xref: /netbsd-src/sys/arch/sparc/fpu/fpu.c (revision 1ffa7b76c40339c17a0fb2a09fac93f287cfc046)
1 /*	$NetBSD: fpu.c,v 1.17 2003/01/18 06:45:00 thorpej 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. All advertising materials mentioning features or use of this software
25  *    must display the following acknowledgement:
26  *	This product includes software developed by the University of
27  *	California, Berkeley and its contributors.
28  * 4. Neither the name of the University nor the names of its contributors
29  *    may be used to endorse or promote products derived from this software
30  *    without specific prior written permission.
31  *
32  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
33  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
34  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
35  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
36  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
37  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
38  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
39  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
40  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
41  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
42  * SUCH DAMAGE.
43  *
44  *	@(#)fpu.c	8.1 (Berkeley) 6/11/93
45  */
46 
47 #include <sys/param.h>
48 #include <sys/proc.h>
49 #include <sys/signal.h>
50 #include <sys/systm.h>
51 #include <sys/syslog.h>
52 #include <sys/signalvar.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
67 fpu_dumpfpn(struct fpn *fp)
68 {
69 	static 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[] = {
106 	X1(FPE_FLTINEX_TRAP),
107 	X2(FPE_FLTDIV_TRAP),
108 	X4(FPE_FLTUND_TRAP),
109 	X8(FPE_FLTOVF_TRAP),
110 	X16(FPE_FLTOPERR_TRAP)
111 };
112 
113 /*
114  * The FPU gave us an exception.  Clean up the mess.  Note that the
115  * fp queue can only have FPops in it, never load/store FP registers
116  * nor FBfcc instructions.  Experiments with `crashme' prove that
117  * unknown FPops do enter the queue, however.
118  */
119 void
120 fpu_cleanup(l, fs)
121 	register struct lwp *l;
122 #ifndef SUN4U
123 	register struct fpstate *fs;
124 #else /* SUN4U */
125 	register struct fpstate64 *fs;
126 #endif /* SUN4U */
127 {
128 	register int i, fsr = fs->fs_fsr, error;
129 	struct proc *p = l->l_proc;
130 	union instr instr;
131 	struct fpemu fe;
132 
133 	switch ((fsr >> FSR_FTT_SHIFT) & FSR_FTT_MASK) {
134 
135 	case FSR_TT_NONE:
136 		panic("fpu_cleanup: No fault");	/* ??? */
137 		break;
138 
139 	case FSR_TT_IEEE:
140 		DPRINTF(FPE_INSN, ("fpu_cleanup: FSR_TT_IEEE\n"));
141 		/* XXX missing trap address! */
142 		if ((i = fsr & FSR_CX) == 0)
143 			panic("fpu ieee trap, but no exception");
144 		KERNEL_PROC_LOCK(l);
145 		trapsignal(l, SIGFPE, fpu_codes[i - 1]);
146 		KERNEL_PROC_UNLOCK(l);
147 		break;		/* XXX should return, but queue remains */
148 
149 	case FSR_TT_UNFIN:
150 		DPRINTF(FPE_INSN, ("fpu_cleanup: FSR_TT_UNFIN\n"));
151 #ifdef SUN4U
152 		if (fs->fs_qsize == 0) {
153 			printf("fpu_cleanup: unfinished fpop");
154 			/* The book sez reexecute or emulate. */
155 			return;
156 		}
157 		break;
158 
159 #endif /* SUN4U */
160 	case FSR_TT_UNIMP:
161 		DPRINTF(FPE_INSN, ("fpu_cleanup: FSR_TT_UNIMP\n"));
162 		if (fs->fs_qsize == 0)
