xref: /freebsd/sys/powerpc/fpu/fpu_emu.c (revision 5ab1c5846ff41be24b1f6beb0317bf8258cd4409)
1 /*	$NetBSD: fpu_emu.c,v 1.14 2005/12/11 12:18:42 christos Exp $ */
2 
3 /*-
4  * SPDX-License-Identifier: BSD-4-Clause
5  *
6  * Copyright 2001 Wasabi Systems, Inc.
7  * All rights reserved.
8  *
9  * Written by Eduardo Horvath and Simon Burge for Wasabi Systems, Inc.
10  *
11  * Redistribution and use in source and binary forms, with or without
12  * modification, are permitted provided that the following conditions
13  * are met:
14  * 1. Redistributions of source code must retain the above copyright
15  *    notice, this list of conditions and the following disclaimer.
16  * 2. Redistributions in binary form must reproduce the above copyright
17  *    notice, this list of conditions and the following disclaimer in the
18  *    documentation and/or other materials provided with the distribution.
19  * 3. All advertising materials mentioning features or use of this software
20  *    must display the following acknowledgement:
21  *      This product includes software developed for the NetBSD Project by
22  *      Wasabi Systems, Inc.
23  * 4. The name of Wasabi Systems, Inc. may not be used to endorse
24  *    or promote products derived from this software without specific prior
25  *    written permission.
26  *
27  * THIS SOFTWARE IS PROVIDED BY WASABI SYSTEMS, INC. ``AS IS'' AND
28  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
29  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
30  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL WASABI SYSTEMS, INC
31  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
32  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
33  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
34  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
35  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
36  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
37  * POSSIBILITY OF SUCH DAMAGE.
38  */
39 
40 /*
41  * Copyright (c) 1992, 1993
42  *	The Regents of the University of California.  All rights reserved.
43  *
44  * This software was developed by the Computer Systems Engineering group
45  * at Lawrence Berkeley Laboratory under DARPA contract BG 91-66 and
46  * contributed to Berkeley.
47  *
48  * All advertising materials mentioning features or use of this software
49  * must display the following acknowledgement:
50  *	This product includes software developed by the University of
51  *	California, Lawrence Berkeley Laboratory.
52  *
53  * Redistribution and use in source and binary forms, with or without
54  * modification, are permitted provided that the following conditions
55  * are met:
56  * 1. Redistributions of source code must retain the above copyright
57  *    notice, this list of conditions and the following disclaimer.
58  * 2. Redistributions in binary form must reproduce the above copyright
59  *    notice, this list of conditions and the following disclaimer in the
60  *    documentation and/or other materials provided with the distribution.
61  * 3. Neither the name of the University nor the names of its contributors
62  *    may be used to endorse or promote products derived from this software
63  *    without specific prior written permission.
64  *
65  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
66  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
67  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
