fpstate *fs;
252 #else /* SUN4U */
253 	struct fpstate64 *fs;
254 #endif /* SUN4U */
255 {
256 
257 	do {
258 		fetch instr from pc
259 		decode
260 		if (integer instr) {
261 			struct pcb *pcb = lwp_getpcb(l);
262 			/*
263 			 * We do this here, rather than earlier, to avoid
264 			 * losing even more badly than usual.
265 			 */
266 			if (pcb->pcb_uw) {
267 				write_user_windows();
268 				if (rwindow_save(l))
269 					sigexit(l, SIGILL);
270 			}
271 			if (loadstore) {
272 				do_it;
273 				pc = npc, npc += 4
274 			} else if (fbfcc) {
275 				do_annul_stuff;
276 			} else
277 				return;
278 		} else if (fpu instr) {
279 			fe.fe_fsr = fs->fs_fsr &= ~FSR_CX;
280 			error = fpu_execute(&fe, fs, instr);
281 			switch (error) {
282 				etc;
283 			}
284 		} else
285 			return;
286 		if (want to reschedule)
287 			return;
288 	} while (error == 0);
289 }
290 #endif
291 
292 /*
293  * Execute an FPU instruction (one that runs entirely in the FPU; not
294  * FBfcc or STF, for instance).  On return, fe->fe_fs->fs_fsr will be
295  * modified to reflect the setting the hardware would have left.
296  *
297  * Note that we do not catch all illegal opcodes, so you can, for instance,
298  * multiply two integers this way.
299  */
300 int
fpu_execute(struct fpemu * fe,union instr instr)301 fpu_execute(struct fpemu *fe, union instr instr)
302 {
303 	struct fpn *fp;
304 #ifndef SUN4U
305 	int opf, rs1, rs2, rd, type, mask, fsr, cx;
306 	struct fpstate *fs;
307 #else /* SUN4U */
308 	int opf, rs1, rs2, rd, type, mask, fsr, cx, i, cond;
309 	struct fpstate64 *fs;
310 #endif /* SUN4U */
311 	u_int space[4];
312 
313 	/*
314 	 * `Decode' and execute instruction.  Start with no exceptions.
315 	 * The type of any i_opf opcode is in the bottom two bits, so we
316 	 * squish them out here.
317 	 */
318 	opf = instr.i_opf.i_opf;
319 	/*
320 	 * The low two bits of the opf field for floating point insns usually
321 	 * correspond to the operation width:
322 	 *
323 	 *	0:	Invalid
324 	 *	1:	Single precision float
325 	 *	2:	Double precision float
326 	 *	3:	Quad precision float
327 	 *
328 	 * The exceptions are the integer to float conversion instructions.
329 	 *
330 	 * For double and quad precision, the low bit if the rs or rd field
331 	 * is actually the high bit of the register number.
332 	 */
333 
334 	type = opf & 3;
335 	mask = 0x3 >> (3 - type);
336 
337 	rs1 = instr.i_opf.i_rs1;
338 	rs1 = (rs1 & ~mask) | ((rs1 & mask & 0x1) << 5);
339 	rs2 = instr.i_opf.i_rs2;
340 	rs2 = (rs2 & ~mask) | ((rs2 & mask & 0x1) << 5);
341 	rd = instr.i_opf.i_rd;
342 	rd = (rd & ~mask) | ((rd & mask & 0x1) << 5);
343 #ifdef DIAGNOSTIC
344 	if ((rs1 | rs2 | rd) & mask)
345 		/* This may be an FPU insn but it is illegal. */
346 		return (NOTFPU);
347 #endif
348 	fs = fe->fe_fpstate;
349 	fe->fe_fsr = fs->fs_fsr & ~FSR_CX;
350 	fe->fe_cx = 0;
351 #ifdef SUN4U
352 	/*
353 	 * Check to see if we're dealing with a fancy cmove and handle
354 	 * it first.
