xref: /freebsd/sys/powerpc/fpu/fpu_emu.c (revision d4ae33f0721c1b170fe37d97e395228ffcfb3f80)
1 /*	$NetBSD: fpu_emu.c,v 1.14 2005/12/11 12:18:42 christos Exp $ */
2 
3 /*
4  * Copyright 2001 Wasabi Systems, Inc.
5  * All rights reserved.
6  *
7  * Written by Eduardo Horvath and Simon Burge for Wasabi Systems, Inc.
8  *
9  * Redistribution and use in source and binary forms, with or without
10  * modification, are permitted provided that the following conditions
11  * are met:
12  * 1. Redistributions of source code must retain the above copyright
13  *    notice, this list of conditions and the following disclaimer.
14  * 2. Redistributions in binary form must reproduce the above copyright
15  *    notice, this list of conditions and the following disclaimer in the
16  *    documentation and/or other materials provided with the distribution.
17  * 3. All advertising materials mentioning features or use of this software
18  *    must display the following acknowledgement:
19  *      This product includes software developed for the NetBSD Project by
20  *      Wasabi Systems, Inc.
21  * 4. The name of Wasabi Systems, Inc. may not be used to endorse
22  *    or promote products derived from this software without specific prior
23  *    written permission.
24  *
25  * THIS SOFTWARE IS PROVIDED BY WASABI SYSTEMS, INC. ``AS IS'' AND
26  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
27  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
28  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL WASABI SYSTEMS, INC
29  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
30  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
31  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
32  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
33  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
34  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
35  * POSSIBILITY OF SUCH DAMAGE.
36  */
37 
38 /*
39  * Copyright (c) 1992, 1993
40  *	The Regents of the University of California.  All rights reserved.
41  *
42  * This software was developed by the Computer Systems Engineering group
43  * at Lawrence Berkeley Laboratory under DARPA contract BG 91-66 and
44  * contributed to Berkeley.
45  *
46  * All advertising materials mentioning features or use of this software
47  * must display the following acknowledgement:
48  *	This product includes software developed by the University of
49  *	California, Lawrence Berkeley Laboratory.
50  *
51  * Redistribution and use in source and binary forms, with or without
52  * modification, are permitted provided that the following conditions
53  * are met:
54  * 1. Redistributions of source code must retain the above copyright
55  *    notice, this list of conditions and the following disclaimer.
56  * 2. Redistributions in binary form must reproduce the above copyright
57  *    notice, this list of conditions and the following disclaimer in the
58  *    documentation and/or other materials provided with the distribution.
59  * 3. Neither the name of the University nor the names of its contributors
60  *    may be used to endorse or promote products derived from this software
61  *    without specific prior written permission.
62  *
63  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
64  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
65  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
66  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
