xref: /freebsd/sys/powerpc/fpu/fpu_emu.c (revision 06c3fb2749bda94cb5201f81ffdb8fa6c3161b2e)
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 
78 #include <sys/cdefs.h>
79 #include "opt_ddb.h"
80 
81 #include <sys/param.h>
82 #include <sys/systm.h>
83 #include <sys/kdb.h>
84 #include <sys/kernel.h>
85 #include <sys/proc.h>
86 #include <sys/sysctl.h>
87 #include <sys/signal.h>
88 #include <sys/syslog.h>
89 #include <sys/signalvar.h>
90 
91 #include <machine/fpu.h>
92 
93 #include <powerpc/fpu/fpu_emu.h>
94 #include <powerpc/fpu/fpu_extern.h>
95 #include <powerpc/fpu/fpu_instr.h>
96 
97 static SYSCTL_NODE(_hw, OID_AUTO, fpu_emu, CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
98     "FPU emulator");
99 
100 #define	FPU_EMU_EVCNT_DECL(name)					\
101 static u_int fpu_emu_evcnt_##name;					\
102 SYSCTL_INT(_hw_fpu_emu, OID_AUTO, evcnt_##name, CTLFLAG_RD,		\
103     &fpu_emu_evcnt_##name, 0, "")
104 
105 #define	FPU_EMU_EVCNT_INCR(name)	fpu_emu_evcnt_##name++
106 
107 FPU_EMU_EVCNT_DECL(stfiwx);
108 FPU_EMU_EVCNT_DECL(fpstore);
109 FPU_EMU_EVCNT_DECL(fpload);
110 FPU_EMU_EVCNT_DECL(fcmpu);
111 FPU_EMU_EVCNT_DECL(frsp);
112 FPU_EMU_EVCNT_DECL(fctiw);
113 FPU_EMU_EVCNT_DECL(fcmpo);
114 FPU_EMU_EVCNT_DECL(mtfsb1);
115 FPU_EMU_EVCNT_DECL(fnegabs);
116 FPU_EMU_EVCNT_DECL(mcrfs);
117 FPU_EMU_EVCNT_DECL(mtfsb0);
118 FPU_EMU_EVCNT_DECL(fmr);
119 FPU_EMU_EVCNT_DECL(mtfsfi);
120 FPU_EMU_EVCNT_DECL(fnabs);
121 FPU_EMU_EVCNT_DECL(fabs);
122 FPU_EMU_EVCNT_DECL(mffs);
123 FPU_EMU_EVCNT_DECL(mtfsf);
124 FPU_EMU_EVCNT_DECL(fctid);
125 FPU_EMU_EVCNT_DECL(fcfid);
126 FPU_EMU_EVCNT_DECL(fdiv);
127 FPU_EMU_EVCNT_DECL(fsub);
128 FPU_EMU_EVCNT_DECL(fadd);
129 FPU_EMU_EVCNT_DECL(fsqrt);
130 FPU_EMU_EVCNT_DECL(fsel);
131 FPU_EMU_EVCNT_DECL(fpres);
132 FPU_EMU_EVCNT_DECL(fmul);
133 FPU_EMU_EVCNT_DECL(frsqrte);
134 FPU_EMU_EVCNT_DECL(fmulsub);
135 FPU_EMU_EVCNT_DECL(fmuladd);
136 FPU_EMU_EVCNT_DECL(fnmsub);
137 FPU_EMU_EVCNT_DECL(fnmadd);
138 
139 /* FPSR exception masks */
140 #define FPSR_EX_MSK	(FPSCR_VX|FPSCR_OX|FPSCR_UX|FPSCR_ZX|		\
141 			FPSCR_XX|FPSCR_VXSNAN|FPSCR_VXISI|FPSCR_VXIDI|	\
142 			FPSCR_VXZDZ|FPSCR_VXIMZ|FPSCR_VXVC|FPSCR_VXSOFT|\
143 			FPSCR_VXSQRT|FPSCR_VXCVI)
144 #define	FPSR_EX		(FPSCR_VE|FPSCR_OE|FPSCR_UE|FPSCR_ZE|FPSCR_XE)
145 #define	FPSR_EXOP	(FPSR_EX_MSK&(~FPSR_EX))
146 
147 int fpe_debug = 0;
148 
149 #ifdef DEBUG
150 vm_offset_t opc_disasm(vm_offset_t, int);
151 
152 /*
153  * Dump a `fpn' structure.