355 	 */
356 	if (instr.i_op3.i_op3 == IOP3_FPop2 && (opf&0xff0) != (FCMP&0xff0)) {
357 		switch (opf >>= 2) {
358 		case FMVFC0 >> 2:
359 			DPRINTF(FPE_INSN, ("fpu_execute: FMVFC0\n"));
360 			cond = (fs->fs_fsr>>FSR_FCC_SHIFT)&FSR_FCC_MASK;
361 			if (instr.i_fmovcc.i_cond != cond) return(0); /* success */
362 			rs1 = fs->fs_regs[rs2];
363 			goto mov;
364 		case FMVFC1 >> 2:
365 			DPRINTF(FPE_INSN, ("fpu_execute: FMVFC1\n"));
366 			cond = (fs->fs_fsr>>FSR_FCC1_SHIFT)&FSR_FCC_MASK;
367 			if (instr.i_fmovcc.i_cond != cond) return(0); /* success */
368 			rs1 = fs->fs_regs[rs2];
369 			goto mov;
370 		case FMVFC2 >> 2:
371 			DPRINTF(FPE_INSN, ("fpu_execute: FMVFC2\n"));
372 			cond = (fs->fs_fsr>>FSR_FCC2_SHIFT)&FSR_FCC_MASK;
373 			if (instr.i_fmovcc.i_cond != cond) return(0); /* success */
374 			rs1 = fs->fs_regs[rs2];
375 			goto mov;
376 		case FMVFC3 >> 2:
377 			DPRINTF(FPE_INSN, ("fpu_execute: FMVFC3\n"));
378 			cond = (fs->fs_fsr>>FSR_FCC3_SHIFT)&FSR_FCC_MASK;
379 			if (instr.i_fmovcc.i_cond != cond) return(0); /* success */
380 			rs1 = fs->fs_regs[rs2];
381 			goto mov;
382 		case FMVIC >> 2:
383 			/* Presume we're curlwp */
384 			DPRINTF(FPE_INSN, ("fpu_execute: FMVIC\n"));
385 			cond = (curlwp->l_md.md_tf->tf_tstate>>TSTATE_CCR_SHIFT)&PSR_ICC;
386 			if (instr.i_fmovcc.i_cond != cond) return(0); /* success */
387 			rs1 = fs->fs_regs[rs2];
388 			goto mov;
389 		case FMVXC >> 2:
390 			/* Presume we're curlwp */
391 			DPRINTF(FPE_INSN, ("fpu_execute: FMVXC\n"));
392 			cond = (curlwp->l_md.md_tf->tf_tstate>>(TSTATE_CCR_SHIFT+XCC_SHIFT))&PSR_ICC;
393 			if (instr.i_fmovcc.i_cond != cond) return(0); /* success */
394 			rs1 = fs->fs_regs[rs2];
395 			goto mov;
396 		case FMVRZ >> 2:
397 			/* Presume we're curlwp */
398 			DPRINTF(FPE_INSN, ("fpu_execute: FMVRZ\n"));
399 			rs1 = instr.i_fmovr.i_rs1;
400 			if (rs1 != 0 && (int64_t)curlwp->l_md.md_tf->tf_global[rs1] != 0)
401 				return (0); /* success */
402 			rs1 = fs->fs_regs[rs2];
403 			goto mov;
404 		case FMVRLEZ >> 2:
405 			/* Presume we're curlwp */
406 			DPRINTF(FPE_INSN, ("fpu_execute: FMVRLEZ\n"));
407 			rs1 = instr.i_fmovr.i_rs1;
408 			if (rs1 != 0 && (int64_t)curlwp->l_md.md_tf->tf_global[rs1] > 0)
409 				return (0); /* success */
410 			rs1 = fs->fs_regs[rs2];
411 			goto mov;
412 		case FMVRLZ >> 2:
413 			/* Presume we're curlwp */
414 			DPRINTF(FPE_INSN, ("fpu_execute: FMVRLZ\n"));
415 			rs1 = instr.i_fmovr.i_rs1;
416 			if (rs1 == 0 || (int64_t)curlwp->l_md.md_tf->tf_global[rs1] >= 0)
417 				return (0); /* success */
418 			rs1 = fs->fs_regs[rs2];
419 			goto mov;
420 		case FMVRNZ >> 2:
421 			/* Presume we're curlwp */
422 			DPRINTF(FPE_INSN, ("fpu_execute: FMVRNZ\n"));
423 			rs1 = instr.i_fmovr.i_rs1;
424 			if (rs1 == 0 || (int64_t)curlwp->l_md.md_tf->tf_global[rs1] == 0)
425 				return (0); /* success */
426 			rs1 = fs->fs_regs[rs2];
427 			goto mov;
428 		case FMVRGZ >> 2:
429 			/* Presume we're curlwp */
430 			DPRINTF(FPE_INSN, ("fpu_execute: FMVRGZ\n"));
431 			rs1 = instr.i_fmovr.i_rs1;