67  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
68  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
69  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
70  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
71  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
72  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
73  * SUCH DAMAGE.
74  *
75  *	@(#)fpu.c	8.1 (Berkeley) 6/11/93
76  */
77 
78 #include <sys/cdefs.h>
79 __FBSDID("$FreeBSD$");
80 
81 #include "opt_ddb.h"
82 
83 #include <sys/param.h>
84 #include <sys/systm.h>
85 #include <sys/kdb.h>
86 #include <sys/kernel.h>
87 #include <sys/proc.h>
88 #include <sys/sysctl.h>
89 #include <sys/signal.h>
90 #include <sys/syslog.h>
91 #include <sys/signalvar.h>
92 
93 #include <machine/fpu.h>
94 #include <machine/reg.h>
95 
96 #include <powerpc/fpu/fpu_emu.h>
97 #include <powerpc/fpu/fpu_extern.h>
98 #include <powerpc/fpu/fpu_instr.h>
99 
100 static SYSCTL_NODE(_hw, OID_AUTO, fpu_emu, CTLFLAG_RW, 0, "FPU emulator");
101 
102 #define	FPU_EMU_EVCNT_DECL(name)					\
103 static u_int fpu_emu_evcnt_##name;					\
104 SYSCTL_INT(_hw_fpu_emu, OID_AUTO, evcnt_##name, CTLFLAG_RD,		\
105     &fpu_emu_evcnt_##name, 0, "")
106 
107 #define	FPU_EMU_EVCNT_INCR(name)	fpu_emu_evcnt_##name++
108 
109 FPU_EMU_EVCNT_DECL(stfiwx);
110 FPU_EMU_EVCNT_DECL(fpstore);
111 FPU_EMU_EVCNT_DECL(fpload);
112 FPU_EMU_EVCNT_DECL(fcmpu);
113 FPU_EMU_EVCNT_DECL(frsp);
114 FPU_EMU_EVCNT_DECL(fctiw);
115 FPU_EMU_EVCNT_DECL(fcmpo);
116 FPU_EMU_EVCNT_DECL(mtfsb1);
117 FPU_EMU_EVCNT_DECL(fnegabs);
118 FPU_EMU_EVCNT_DECL(mcrfs);
119 FPU_EMU_EVCNT_DECL(mtfsb0);
120 FPU_EMU_EVCNT_DECL(fmr);
121 FPU_EMU_EVCNT_DECL(mtfsfi);
122 FPU_EMU_EVCNT_DECL(fnabs);
123 FPU_EMU_EVCNT_DECL(fabs);
124 FPU_EMU_EVCNT_DECL(mffs);
125 FPU_EMU_EVCNT_DECL(mtfsf);
126 FPU_EMU_EVCNT_DECL(fctid);
127 FPU_EMU_EVCNT_DECL(fcfid);
128 FPU_EMU_EVCNT_DECL(fdiv);
129 FPU_EMU_EVCNT_DECL(fsub);
130 FPU_EMU_EVCNT_DECL(fadd);
131 FPU_EMU_EVCNT_DECL(fsqrt);
132 FPU_EMU_EVCNT_DECL(fsel);
133 FPU_EMU_EVCNT_DECL(fpres);
134 FPU_EMU_EVCNT_DECL(fmul);
135 FPU_EMU_EVCNT_DECL(frsqrte);
136 FPU_EMU_EVCNT_DECL(fmulsub);
137 FPU_EMU_EVCNT_DECL(fmuladd);
138 FPU_EMU_EVCNT_DECL(fnmsub);
139 FPU_EMU_EVCNT_DECL(fnmadd);
140 
141 /* FPSR exception masks */
142 #define FPSR_EX_MSK	(FPSCR_VX|FPSCR_OX|FPSCR_UX|FPSCR_ZX|		\
143 			FPSCR_XX|FPSCR_VXSNAN|FPSCR_VXISI|FPSCR_VXIDI|	\
144 			FPSCR_VXZDZ|FPSCR_VXIMZ|FPSCR_VXVC|FPSCR_VXSOFT|\
145 			FPSCR_VXSQRT|FPSCR_VXCVI)
146 #define	FPSR_EX		(FPSCR_VE|FPSCR_OE|FPSCR_UE|FPSCR_ZE|FPSCR_XE)
147 #define	FPSR_EXOP	(FPSR_EX_MSK&(~FPSR_EX))
148 
149 int fpe_debug = 0;
150 
151 #ifdef DEBUG
152 vm_offset_t opc_disasm(vm_offset_t, int);
153 
154 /*
155  * Dump a `fpn' structure.
156  */
157 void
158 fpu_dumpfpn(struct fpn *fp)
159 {
160 	static const char *class[] = {
161 		"SNAN", "QNAN", "ZERO", "NUM", "INF"
162 	};
163 
164 	printf("%s %c.%x %x %x %xE%d", class[fp->fp_class + 2],
165 		fp->fp_sign ? '-' : ' ',
166 		fp->fp_mant[0],	fp->fp_mant[1],
167 		fp->fp_mant[2], fp->fp_mant[3],
168 		fp->fp_exp);
169 }
170 #endif
171 
172 /*
173  * fpu_execute returns the following error numbers (0 = no error):
174  */
175 #define	FPE		1	/* take a floating point exception */
176 #define	NOTFPU		2	/* not an FPU instruction */
177 #define	FAULT		3
178 
179 
180 /*
181  * Emulate a floating-point instruction.
182  * Return zero for success, else signal number.