154  */
155 void
156 fpu_dumpfpn(struct fpn *fp)
157 {
158 	static const char *class[] = {
159 		"SNAN", "QNAN", "ZERO", "NUM", "INF"
160 	};
161 
162 	printf("%s %c.%x %x %x %xE%d", class[fp->fp_class + 2],
163 		fp->fp_sign ? '-' : ' ',
164 		fp->fp_mant[0],	fp->fp_mant[1],
165 		fp->fp_mant[2], fp->fp_mant[3],
166 		fp->fp_exp);
167 }
168 #endif
169 
170 /*
171  * fpu_execute returns the following error numbers (0 = no error):
172  */
173 #define	FPE		1	/* take a floating point exception */
174 #define	NOTFPU		2	/* not an FPU instruction */
175 #define	FAULT		3
176 
177 /*
178  * Emulate a floating-point instruction.
179  * Return zero for success, else signal number.
180  * (Typically: zero, SIGFPE, SIGILL, SIGSEGV)
181  */
182 int
183 fpu_emulate(struct trapframe *frame, struct fpu *fpf)
184 {
185 	union instr insn;
186 	struct fpemu fe;
187 	int sig;
188 
189 	/* initialize insn.is_datasize to tell it is *not* initialized */
190 	fe.fe_fpstate = fpf;
191 	fe.fe_cx = 0;
192 
193 	/* always set this (to avoid a warning) */
194 
195 	if (copyin((void *) (frame->srr0), &insn.i_int, sizeof (insn.i_int))) {
196 #ifdef DEBUG
197 		printf("fpu_emulate: fault reading opcode\n");
198 #endif
199 		return SIGSEGV;
200 	}
201 
202 	DPRINTF(FPE_EX, ("fpu_emulate: emulating insn %x at %p\n",
203 	    insn.i_int, (void *)frame->srr0));
204 
205 	if ((insn.i_any.i_opcd == OPC_TWI) ||
206 	    ((insn.i_any.i_opcd == OPC_integer_31) &&
207 	    (insn.i_x.i_xo == OPC31_TW))) {
208 		/* Check for the two trap insns. */
209 		DPRINTF(FPE_EX, ("fpu_emulate: SIGTRAP\n"));
210 		return (SIGTRAP);
211 	}
212 	sig = 0;
213 	switch (fpu_execute(frame, &fe, &insn)) {
214 	case 0:
215 		DPRINTF(FPE_EX, ("fpu_emulate: success\n"));
216 		frame->srr0 += 4;
217 		break;
218 
219 	case FPE:
220 		DPRINTF(FPE_EX, ("fpu_emulate: SIGFPE\n"));
221 		sig = SIGFPE;
222 		break;
223 
224 	case FAULT:
225 		DPRINTF(FPE_EX, ("fpu_emulate: SIGSEGV\n"));
226 		sig = SIGSEGV;
227 		break;
228 
229 	case NOTFPU:
230 	default:
231 		DPRINTF(FPE_EX, ("fpu_emulate: SIGILL\n"));
232 #ifdef DEBUG
233 		if (fpe_debug & FPE_EX) {
234 			printf("fpu_emulate:  illegal insn %x at %p:",
235 			insn.i_int, (void *) (frame->srr0));
236 			opc_disasm(frame->srr0, insn.i_int);
237 		}
238 #endif
239 		sig = SIGILL;
240 #ifdef DEBUG
241 		if (fpe_debug & FPE_EX)
242 			kdb_enter(KDB_WHY_UNSET, "illegal instruction");
243 #endif
244 		break;
245 	}
246 
247 	return (sig);
248 }
249 
250 /*
251  * Execute an FPU instruction (one that runs entirely in the FPU; not
252  * FBfcc or STF, for instance).  On return, fe->fe_fs->fs_fsr will be
253  * modified to reflect the setting the hardware would have left.
