fpu.h revision 77015 
1/*-
2 * Copyright (c) 1990 The Regents of the University of California.
3 * All rights reserved.
4 *
5 * This code is derived from software contributed to Berkeley by
6 * William Jolitz.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 * 1. Redistributions of source code must retain the above copyright
12 *    notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 *    notice, this list of conditions and the following disclaimer in the
15 *    documentation and/or other materials provided with the distribution.
16 * 3. All advertising materials mentioning features or use of this software
17 *    must display the following acknowledgement:
18 *	This product includes software developed by the University of
19 *	California, Berkeley and its contributors.
20 * 4. Neither the name of the University nor the names of its contributors
21 *    may be used to endorse or promote products derived from this software
22 *    without specific prior written permission.
23 *
24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
27 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
34 * SUCH DAMAGE.
35 *
36 *	from: @(#)npx.h	5.3 (Berkeley) 1/18/91
37 * $FreeBSD: head/sys/amd64/include/fpu.h 77015 2001-05-22 21:20:49Z bde $
38 */
39
40/*
41 * 287/387 NPX Coprocessor Data Structures and Constants
42 * W. Jolitz 1/90
43 */
44
45#ifndef _MACHINE_NPX_H_
46#define	_MACHINE_NPX_H_
47
48/* Environment information of floating point unit */
49struct	env87 {
50	long	en_cw;		/* control word (16bits) */
51	long	en_sw;		/* status word (16bits) */
52	long	en_tw;		/* tag word (16bits) */
53	long	en_fip;		/* floating point instruction pointer */
54	u_short	en_fcs;		/* floating code segment selector */
55	u_short	en_opcode;	/* opcode last executed (11 bits ) */
56	long	en_foo;		/* floating operand offset */
57	long	en_fos;		/* floating operand segment selector */
58};
59
60/* Contents of each floating point accumulator */
61struct	fpacc87 {
62#ifdef dontdef /* too unportable */
63	u_long	fp_mantlo;	/* mantissa low (31:0) */
64	u_long	fp_manthi;	/* mantissa high (63:32) */
65	int	fp_exp:15;	/* exponent */
66	int	fp_sgn:1;	/* mantissa sign */
67#else
68	u_char	fp_bytes[10];
69#endif
70};
71
72/* Floating point context */
73struct	save87 {
74	struct	env87 sv_env;	/* floating point control/status */
75	struct	fpacc87	sv_ac[8];	/* accumulator contents, 0-7 */
76	u_long	sv_ex_sw;	/* status word for last exception */
77	/*
78	 * Bogus padding for emulators.  Emulators should use their own
79	 * struct and arrange to store into this struct (ending here)
80	 * before it is inspected for ptracing or for core dumps.  Some
81	 * emulators overwrite the whole struct.  We have no good way of
82	 * knowing how much padding to leave.  Leave just enough for the
83	 * GPL emulator's i387_union (176 bytes total).
84	 */
85	u_char	sv_pad[64];	/* padding; used by emulators */
86};
87
88/*
89 * The hardware default control word for i387's and later coprocessors is
90 * 0x37F, giving:
91 *
92 *	round to nearest
93 *	64-bit precision
94 *	all exceptions masked.
95 *
96 * We modify the affine mode bit and precision bits in this to give:
97 *
98 *	affine mode for 287's (if they work at all) (1 in bitfield 1<<12)
99 *	53-bit precision (2 in bitfield 3<<8)
100 *
101 * 64-bit precision often gives bad results with high level languages
102 * because it makes the results of calculations depend on whether
103 * intermediate values are stored in memory or in FPU registers.
104 */
105#define	__INITIAL_NPXCW__	0x127F
106
107#ifdef _KERNEL
108int	npxdna __P((void));
109void	npxexit __P((struct proc *p));
110void	npxinit __P((int control));
111void	npxsave __P((struct save87 *addr));
112int	npxtrap __P((void));
113#endif
114
115#endif /* !_MACHINE_NPX_H_ */
116