163 			panic("fpu_cleanup: unimplemented fpop");
164 		break;
165 
166 	case FSR_TT_SEQ:
167 		panic("fpu sequence error");
168 		/* NOTREACHED */
169 
170 	case FSR_TT_HWERR:
171 		DPRINTF(FPE_INSN, ("fpu_cleanup: FSR_TT_HWERR\n"));
172 		log(LOG_ERR, "fpu hardware error (%s[%d])\n",
173 		    p->p_comm, p->p_pid);
174 		uprintf("%s[%d]: fpu hardware error\n", p->p_comm, p->p_pid);
175 		KERNEL_PROC_LOCK(l);
176 		trapsignal(l, SIGFPE, -1);	/* ??? */
177 		KERNEL_PROC_UNLOCK(l);
178 		goto out;
179 
180 	default:
181 		printf("fsr=0x%x\n", fsr);
182 		panic("fpu error");
183 	}
184 
185 	/* emulate the instructions left in the queue */
186 	fe.fe_fpstate = fs;
187 	for (i = 0; i < fs->fs_qsize; i++) {
188 		instr.i_int = fs->fs_queue[i].fq_instr;
189 		if (instr.i_any.i_op != IOP_reg ||
190 		    (instr.i_op3.i_op3 != IOP3_FPop1 &&
191 		     instr.i_op3.i_op3 != IOP3_FPop2))
192 			panic("bogus fpu queue");
193 		error = fpu_execute(&fe, instr);
194 		if (error == 0)
195 			continue;
196 
197 		KERNEL_PROC_LOCK(l);
198 		switch (error) {
199 		case FPE:
200 			trapsignal(l, SIGFPE,
201 			    fpu_codes[(fs->fs_fsr & FSR_CX) - 1]);
202 			break;
203 
204 		case NOTFPU:
205 #ifdef SUN4U
206 #ifdef DEBUG
207 			printf("fpu_cleanup: not an FPU error -- sending SIGILL\n");
208 			Debugger();
209 #endif
210 #endif /* SUN4U */
211 			trapsignal(l, SIGILL, 0);	/* ??? code?  */
212 			break;
213 
214 		default:
215 			panic("fpu_cleanup 3");
216 			/* NOTREACHED */
217 		}
218 		KERNEL_PROC_UNLOCK(l);
219 		/* XXX should stop here, but queue remains */
220 	}
221 out:
222 	fs->fs_qsize = 0;
223 }
224 
225 #ifdef notyet
226 /*
227  * If we have no FPU at all (are there any machines like this out
228  * there!?) we have to emulate each instruction, and we need a pointer
229  * to the trapframe so that we can step over them and do FBfcc's.
230  * We know the `queue' is empty, though; we just want to emulate
231  * the instruction at tf->tf_pc.
232  */
233 fpu_emulate(l, tf, fs)
234 	struct lwp *l;
235 	register struct trapframe *tf;
236 #ifndef SUN4U
237 	register struct fpstate *fs;
238 #else /* SUN4U */
239 	register struct fpstate64 *fs;
240 #endif /* SUN4U */
241 {
242 
243 	do {
244 		fetch instr from pc
245 		decode
246 		if (integer instr) {
247 			/*
248 			 * We do this here, rather than earlier, to avoid
249 			 * losing even more badly than usual.
250 			 */
251 			if (l->l_addr->u_pcb.pcb_uw) {
252 				write_user_windows();
253 				if (rwindow_save(l))
254 					sigexit(l, SIGILL);
255 			}
256 			if (loadstore) {
257 				do_it;
258 				pc = npc, npc += 4
259 			} else if (fbfcc) {
260 				do_annul_stuff;
261 			} else
262 				return;
263 		} else if (fpu instr) {
264 			fe.fe_fsr = fs->fs_fsr &= ~FSR_CX;
265 			error = fpu_execute(&fe, fs, instr);
266 			switch (error) {
267 				etc;
268 			}
269 		} else
270 			return;
271 		if (want to reschedule)
272 			return;
273 	} while (error == 0);
274 }
275 #endif
276 
277 /*
278  * Execute an FPU instruction (one that runs entirely in the FPU; not
279  * FBfcc or STF, for instance).  On return, fe->fe_fs->fs_fsr will be
280  * modified to reflect the setting the hardware would have left.
281  *
282  * Note that we do not catch all illegal opcodes, so you can, for instance,
283  * multiply two integers this way.