183  * (Typically: zero, SIGFPE, SIGILL, SIGSEGV)
184  */
185 int
186 fpu_emulate(struct trapframe *frame, struct fpreg *fpf)
187 {
188 	static union instr insn;
189 	static struct fpemu fe;
190 	static int lastill = 0;
191 	int sig;
192 
193 	/* initialize insn.is_datasize to tell it is *not* initialized */
194 	fe.fe_fpstate = fpf;
195 	fe.fe_cx = 0;
196 
197 	/* always set this (to avoid a warning) */
198 
199 	if (copyin((void *) (frame->srr0), &insn.i_int, sizeof (insn.i_int))) {
200 #ifdef DEBUG
201 		printf("fpu_emulate: fault reading opcode\n");
202 #endif
203 		return SIGSEGV;
204 	}
205 
206 	DPRINTF(FPE_EX, ("fpu_emulate: emulating insn %x at %p\n",
207 	    insn.i_int, (void *)frame->srr0));
208 
209 
210 	if ((insn.i_any.i_opcd == OPC_TWI) ||
211 	    ((insn.i_any.i_opcd == OPC_integer_31) &&
212 	    (insn.i_x.i_xo == OPC31_TW))) {
213 		/* Check for the two trap insns. */
214 		DPRINTF(FPE_EX, ("fpu_emulate: SIGTRAP\n"));
215 		return (SIGTRAP);
216 	}
217 	sig = 0;
218 	switch (fpu_execute(frame, &fe, &insn)) {
219 	case 0:
220 		DPRINTF(FPE_EX, ("fpu_emulate: success\n"));
221 		frame->srr0 += 4;
222 		break;
223 
224 	case FPE:
225 		DPRINTF(FPE_EX, ("fpu_emulate: SIGFPE\n"));
226 		sig = SIGFPE;
227 		break;
228 
229 	case FAULT:
230 		DPRINTF(FPE_EX, ("fpu_emulate: SIGSEGV\n"));
231 		sig = SIGSEGV;
232 		break;
233 
234 	case NOTFPU:
235 	default:
236 		DPRINTF(FPE_EX, ("fpu_emulate: SIGILL\n"));
237 #ifdef DEBUG
238 		if (fpe_debug & FPE_EX) {
239 			printf("fpu_emulate:  illegal insn %x at %p:",
240 			insn.i_int, (void *) (frame->srr0));
241 			opc_disasm(frame->srr0, insn.i_int);
242 		}
243 #endif
244 		/*
245 		* XXXX retry an illegal insn once due to cache issues.
246 		*/
247 		if (lastill == frame->srr0) {
248 			sig = SIGILL;
249 #ifdef DEBUG
250 			if (fpe_debug & FPE_EX)
251 				kdb_enter(KDB_WHY_UNSET, "illegal instruction");
252 #endif
253 		}
254 		lastill = frame->srr0;
255 		break;
256 	}
257 
258 	return (sig);
259 }
260 
261 /*
262  * Execute an FPU instruction (one that runs entirely in the FPU; not
263  * FBfcc or STF, for instance).  On return, fe->fe_fs->fs_fsr will be
264  * modified to reflect the setting the hardware would have left.
265  *
266  * Note that we do not catch all illegal opcodes, so you can, for instance,
267  * multiply two integers this way.
268  */
269 int
270 fpu_execute(struct trapframe *tf, struct fpemu *fe, union instr *insn)
271 {
272 	struct fpn *fp;
273 	union instr instr = *insn;
274 	int *a;
275 	vm_offset_t addr;
276 	int ra, rb, rc, rt, type, mask, fsr, cx, bf, setcr;
277 	unsigned int cond;
278 	struct fpreg *fs;
279 
280 	/* Setup work. */
281 	fp = NULL;
282 	fs = fe->fe_fpstate;
283 	fe->fe_fpscr = ((int *)&fs->fpscr)[1];
284 
285 	/*
286 	 * On PowerPC all floating point values are stored in registers
287 	 * as doubles, even when used for single precision operations.
288 	 */
289 	type = FTYPE_DBL;
290 	cond = instr.i_any.i_rc;
291 	setcr = 0;
292 	bf = 0;	/* XXX gcc */
293 
294 #if defined(DDB) && defined(DEBUG)
295 	if (fpe_debug & FPE_EX) {
296 		vm_offset_t loc = tf->srr0;
297 
298 		printf("Trying to emulate: %p ", (void *)loc);
299 		opc_disasm(loc, instr.i_int);
300 	}
301 #endif
302 
303 	/*
304 	 * `Decode' and execute instruction.
305 	 */
306 
307 	if ((instr.i_any.i_opcd >= OPC_LFS && instr.i_any.i_opcd <= OPC_STFDU) ||
308 	    instr.i_any.i_opcd == OPC_integer_31) {
309 		/*
310 		 * Handle load/store insns:
311 		 *
312 		 * Convert to/from single if needed, calculate addr,
313 		 * and update index reg if needed.
