xref: /freebsd/sys/powerpc/fpu/fpu_emu.c (revision a18eacbefdfa1085ca3db829e86ece78cd416493)
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, ("reg %d has %x reg %d has %x\n",
330 					ra, tf->fixreg[ra], rb, tf->fixreg[rb]));
331 
332 				addr = tf->fixreg[rb];
333 				if (ra != 0)
334 					addr += tf->fixreg[ra];
335 				rt = instr.i_x.i_rt;
336 				a = (int *)&fs->fpreg[rt];
337 				DPRINTF(FPE_INSN,
338 					("fpu_execute: Store INT %x at %p\n",
339 						a[1], (void *)addr));
340 				if (copyout(&a[1], (void *)addr, sizeof(int)))
341 					return (FAULT);
342 				return (0);
343 			}
344 
345 			if ((instr.i_x.i_xo & OPC31_FPMASK) != OPC31_FPOP)
346 				/* Not an indexed FP load/store op */
347 				return (NOTFPU);
348 
349 			store = (instr.i_x.i_xo & 0x80);
350 			if (instr.i_x.i_xo & 0x40)
351 				size = sizeof(double);
352 			else
353 				type = FTYPE_SNG;
354 			update = (instr.i_x.i_xo & 0x20);
355 
356 			/* calculate EA of load/store */
357 			ra = instr.i_x.i_ra;
358 			rb = instr.i_x.i_rb;
359 			DPRINTF(FPE_INSN, ("reg %d has %x reg %d has %x\n",
360 				ra, tf->fixreg[ra], rb, tf->fixreg[rb]));
361 			addr = tf->fixreg[rb];
362 			if (ra != 0)
363 				addr += tf->fixreg[ra];
364 			rt = instr.i_x.i_rt;
365 		} else {
366 			store = instr.i_d.i_opcd & 0x4;
367 			if (instr.i_d.i_opcd & 0x2)
368 				size = sizeof(double);
369 			else
370 				type = FTYPE_SNG;
371 			update = instr.i_d.i_opcd & 0x1;
372 
373 			/* calculate EA of load/store */
374 			ra = instr.i_d.i_ra;
375 			addr = instr.i_d.i_d;
376 			DPRINTF(FPE_INSN, ("reg %d has %x displ %x\n",
377 				ra, tf->fixreg[ra], addr));
378 			if (ra != 0)
379 				addr += tf->fixreg[ra];
380 			rt = instr.i_d.i_rt;
381 		}
382 
383 		if (update && ra == 0)
384 			return (NOTFPU);
385 
386 		if (store) {
387 			/* Store */
388 			FPU_EMU_EVCNT_INCR(fpstore);
389 			if (type != FTYPE_DBL) {
390 				DPRINTF(FPE_INSN,
391 					("fpu_execute: Store SNG at %p\n",
392 						(void *)addr));
393 				fpu_explode(fe, fp = &fe->fe_f1, FTYPE_DBL, rt);
394 				fpu_implode(fe, fp, type, (void *)&buf);
395 				if (copyout(&buf, (void *)addr, size))
396 					return (FAULT);
397 			} else {
398 				DPRINTF(FPE_INSN,
399 					("fpu_execute: Store DBL at %p\n",
400 						(void *)addr));
401 				if (copyout(&fs->fpreg[rt], (void *)addr, size))
402 					return (FAULT);
403 			}
404 		} else {
405 			/* Load */
406 			FPU_EMU_EVCNT_INCR(fpload);
407 			DPRINTF(FPE_INSN, ("fpu_execute: Load from %p\n",
408 				(void *)addr));
409 			if (copyin((const void *)addr, &fs->fpreg[rt], size))
410 				return (FAULT);
411 			if (type != FTYPE_DBL) {
412 				fpu_explode(fe, fp = &fe->fe_f1, type, rt);
413 				fpu_implode(fe, fp, FTYPE_DBL,
414 					(u_int *)&fs->fpreg[rt]);
415 			}
416 		}
417 		if (update)
418 			tf->fixreg[ra] = addr;
419 		/* Complete. */
420 		return (0);
421 #ifdef notyet
422 	} else if (instr.i_any.i_opcd == OPC_load_st_62) {
423 		/* These are 64-bit extenstions */
424 		return (NOTFPU);
425 #endif
426 	} else if (instr.i_any.i_opcd == OPC_sp_fp_59 ||
427 		instr.i_any.i_opcd == OPC_dp_fp_63) {
428 
429 
430 		if (instr.i_any.i_opcd == OPC_dp_fp_63 &&
431 		    !(instr.i_a.i_xo & OPC63M_MASK)) {
432 			/* Format X */
433 			rt = instr.i_x.i_rt;
434 			ra = instr.i_x.i_ra;
435 			rb = instr.i_x.i_rb;
436 
437 
438 			/* One of the special opcodes.... */
439 			switch (instr.i_x.i_xo) {
440 			case	OPC63_FCMPU:
441 				FPU_EMU_EVCNT_INCR(fcmpu);
442 				DPRINTF(FPE_INSN, ("fpu_execute: FCMPU\n"));
443 				rt >>= 2;
444 				fpu_explode(fe, &fe->fe_f1, type, ra);
445 				fpu_explode(fe, &fe->fe_f2, type, rb);
446 				fpu_compare(fe, 0);
447 				/* Make sure we do the condition regs. */
448 				cond = 0;
449 				/* N.B.: i_rs is already left shifted by two. */
450 				bf = instr.i_x.i_rs & 0xfc;
451 				setcr = 1;
452 				break;
453 
454 			case	OPC63_FRSP:
455 				/*
456 				 * Convert to single:
457 				 *
458 				 * PowerPC uses this to round a double
459 				 * precision value to single precision,
460 				 * but values in registers are always
461 				 * stored in double precision format.