254  *
255  * Note that we do not catch all illegal opcodes, so you can, for instance,
256  * multiply two integers this way.
257  */
258 int
259 fpu_execute(struct trapframe *tf, struct fpemu *fe, union instr *insn)
260 {
261 	struct fpn *fp;
262 	union instr instr = *insn;
263 	int *a;
264 	vm_offset_t addr;
265 	int ra, rb, rc, rt, type, mask, fsr, cx, bf, setcr;
266 	unsigned int cond;
267 	struct fpu *fs;
268 
269 	/* Setup work. */
270 	fp = NULL;
271 	fs = fe->fe_fpstate;
272 	fe->fe_fpscr = ((int *)&fs->fpscr)[1];
273 
274 	/*
275 	 * On PowerPC all floating point values are stored in registers
276 	 * as doubles, even when used for single precision operations.
277 	 */
278 	type = FTYPE_DBL;
279 	cond = instr.i_any.i_rc;
280 	setcr = 0;
281 	bf = 0;	/* XXX gcc */
282 
283 #if defined(DDB) && defined(DEBUG)
284 	if (fpe_debug & FPE_EX) {
285 		vm_offset_t loc = tf->srr0;
286 
287 		printf("Trying to emulate: %p ", (void *)loc);
288 		opc_disasm(loc, instr.i_int);
289 	}
290 #endif
291 
292 	/*
293 	 * `Decode' and execute instruction.
294 	 */
295 
296 	if ((instr.i_any.i_opcd >= OPC_LFS && instr.i_any.i_opcd <= OPC_STFDU) ||
297 	    instr.i_any.i_opcd == OPC_integer_31) {
298 		/*
299 		 * Handle load/store insns:
300 		 *
301 		 * Convert to/from single if needed, calculate addr,
302 		 * and update index reg if needed.
303 		 */
304 		double buf;
305 		size_t size = sizeof(float);
306 		int store, update;
307 
308 		cond = 0; /* ld/st never set condition codes */
309 
310 		if (instr.i_any.i_opcd == OPC_integer_31) {
311 			if (instr.i_x.i_xo == OPC31_STFIWX) {
312 				FPU_EMU_EVCNT_INCR(stfiwx);
313 
314 				/* Store as integer */
315 				ra = instr.i_x.i_ra;
316 				rb = instr.i_x.i_rb;
317 				DPRINTF(FPE_INSN,
318 					("reg %d has %jx reg %d has %jx\n",
319 					ra, (uintmax_t)tf->fixreg[ra], rb,
320 					(uintmax_t)tf->fixreg[rb]));
321 
322 				addr = tf->fixreg[rb];
323 				if (ra != 0)
324 					addr += tf->fixreg[ra];
325 				rt = instr.i_x.i_rt;
326 				a = (int *)&fs->fpr[rt].fpr;
327 				DPRINTF(FPE_INSN,
328 					("fpu_execute: Store INT %x at %p\n",
329 						a[1], (void *)addr));
330 				if (copyout(&a[1], (void *)addr, sizeof(int)))
331 					return (FAULT);
332 				return (0);
333 			}
334 
335 			if ((instr.i_x.i_xo & OPC31_FPMASK) != OPC31_FPOP)
336 				/* Not an indexed FP load/store op */
337 				return (NOTFPU);
338 
339 			store = (instr.i_x.i_xo & 0x80);
340 			if (instr.i_x.i_xo & 0x40)
341 				size = sizeof(double);
342 			else
343 				type = FTYPE_SNG;
344 			update = (instr.i_x.i_xo & 0x20);
345 
346 			/* calculate EA of load/store */
347 			ra = instr.i_x.i_ra;
348 			rb = instr.i_x.i_rb;
349 			DPRINTF(FPE_INSN, ("reg %d has %jx reg %d has %jx\n",
350 				ra, (uintmax_t)tf->fixreg[ra], rb,
351 				(uintmax_t)tf->fixreg[rb]));
352 			addr = tf->fixreg[rb];
353 			if (ra != 0)
354 				addr += tf->fixreg[ra];
355 			rt = instr.i_x.i_rt;