68  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
69  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
70  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
71  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
72  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
73  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
74  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
75  * SUCH DAMAGE.
76  *
77  *	@(#)fpu.c	8.1 (Berkeley) 6/11/93
78  */
79 
80 #include <sys/cdefs.h>
81 __FBSDID("$FreeBSD$");
82 
83 #include "opt_ddb.h"
84 
85 #include <sys/param.h>
86 #include <sys/systm.h>
87 #include <sys/kdb.h>
88 #include <sys/kernel.h>
89 #include <sys/proc.h>
90 #include <sys/sysctl.h>
91 #include <sys/signal.h>
92 #include <sys/syslog.h>
93 #include <sys/signalvar.h>
94 
95 #include <machine/fpu.h>
96 #include <machine/reg.h>
97 
98 #include <powerpc/fpu/fpu_emu.h>
99 #include <powerpc/fpu/fpu_extern.h>
100 #include <powerpc/fpu/fpu_instr.h>
101 
102 static SYSCTL_NODE(_hw, OID_AUTO, fpu_emu, CTLFLAG_RW, 0, "FPU emulator");
103 
104 #define	FPU_EMU_EVCNT_DECL(name)					\
105 static u_int fpu_emu_evcnt_##name;					\
106 SYSCTL_INT(_hw_fpu_emu, OID_AUTO, evcnt_##name, CTLFLAG_RD,		\
107     &fpu_emu_evcnt_##name, 0, "")
108 
109 #define	FPU_EMU_EVCNT_INCR(name)	fpu_emu_evcnt_##name++
110 
111 FPU_EMU_EVCNT_DECL(stfiwx);
112 FPU_EMU_EVCNT_DECL(fpstore);
113 FPU_EMU_EVCNT_DECL(fpload);
114 FPU_EMU_EVCNT_DECL(fcmpu);
115 FPU_EMU_EVCNT_DECL(frsp);
116 FPU_EMU_EVCNT_DECL(fctiw);
117 FPU_EMU_EVCNT_DECL(fcmpo);
118 FPU_EMU_EVCNT_DECL(mtfsb1);
119 FPU_EMU_EVCNT_DECL(fnegabs);
120 FPU_EMU_EVCNT_DECL(mcrfs);
121 FPU_EMU_EVCNT_DECL(mtfsb0);
122 FPU_EMU_EVCNT_DECL(fmr);
123 FPU_EMU_EVCNT_DECL(mtfsfi);
124 FPU_EMU_EVCNT_DECL(fnabs);
125 FPU_EMU_EVCNT_DECL(fabs);
126 FPU_EMU_EVCNT_DECL(mffs);
127 FPU_EMU_EVCNT_DECL(mtfsf);
128 FPU_EMU_EVCNT_DECL(fctid);
129 FPU_EMU_EVCNT_DECL(fcfid);
130 FPU_EMU_EVCNT_DECL(fdiv);
131 FPU_EMU_EVCNT_DECL(fsub);
132 FPU_EMU_EVCNT_DECL(fadd);
133 FPU_EMU_EVCNT_DECL(fsqrt);
134 FPU_EMU_EVCNT_DECL(fsel);
135 FPU_EMU_EVCNT_DECL(fpres);
136 FPU_EMU_EVCNT_DECL(fmul);
137 FPU_EMU_EVCNT_DECL(frsqrte);
138 FPU_EMU_EVCNT_DECL(fmulsub);
139 FPU_EMU_EVCNT_DECL(fmuladd);
140 FPU_EMU_EVCNT_DECL(fnmsub);
141 FPU_EMU_EVCNT_DECL(fnmadd);
142 
143 /* FPSR exception masks */
144 #define FPSR_EX_MSK	(FPSCR_VX|FPSCR_OX|FPSCR_UX|FPSCR_ZX|		\
145 			FPSCR_XX|FPSCR_VXSNAN|FPSCR_VXISI|FPSCR_VXIDI|	\
146 			FPSCR_VXZDZ|FPSCR_VXIMZ|FPSCR_VXVC|FPSCR_VXSOFT|\
147 			FPSCR_VXSQRT|FPSCR_VXCVI)
148 #define	FPSR_EX		(FPSCR_VE|FPSCR_OE|FPSCR_UE|FPSCR_ZE|FPSCR_XE)
149 #define	FPSR_EXOP	(FPSR_EX_MSK&(~FPSR_EX))
150 
151 int fpe_debug = 0;
152 
153 #ifdef DEBUG
154 vm_offset_t opc_disasm(vm_offset_t, int);
155 
156 /*
157  * Dump a `fpn' structure.
158  */
159 void
160 fpu_dumpfpn(struct fpn *fp)
161 {
162 	static const char *class[] = {
163 		"SNAN", "QNAN", "ZERO", "NUM", "INF"
164 	};
165 
166 	printf("%s %c.%x %x %x %xE%d", class[fp->fp_class + 2],
167 		fp->fp_sign ? '-' : ' ',
168 		fp->fp_mant[0],	fp->fp_mant[1],
169 		fp->fp_mant[2], fp->fp_mant[3],
170 		fp->fp_exp);
171 }
172 #endif
173 
174 /*
175  * fpu_execute returns the following error numbers (0 = no error):
176  */
177 #define	FPE		1	/* take a floating point exception */
178 #define	NOTFPU		2	/* not an FPU instruction */
179 #define	FAULT		3
180 
181 
182 /*
183  * Emulate a floating-point instruction.
184  * Return zero for success, else signal number.