432 			if (rs1 == 0 || (int64_t)curlwp->l_md.md_tf->tf_global[rs1] <= 0)
433 				return (0); /* success */
434 			rs1 = fs->fs_regs[rs2];
435 			goto mov;
436 		case FMVRGEZ >> 2:
437 			/* Presume we're curlwp */
438 			DPRINTF(FPE_INSN, ("fpu_execute: FMVRGEZ\n"));
439 			rs1 = instr.i_fmovr.i_rs1;
440 			if (rs1 != 0 && (int64_t)curlwp->l_md.md_tf->tf_global[rs1] < 0)
441 				return (0); /* success */
442 			rs1 = fs->fs_regs[rs2];
443 			goto mov;
444 		default:
445 			DPRINTF(FPE_INSN,
446 				("fpu_execute: unknown v9 FP inst %x opf %x\n",
447 					instr.i_int, opf));
448 			return (NOTFPU);
449 		}
450 	}
451 #endif /* SUN4U */
452 	switch (opf >>= 2) {
453 
454 	default:
455 		DPRINTF(FPE_INSN,
456 			("fpu_execute: unknown basic FP inst %x opf %x\n",
457 				instr.i_int, opf));
458 		return (NOTFPU);
459 
460 	case FMOV >> 2:		/* these should all be pretty obvious */
461 		DPRINTF(FPE_INSN, ("fpu_execute: FMOV\n"));
462 		rs1 = fs->fs_regs[rs2];
463 		goto mov;
464 
465 	case FNEG >> 2:
466 		DPRINTF(FPE_INSN, ("fpu_execute: FNEG\n"));
467 		rs1 = fs->fs_regs[rs2] ^ (1 << 31);
468 		goto mov;
469 
470 	case FABS >> 2:
471 		DPRINTF(FPE_INSN, ("fpu_execute: FABS\n"));
472 		rs1 = fs->fs_regs[rs2] & ~(1 << 31);
473 	mov:
474 #ifndef SUN4U
475 		fs->fs_regs[rd] = rs1;
476 #else /* SUN4U */
477 		i = 1<<(type-1);
478 		fs->fs_regs[rd++] = rs1;
479 		while (--i > 0)
480 			fs->fs_regs[rd++] = fs->fs_regs[++rs2];
481 #endif /* SUN4U */
482 		fs->fs_fsr = fe->fe_fsr;
483 		return (0);	/* success */
484 
485 	case FSQRT >> 2:
486 		DPRINTF(FPE_INSN, ("fpu_execute: FSQRT\n"));
487 		fpu_explode(fe, &fe->fe_f1, type, rs2);
488 		fp = fpu_sqrt(fe);
489 		break;
490 
491 	case FADD >> 2:
492 		DPRINTF(FPE_INSN, ("fpu_execute: FADD\n"));
493 		fpu_explode(fe, &fe->fe_f1, type, rs1);
494 		fpu_explode(fe, &fe->fe_f2, type, rs2);
495 		fp = fpu_add(fe);
496 		break;
497 
498 	case FSUB >> 2:
499 		DPRINTF(FPE_INSN, ("fpu_execute: FSUB\n"));
500 		fpu_explode(fe, &fe->fe_f1, type, rs1);
501 		fpu_explode(fe, &fe->fe_f2, type, rs2);
502 		fp = fpu_sub(fe);
503 		break;
504 
505 	case FMUL >> 2:
506 		DPRINTF(FPE_INSN, ("fpu_execute: FMUL\n"));
507 		fpu_explode(fe, &fe->fe_f1, type, rs1);
508 		fpu_explode(fe, &fe->fe_f2, type, rs2);
509 		fp = fpu_mul(fe);
510 		break;
511 
512 	case FDIV >> 2:
513 		DPRINTF(FPE_INSN, ("fpu_execute: FDIV\n"));
514 		fpu_explode(fe, &fe->fe_f1, type, rs1);
515 		fpu_explode(fe, &fe->fe_f2, type, rs2);
516 		fp = fpu_div(fe);
517 		break;
518 
519 	case FCMP >> 2:
520 		DPRINTF(FPE_INSN, ("fpu_execute: FCMP\n"));
521 		fpu_explode(fe, &fe->fe_f1, type, rs1);
522 		fpu_explode(fe, &fe->fe_f2, type, rs2);
523 		fpu_compare(fe, 0);
524 		goto cmpdone;
525 
526 	case FCMPE >> 2:
527 		DPRINTF(FPE_INSN, ("fpu_execute: FCMPE\n"));
528 		fpu_explode(fe, &fe->fe_f1, type, rs1);
529 		fpu_explode(fe, &fe->fe_f2, type, rs2);
530 		fpu_compare(fe, 1);
531 	cmpdone:
532 		/*
533 		 * The only possible exception here is NV; catch it
534 		 * early and get out, as there is no result register.