356 		} else {
357 			store = instr.i_d.i_opcd & 0x4;
358 			if (instr.i_d.i_opcd & 0x2)
359 				size = sizeof(double);
360 			else
361 				type = FTYPE_SNG;
362 			update = instr.i_d.i_opcd & 0x1;
363 
364 			/* calculate EA of load/store */
365 			ra = instr.i_d.i_ra;
366 			addr = instr.i_d.i_d;
367 			DPRINTF(FPE_INSN, ("reg %d has %jx displ %jx\n",
368 				ra, (uintmax_t)tf->fixreg[ra],
369 				(uintmax_t)addr));
370 			if (ra != 0)
371 				addr += tf->fixreg[ra];
372 			rt = instr.i_d.i_rt;
373 		}
374 
375 		if (update && ra == 0)
376 			return (NOTFPU);
377 
378 		if (store) {
379 			/* Store */
380 			FPU_EMU_EVCNT_INCR(fpstore);
381 			if (type != FTYPE_DBL) {
382 				DPRINTF(FPE_INSN,
383 					("fpu_execute: Store SNG at %p\n",
384 						(void *)addr));
385 				fpu_explode(fe, fp = &fe->fe_f1, FTYPE_DBL, rt);
386 				fpu_implode(fe, fp, type, (void *)&buf);
387 				if (copyout(&buf, (void *)addr, size))
388 					return (FAULT);
389 			} else {
390 				DPRINTF(FPE_INSN,
391 					("fpu_execute: Store DBL at %p\n",
392 						(void *)addr));
393 				if (copyout(&fs->fpr[rt].fpr, (void *)addr,
394 				    size))
395 					return (FAULT);
396 			}
397 		} else {
398 			/* Load */
399 			FPU_EMU_EVCNT_INCR(fpload);
400 			DPRINTF(FPE_INSN, ("fpu_execute: Load from %p\n",
401 				(void *)addr));
402 			if (copyin((const void *)addr, &fs->fpr[rt].fpr,
403 			    size))
404 				return (FAULT);
405 			if (type != FTYPE_DBL) {
406 				fpu_explode(fe, fp = &fe->fe_f1, type, rt);
407 				fpu_implode(fe, fp, FTYPE_DBL,
408 					(u_int *)&fs->fpr[rt].fpr);
409 			}
410 		}
411 		if (update)
412 			tf->fixreg[ra] = addr;
413 		/* Complete. */
414 		return (0);
415 #ifdef notyet
416 	} else if (instr.i_any.i_opcd == OPC_load_st_62) {
417 		/* These are 64-bit extensions */
418 		return (NOTFPU);
419 #endif
420 	} else if (instr.i_any.i_opcd == OPC_sp_fp_59 ||
421 		instr.i_any.i_opcd == OPC_dp_fp_63) {
422 		if (instr.i_any.i_opcd == OPC_dp_fp_63 &&
423 		    !(instr.i_a.i_xo & OPC63M_MASK)) {
424 			/* Format X */
425 			rt = instr.i_x.i_rt;
426 			ra = instr.i_x.i_ra;
427 			rb = instr.i_x.i_rb;
428 
429 			/* One of the special opcodes.... */
430 			switch (instr.i_x.i_xo) {
431 			case	OPC63_FCMPU:
432 				FPU_EMU_EVCNT_INCR(fcmpu);
433 				DPRINTF(FPE_INSN, ("fpu_execute: FCMPU\n"));
434 				rt >>= 2;
435 				fpu_explode(fe, &fe->fe_f1, type, ra);
436 				fpu_explode(fe, &fe->fe_f2, type, rb);
437 				fpu_compare(fe, 0);
438 				/* Make sure we do the condition regs. */
439 				cond = 0;
440 				/* N.B.: i_rs is already left shifted by two. */
441 				bf = instr.i_x.i_rs & 0xfc;
442 				setcr = 1;
443 				break;
444 
445 			case	OPC63_FRSP:
446 				/*
447 				 * Convert to single:
448 				 *
449 				 * PowerPC uses this to round a double
450 				 * precision value to single precision,
451 				 * but values in registers are always
452 				 * stored in double precision format.