185  * (Typically: zero, SIGFPE, SIGILL, SIGSEGV)
186  */
187 int
188 fpu_emulate(struct trapframe *frame, struct fpu *fpf)
189 {
190 	union instr insn;
191 	struct fpemu fe;
192 	int sig;
193 
194 	/* initialize insn.is_datasize to tell it is *not* initialized */
195 	fe.fe_fpstate = fpf;
196 	fe.fe_cx = 0;
197 
198 	/* always set this (to avoid a warning) */
199 
200 	if (copyin((void *) (frame->srr0), &insn.i_int, sizeof (insn.i_int))) {
201 #ifdef DEBUG
202 		printf("fpu_emulate: fault reading opcode\n");
203 #endif
204 		return SIGSEGV;
205 	}
206 
207 	DPRINTF(FPE_EX, ("fpu_emulate: emulating insn %x at %p\n",
208 	    insn.i_int, (void *)frame->srr0));
209 
210 
211 	if ((insn.i_any.i_opcd == OPC_TWI) ||
212 	    ((insn.i_any.i_opcd == OPC_integer_31) &&
213 	    (insn.i_x.i_xo == OPC31_TW))) {
214 		/* Check for the two trap insns. */
215 		DPRINTF(FPE_EX, ("fpu_emulate: SIGTRAP\n"));
216 		return (SIGTRAP);
217 	}
218 	sig = 0;
219 	switch (fpu_execute(frame, &fe, &insn)) {
220 	case 0:
221 		DPRINTF(FPE_EX, ("fpu_emulate: success\n"));
222 		frame->srr0 += 4;
223 		break;
224 
225 	case FPE:
226 		DPRINTF(FPE_EX, ("fpu_emulate: SIGFPE\n"));
227 		sig = SIGFPE;
228 		break;
229 
230 	case FAULT:
231 		DPRINTF(FPE_EX, ("fpu_emulate: SIGSEGV\n"));
232 		sig = SIGSEGV;
233 		break;
234 
235 	case NOTFPU:
236 	default:
237 		DPRINTF(FPE_EX, ("fpu_emulate: SIGILL\n"));
238 #ifdef DEBUG
239 		if (fpe_debug & FPE_EX) {
240 			printf("fpu_emulate:  illegal insn %x at %p:",
241 			insn.i_int, (void *) (frame->srr0));
242 			opc_disasm(frame->srr0, insn.i_int);
243 		}
244 #endif
245 		sig = SIGILL;
246 #ifdef DEBUG
247 		if (fpe_debug & FPE_EX)
248 			kdb_enter(KDB_WHY_UNSET, "illegal instruction");
249 #endif
250 		break;
251 	}
252 
253 	return (sig);
254 }
255 
256 /*
257  * Execute an FPU instruction (one that runs entirely in the FPU; not
258  * FBfcc or STF, for instance).  On return, fe->fe_fs->fs_fsr will be
259  * modified to reflect the setting the hardware would have left.
260  *
261  * Note that we do not catch all illegal opcodes, so you can, for instance,
262  * multiply two integers this way.
263  */
264 int
265 fpu_execute(struct trapframe *tf, struct fpemu *fe, union instr *insn)
266 {
267 	struct fpn *fp;
268 	union instr instr = *insn;
269 	int *a;
270 	vm_offset_t addr;
271 	int ra, rb, rc, rt, type, mask, fsr, cx, bf, setcr;
272 	unsigned int cond;
273 	struct fpu *fs;
274 
275 	/* Setup work. */
276 	fp = NULL;
277 	fs = fe->fe_fpstate;
278 	fe->fe_fpscr = ((int *)&fs->fpscr)[1];
279 
280 	/*
281 	 * On PowerPC all floating point values are stored in registers
282 	 * as doubles, even when used for single precision operations.
283 	 */
284 	type = FTYPE_DBL;
285 	cond = instr.i_any.i_rc;
286 	setcr = 0;
287 	bf = 0;	/* XXX gcc */
288 
289 #if defined(DDB) && defined(DEBUG)
290 	if (fpe_debug & FPE_EX) {
291 		vm_offset_t loc = tf->srr0;
292 
293 		printf("Trying to emulate: %p ", (void *)loc);
294 		opc_disasm(loc, instr.i_int);
295 	}
296 #endif
297 
298 	/*
299 	 * `Decode' and execute instruction.
300 	 */
301 
302 	if ((instr.i_any.i_opcd >= OPC_LFS && instr.i_any.i_opcd <= OPC_STFDU) ||
303 	    instr.i_any.i_opcd == OPC_integer_31) {
304 		/*
305 		 * Handle load/store insns:
306 		 *
307 		 * Convert to/from single if needed, calculate addr,
308 		 * and update index reg if needed.