314 		 */
315 		double buf;
316 		size_t size = sizeof(float);
317 		int store, update;
318 
319 		cond = 0; /* ld/st never set condition codes */
320 
321 
322 		if (instr.i_any.i_opcd == OPC_integer_31) {
323 			if (instr.i_x.i_xo == OPC31_STFIWX) {
324 				FPU_EMU_EVCNT_INCR(stfiwx);
325 
326 				/* Store as integer */
327 				ra = instr.i_x.i_ra;
328 				rb = instr.i_x.i_rb;
329 				DPRINTF(FPE_INSN,
330 					("reg %d has %jx reg %d has %jx\n",
331 					ra, (uintmax_t)tf->fixreg[ra], rb,
332 					(uintmax_t)tf->fixreg[rb]));
333 
334 				addr = tf->fixreg[rb];
335 				if (ra != 0)
336 					addr += tf->fixreg[ra];
337 				rt = instr.i_x.i_rt;
338 				a = (int *)&fs->fpreg[rt];
339 				DPRINTF(FPE_INSN,
340 					("fpu_execute: Store INT %x at %p\n",
341 						a[1], (void *)addr));
342 				if (copyout(&a[1], (void *)addr, sizeof(int)))
343 					return (FAULT);
344 				return (0);
345 			}
346 
347 			if ((instr.i_x.i_xo & OPC31_FPMASK) != OPC31_FPOP)
348 				/* Not an indexed FP load/store op */
349 				return (NOTFPU);
350 
351 			store = (instr.i_x.i_xo & 0x80);
352 			if (instr.i_x.i_xo & 0x40)
353 				size = sizeof(double);
354 			else
355 				type = FTYPE_SNG;
356 			update = (instr.i_x.i_xo & 0x20);
357 
358 			/* calculate EA of load/store */
359 			ra = instr.i_x.i_ra;
360 			rb = instr.i_x.i_rb;
361 			DPRINTF(FPE_INSN, ("reg %d has %jx reg %d has %jx\n",
362 				ra, (uintmax_t)tf->fixreg[ra], rb,
363 				(uintmax_t)tf->fixreg[rb]));
364 			addr = tf->fixreg[rb];
365 			if (ra != 0)
366 				addr += tf->fixreg[ra];
367 			rt = instr.i_x.i_rt;
368 		} else {
369 			store = instr.i_d.i_opcd & 0x4;
370 			if (instr.i_d.i_opcd & 0x2)
371 				size = sizeof(double);
372 			else
373 				type = FTYPE_SNG;
374 			update = instr.i_d.i_opcd & 0x1;
375 
376 			/* calculate EA of load/store */
377 			ra = instr.i_d.i_ra;
378 			addr = instr.i_d.i_d;
379 			DPRINTF(FPE_INSN, ("reg %d has %jx displ %jx\n",
380 				ra, (uintmax_t)tf->fixreg[ra],
381 				(uintmax_t)addr));
382 			if (ra != 0)
383 				addr += tf->fixreg[ra];
384 			rt = instr.i_d.i_rt;
385 		}
386 
387 		if (update && ra == 0)
388 			return (NOTFPU);
389 
390 		if (store) {
391 			/* Store */
392 			FPU_EMU_EVCNT_INCR(fpstore);
393 			if (type != FTYPE_DBL) {
394 				DPRINTF(FPE_INSN,
395 					("fpu_execute: Store SNG at %p\n",
396 						(void *)addr));
397 				fpu_explode(fe, fp = &fe->fe_f1, FTYPE_DBL, rt);
398 				fpu_implode(fe, fp, type, (void *)&buf);
399 				if (copyout(&buf, (void *)addr, size))
400 					return (FAULT);
401 			} else {
402 				DPRINTF(FPE_INSN,
403 					("fpu_execute: Store DBL at %p\n",
404 						(void *)addr));
405 				if (copyout(&fs->fpreg[rt], (void *)addr, size))
406 					return (FAULT);
407 			}
408 		} else {
409 			/* Load */
410 			FPU_EMU_EVCNT_INCR(fpload);
411 			DPRINTF(FPE_INSN, ("fpu_execute: Load from %p\n",
412 				(void *)addr));
413 			if (copyin((const void *)addr, &fs->fpreg[rt], size))
414 				return (FAULT);
415 			if (type != FTYPE_DBL) {
416 				fpu_explode(fe, fp = &fe->fe_f1, type, rt);
417 				fpu_implode(fe, fp, FTYPE_DBL,
418 					(u_int *)&fs->fpreg[rt]);
419 			}
420 		}
421 		if (update)
422 			tf->fixreg[ra] = addr;
423 		/* Complete. */
424 		return (0);
425 #ifdef notyet
426 	} else if (instr.i_any.i_opcd == OPC_load_st_62) {
427 		/* These are 64-bit extensions */
428 		return (NOTFPU);
429 #endif
430 	} else if (instr.i_any.i_opcd == OPC_sp_fp_59 ||
431 		instr.i_any.i_opcd == OPC_dp_fp_63) {
432 
433 
434 		if (instr.i_any.i_opcd == OPC_dp_fp_63 &&
435 		    !(instr.i_a.i_xo & OPC63M_MASK)) {
436 			/* Format X */
437 			rt = instr.i_x.i_rt;
438 			ra = instr.i_x.i_ra;
439 			rb = instr.i_x.i_rb;
440 
441 
442 			/* One of the special opcodes.... */
443 			switch (instr.i_x.i_xo) {
444 			case	OPC63_FCMPU:
445 				FPU_EMU_EVCNT_INCR(fcmpu);
446 				DPRINTF(FPE_INSN, ("fpu_execute: FCMPU\n"));
447 				rt >>= 2;
448 				fpu_explode(fe, &fe->fe_f1, type, ra);
449 				fpu_explode(fe, &fe->fe_f2, type, rb);
450 				fpu_compare(fe, 0);
451 				/* Make sure we do the condition regs. */
452 				cond = 0;
453 				/* N.B.: i_rs is already left shifted by two. */
454 				bf = instr.i_x.i_rs & 0xfc;
455 				setcr = 1;
456 				break;
457 
458 			case	OPC63_FRSP:
459 				/*
460 				 * Convert to single:
461 				 *
462 				 * PowerPC uses this to round a double
463 				 * precision value to single precision,
464 				 * but values in registers are always
465 				 * stored in double precision format.