453 				 */
454 				FPU_EMU_EVCNT_INCR(frsp);
455 				DPRINTF(FPE_INSN, ("fpu_execute: FRSP\n"));
456 				fpu_explode(fe, fp = &fe->fe_f1, FTYPE_DBL, rb);
457 				fpu_implode(fe, fp, FTYPE_SNG,
458 					(u_int *)&fs->fpr[rt].fpr);
459 				fpu_explode(fe, fp = &fe->fe_f1, FTYPE_SNG, rt);
460 				type = FTYPE_DBL;
461 				break;
462 			case	OPC63_FCTIW:
463 			case	OPC63_FCTIWZ:
464 				FPU_EMU_EVCNT_INCR(fctiw);
465 				DPRINTF(FPE_INSN, ("fpu_execute: FCTIW\n"));
466 				fpu_explode(fe, fp = &fe->fe_f1, type, rb);
467 				type = FTYPE_INT;
468 				break;
469 			case	OPC63_FCMPO:
470 				FPU_EMU_EVCNT_INCR(fcmpo);
471 				DPRINTF(FPE_INSN, ("fpu_execute: FCMPO\n"));
472 				rt >>= 2;
473 				fpu_explode(fe, &fe->fe_f1, type, ra);
474 				fpu_explode(fe, &fe->fe_f2, type, rb);
475 				fpu_compare(fe, 1);
476 				/* Make sure we do the condition regs. */
477 				cond = 0;
478 				/* N.B.: i_rs is already left shifted by two. */
479 				bf = instr.i_x.i_rs & 0xfc;
480 				setcr = 1;
481 				break;
482 			case	OPC63_MTFSB1:
483 				FPU_EMU_EVCNT_INCR(mtfsb1);
484 				DPRINTF(FPE_INSN, ("fpu_execute: MTFSB1\n"));
485 				fe->fe_fpscr |=
486 					(~(FPSCR_VX|FPSR_EX) & (1<<(31-rt)));
487 				break;
488 			case	OPC63_FNEG:
489 				FPU_EMU_EVCNT_INCR(fnegabs);
490 				DPRINTF(FPE_INSN, ("fpu_execute: FNEGABS\n"));
491 				memcpy(&fs->fpr[rt].fpr, &fs->fpr[rb].fpr,
492 					sizeof(double));
493 				a = (int *)&fs->fpr[rt].fpr;
494 				*a ^= (1U << 31);
495 				break;
496 			case	OPC63_MCRFS:
497 				FPU_EMU_EVCNT_INCR(mcrfs);
498 				DPRINTF(FPE_INSN, ("fpu_execute: MCRFS\n"));
499 				cond = 0;
500 				rt &= 0x1c;
501 				ra &= 0x1c;
502 				/* Extract the bits we want */
503 				mask = (fe->fe_fpscr >> (28 - ra)) & 0xf;
504 				/* Clear the bits we copied. */
505 				fe->fe_cx =
506 					(FPSR_EX_MSK | (0xf << (28 - ra)));
507 				fe->fe_fpscr &= fe->fe_cx;
508 				/* Now shove them in the right part of cr */
509 				tf->cr &= ~(0xf << (28 - rt));
510 				tf->cr |= (mask << (28 - rt));
511 				break;
512 			case	OPC63_MTFSB0:
513 				FPU_EMU_EVCNT_INCR(mtfsb0);
514 				DPRINTF(FPE_INSN, ("fpu_execute: MTFSB0\n"));
515 				fe->fe_fpscr &=
516 					((FPSCR_VX|FPSR_EX) & ~(1<<(31-rt)));
517 				break;
518 			case	OPC63_FMR:
519 				FPU_EMU_EVCNT_INCR(fmr);
520 				DPRINTF(FPE_INSN, ("fpu_execute: FMR\n"));
521 				memcpy(&fs->fpr[rt].fpr, &fs->fpr[rb].fpr,
522 					sizeof(double));
523 				break;
524 			case	OPC63_MTFSFI:
525 				FPU_EMU_EVCNT_INCR(mtfsfi);
526 				DPRINTF(FPE_INSN, ("fpu_execute: MTFSFI\n"));
527 				rb >>= 1;
528 				rt &= 0x1c; /* Already left-shifted 4 */
529 				fe->fe_cx = rb << (28 - rt);
530 				mask = 0xf<<(28 - rt);
531 				fe->fe_fpscr = (fe->fe_fpscr & ~mask) |
532 					fe->fe_cx;
533 /* XXX weird stuff about OX, FX, FEX, and VX should be handled */
534 				break;
535 			case	OPC63_FNABS:
536 				FPU_EMU_EVCNT_INCR(fnabs);
537 				DPRINTF(FPE_INSN, ("fpu_execute: FABS\n"));
538 				memcpy(&fs->fpr[rt].fpr, &fs->fpr[rb].fpr,
539 					sizeof(double));
540 				a = (int *)&fs->fpr[rt].fpr;
541 				*a |= (1U << 31);
542 				break;
543 			case	OPC63_FABS:
544 				FPU_EMU_EVCNT_INCR(fabs);
545 				DPRINTF(FPE_INSN, ("fpu_execute: FABS\n"));
546 				memcpy(&fs->fpr[rt].fpr, &fs->fpr[rb].fpr,
547 					sizeof(double));
548 				a = (int *)&fs->fpr[rt].fpr;
549 				*a &= ~(1U << 31);
550 				break;
551 			case	OPC63_MFFS:
552 				FPU_EMU_EVCNT_INCR(mffs);
553 				DPRINTF(FPE_INSN, ("fpu_execute: MFFS\n"));
554 				memcpy(&fs->fpr[rt].fpr, &fs->fpscr,
555 					sizeof(fs->fpscr));
556 				break;
557 			case	OPC63_MTFSF:
558 				FPU_EMU_EVCNT_INCR(mtfsf);
559 				DPRINTF(FPE_INSN, ("fpu_execute: MTFSF\n"));
560 				if ((rt = instr.i_xfl.i_flm) == -1)
561 					mask = -1;
562 				else {
563 					mask = 0;
564 					/* Convert 1 bit -> 4 bits */
565 					for (ra = 0; ra < 8; ra ++)
566 						if (rt & (1<<ra))
567 							mask |= (0xf<<(4*ra));
568 				}
569 				a = (int *)&fs->fpr[rt].fpr;
570 				fe->fe_cx = mask & a[1];
571 				fe->fe_fpscr = (fe->fe_fpscr&~mask) |
572 					(fe->fe_cx);
573 /* XXX weird stuff about OX, FX, FEX, and VX should be handled */
574 				break;
575 			case	OPC63_FCTID:
576 			case	OPC63_FCTIDZ:
577 				FPU_EMU_EVCNT_INCR(fctid);
578 				DPRINTF(FPE_INSN, ("fpu_execute: FCTID\n"));
579 				fpu_explode(fe, fp = &fe->fe_f1, type, rb);
580 				type = FTYPE_LNG;
581 				break;
582 			case	OPC63_FCFID:
583 				FPU_EMU_EVCNT_INCR(fcfid);
584 				DPRINTF(FPE_INSN, ("fpu_execute: FCFID\n"));
585 				type = FTYPE_LNG;
586 				fpu_explode(fe, fp = &fe->fe_f1, type, rb);
587 				type = FTYPE_DBL;
588 				break;
589 			default:
590 				return (NOTFPU);
591 				break;
592 			}
593 		} else {
594 			/* Format A */
595 			rt = instr.i_a.i_frt;
596 			ra = instr.i_a.i_fra;
597 			rb = instr.i_a.i_frb;
598 			rc = instr.i_a.i_frc;
599 
600 			/*
601 			 * All arithmetic operations work on registers, which
602 			 * are stored as doubles.