535 		 */
536 		cx = fe->fe_cx;
537 		fsr = fe->fe_fsr | (cx << FSR_CX_SHIFT);
538 		if (cx != 0) {
539 			if (fsr & (FSR_NV << FSR_TEM_SHIFT)) {
540 				fs->fs_fsr = (fsr & ~FSR_FTT) |
541 				    (FSR_TT_IEEE << FSR_FTT_SHIFT);
542 				return (FPE);
543 			}
544 			fsr |= FSR_NV << FSR_AX_SHIFT;
545 		}
546 		fs->fs_fsr = fsr;
547 		return (0);
548 
549 	case FSMULD >> 2:
550 	case FDMULX >> 2:
551 		DPRINTF(FPE_INSN, ("fpu_execute: FSMULx\n"));
552 		if (type == FTYPE_EXT)
553 			return (NOTFPU);
554 		fpu_explode(fe, &fe->fe_f1, type, rs1);
555 		fpu_explode(fe, &fe->fe_f2, type, rs2);
556 		type++;	/* single to double, or double to quad */
557 		fp = fpu_mul(fe);
558 		break;
559 
560 #ifdef SUN4U
561 	case FXTOS >> 2:
562 	case FXTOD >> 2:
563 	case FXTOQ >> 2:
564 		DPRINTF(FPE_INSN, ("fpu_execute: FXTOx\n"));
565 		type = FTYPE_LNG;
566 		fpu_explode(fe, fp = &fe->fe_f1, type, rs2);
567 		type = opf & 3;	/* sneaky; depends on instruction encoding */
568 		break;
569 
570 	case FTOX >> 2:
571 		DPRINTF(FPE_INSN, ("fpu_execute: FTOX\n"));
572 		fpu_explode(fe, fp = &fe->fe_f1, type, rs2);
573 		type = FTYPE_LNG;
574 		/* Recalculate destination register */
575 		rd = instr.i_opf.i_rd;
576 		break;
577 
578 #endif /* SUN4U */
579 	case FTOI >> 2:
580 		DPRINTF(FPE_INSN, ("fpu_execute: FTOI\n"));
581 		fpu_explode(fe, fp = &fe->fe_f1, type, rs2);
582 		type = FTYPE_INT;
583 		/* Recalculate destination register */
584 		rd = instr.i_opf.i_rd;
585 		break;
586 
587 	case FTOS >> 2:
588 	case FTOD >> 2:
589 	case FTOQ >> 2:
590 		DPRINTF(FPE_INSN, ("fpu_execute: FTOx\n"));
591 		fpu_explode(fe, fp = &fe->fe_f1, type, rs2);
592 		/* Recalculate rd with correct type info. */
593 		type = opf & 3;	/* sneaky; depends on instruction encoding */
594 		mask = 0x3 >> (3 - type);
595 		rd = instr.i_opf.i_rd;
596 		rd = (rd & ~mask) | ((rd & mask & 0x1) << 5);
597 		break;
598 	}
599 
600 	/*
601 	 * ALU operation is complete.  Collapse the result and then check
602 	 * for exceptions.  If we got any, and they are enabled, do not
603 	 * alter the destination register, just stop with an exception.
604 	 * Otherwise set new current exceptions and accrue.
605 	 */
606 	fpu_implode(fe, fp, type, space);
607 	cx = fe->fe_cx;
608 	fsr = fe->fe_fsr;
609 	if (cx != 0) {
610 		mask = (fsr >> FSR_TEM_SHIFT) & FSR_TEM_MASK;
611 		if (cx & mask) {
612 			/* not accrued??? */
613 			fs->fs_fsr = (fsr & ~FSR_FTT) |
614 			    (FSR_TT_IEEE << FSR_FTT_SHIFT) |
615 			    (cx_to_trapx[(cx & mask) - 1] << FSR_CX_SHIFT);
616 			return (FPE);
617 		}
618 		fsr |= (cx << FSR_CX_SHIFT) | (cx << FSR_AX_SHIFT);
619 	}
620 	fs->fs_fsr = fsr;
621 	DPRINTF(FPE_REG, ("-> %c%d\n", (type == FTYPE_LNG) ? 'x' :
622 		((type == FTYPE_INT) ? 'i' :
623 			((type == FTYPE_SNG) ? 's' :
624 				((type == FTYPE_DBL) ? 'd' :
625 					((type == FTYPE_EXT) ? 'q' : '?')))),
626 		rd));
627 	fs->fs_regs[rd] = space[0];
628 	if (type >= FTYPE_DBL || type == FTYPE_LNG) {
629 		fs->fs_regs[rd + 1] = space[1];
630 		if (type > FTYPE_DBL) {
631 			fs->fs_regs[rd + 2] = space[2];
632 			fs->fs_regs[rd + 3] = space[3];
633 		}
634 	}
635 	return (0);	/* success */
636 }
637