466 				 */
467 				FPU_EMU_EVCNT_INCR(frsp);
468 				DPRINTF(FPE_INSN, ("fpu_execute: FRSP\n"));
469 				fpu_explode(fe, fp = &fe->fe_f1, FTYPE_DBL, rb);
470 				fpu_implode(fe, fp, FTYPE_SNG,
471 					(u_int *)&fs->fpreg[rt]);
472 				fpu_explode(fe, fp = &fe->fe_f1, FTYPE_SNG, rt);
473 				type = FTYPE_DBL;
474 				break;
475 			case	OPC63_FCTIW:
476 			case	OPC63_FCTIWZ:
477 				FPU_EMU_EVCNT_INCR(fctiw);
478 				DPRINTF(FPE_INSN, ("fpu_execute: FCTIW\n"));
479 				fpu_explode(fe, fp = &fe->fe_f1, type, rb);
480 				type = FTYPE_INT;
481 				break;
482 			case	OPC63_FCMPO:
483 				FPU_EMU_EVCNT_INCR(fcmpo);
484 				DPRINTF(FPE_INSN, ("fpu_execute: FCMPO\n"));
485 				rt >>= 2;
486 				fpu_explode(fe, &fe->fe_f1, type, ra);
487 				fpu_explode(fe, &fe->fe_f2, type, rb);
488 				fpu_compare(fe, 1);
489 				/* Make sure we do the condition regs. */
490 				cond = 0;
491 				/* N.B.: i_rs is already left shifted by two. */
492 				bf = instr.i_x.i_rs & 0xfc;
493 				setcr = 1;
494 				break;
495 			case	OPC63_MTFSB1:
496 				FPU_EMU_EVCNT_INCR(mtfsb1);
497 				DPRINTF(FPE_INSN, ("fpu_execute: MTFSB1\n"));
498 				fe->fe_fpscr |=
499 					(~(FPSCR_VX|FPSR_EX) & (1<<(31-rt)));
500 				break;
501 			case	OPC63_FNEG:
502 				FPU_EMU_EVCNT_INCR(fnegabs);
503 				DPRINTF(FPE_INSN, ("fpu_execute: FNEGABS\n"));
504 				memcpy(&fs->fpreg[rt], &fs->fpreg[rb],
505 					sizeof(double));
506 				a = (int *)&fs->fpreg[rt];
507 				*a ^= (1U << 31);
508 				break;
509 			case	OPC63_MCRFS:
510 				FPU_EMU_EVCNT_INCR(mcrfs);
511 				DPRINTF(FPE_INSN, ("fpu_execute: MCRFS\n"));
512 				cond = 0;
513 				rt &= 0x1c;
514 				ra &= 0x1c;
515 				/* Extract the bits we want */
516 				mask = (fe->fe_fpscr >> (28 - ra)) & 0xf;
517 				/* Clear the bits we copied. */
518 				fe->fe_cx =
519 					(FPSR_EX_MSK | (0xf << (28 - ra)));
520 				fe->fe_fpscr &= fe->fe_cx;
521 				/* Now shove them in the right part of cr */
522 				tf->cr &= ~(0xf << (28 - rt));
523 				tf->cr |= (mask << (28 - rt));
524 				break;
525 			case	OPC63_MTFSB0:
526 				FPU_EMU_EVCNT_INCR(mtfsb0);
527 				DPRINTF(FPE_INSN, ("fpu_execute: MTFSB0\n"));
528 				fe->fe_fpscr &=
529 					((FPSCR_VX|FPSR_EX) & ~(1<<(31-rt)));
530 				break;
531 			case	OPC63_FMR:
532 				FPU_EMU_EVCNT_INCR(fmr);
533 				DPRINTF(FPE_INSN, ("fpu_execute: FMR\n"));
534 				memcpy(&fs->fpreg[rt], &fs->fpreg[rb],
535 					sizeof(double));
536 				break;
537 			case	OPC63_MTFSFI:
538 				FPU_EMU_EVCNT_INCR(mtfsfi);
539 				DPRINTF(FPE_INSN, ("fpu_execute: MTFSFI\n"));
540 				rb >>= 1;
541 				rt &= 0x1c; /* Already left-shifted 4 */
542 				fe->fe_cx = rb << (28 - rt);
543 				mask = 0xf<<(28 - rt);
544 				fe->fe_fpscr = (fe->fe_fpscr & ~mask) |
545 					fe->fe_cx;
546 /* XXX weird stuff about OX, FX, FEX, and VX should be handled */
547 				break;
548 			case	OPC63_FNABS:
549 				FPU_EMU_EVCNT_INCR(fnabs);
550 				DPRINTF(FPE_INSN, ("fpu_execute: FABS\n"));
551 				memcpy(&fs->fpreg[rt], &fs->fpreg[rb],
552 					sizeof(double));
553 				a = (int *)&fs->fpreg[rt];
554 				*a |= (1U << 31);
555 				break;
556 			case	OPC63_FABS:
557 				FPU_EMU_EVCNT_INCR(fabs);
558 				DPRINTF(FPE_INSN, ("fpu_execute: FABS\n"));
559 				memcpy(&fs->fpreg[rt], &fs->fpreg[rb],
560 					sizeof(double));
561 				a = (int *)&fs->fpreg[rt];
562 				*a &= ~(1U << 31);
563 				break;
564 			case	OPC63_MFFS:
565 				FPU_EMU_EVCNT_INCR(mffs);
566 				DPRINTF(FPE_INSN, ("fpu_execute: MFFS\n"));
567 				memcpy(&fs->fpreg[rt], &fs->fpscr,
568 					sizeof(fs->fpscr));
569 				break;
570 			case	OPC63_MTFSF:
571 				FPU_EMU_EVCNT_INCR(mtfsf);
572 				DPRINTF(FPE_INSN, ("fpu_execute: MTFSF\n"));
573 				if ((rt = instr.i_xfl.i_flm) == -1)
574 					mask = -1;
575 				else {
576 					mask = 0;
577 					/* Convert 1 bit -> 4 bits */
578 					for (ra = 0; ra < 8; ra ++)
579 						if (rt & (1<<ra))
580 							mask |= (0xf<<(4*ra));
581 				}
582 				a = (int *)&fs->fpreg[rt];
583 				fe->fe_cx = mask & a[1];
584 				fe->fe_fpscr = (fe->fe_fpscr&~mask) |
585 					(fe->fe_cx);
586 /* XXX weird stuff about OX, FX, FEX, and VX should be handled */
587 				break;
588 			case	OPC63_FCTID:
589 			case	OPC63_FCTIDZ:
590 				FPU_EMU_EVCNT_INCR(fctid);
591 				DPRINTF(FPE_INSN, ("fpu_execute: FCTID\n"));
592 				fpu_explode(fe, fp = &fe->fe_f1, type, rb);
593 				type = FTYPE_LNG;
594 				break;
595 			case	OPC63_FCFID:
596 				FPU_EMU_EVCNT_INCR(fcfid);
597 				DPRINTF(FPE_INSN, ("fpu_execute: FCFID\n"));
598 				type = FTYPE_LNG;
599 				fpu_explode(fe, fp = &fe->fe_f1, type, rb);
600 				type = FTYPE_DBL;
601 				break;
602 			default:
603 				return (NOTFPU);
604 				break;
605 			}
606 		} else {
607 			/* Format A */
608 			rt = instr.i_a.i_frt;
609 			ra = instr.i_a.i_fra;
610 			rb = instr.i_a.i_frb;
611 			rc = instr.i_a.i_frc;
612 
613 			/*
614 			 * All arithmetic operations work on registers, which
615 			 * are stored as doubles.