603 			 */
604 			type = FTYPE_DBL;
605 			switch ((unsigned int)instr.i_a.i_xo) {
606 			case	OPC59_FDIVS:
607 				FPU_EMU_EVCNT_INCR(fdiv);
608 				DPRINTF(FPE_INSN, ("fpu_execute: FDIV\n"));
609 				fpu_explode(fe, &fe->fe_f1, type, ra);
610 				fpu_explode(fe, &fe->fe_f2, type, rb);
611 				fp = fpu_div(fe);
612 				break;
613 			case	OPC59_FSUBS:
614 				FPU_EMU_EVCNT_INCR(fsub);
615 				DPRINTF(FPE_INSN, ("fpu_execute: FSUB\n"));
616 				fpu_explode(fe, &fe->fe_f1, type, ra);
617 				fpu_explode(fe, &fe->fe_f2, type, rb);
618 				fp = fpu_sub(fe);
619 				break;
620 			case	OPC59_FADDS:
621 				FPU_EMU_EVCNT_INCR(fadd);
622 				DPRINTF(FPE_INSN, ("fpu_execute: FADD\n"));
623 				fpu_explode(fe, &fe->fe_f1, type, ra);
624 				fpu_explode(fe, &fe->fe_f2, type, rb);
625 				fp = fpu_add(fe);
626 				break;
627 			case	OPC59_FSQRTS:
628 				FPU_EMU_EVCNT_INCR(fsqrt);
629 				DPRINTF(FPE_INSN, ("fpu_execute: FSQRT\n"));
630 				fpu_explode(fe, &fe->fe_f1, type, rb);
631 				fp = fpu_sqrt(fe);
632 				break;
633 			case	OPC63M_FSEL:
634 				FPU_EMU_EVCNT_INCR(fsel);
635 				DPRINTF(FPE_INSN, ("fpu_execute: FSEL\n"));
636 				a = (int *)&fe->fe_fpstate->fpr[ra].fpr;
637 				if ((*a & 0x80000000) && (*a & 0x7fffffff))
638 					/* fra < 0 */
639 					rc = rb;
640 				DPRINTF(FPE_INSN, ("f%d => f%d\n", rc, rt));
641 				memcpy(&fs->fpr[rt].fpr, &fs->fpr[rc].fpr,
642 					sizeof(double));
643 				break;
644 			case	OPC59_FRES:
645 				FPU_EMU_EVCNT_INCR(fpres);
646 				DPRINTF(FPE_INSN, ("fpu_execute: FPRES\n"));
647 				fpu_explode(fe, &fe->fe_f1, type, rb);
648 				fp = fpu_sqrt(fe);
649 				/* now we've gotta overwrite the dest reg */
650 				*((int *)&fe->fe_fpstate->fpr[rt].fpr) = 1;
651 				fpu_explode(fe, &fe->fe_f1, FTYPE_INT, rt);
652 				fpu_div(fe);
653 				break;
654 			case	OPC59_FMULS:
655 				FPU_EMU_EVCNT_INCR(fmul);
656 				DPRINTF(FPE_INSN, ("fpu_execute: FMUL\n"));
657 				fpu_explode(fe, &fe->fe_f1, type, ra);
658 				fpu_explode(fe, &fe->fe_f2, type, rc);
659 				fp = fpu_mul(fe);
660 				break;
661 			case	OPC63M_FRSQRTE:
662 				/* Reciprocal sqrt() estimate */
663 				FPU_EMU_EVCNT_INCR(frsqrte);
664 				DPRINTF(FPE_INSN, ("fpu_execute: FRSQRTE\n"));
665 				fpu_explode(fe, &fe->fe_f1, type, rb);
666 				fp = fpu_sqrt(fe);
667 				fe->fe_f2 = *fp;
668 				/* now we've gotta overwrite the dest reg */
669 				*((int *)&fe->fe_fpstate->fpr[rt].fpr) = 1;
670 				fpu_explode(fe, &fe->fe_f1, FTYPE_INT, rt);
671 				fpu_div(fe);
672 				break;
673 			case	OPC59_FMSUBS:
674 				FPU_EMU_EVCNT_INCR(fmulsub);
675 				DPRINTF(FPE_INSN, ("fpu_execute: FMULSUB\n"));
676 				fpu_explode(fe, &fe->fe_f1, type, ra);
677 				fpu_explode(fe, &fe->fe_f2, type, rc);
678 				fp = fpu_mul(fe);
679 				fe->fe_f1 = *fp;
680 				fpu_explode(fe, &fe->fe_f2, type, rb);