309 		 */
310 		double buf;
311 		size_t size = sizeof(float);
312 		int store, update;
313 
314 		cond = 0; /* ld/st never set condition codes */
315 
316 
317 		if (instr.i_any.i_opcd == OPC_integer_31) {
318 			if (instr.i_x.i_xo == OPC31_STFIWX) {
319 				FPU_EMU_EVCNT_INCR(stfiwx);
320 
321 				/* Store as integer */
322 				ra = instr.i_x.i_ra;
323 				rb = instr.i_x.i_rb;
324 				DPRINTF(FPE_INSN,
325 					("reg %d has %jx reg %d has %jx\n",
326 					ra, (uintmax_t)tf->fixreg[ra], rb,
327 					(uintmax_t)tf->fixreg[rb]));
328 
329 				addr = tf->fixreg[rb];
330 				if (ra != 0)
331 					addr += tf->fixreg[ra];
332 				rt = instr.i_x.i_rt;
333 				a = (int *)&fs->fpr[rt].fpr;
334 				DPRINTF(FPE_INSN,
335 					("fpu_execute: Store INT %x at %p\n",
336 						a[1], (void *)addr));
337 				if (copyout(&a[1], (void *)addr, sizeof(int)))
338 					return (FAULT);
339 				return (0);
340 			}
341 
342 			if ((instr.i_x.i_xo & OPC31_FPMASK) != OPC31_FPOP)
343 				/* Not an indexed FP load/store op */
344 				return (NOTFPU);
345 
346 			store = (instr.i_x.i_xo & 0x80);
347 			if (instr.i_x.i_xo & 0x40)
348 				size = sizeof(double);
349 			else
350 				type = FTYPE_SNG;
351 			update = (instr.i_x.i_xo & 0x20);
352 
353 			/* calculate EA of load/store */
354 			ra = instr.i_x.i_ra;
355 			rb = instr.i_x.i_rb;
356 			DPRINTF(FPE_INSN, ("reg %d has %jx reg %d has %jx\n",
357 				ra, (uintmax_t)tf->fixreg[ra], rb,
358 				(uintmax_t)tf->fixreg[rb]));
359 			addr = tf->fixreg[rb];
360 			if (ra != 0)
361 				addr += tf->fixreg[ra];
362 			rt = instr.i_x.i_rt;
363 		} else {
364 			store = instr.i_d.i_opcd & 0x4;
365 			if (instr.i_d.i_opcd & 0x2)
366 				size = sizeof(double);
367 			else
368 				type = FTYPE_SNG;
369 			update = instr.i_d.i_opcd & 0x1;
370 
371 			/* calculate EA of load/store */
372 			ra = instr.i_d.i_ra;
373 			addr = instr.i_d.i_d;
374 			DPRINTF(FPE_INSN, ("reg %d has %jx displ %jx\n",
375 				ra, (uintmax_t)tf->fixreg[ra],
376 				(uintmax_t)addr));
377 			if (ra != 0)
378 				addr += tf->fixreg[ra];
379 			rt = instr.i_d.i_rt;
380 		}
381 
382 		if (update && ra == 0)
383 			return (NOTFPU);
384 
385 		if (store) {
386 			/* Store */
387 			FPU_EMU_EVCNT_INCR(fpstore);
388 			if (type != FTYPE_DBL) {
389 				DPRINTF(FPE_INSN,
390 					("fpu_execute: Store SNG at %p\n",
391 						(void *)addr));
392 				fpu_explode(fe, fp = &fe->fe_f1, FTYPE_DBL, rt);
393 				fpu_implode(fe, fp, type, (void *)&buf);
394 				if (copyout(&buf, (void *)addr, size))
395 					return (FAULT);
396 			} else {
397 				DPRINTF(FPE_INSN,
398 					("fpu_execute: Store DBL at %p\n",
399 						(void *)addr));
400 				if (copyout(&fs->fpr[rt].fpr, (void *)addr,
401 				    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->fpr[rt].fpr,
410 			    size))
411 				return (FAULT);
412 			if (type != FTYPE_DBL) {
413 				fpu_explode(fe, fp = &fe->fe_f1, type, rt);
414 				fpu_implode(fe, fp, FTYPE_DBL,
415 					(u_int *)&fs->fpr[rt].fpr);
416 			}
417 		}
418 		if (update)
419 			tf->fixreg[ra] = addr;
420 		/* Complete. */
421 		return (0);
422 #ifdef notyet
423 	} else if (instr.i_any.i_opcd == OPC_load_st_62) {
424 		/* These are 64-bit extensions */
425 		return (NOTFPU);
426 #endif
427 	} else if (instr.i_any.i_opcd == OPC_sp_fp_59 ||
428 		instr.i_any.i_opcd == OPC_dp_fp_63) {
429 
430 
431 		if (instr.i_any.i_opcd == OPC_dp_fp_63 &&
432 		    !(instr.i_a.i_xo & OPC63M_MASK)) {
433 			/* Format X */
434 			rt = instr.i_x.i_rt;
435 			ra = instr.i_x.i_ra;
436 			rb = instr.i_x.i_rb;
437 
438 
439 			/* One of the special opcodes.... */
440 			switch (instr.i_x.i_xo) {
441 			case	OPC63_FCMPU:
442 				FPU_EMU_EVCNT_INCR(fcmpu);
443 				DPRINTF(FPE_INSN, ("fpu_execute: FCMPU\n"));
444 				rt >>= 2;
445 				fpu_explode(fe, &fe->fe_f1, type, ra);
446 				fpu_explode(fe, &fe->fe_f2, type, rb);
447 				fpu_compare(fe, 0);
448 				/* Make sure we do the condition regs. */
449 				cond = 0;
450 				/* N.B.: i_rs is already left shifted by two. */
451 				bf = instr.i_x.i_rs & 0xfc;
452 				setcr = 1;
453 				break;
454 
455 			case	OPC63_FRSP:
456 				/*
457 				 * Convert to single:
458 				 *
459 				 * PowerPC uses this to round a double
460 				 * precision value to single precision,
461 				 * but values in registers are always
462 				 * stored in double precision format.