616 			 */
617 			type = FTYPE_DBL;
618 			switch ((unsigned int)instr.i_a.i_xo) {
619 			case	OPC59_FDIVS:
620 				FPU_EMU_EVCNT_INCR(fdiv);
621 				DPRINTF(FPE_INSN, ("fpu_execute: FDIV\n"));
622 				fpu_explode(fe, &fe->fe_f1, type, ra);
623 				fpu_explode(fe, &fe->fe_f2, type, rb);
624 				fp = fpu_div(fe);
625 				break;
626 			case	OPC59_FSUBS:
627 				FPU_EMU_EVCNT_INCR(fsub);
628 				DPRINTF(FPE_INSN, ("fpu_execute: FSUB\n"));
629 				fpu_explode(fe, &fe->fe_f1, type, ra);
630 				fpu_explode(fe, &fe->fe_f2, type, rb);
631 				fp = fpu_sub(fe);
632 				break;
633 			case	OPC59_FADDS:
634 				FPU_EMU_EVCNT_INCR(fadd);
635 				DPRINTF(FPE_INSN, ("fpu_execute: FADD\n"));
636 				fpu_explode(fe, &fe->fe_f1, type, ra);
637 				fpu_explode(fe, &fe->fe_f2, type, rb);
638 				fp = fpu_add(fe);
639 				break;
640 			case	OPC59_FSQRTS:
641 				FPU_EMU_EVCNT_INCR(fsqrt);
642 				DPRINTF(FPE_INSN, ("fpu_execute: FSQRT\n"));
643 				fpu_explode(fe, &fe->fe_f1, type, rb);
644 				fp = fpu_sqrt(fe);
645 				break;
646 			case	OPC63M_FSEL:
647 				FPU_EMU_EVCNT_INCR(fsel);
648 				DPRINTF(FPE_INSN, ("fpu_execute: FSEL\n"));
649 				a = (int *)&fe->fe_fpstate->fpreg[ra];
650 				if ((*a & 0x80000000) && (*a & 0x7fffffff))
651 					/* fra < 0 */
652 					rc = rb;
653 				DPRINTF(FPE_INSN, ("f%d => f%d\n", rc, rt));
654 				memcpy(&fs->fpreg[rt], &fs->fpreg[rc],
655 					sizeof(double));
656 				break;
657 			case	OPC59_FRES:
658 				FPU_EMU_EVCNT_INCR(fpres);
659 				DPRINTF(FPE_INSN, ("fpu_execute: FPRES\n"));
660 				fpu_explode(fe, &fe->fe_f1, type, rb);
661 				fp = fpu_sqrt(fe);
662 				/* now we've gotta overwrite the dest reg */
663 				*((int *)&fe->fe_fpstate->fpreg[rt]) = 1;
664 				fpu_explode(fe, &fe->fe_f1, FTYPE_INT, rt);
665 				fpu_div(fe);
666 				break;
667 			case	OPC59_FMULS:
668 				FPU_EMU_EVCNT_INCR(fmul);
669 				DPRINTF(FPE_INSN, ("fpu_execute: FMUL\n"));
670 				fpu_explode(fe, &fe->fe_f1, type, ra);
671 				fpu_explode(fe, &fe->fe_f2, type, rc);
672 				fp = fpu_mul(fe);
673 				break;
674 			case	OPC63M_FRSQRTE:
675 				/* Reciprocal sqrt() estimate */
676 				FPU_EMU_EVCNT_INCR(frsqrte);
677 				DPRINTF(FPE_INSN, ("fpu_execute: FRSQRTE\n"));
678 				fpu_explode(fe, &fe->fe_f1, type, rb);
679 				fp = fpu_sqrt(fe);
680 				fe->fe_f2 = *fp;
681 				/* now we've gotta overwrite the dest reg */
682 				*((int *)&fe->fe_fpstate->fpreg[rt]) = 1;
683 				fpu_explode(fe, &fe->fe_f1, FTYPE_INT, rt);
684 				fpu_div(fe);
685 				break;
686 			case	OPC59_FMSUBS:
687 				FPU_EMU_EVCNT_INCR(fmulsub);
688 				DPRINTF(FPE_INSN, ("fpu_execute: FMULSUB\n"));
689 				fpu_explode(fe, &fe->fe_f1, type, ra);
690 				fpu_explode(fe, &fe->fe_f2, type, rc);
691 				fp = fpu_mul(fe);
692 				fe->fe_f1 = *fp;
693 				fpu_explode(fe, &fe->fe_f2, type, rb);
694 				fp = fpu_sub(fe);
695 				break;
696 			case	OPC59_FMADDS:
697 				FPU_EMU_EVCNT_INCR(fmuladd);
698 				DPRINTF(FPE_INSN, ("fpu_execute: FMULADD\n"));
