fpu.h revision 55205
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 55205 1999-12-29 04:46:21Z peter $ 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#include <machine/globals.h> 49 50/* Environment information of floating point unit */ 51struct env87 { 52 long en_cw; /* control word (16bits) */ 53 long en_sw; /* status word (16bits) */ 54 long en_tw; /* tag word (16bits) */ 55 long en_fip; /* floating point instruction pointer */ 56 u_short en_fcs; /* floating code segment selector */ 57 u_short en_opcode; /* opcode last executed (11 bits ) */ 58 long en_foo; /* floating operand offset */ 59 long en_fos; /* floating operand segment selector */ 60}; 61 62/* Contents of each floating point accumulator */ 63struct fpacc87 { 64#ifdef dontdef /* too unportable */ 65 u_long fp_mantlo; /* mantissa low (31:0) */ 66 u_long fp_manthi; /* mantissa high (63:32) */ 67 int fp_exp:15; /* exponent */ 68 int fp_sgn:1; /* mantissa sign */ 69#else 70 u_char fp_bytes[10]; 71#endif 72}; 73 74/* Floating point context */ 75struct save87 { 76 struct env87 sv_env; /* floating point control/status */ 77 struct fpacc87 sv_ac[8]; /* accumulator contents, 0-7 */ 78 u_long sv_ex_sw; /* status word for last exception */ 79 /* 80 * Bogus padding for emulators. Emulators should use their own 81 * struct and arrange to store into this struct (ending here) 82 * before it is inspected for ptracing or for core dumps. Some 83 * emulators overwrite the whole struct. We have no good way of 84 * knowing how much padding to leave. Leave just enough for the 85 * GPL emulator's i387_union (176 bytes total). 86 */ 87 u_char sv_pad[64]; /* padding; used by emulators */ 88}; 89 90/* Intel prefers long real (53 bit) precision */ 91#define __iBCS_NPXCW__ 0x262 92/* wfj prefers temporary real (64 bit) precision */ 93#define __386BSD_NPXCW__ 0x362 94/* 95 * bde prefers 53 bit precision and all exceptions masked. 96 * 97 * The standard control word from finit is 0x37F, giving: 98 * 99 * round to nearest 100 * 64-bit precision 101 * all exceptions masked. 102 * 103 * Now I want: 104 * 105 * affine mode for 287's (if they work at all) (1 in bitfield 1<<12) 106 * 53-bit precision (2 in bitfield 3<<8) 107 * overflow exception unmasked (0 in bitfield 1<<3) 108 * zero divide exception unmasked (0 in bitfield 1<<2) 109 * invalid-operand exception unmasked (0 in bitfield 1<<0). 110 * 111 * 64-bit precision often gives bad results with high level languages 112 * because it makes the results of calculations depend on whether 113 * intermediate values are stored in memory or in FPU registers. 114 * 115 * The "Intel" and wfj control words have: 116 * 117 * underflow exception unmasked (0 in bitfield 1<<4) 118 * 119 * but that causes an unexpected exception in the test program 'paranoia' 120 * and makes denormals useless (DBL_MIN / 2 underflows). It doesn't make 121 * a lot of sense to trap underflow without trapping denormals. 122 * 123 * Later I will want the IEEE default of all exceptions masked. See the 124 * 0.0 math manpage for why this is better. The 0.1 math manpage is empty. 125 */ 126#define __BDE_NPXCW__ 0x1272 127#define __BETTER_BDE_NPXCW__ 0x127f 128 129#ifdef __BROKEN_NPXCW__ 130#ifdef __FreeBSD__ 131#define __INITIAL_NPXCW__ __386BSD_NPXCW__ 132#else 133#define __INITIAL_NPXCW__ __iBCS_NPXCW__ 134#endif 135#else 136#define __INITIAL_NPXCW__ __BDE_NPXCW__ 137#endif 138 139#ifdef _KERNEL 140#ifndef npxproc 141extern struct proc *npxproc; 142#endif 143 144int npxdna __P((void)); 145void npxexit __P((struct proc *p)); 146void npxinit __P((int control)); 147void npxsave __P((struct save87 *addr)); 148#endif 149 150#endif /* !_MACHINE_NPX_H_ */ 151