462 				 */
463 				FPU_EMU_EVCNT_INCR(frsp);
464 				DPRINTF(FPE_INSN, ("fpu_execute: FRSP\n"));
465 				fpu_explode(fe, fp = &fe->fe_f1, FTYPE_DBL, rb);
466 				fpu_implode(fe, fp, FTYPE_SNG,
467 					(u_int *)&fs->fpreg[rt]);
468 				fpu_explode(fe, fp = &fe->fe_f1, FTYPE_SNG, rt);
469 				type = FTYPE_DBL;
470 				break;
471 			case	OPC63_FCTIW:
472 			case	OPC63_FCTIWZ:
473 				FPU_EMU_EVCNT_INCR(fctiw);
474 				DPRINTF(FPE_INSN, ("fpu_execute: FCTIW\n"));
475 				fpu_explode(fe, fp = &fe->fe_f1, type, rb);
476 				type = FTYPE_INT;
477 				break;
478 			case	OPC63_FCMPO:
479 				FPU_EMU_EVCNT_INCR(fcmpo);
480 				DPRINTF(FPE_INSN, ("fpu_execute: FCMPO\n"));
481 				rt >>= 2;
482 				fpu_explode(fe, &fe->fe_f1, type, ra);
483 				fpu_explode(fe, &fe->fe_f2, type, rb);
484 				fpu_compare(fe, 1);
485 				/* Make sure we do the condition regs. */
486 				cond = 0;
487 				/* N.B.: i_rs is already left shifted by two. */
488 				bf = instr.i_x.i_rs & 0xfc;
489 				setcr = 1;
490 				break;
491 			case	OPC63_MTFSB1:
492 				FPU_EMU_EVCNT_INCR(mtfsb1);
493 				DPRINTF(FPE_INSN, ("fpu_execute: MTFSB1\n"));
494 				fe->fe_fpscr |=
495 					(~(FPSCR_VX|FPSR_EX) & (1<<(31-rt)));
496 				break;
497 			case	OPC63_FNEG:
498 				FPU_EMU_EVCNT_INCR(fnegabs);
499 				DPRINTF(FPE_INSN, ("fpu_execute: FNEGABS\n"));
500 				memcpy(&fs->fpreg[rt], &fs->fpreg[rb],
501 					sizeof(double));
502 				a = (int *)&fs->fpreg[rt];
503 				*a ^= (1 << 31);
504 				break;
505 			case	OPC63_MCRFS:
506 				FPU_EMU_EVCNT_INCR(mcrfs);
507 				DPRINTF(FPE_INSN, ("fpu_execute: MCRFS\n"));
508 				cond = 0;
509 				rt &= 0x1c;
510 				ra &= 0x1c;
511 				/* Extract the bits we want */
512 				mask = (fe->fe_fpscr >> (28 - ra)) & 0xf;
513 				/* Clear the bits we copied. */
514 				fe->fe_cx =
515 					(FPSR_EX_MSK | (0xf << (28 - ra)));
516 				fe->fe_fpscr &= fe->fe_cx;
517 				/* Now shove them in the right part of cr */
518 				tf->cr &= ~(0xf << (28 - rt));
519 				tf->cr |= (mask << (28 - rt));
520 				break;
521 			case	OPC63_MTFSB0:
522 				FPU_EMU_EVCNT_INCR(mtfsb0);
523 				DPRINTF(FPE_INSN, ("fpu_execute: MTFSB0\n"));
524 				fe->fe_fpscr &=
525 					((FPSCR_VX|FPSR_EX) & ~(1<<(31-rt)));
526 				break;
527 			case	OPC63_FMR:
528 				FPU_EMU_EVCNT_INCR(fmr);
529 				DPRINTF(FPE_INSN, ("fpu_execute: FMR\n"));
530 				memcpy(&fs->fpreg[rt], &fs->fpreg[rb],
531 					sizeof(double));
532 				break;
533 			case	OPC63_MTFSFI:
534 				FPU_EMU_EVCNT_INCR(mtfsfi);
535 				DPRINTF(FPE_INSN, ("fpu_execute: MTFSFI\n"));
536 				rb >>= 1;
537 				rt &= 0x1c; /* Already left-shifted 4 */
538 				fe->fe_cx = rb << (28 - rt);
539 				mask = 0xf<<(28 - rt);
540 				fe->fe_fpscr = (fe->fe_fpscr & ~mask) |
541 					fe->fe_cx;
542 /* XXX weird stuff about OX, FX, FEX, and VX should be handled */
543 				break;
544 			case	OPC63_FNABS:
545 				FPU_EMU_EVCNT_INCR(fnabs);
546 				DPRINTF(FPE_INSN, ("fpu_execute: FABS\n"));
547 				memcpy(&fs->fpreg[rt], &fs->fpreg[rb],
548 					sizeof(double));
549 				a = (int *)&fs->fpreg[rt];
550 				*a |= (1 << 31);
551 				break;
552 			case	OPC63_FABS:
553 				FPU_EMU_EVCNT_INCR(fabs);
554 				DPRINTF(FPE_INSN, ("fpu_execute: FABS\n"));
555 				memcpy(&fs->fpreg[rt], &fs->fpreg[rb],
556 					sizeof(double));
557 				a = (int *)&fs->fpreg[rt];
558 				*a &= ~(1 << 31);
559 				break;
560 			case	OPC63_MFFS:
561 				FPU_EMU_EVCNT_INCR(mffs);
562 				DPRINTF(FPE_INSN, ("fpu_execute: MFFS\n"));
563 				memcpy(&fs->fpreg[rt], &fs->fpscr,
564 					sizeof(fs->fpscr));
565 				break;
566 			case	OPC63_MTFSF:
567 				FPU_EMU_EVCNT_INCR(mtfsf);
568 				DPRINTF(FPE_INSN, ("fpu_execute: MTFSF\n"));
569 				if ((rt = instr.i_xfl.i_flm) == -1)
570 					mask = -1;
571 				else {
572 					mask = 0;
573 					/* Convert 1 bit -> 4 bits */
574 					for (ra = 0; ra < 8; ra ++)
575 						if (rt & (1<<ra))
576 							mask |= (0xf<<(4*ra));
577 				}
578 				a = (int *)&fs->fpreg[rt];
579 				fe->fe_cx = mask & a[1];
580 				fe->fe_fpscr = (fe->fe_fpscr&~mask) |
581 					(fe->fe_cx);
582 /* XXX weird stuff about OX, FX, FEX, and VX should be handled */
583 				break;
584 			case	OPC63_FCTID:
585 			case	OPC63_FCTIDZ:
586 				FPU_EMU_EVCNT_INCR(fctid);
587 				DPRINTF(FPE_INSN, ("fpu_execute: FCTID\n"));
588 				fpu_explode(fe, fp = &fe->fe_f1, type, rb);
589 				type = FTYPE_LNG;
590 				break;
591 			case	OPC63_FCFID:
592 				FPU_EMU_EVCNT_INCR(fcfid);
593 				DPRINTF(FPE_INSN, ("fpu_execute: FCFID\n"));
594 				type = FTYPE_LNG;
595 				fpu_explode(fe, fp = &fe->fe_f1, type, rb);
596 				type = FTYPE_DBL;
597 				break;
598 			default:
599 				return (NOTFPU);
600 				break;
601 			}
602 		} else {
603 			/* Format A */
604 			rt = instr.i_a.i_frt;
605 			ra = instr.i_a.i_fra;
606 			rb = instr.i_a.i_frb;
607 			rc = instr.i_a.i_frc;
608 
609 			/*
610 			 * All arithmetic operations work on registers, which
611 			 * are stored as doubles.