463 				 */
464 				FPU_EMU_EVCNT_INCR(frsp);
465 				DPRINTF(FPE_INSN, ("fpu_execute: FRSP\n"));
466 				fpu_explode(fe, fp = &fe->fe_f1, FTYPE_DBL, rb);
467 				fpu_implode(fe, fp, FTYPE_SNG,
468 					(u_int *)&fs->fpr[rt].fpr);
469 				fpu_explode(fe, fp = &fe->fe_f1, FTYPE_SNG, rt);
470 				type = FTYPE_DBL;
471 				break;
472 			case	OPC63_FCTIW:
473 			case	OPC63_FCTIWZ:
474 				FPU_EMU_EVCNT_INCR(fctiw);
475 				DPRINTF(FPE_INSN, ("fpu_execute: FCTIW\n"));
476 				fpu_explode(fe, fp = &fe->fe_f1, type, rb);
477 				type = FTYPE_INT;
478 				break;
479 			case	OPC63_FCMPO:
480 				FPU_EMU_EVCNT_INCR(fcmpo);
481 				DPRINTF(FPE_INSN, ("fpu_execute: FCMPO\n"));
482 				rt >>= 2;
483 				fpu_explode(fe, &fe->fe_f1, type, ra);
484 				fpu_explode(fe, &fe->fe_f2, type, rb);
485 				fpu_compare(fe, 1);
486 				/* Make sure we do the condition regs. */
487 				cond = 0;
488 				/* N.B.: i_rs is already left shifted by two. */
489 				bf = instr.i_x.i_rs & 0xfc;
490 				setcr = 1;
491 				break;
492 			case	OPC63_MTFSB1:
493 				FPU_EMU_EVCNT_INCR(mtfsb1);
494 				DPRINTF(FPE_INSN, ("fpu_execute: MTFSB1\n"));
495 				fe->fe_fpscr |=
496 					(~(FPSCR_VX|FPSR_EX) & (1<<(31-rt)));
497 				break;
498 			case	OPC63_FNEG:
499 				FPU_EMU_EVCNT_INCR(fnegabs);
500 				DPRINTF(FPE_INSN, ("fpu_execute: FNEGABS\n"));
501 				memcpy(&fs->fpr[rt].fpr, &fs->fpr[rb].fpr,
502 					sizeof(double));
503 				a = (int *)&fs->fpr[rt].fpr;
504 				*a ^= (1U << 31);
505 				break;
506 			case	OPC63_MCRFS:
507 				FPU_EMU_EVCNT_INCR(mcrfs);
508 				DPRINTF(FPE_INSN, ("fpu_execute: MCRFS\n"));
509 				cond = 0;
510 				rt &= 0x1c;
511 				ra &= 0x1c;
512 				/* Extract the bits we want */
513 				mask = (fe->fe_fpscr >> (28 - ra)) & 0xf;
514 				/* Clear the bits we copied. */
515 				fe->fe_cx =
516 					(FPSR_EX_MSK | (0xf << (28 - ra)));
517 				fe->fe_fpscr &= fe->fe_cx;
518 				/* Now shove them in the right part of cr */
519 				tf->cr &= ~(0xf << (28 - rt));
520 				tf->cr |= (mask << (28 - rt));
521 				break;
522 			case	OPC63_MTFSB0:
523 				FPU_EMU_EVCNT_INCR(mtfsb0);
524 				DPRINTF(FPE_INSN, ("fpu_execute: MTFSB0\n"));
525 				fe->fe_fpscr &=
526 					((FPSCR_VX|FPSR_EX) & ~(1<<(31-rt)));
527 				break;
528 			case	OPC63_FMR:
529 				FPU_EMU_EVCNT_INCR(fmr);
530 				DPRINTF(FPE_INSN, ("fpu_execute: FMR\n"));
531 				memcpy(&fs->fpr[rt].fpr, &fs->fpr[rb].fpr,
532 					sizeof(double));
533 				break;
534 			case	OPC63_MTFSFI:
535 				FPU_EMU_EVCNT_INCR(mtfsfi);
536 				DPRINTF(FPE_INSN, ("fpu_execute: MTFSFI\n"));
537 				rb >>= 1;
538 				rt &= 0x1c; /* Already left-shifted 4 */
539 				fe->fe_cx = rb << (28 - rt);
540 				mask = 0xf<<(28 - rt);
541 				fe->fe_fpscr = (fe->fe_fpscr & ~mask) |
542 					fe->fe_cx;
543 /* XXX weird stuff about OX, FX, FEX, and VX should be handled */
544 				break;
545 			case	OPC63_FNABS:
546 				FPU_EMU_EVCNT_INCR(fnabs);
547 				DPRINTF(FPE_INSN, ("fpu_execute: FABS\n"));
548 				memcpy(&fs->fpr[rt].fpr, &fs->fpr[rb].fpr,
549 					sizeof(double));
550 				a = (int *)&fs->fpr[rt].fpr;
551 				*a |= (1U << 31);
552 				break;
553 			case	OPC63_FABS:
554 				FPU_EMU_EVCNT_INCR(fabs);
555 				DPRINTF(FPE_INSN, ("fpu_execute: FABS\n"));
556 				memcpy(&fs->fpr[rt].fpr, &fs->fpr[rb].fpr,
557 					sizeof(double));
558 				a = (int *)&fs->fpr[rt].fpr;
559 				*a &= ~(1U << 31);
560 				break;
561 			case	OPC63_MFFS:
562 				FPU_EMU_EVCNT_INCR(mffs);
563 				DPRINTF(FPE_INSN, ("fpu_execute: MFFS\n"));
564 				memcpy(&fs->fpr[rt].fpr, &fs->fpscr,
565 					sizeof(fs->fpscr));
566 				break;
567 			case	OPC63_MTFSF:
568 				FPU_EMU_EVCNT_INCR(mtfsf);
569 				DPRINTF(FPE_INSN, ("fpu_execute: MTFSF\n"));
570 				if ((rt = instr.i_xfl.i_flm) == -1)
571 					mask = -1;
572 				else {
573 					mask = 0;
574 					/* Convert 1 bit -> 4 bits */
575 					for (ra = 0; ra < 8; ra ++)
576 						if (rt & (1<<ra))
577 							mask |= (0xf<<(4*ra));
578 				}
579 				a = (int *)&fs->fpr[rt].fpr;
580 				fe->fe_cx = mask & a[1];
581 				fe->fe_fpscr = (fe->fe_fpscr&~mask) |
582 					(fe->fe_cx);
583 /* XXX weird stuff about OX, FX, FEX, and VX should be handled */
584 				break;
585 			case	OPC63_FCTID:
586 			case	OPC63_FCTIDZ:
587 				FPU_EMU_EVCNT_INCR(fctid);
588 				DPRINTF(FPE_INSN, ("fpu_execute: FCTID\n"));
589 				fpu_explode(fe, fp = &fe->fe_f1, type, rb);
590 				type = FTYPE_LNG;
591 				break;
592 			case	OPC63_FCFID:
593 				FPU_EMU_EVCNT_INCR(fcfid);
594 				DPRINTF(FPE_INSN, ("fpu_execute: FCFID\n"));
595 				type = FTYPE_LNG;
596 				fpu_explode(fe, fp = &fe->fe_f1, type, rb);
597 				type = FTYPE_DBL;
598 				break;
599 			default:
600 				return (NOTFPU);
601 				break;
602 			}
603 		} else {
604 			/* Format A */
605 			rt = instr.i_a.i_frt;
606 			ra = instr.i_a.i_fra;
607 			rb = instr.i_a.i_frb;
608 			rc = instr.i_a.i_frc;
609 
610 			/*
611 			 * All arithmetic operations work on registers, which
612 			 * are stored as doubles.