284  */
285 int
286 fpu_execute(fe, instr)
287 	register struct fpemu *fe;
288 	union instr instr;
289 {
290 	register struct fpn *fp;
291 #ifndef SUN4U
292 	register int opf, rs1, rs2, rd, type, mask, fsr, cx;
293 	register struct fpstate *fs;
294 #else /* SUN4U */
295 	register int opf, rs1, rs2, rd, type, mask, fsr, cx, i, cond;
296 	register struct fpstate64 *fs;
297 #endif /* SUN4U */
298 	u_int space[4];
299 
300 	/*
301 	 * `Decode' and execute instruction.  Start with no exceptions.
302 	 * The type of any i_opf opcode is in the bottom two bits, so we
303 	 * squish them out here.
304 	 */
305 	opf = instr.i_opf.i_opf;
306 	/*
307 	 * The low two bits of the opf field for floating point insns usually
308 	 * correspond to the operation width:
309 	 *
310 	 *	0:	Invalid
311 	 *	1:	Single precision float
312 	 *	2:	Double precision float
313 	 *	3:	Quad precision float
314 	 *
315 	 * The exceptions are the integer to float conversion instructions.
316 	 *
317 	 * For double and quad precision, the low bit if the rs or rd field
318 	 * is actually the high bit of the register number.
319 	 */
320 
321 	type = opf & 3;
322 	mask = 0x3 >> (3 - type);
323 
324 	rs1 = instr.i_opf.i_rs1;
325 	rs1 = (rs1 & ~mask) | ((rs1 & mask & 0x1) << 5);
326 	rs2 = instr.i_opf.i_rs2;
327 	rs2 = (rs2 & ~mask) | ((rs2 & mask & 0x1) << 5);
328 	rd = instr.i_opf.i_rd;
329 	rd = (rd & ~mask) | ((rd & mask & 0x1) << 5);
330 #ifdef DIAGNOSTIC
331 	if ((rs1 | rs2 | rd) & mask)
332 		/* This may be an FPU insn but it is illegal. */
333 		return (NOTFPU);
334 #endif
335 	fs = fe->fe_fpstate;
336 	fe->fe_fsr = fs->fs_fsr & ~FSR_CX;
337 	fe->fe_cx = 0;
338 #ifdef SUN4U
339 	/*
340 	 * Check to see if we're dealing with a fancy cmove and handle
341 	 * it first.
342 	 */
343 	if (instr.i_op3.i_op3 == IOP3_FPop2 && (opf&0xff0) != (FCMP&0xff0)) {
344 		switch (opf >>= 2) {
345 		case FMVFC0 >> 2:
346 			DPRINTF(FPE_INSN, ("fpu_execute: FMVFC0\n"));
347 			cond = (fs->fs_fsr>>FSR_FCC_SHIFT)&FSR_FCC_MASK;
348 			if (instr.i_fmovcc.i_cond != cond) return(0); /* success */
349 			rs1 = fs->fs_regs[rs2];
350 			goto mov;
351 		case FMVFC1 >> 2:
352 			DPRINTF(FPE_INSN, ("fpu_execute: FMVFC1\n"));
353 			cond = (fs->fs_fsr>>FSR_FCC1_SHIFT)&FSR_FCC_MASK;
354 			if (instr.i_fmovcc.i_cond != cond) return(0); /* success */
355 			rs1 = fs->fs_regs[rs2];
356 			goto mov;
357 		case FMVFC2 >> 2:
358 			DPRINTF(FPE_INSN, ("fpu_execute: FMVFC2\n"));
359 			cond = (fs->fs_fsr>>FSR_FCC2_SHIFT)&FSR_FCC_MASK;
360 			if (instr.i_fmovcc.i_cond != cond) return(0); /* success */
361 			rs1 = fs->fs_regs[rs2];
362 			goto mov;