612 			 */
613 			type = FTYPE_DBL;
614 			switch ((unsigned int)instr.i_a.i_xo) {
615 			case	OPC59_FDIVS:
616 				FPU_EMU_EVCNT_INCR(fdiv);
617 				DPRINTF(FPE_INSN, ("fpu_execute: FDIV\n"));
618 				fpu_explode(fe, &fe->fe_f1, type, ra);
619 				fpu_explode(fe, &fe->fe_f2, type, rb);
620 				fp = fpu_div(fe);
621 				break;
622 			case	OPC59_FSUBS:
623 				FPU_EMU_EVCNT_INCR(fsub);
624 				DPRINTF(FPE_INSN, ("fpu_execute: FSUB\n"));
625 				fpu_explode(fe, &fe->fe_f1, type, ra);
626 				fpu_explode(fe, &fe->fe_f2, type, rb);
627 				fp = fpu_sub(fe);
628 				break;
629 			case	OPC59_FADDS:
630 				FPU_EMU_EVCNT_INCR(fadd);
631 				DPRINTF(FPE_INSN, ("fpu_execute: FADD\n"));
632 				fpu_explode(fe, &fe->fe_f1, type, ra);
633 				fpu_explode(fe, &fe->fe_f2, type, rb);
634 				fp = fpu_add(fe);
635 				break;
636 			case	OPC59_FSQRTS:
637 				FPU_EMU_EVCNT_INCR(fsqrt);
638 				DPRINTF(FPE_INSN, ("fpu_execute: FSQRT\n"));
639 				fpu_explode(fe, &fe->fe_f1, type, rb);
640 				fp = fpu_sqrt(fe);
641 				break;
642 			case	OPC63M_FSEL:
643 				FPU_EMU_EVCNT_INCR(fsel);
644 				DPRINTF(FPE_INSN, ("fpu_execute: FSEL\n"));
645 				a = (int *)&fe->fe_fpstate->fpreg[ra];
646 				if ((*a & 0x80000000) && (*a & 0x7fffffff))
647 					/* fra < 0 */
648 					rc = rb;
649 				DPRINTF(FPE_INSN, ("f%d => f%d\n", rc, rt));
650 				memcpy(&fs->fpreg[rt], &fs->fpreg[rc],
651 					sizeof(double));
652 				break;
653 			case	OPC59_FRES:
654 				FPU_EMU_EVCNT_INCR(fpres);
655 				DPRINTF(FPE_INSN, ("fpu_execute: FPRES\n"));
656 				fpu_explode(fe, &fe->fe_f1, type, rb);
657 				fp = fpu_sqrt(fe);
658 				/* now we've gotta overwrite the dest reg */
659 				*((int *)&fe->fe_fpstate->fpreg[rt]) = 1;
660 				fpu_explode(fe, &fe->fe_f1, FTYPE_INT, rt);
661 				fpu_div(fe);
662 				break;
663 			case	OPC59_FMULS:
664 				FPU_EMU_EVCNT_INCR(fmul);
665 				DPRINTF(FPE_INSN, ("fpu_execute: FMUL\n"));
666 				fpu_explode(fe, &fe->fe_f1, type, ra);
667 				fpu_explode(fe, &fe->fe_f2, type, rc);
668 				fp = fpu_mul(fe);
669 				break;
670 			case	OPC63M_FRSQRTE:
671 				/* Reciprocal sqrt() estimate */
672 				FPU_EMU_EVCNT_INCR(frsqrte);
673 				DPRINTF(FPE_INSN, ("fpu_execute: FRSQRTE\n"));
674 				fpu_explode(fe, &fe->fe_f1, type, rb);
675 				fp = fpu_sqrt(fe);
676 				fe->fe_f2 = *fp;
677 				/* now we've gotta overwrite the dest reg */
678 				*((int *)&fe->fe_fpstate->fpreg[rt]) = 1;
679 				fpu_explode(fe, &fe->fe_f1, FTYPE_INT, rt);
680 				fpu_div(fe);
681 				break;
682 			case	OPC59_FMSUBS:
683 				FPU_EMU_EVCNT_INCR(fmulsub);
684 				DPRINTF(FPE_INSN, ("fpu_execute: FMULSUB\n"));
685 				fpu_explode(fe, &fe->fe_f1, type, ra);
686 				fpu_explode(fe, &fe->fe_f2, type, rc);
687 				fp = fpu_mul(fe);
688 				fe->fe_f1 = *fp;
689 				fpu_explode(fe, &fe->fe_f2, type, rb);
690 				fp = fpu_sub(fe);
691 				break;
692 			case	OPC59_FMADDS:
693 				FPU_EMU_EVCNT_INCR(fmuladd);
694 				DPRINTF(FPE_INSN, ("fpu_execute: FMULADD\n"));