613 			 */
614 			type = FTYPE_DBL;
615 			switch ((unsigned int)instr.i_a.i_xo) {
616 			case	OPC59_FDIVS:
617 				FPU_EMU_EVCNT_INCR(fdiv);
618 				DPRINTF(FPE_INSN, ("fpu_execute: FDIV\n"));
619 				fpu_explode(fe, &fe->fe_f1, type, ra);
620 				fpu_explode(fe, &fe->fe_f2, type, rb);
621 				fp = fpu_div(fe);
622 				break;
623 			case	OPC59_FSUBS:
624 				FPU_EMU_EVCNT_INCR(fsub);
625 				DPRINTF(FPE_INSN, ("fpu_execute: FSUB\n"));
626 				fpu_explode(fe, &fe->fe_f1, type, ra);
627 				fpu_explode(fe, &fe->fe_f2, type, rb);
628 				fp = fpu_sub(fe);
629 				break;
630 			case	OPC59_FADDS:
631 				FPU_EMU_EVCNT_INCR(fadd);
632 				DPRINTF(FPE_INSN, ("fpu_execute: FADD\n"));
633 				fpu_explode(fe, &fe->fe_f1, type, ra);
634 				fpu_explode(fe, &fe->fe_f2, type, rb);
635 				fp = fpu_add(fe);
636 				break;
637 			case	OPC59_FSQRTS:
638 				FPU_EMU_EVCNT_INCR(fsqrt);
639 				DPRINTF(FPE_INSN, ("fpu_execute: FSQRT\n"));
640 				fpu_explode(fe, &fe->fe_f1, type, rb);
641 				fp = fpu_sqrt(fe);
642 				break;
643 			case	OPC63M_FSEL:
644 				FPU_EMU_EVCNT_INCR(fsel);
645 				DPRINTF(FPE_INSN, ("fpu_execute: FSEL\n"));
646 				a = (int *)&fe->fe_fpstate->fpr[ra].fpr;
647 				if ((*a & 0x80000000) && (*a & 0x7fffffff))
648 					/* fra < 0 */
649 					rc = rb;
650 				DPRINTF(FPE_INSN, ("f%d => f%d\n", rc, rt));
651 				memcpy(&fs->fpr[rt].fpr, &fs->fpr[rc].fpr,
652 					sizeof(double));
653 				break;
654 			case	OPC59_FRES:
655 				FPU_EMU_EVCNT_INCR(fpres);
656 				DPRINTF(FPE_INSN, ("fpu_execute: FPRES\n"));
657 				fpu_explode(fe, &fe->fe_f1, type, rb);
658 				fp = fpu_sqrt(fe);
659 				/* now we've gotta overwrite the dest reg */
660 				*((int *)&fe->fe_fpstate->fpr[rt].fpr) = 1;
661 				fpu_explode(fe, &fe->fe_f1, FTYPE_INT, rt);
662 				fpu_div(fe);
663 				break;
664 			case	OPC59_FMULS:
665 				FPU_EMU_EVCNT_INCR(fmul);
666 				DPRINTF(FPE_INSN, ("fpu_execute: FMUL\n"));
667 				fpu_explode(fe, &fe->fe_f1, type, ra);
668 				fpu_explode(fe, &fe->fe_f2, type, rc);
669 				fp = fpu_mul(fe);
670 				break;
671 			case	OPC63M_FRSQRTE:
672 				/* Reciprocal sqrt() estimate */
673 				FPU_EMU_EVCNT_INCR(frsqrte);
674 				DPRINTF(FPE_INSN, ("fpu_execute: FRSQRTE\n"));
675 				fpu_explode(fe, &fe->fe_f1, type, rb);
676 				fp = fpu_sqrt(fe);
677 				fe->fe_f2 = *fp;
678 				/* now we've gotta overwrite the dest reg */
679 				*((int *)&fe->fe_fpstate->fpr[rt].fpr) = 1;
680 				fpu_explode(fe, &fe->fe_f1, FTYPE_INT, rt);
681 				fpu_div(fe);
682 				break;
683 			case	OPC59_FMSUBS:
684 				FPU_EMU_EVCNT_INCR(fmulsub);
685 				DPRINTF(FPE_INSN, ("fpu_execute: FMULSUB\n"));
686 				fpu_explode(fe, &fe->fe_f1, type, ra);
687 				fpu_explode(fe, &fe->fe_f2, type, rc);
688 				fp = fpu_mul(fe);
689 				fe->fe_f1 = *fp;
690 				fpu_explode(fe, &fe->fe_f2, type, rb);
691 				fp = fpu_sub(fe);
692 				break;
693 			case	OPC59_FMADDS:
694 				FPU_EMU_EVCNT_INCR(fmuladd);
695 				DPRINTF(FPE_INSN, ("fpu_execute: FMULADD\n"));