363 		case FMVFC3 >> 2:
364 			DPRINTF(FPE_INSN, ("fpu_execute: FMVFC3\n"));
365 			cond = (fs->fs_fsr>>FSR_FCC3_SHIFT)&FSR_FCC_MASK;
366 			if (instr.i_fmovcc.i_cond != cond) return(0); /* success */
367 			rs1 = fs->fs_regs[rs2];
368 			goto mov;
369 		case FMVIC >> 2:
370 			/* Presume we're curlwp */
371 			DPRINTF(FPE_INSN, ("fpu_execute: FMVIC\n"));
372 			cond = (curlwp->l_md.md_tf->tf_tstate>>TSTATE_CCR_SHIFT)&PSR_ICC;
373 			if (instr.i_fmovcc.i_cond != cond) return(0); /* success */
374 			rs1 = fs->fs_regs[rs2];
375 			goto mov;
376 		case FMVXC >> 2:
377 			/* Presume we're curlwp */
378 			DPRINTF(FPE_INSN, ("fpu_execute: FMVXC\n"));
379 			cond = (curlwp->l_md.md_tf->tf_tstate>>(TSTATE_CCR_SHIFT+XCC_SHIFT))&PSR_ICC;
380 			if (instr.i_fmovcc.i_cond != cond) return(0); /* success */
381 			rs1 = fs->fs_regs[rs2];
382 			goto mov;
383 		case FMVRZ >> 2:
384 			/* Presume we're curlwp */
385 			DPRINTF(FPE_INSN, ("fpu_execute: FMVRZ\n"));
386 			rs1 = instr.i_fmovr.i_rs1;
387 			if (rs1 != 0 && (int64_t)curlwp->l_md.md_tf->tf_global[rs1] != 0)
388 				return (0); /* success */
389 			rs1 = fs->fs_regs[rs2];
390 			goto mov;
391 		case FMVRLEZ >> 2:
392 			/* Presume we're curlwp */
393 			DPRINTF(FPE_INSN, ("fpu_execute: FMVRLEZ\n"));
394 			rs1 = instr.i_fmovr.i_rs1;
395 			if (rs1 != 0 && (int64_t)curlwp->l_md.md_tf->tf_global[rs1] > 0)
396 				return (0); /* success */
397 			rs1 = fs->fs_regs[rs2];
398 			goto mov;
399 		case FMVRLZ >> 2:
400 			/* Presume we're curlwp */
401 			DPRINTF(FPE_INSN, ("fpu_execute: FMVRLZ\n"));
402 			rs1 = instr.i_fmovr.i_rs1;
403 			if (rs1 == 0 || (int64_t)curlwp->l_md.md_tf->tf_global[rs1] >= 0)
404 				return (0); /* success */
405 			rs1 = fs->fs_regs[rs2];
406 			goto mov;
407 		case FMVRNZ >> 2:
408 			/* Presume we're curlwp */
409 			DPRINTF(FPE_INSN, ("fpu_execute: FMVRNZ\n"));
410 			rs1 = instr.i_fmovr.i_rs1;
411 			if (rs1 == 0 || (int64_t)curlwp->l_md.md_tf->tf_global[rs1] == 0)
412 				return (0); /* success */
413 			rs1 = fs->fs_regs[rs2];
414 			goto mov;
415 		case FMVRGZ >> 2:
416 			/* Presume we're curlwp */
417 			DPRINTF(FPE_INSN, ("fpu_execute: FMVRGZ\n"));
418 			rs1 = instr.i_fmovr.i_rs1;
419 			if (rs1 == 0 || (int64_t)curlwp->l_md.md_tf->tf_global[rs1] <= 0)
420 				return (0); /* success */
421 			rs1 = fs->fs_regs[rs2];
422 			goto mov;
423 		case FMVRGEZ >> 2:
424 			/* Presume we're curlwp */
425 			DPRINTF(FPE_INSN, ("fpu_execute: FMVRGEZ\n"));
426 			rs1 = instr.i_fmovr.i_rs1;
427 			if (rs1 != 0 && (int64_t)curlwp->l_md.md_tf->tf_global[rs1] < 0)
428 				return (0); /* success */
429 			rs1 = fs->fs_regs[rs2];