695 				fpu_explode(fe, &fe->fe_f1, type, ra);
696 				fpu_explode(fe, &fe->fe_f2, type, rc);
697 				fp = fpu_mul(fe);
698 				fe->fe_f1 = *fp;
699 				fpu_explode(fe, &fe->fe_f2, type, rb);
700 				fp = fpu_add(fe);
701 				break;
702 			case	OPC59_FNMSUBS:
703 				FPU_EMU_EVCNT_INCR(fnmsub);
704 				DPRINTF(FPE_INSN, ("fpu_execute: FNMSUB\n"));
705 				fpu_explode(fe, &fe->fe_f1, type, ra);
706 				fpu_explode(fe, &fe->fe_f2, type, rc);
707 				fp = fpu_mul(fe);
708 				fe->fe_f1 = *fp;
709 				fpu_explode(fe, &fe->fe_f2, type, rb);
710 				fp = fpu_sub(fe);
711 				/* Negate */
712 				fp->fp_sign ^= 1;
713 				break;
714 			case	OPC59_FNMADDS:
715 				FPU_EMU_EVCNT_INCR(fnmadd);
716 				DPRINTF(FPE_INSN, ("fpu_execute: FNMADD\n"));
717 				fpu_explode(fe, &fe->fe_f1, type, ra);
718 				fpu_explode(fe, &fe->fe_f2, type, rc);
719 				fp = fpu_mul(fe);
720 				fe->fe_f1 = *fp;
721 				fpu_explode(fe, &fe->fe_f2, type, rb);
722 				fp = fpu_add(fe);
723 				/* Negate */
724 				fp->fp_sign ^= 1;
725 				break;
726 			default:
727 				return (NOTFPU);
728 				break;
729 			}
730 
731 			/* If the instruction was single precision, round */
732 			if (!(instr.i_any.i_opcd & 0x4)) {
733 				fpu_implode(fe, fp, FTYPE_SNG,
734 					(u_int *)&fs->fpreg[rt]);
735 				fpu_explode(fe, fp = &fe->fe_f1, FTYPE_SNG, rt);
736 			}
737 		}
738 	} else {
739 		return (NOTFPU);
740 	}
741 
742 	/*
743 	 * ALU operation is complete.  Collapse the result and then check
744 	 * for exceptions.  If we got any, and they are enabled, do not
745 	 * alter the destination register, just stop with an exception.
746 	 * Otherwise set new current exceptions and accrue.
747 	 */
748 	if (fp)
749 		fpu_implode(fe, fp, type, (u_int *)&fs->fpreg[rt]);
750 	cx = fe->fe_cx;
751 	fsr = fe->fe_fpscr;
752 	if (cx != 0) {
753 		fsr &= ~FPSCR_FX;
754 		if ((cx^fsr)&FPSR_EX_MSK)
755 			fsr |= FPSCR_FX;
756 		mask = fsr & FPSR_EX;
757 		mask <<= (25-3);
758 		if (cx & mask)
759 			fsr |= FPSCR_FEX;
760 		if (cx & FPSCR_FPRF) {
761 			/* Need to replace CC */
762 			fsr &= ~FPSCR_FPRF;
763 		}
764 		if (cx & (FPSR_EXOP))
765 			fsr |= FPSCR_VX;
766 		fsr |= cx;
767 		DPRINTF(FPE_INSN, ("fpu_execute: cx %x, fsr %x\n", cx, fsr));
768 	}
769 
770 	if (cond) {
771 		cond = fsr & 0xf0000000;
772 		/* Isolate condition codes */
773 		cond >>= 28;
774 		/* Move fpu condition codes to cr[1] */
775 		tf->cr &= (0x0f000000);
776 		tf->cr |= (cond<<24);
777 		DPRINTF(FPE_INSN, ("fpu_execute: cr[1] <= %x\n", cond));
778 	}
779 
780 	if (setcr) {
781 		cond = fsr & FPSCR_FPCC;
782 		/* Isolate condition codes */
783 		cond <<= 16;
784 		/* Move fpu condition codes to cr[1] */
785 		tf->cr &= ~(0xf0000000>>bf);
786 		tf->cr |= (cond>>bf);
787 		DPRINTF(FPE_INSN, ("fpu_execute: cr[%d] (cr=%x) <= %x\n", bf/4, tf->cr, cond));
788 	}
789 
790 	((int *)&fs->fpscr)[1] = fsr;
791 	if (fsr & FPSCR_FEX)
792 		return(FPE);
793 	return (0);	/* success */
794 }
795