FreeBSD/Linux Kernel Cross Reference
sys/i386/include/npx.h
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: src/sys/i386/include/npx.h,v 1.10.4.1 1999/09/05 08:11:55 peter Exp $
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 */
49 struct 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 */
61 struct 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 */
73 struct 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 /* Intel prefers long real (53 bit) precision */
89 #define __iBCS_NPXCW__ 0x262
90 /* wfj prefers temporary real (64 bit) precision */
91 #define __386BSD_NPXCW__ 0x362
92 /*
93 * bde prefers 53 bit precision and all exceptions masked.
94 *
95 * The standard control word from finit is 0x37F, giving:
96 *
97 * round to nearest
98 * 64-bit precision
99 * all exceptions masked.
100 *
101 * Now I want:
102 *
103 * affine mode for 287's (if they work at all) (1 in bitfield 1<<12)
104 * 53-bit precision (2 in bitfield 3<<8)
105 * overflow exception unmasked (0 in bitfield 1<<3)
106 * zero divide exception unmasked (0 in bitfield 1<<2)
107 * invalid-operand exception unmasked (0 in bitfield 1<<0).
108 *
109 * 64-bit precision often gives bad results with high level languages
110 * because it makes the results of calculations depend on whether
111 * intermediate values are stored in memory or in FPU registers.
112 *
113 * The "Intel" and wfj control words have:
114 *
115 * underflow exception unmasked (0 in bitfield 1<<4)
116 *
117 * but that causes an unexpected exception in the test program 'paranoia'
118 * and makes denormals useless (DBL_MIN / 2 underflows). It doesn't make
119 * a lot of sense to trap underflow without trapping denormals.
120 *
121 * Later I will want the IEEE default of all exceptions masked. See the
122 * 0.0 math manpage for why this is better. The 0.1 math manpage is empty.
123 */
124 #define __BDE_NPXCW__ 0x1272
125 #define __BETTER_BDE_NPXCW__ 0x127f
126
127 #ifdef __BROKEN_NPXCW__
128 #ifdef __FreeBSD__
129 #define __INITIAL_NPXCW__ __386BSD_NPXCW__
130 #else
131 #define __INITIAL_NPXCW__ __iBCS_NPXCW__
132 #endif
133 #else
134 #define __INITIAL_NPXCW__ __BDE_NPXCW__
135 #endif
136
137 #ifdef KERNEL
138 #include <sys/cdefs.h>
139 #include <machine/frame.h>
140
141 struct proc;
142
143 int npxdna __P((void));
144 void npxexit __P((struct proc *p));
145 void npxinit __P((int control));
146 void npxsave __P((struct save87 *addr));
147 #endif
148
149 #endif /* !_MACHINE_NPX_H_ */
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