430 			goto mov;
431 		default:
432 			DPRINTF(FPE_INSN,
433 				("fpu_execute: unknown v9 FP inst %x opf %x\n",
434 					instr.i_int, opf));
435 			return (NOTFPU);
436 		}
437 	}
438 #endif /* SUN4U */
439 	switch (opf >>= 2) {
440 
441 	default:
442 		DPRINTF(FPE_INSN,
443 			("fpu_execute: unknown basic FP inst %x opf %x\n",
444 				instr.i_int, opf));
445 		return (NOTFPU);
446 
447 	case FMOV >> 2:		/* these should all be pretty obvious */
448 		DPRINTF(FPE_INSN, ("fpu_execute: FMOV\n"));
449 		rs1 = fs->fs_regs[rs2];
450 		goto mov;
451 
452 	case FNEG >> 2:
453 		DPRINTF(FPE_INSN, ("fpu_execute: FNEG\n"));
454 		rs1 = fs->fs_regs[rs2] ^ (1 << 31);
455 		goto mov;
456 
457 	case FABS >> 2:
458 		DPRINTF(FPE_INSN, ("fpu_execute: FABS\n"));
459 		rs1 = fs->fs_regs[rs2] & ~(1 << 31);
460 	mov:
461 #ifndef SUN4U
462 		fs->fs_regs[rd] = rs1;
463 #else /* SUN4U */
464 		i = 1<<(type-1);
465 		fs->fs_regs[rd++] = rs1;
466 		while (--i > 0)
467 			fs->fs_regs[rd++] = fs->fs_regs[++rs2];
468 #endif /* SUN4U */
469 		fs->fs_fsr = fe->fe_fsr;
470 		return (0);	/* success */
471 
472 	case FSQRT >> 2:
473 		DPRINTF(FPE_INSN, ("fpu_execute: FSQRT\n"));
474 		fpu_explode(fe, &fe->fe_f1, type, rs2);
475 		fp = fpu_sqrt(fe);
476 		break;
477 
478 	case FADD >> 2:
479 		DPRINTF(FPE_INSN, ("fpu_execute: FADD\n"));
480 		fpu_explode(fe, &fe->fe_f1, type, rs1);
481 		fpu_explode(fe, &fe->fe_f2, type, rs2);
482 		fp = fpu_add(fe);
483 		break;
484 
485 	case FSUB >> 2:
486 		DPRINTF(FPE_INSN, ("fpu_execute: FSUB\n"));
487 		fpu_explode(fe, &fe->fe_f1, type, rs1);
488 		fpu_explode(fe, &fe->fe_f2, type, rs2);
489 		fp = fpu_sub(fe);
490 		break;
491 
492 	case FMUL >> 2:
493 		DPRINTF(FPE_INSN, ("fpu_execute: FMUL\n"));
494 		fpu_explode(fe, &fe->fe_f1, type, rs1);
495 		fpu_explode(fe, &fe->fe_f2, type, rs2);
496 		fp = fpu_mul(fe);
497 		break;
498 
499 	case FDIV >> 2:
500 		DPRINTF(FPE_INSN, ("fpu_execute: FDIV\n"));
501 		fpu_explode(fe, &fe->fe_f1, type, rs1);
502 		fpu_explode(fe, &fe->fe_f2, type, rs2);
503 		fp = fpu_div(fe);
504 		break;
505 
506 	case FCMP >> 2:
507 		DPRINTF(FPE_INSN, ("fpu_execute: FCMP\n"));
508 		fpu_explode(fe, &fe->fe_f1, type, rs1);
509 		fpu_explode(fe, &fe->fe_f2, type, rs2);
510 		fpu_compare(fe, 0);
511 		goto cmpdone;
512 
513 	case FCMPE >> 2:
514 		DPRINTF(FPE_INSN, ("fpu_execute: FCMPE\n"));
515 		fpu_explode(fe, &fe->fe_f1, type, rs1);
516 		fpu_explode(fe, &fe->fe_f2, type, rs2);
517 		fpu_compare(fe, 1);
518 	cmpdone:
519 		/*
520 		 * The only possible exception here is NV; catch it
521 		 * early and get out, as there is no result register.