699 				fpu_explode(fe, &fe->fe_f1, type, ra);
700 				fpu_explode(fe, &fe->fe_f2, type, rc);
701 				fp = fpu_mul(fe);
702 				fe->fe_f1 = *fp;
703 				fpu_explode(fe, &fe->fe_f2, type, rb);
704 				fp = fpu_add(fe);
705 				break;
706 			case	OPC59_FNMSUBS:
707 				FPU_EMU_EVCNT_INCR(fnmsub);
708 				DPRINTF(FPE_INSN, ("fpu_execute: FNMSUB\n"));
709 				fpu_explode(fe, &fe->fe_f1, type, ra);
710 				fpu_explode(fe, &fe->fe_f2, type, rc);
711 				fp = fpu_mul(fe);
712 				fe->fe_f1 = *fp;
713 				fpu_explode(fe, &fe->fe_f2, type, rb);
714 				fp = fpu_sub(fe);
715 				/* Negate */
716 				fp->fp_sign ^= 1;
717 				break;
718 			case	OPC59_FNMADDS:
719 				FPU_EMU_EVCNT_INCR(fnmadd);
720 				DPRINTF(FPE_INSN, ("fpu_execute: FNMADD\n"));
721 				fpu_explode(fe, &fe->fe_f1, type, ra);
722 				fpu_explode(fe, &fe->fe_f2, type, rc);
723 				fp = fpu_mul(fe);
724 				fe->fe_f1 = *fp;
725 				fpu_explode(fe, &fe->fe_f2, type, rb);
726 				fp = fpu_add(fe);
727 				/* Negate */
728 				fp->fp_sign ^= 1;
729 				break;
730 			default:
731 				return (NOTFPU);
732 				break;
733 			}
734 
735 			/* If the instruction was single precision, round */
736 			if (!(instr.i_any.i_opcd & 0x4)) {
737 				fpu_implode(fe, fp, FTYPE_SNG,
738 					(u_int *)&fs->fpreg[rt]);
739 				fpu_explode(fe, fp = &fe->fe_f1, FTYPE_SNG, rt);
740 			}
741 		}
742 	} else {
743 		return (NOTFPU);
744 	}
745 
746 	/*
747 	 * ALU operation is complete.  Collapse the result and then check
748 	 * for exceptions.  If we got any, and they are enabled, do not
749 	 * alter the destination register, just stop with an exception.
750 	 * Otherwise set new current exceptions and accrue.
751 	 */
752 	if (fp)
753 		fpu_implode(fe, fp, type, (u_int *)&fs->fpreg[rt]);
754 	cx = fe->fe_cx;
755 	fsr = fe->fe_fpscr;
756 	if (cx != 0) {
757 		fsr &= ~FPSCR_FX;
758 		if ((cx^fsr)&FPSR_EX_MSK)
759 			fsr |= FPSCR_FX;
760 		mask = fsr & FPSR_EX;
761 		mask <<= (25-3);
762 		if (cx & mask)
763 			fsr |= FPSCR_FEX;
764 		if (cx & FPSCR_FPRF) {
765 			/* Need to replace CC */
766 			fsr &= ~FPSCR_FPRF;
767 		}
768 		if (cx & (FPSR_EXOP))
769 			fsr |= FPSCR_VX;
770 		fsr |= cx;
771 		DPRINTF(FPE_INSN, ("fpu_execute: cx %x, fsr %x\n", cx, fsr));
772 	}
773 
774 	if (cond) {
775 		cond = fsr & 0xf0000000;
776 		/* Isolate condition codes */
777 		cond >>= 28;
778 		/* Move fpu condition codes to cr[1] */
779 		tf->cr &= (0x0f000000);
780 		tf->cr |= (cond<<24);
781 		DPRINTF(FPE_INSN, ("fpu_execute: cr[1] <= %x\n", cond));
782 	}
783 
784 	if (setcr) {
785 		cond = fsr & FPSCR_FPCC;
786 		/* Isolate condition codes */
787 		cond <<= 16;
788 		/* Move fpu condition codes to cr[1] */
789 		tf->cr &= ~(0xf0000000>>bf);
790 		tf->cr |= (cond>>bf);
791 		DPRINTF(FPE_INSN, ("fpu_execute: cr[%d] (cr=%jx) <= %x\n",
792 			bf/4, (uintmax_t)tf->cr, cond));
793 	}
794 
795 	((int *)&fs->fpscr)[1] = fsr;
796 	if (fsr & FPSCR_FEX)
797 		return(FPE);
798 	return (0);	/* success */
799 }
800