681 				fp = fpu_sub(fe);
682 				break;
683 			case	OPC59_FMADDS:
684 				FPU_EMU_EVCNT_INCR(fmuladd);
685 				DPRINTF(FPE_INSN, ("fpu_execute: FMULADD\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_add(fe);
692 				break;
693 			case	OPC59_FNMSUBS:
694 				FPU_EMU_EVCNT_INCR(fnmsub);
695 				DPRINTF(FPE_INSN, ("fpu_execute: FNMSUB\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_sub(fe);
702 				/* Negate */
703 				fp->fp_sign ^= 1;
704 				break;
705 			case	OPC59_FNMADDS:
706 				FPU_EMU_EVCNT_INCR(fnmadd);
707 				DPRINTF(FPE_INSN, ("fpu_execute: FNMADD\n"));
708 				fpu_explode(fe, &fe->fe_f1, type, ra);
709 				fpu_explode(fe, &fe->fe_f2, type, rc);
710 				fp = fpu_mul(fe);
711 				fe->fe_f1 = *fp;
712 				fpu_explode(fe, &fe->fe_f2, type, rb);
713 				fp = fpu_add(fe);
714 				/* Negate */
715 				fp->fp_sign ^= 1;
716 				break;
717 			default:
718 				return (NOTFPU);
719 				break;
720 			}
721 
722 			/* If the instruction was single precision, round */
723 			if (!(instr.i_any.i_opcd & 0x4)) {
724 				fpu_implode(fe, fp, FTYPE_SNG,
725 					(u_int *)&fs->fpr[rt].fpr);
726 				fpu_explode(fe, fp = &fe->fe_f1, FTYPE_SNG, rt);
727 			}
728 		}
729 	} else {
730 		return (NOTFPU);
731 	}
732 
733 	/*
734 	 * ALU operation is complete.  Collapse the result and then check
735 	 * for exceptions.  If we got any, and they are enabled, do not
736 	 * alter the destination register, just stop with an exception.
737 	 * Otherwise set new current exceptions and accrue.
738 	 */
739 	if (fp)
740 		fpu_implode(fe, fp, type, (u_int *)&fs->fpr[rt].fpr);
741 	cx = fe->fe_cx;
742 	fsr = fe->fe_fpscr;
743 	if (cx != 0) {
744 		fsr &= ~FPSCR_FX;
745 		if ((cx^fsr)&FPSR_EX_MSK)
746 			fsr |= FPSCR_FX;
747 		mask = fsr & FPSR_EX;
748 		mask <<= (25-3);
749 		if (cx & mask)
750 			fsr |= FPSCR_FEX;
751 		if (cx & FPSCR_FPRF) {
752 			/* Need to replace CC */
753 			fsr &= ~FPSCR_FPRF;
754 		}
755 		if (cx & (FPSR_EXOP))
756 			fsr |= FPSCR_VX;
757 		fsr |= cx;
758 		DPRINTF(FPE_INSN, ("fpu_execute: cx %x, fsr %x\n", cx, fsr));
759 	}
760 
761 	if (cond) {
762 		cond = fsr & 0xf0000000;
763 		/* Isolate condition codes */
764 		cond >>= 28;
765 		/* Move fpu condition codes to cr[1] */
766 		tf->cr &= (0x0f000000);
767 		tf->cr |= (cond<<24);
768 		DPRINTF(FPE_INSN, ("fpu_execute: cr[1] <= %x\n", cond));
769 	}
770 
771 	if (setcr) {
772 		cond = fsr & FPSCR_FPCC;
773 		/* Isolate condition codes */
774 		cond <<= 16;
775 		/* Move fpu condition codes to cr[1] */
776 		tf->cr &= ~(0xf0000000>>bf);
777 		tf->cr |= (cond>>bf);
778 		DPRINTF(FPE_INSN, ("fpu_execute: cr[%d] (cr=%jx) <= %x\n",
779 			bf/4, (uintmax_t)tf->cr, cond));
780 	}
781 
782 	((int *)&fs->fpscr)[1] = fsr;
783 	if (fsr & FPSCR_FEX)
784 		return(FPE);
785 	return (0);	/* success */
786 }
787