522 		 */
523 		cx = fe->fe_cx;
524 		fsr = fe->fe_fsr | (cx << FSR_CX_SHIFT);
525 		if (cx != 0) {
526 			if (fsr & (FSR_NV << FSR_TEM_SHIFT)) {
527 				fs->fs_fsr = (fsr & ~FSR_FTT) |
528 				    (FSR_TT_IEEE << FSR_FTT_SHIFT);
529 				return (FPE);
530 			}
531 			fsr |= FSR_NV << FSR_AX_SHIFT;
532 		}
533 		fs->fs_fsr = fsr;
534 		return (0);
535 
536 	case FSMULD >> 2:
537 	case FDMULX >> 2:
538 		DPRINTF(FPE_INSN, ("fpu_execute: FSMULx\n"));
539 		if (type == FTYPE_EXT)
540 			return (NOTFPU);
541 		fpu_explode(fe, &fe->fe_f1, type, rs1);
542 		fpu_explode(fe, &fe->fe_f2, type, rs2);
543 		type++;	/* single to double, or double to quad */
544 		fp = fpu_mul(fe);
545 		break;
546 
547 #ifdef SUN4U
548 	case FXTOS >> 2:
549 	case FXTOD >> 2:
550 	case FXTOQ >> 2:
551 		DPRINTF(FPE_INSN, ("fpu_execute: FXTOx\n"));
552 		type = FTYPE_LNG;
553 		fpu_explode(fe, fp = &fe->fe_f1, type, rs2);
554 		type = opf & 3;	/* sneaky; depends on instruction encoding */
555 		break;
556 
557 	case FTOX >> 2:
558 		DPRINTF(FPE_INSN, ("fpu_execute: FTOX\n"));
559 		fpu_explode(fe, fp = &fe->fe_f1, type, rs2);
560 		type = FTYPE_LNG;
561 		/* Recalculate destination register */
562 		rd = instr.i_opf.i_rd;
563 		break;
564 
565 #endif /* SUN4U */
566 	case FTOI >> 2:
567 		DPRINTF(FPE_INSN, ("fpu_execute: FTOI\n"));
568 		fpu_explode(fe, fp = &fe->fe_f1, type, rs2);
569 		type = FTYPE_INT;
570 		/* Recalculate destination register */
571 		rd = instr.i_opf.i_rd;
572 		break;
573 
574 	case FTOS >> 2:
575 	case FTOD >> 2:
576 	case FTOQ >> 2:
577 		DPRINTF(FPE_INSN, ("fpu_execute: FTOx\n"));
578 		fpu_explode(fe, fp = &fe->fe_f1, type, rs2);
579 		/* Recalculate rd with correct type info. */
580 		type = opf & 3;	/* sneaky; depends on instruction encoding */
581 		mask = 0x3 >> (3 - type);
582 		rd = instr.i_opf.i_rd;
583 		rd = (rd & ~mask) | ((rd & mask & 0x1) << 5);
584 		break;
585 	}
586 
587 	/*
588 	 * ALU operation is complete.  Collapse the result and then check
589 	 * for exceptions.  If we got any, and they are enabled, do not
590 	 * alter the destination register, just stop with an exception.
591 	 * Otherwise set new current exceptions and accrue.
592 	 */
593 	fpu_implode(fe, fp, type, space);
594 	cx = fe->fe_cx;
595 	fsr = fe->fe_fsr;
596 	if (cx != 0) {
597 		mask = (fsr >> FSR_TEM_SHIFT) & FSR_TEM_MASK;
598 		if (cx & mask) {
599 			/* not accrued??? */
600 			fs->fs_fsr = (fsr & ~FSR_FTT) |
601 			    (FSR_TT_IEEE << FSR_FTT_SHIFT) |
602 			    (cx_to_trapx[(cx & mask) - 1] << FSR_CX_SHIFT);
603 			return (FPE);
604 		}
605 		fsr |= (cx << FSR_CX_SHIFT) | (cx << FSR_AX_SHIFT);
606 	}
607 	fs->fs_fsr = fsr;
608 	DPRINTF(FPE_REG, ("-> %c%d\n", (type == FTYPE_LNG) ? 'x' :
609 		((type == FTYPE_INT) ? 'i' :
610 			((type == FTYPE_SNG) ? 's' :
611 				((type == FTYPE_DBL) ? 'd' :
612 					((type == FTYPE_EXT) ? 'q' : '?')))),
613 		rd));
614 	fs->fs_regs[rd] = space[0];
615 	if (type >= FTYPE_DBL || type == FTYPE_LNG) {
616 		fs->fs_regs[rd + 1] = space[1];
617 		if (type > FTYPE_DBL) {
618 			fs->fs_regs[rd + 2] = space[2];
619 			fs->fs_regs[rd + 3] = space[3];
620 		}
621 	}
622 	return (0);	/* success */
623 }
624