696 				fpu_explode(fe, &fe->fe_f1, type, ra);
697 				fpu_explode(fe, &fe->fe_f2, type, rc);
698 				fp = fpu_mul(fe);
699 				fe->fe_f1 = *fp;
700 				fpu_explode(fe, &fe->fe_f2, type, rb);
701 				fp = fpu_add(fe);
702 				break;
703 			case	OPC59_FNMSUBS:
704 				FPU_EMU_EVCNT_INCR(fnmsub);
705 				DPRINTF(FPE_INSN, ("fpu_execute: FNMSUB\n"));
706 				fpu_explode(fe, &fe->fe_f1, type, ra);
707 				fpu_explode(fe, &fe->fe_f2, type, rc);
708 				fp = fpu_mul(fe);
709 				fe->fe_f1 = *fp;
710 				fpu_explode(fe, &fe->fe_f2, type, rb);
711 				fp = fpu_sub(fe);
712 				/* Negate */
713 				fp->fp_sign ^= 1;
714 				break;
715 			case	OPC59_FNMADDS:
716 				FPU_EMU_EVCNT_INCR(fnmadd);
717 				DPRINTF(FPE_INSN, ("fpu_execute: FNMADD\n"));
718 				fpu_explode(fe, &fe->fe_f1, type, ra);
719 				fpu_explode(fe, &fe->fe_f2, type, rc);
720 				fp = fpu_mul(fe);
721 				fe->fe_f1 = *fp;
722 				fpu_explode(fe, &fe->fe_f2, type, rb);
723 				fp = fpu_add(fe);
724 				/* Negate */
725 				fp->fp_sign ^= 1;
726 				break;
727 			default:
728 				return (NOTFPU);
729 				break;
730 			}
731 
732 			/* If the instruction was single precision, round */
733 			if (!(instr.i_any.i_opcd & 0x4)) {
734 				fpu_implode(fe, fp, FTYPE_SNG,
735 					(u_int *)&fs->fpr[rt].fpr);
736 				fpu_explode(fe, fp = &fe->fe_f1, FTYPE_SNG, rt);
737 			}
738 		}
739 	} else {
740 		return (NOTFPU);
741 	}
742 
743 	/*
744 	 * ALU operation is complete.  Collapse the result and then check
745 	 * for exceptions.  If we got any, and they are enabled, do not
746 	 * alter the destination register, just stop with an exception.
747 	 * Otherwise set new current exceptions and accrue.
748 	 */
749 	if (fp)
750 		fpu_implode(fe, fp, type, (u_int *)&fs->fpr[rt].fpr);
751 	cx = fe->fe_cx;
752 	fsr = fe->fe_fpscr;
753 	if (cx != 0) {
754 		fsr &= ~FPSCR_FX;
755 		if ((cx^fsr)&FPSR_EX_MSK)
756 			fsr |= FPSCR_FX;
757 		mask = fsr & FPSR_EX;
758 		mask <<= (25-3);
759 		if (cx & mask)
760 			fsr |= FPSCR_FEX;
761 		if (cx & FPSCR_FPRF) {
762 			/* Need to replace CC */
763 			fsr &= ~FPSCR_FPRF;
764 		}
765 		if (cx & (FPSR_EXOP))
766 			fsr |= FPSCR_VX;
767 		fsr |= cx;
768 		DPRINTF(FPE_INSN, ("fpu_execute: cx %x, fsr %x\n", cx, fsr));
769 	}
770 
771 	if (cond) {
772 		cond = fsr & 0xf0000000;
773 		/* Isolate condition codes */
774 		cond >>= 28;
775 		/* Move fpu condition codes to cr[1] */
776 		tf->cr &= (0x0f000000);
777 		tf->cr |= (cond<<24);
778 		DPRINTF(FPE_INSN, ("fpu_execute: cr[1] <= %x\n", cond));
779 	}
780 
781 	if (setcr) {
782 		cond = fsr & FPSCR_FPCC;
783 		/* Isolate condition codes */
784 		cond <<= 16;
785 		/* Move fpu condition codes to cr[1] */
786 		tf->cr &= ~(0xf0000000>>bf);
787 		tf->cr |= (cond>>bf);
788 		DPRINTF(FPE_INSN, ("fpu_execute: cr[%d] (cr=%jx) <= %x\n",
789 			bf/4, (uintmax_t)tf->cr, cond));
790 	}
791 
792 	((int *)&fs->fpscr)[1] = fsr;
793 	if (fsr & FPSCR_FEX)
794 		return(FPE);
795 	return (0);	/* success */
796 }
797