fpu.h revision 4
14Srgrimes/*- 24Srgrimes * Copyright (c) 1990 The Regents of the University of California. 34Srgrimes * All rights reserved. 44Srgrimes * 54Srgrimes * This code is derived from software contributed to Berkeley by 64Srgrimes * William Jolitz. 74Srgrimes * 84Srgrimes * Redistribution and use in source and binary forms, with or without 94Srgrimes * modification, are permitted provided that the following conditions 104Srgrimes * are met: 114Srgrimes * 1. Redistributions of source code must retain the above copyright 124Srgrimes * notice, this list of conditions and the following disclaimer. 134Srgrimes * 2. Redistributions in binary form must reproduce the above copyright 144Srgrimes * notice, this list of conditions and the following disclaimer in the 154Srgrimes * documentation and/or other materials provided with the distribution. 164Srgrimes * 3. All advertising materials mentioning features or use of this software 174Srgrimes * must display the following acknowledgement: 184Srgrimes * This product includes software developed by the University of 194Srgrimes * California, Berkeley and its contributors. 204Srgrimes * 4. Neither the name of the University nor the names of its contributors 214Srgrimes * may be used to endorse or promote products derived from this software 224Srgrimes * without specific prior written permission. 234Srgrimes * 244Srgrimes * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 254Srgrimes * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 264Srgrimes * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 274Srgrimes * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 284Srgrimes * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 294Srgrimes * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 304Srgrimes * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 314Srgrimes * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 324Srgrimes * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 334Srgrimes * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 344Srgrimes * SUCH DAMAGE. 354Srgrimes * 364Srgrimes * @(#)npx.h 5.3 (Berkeley) 1/18/91 374Srgrimes * 384Srgrimes * PATCHES MAGIC LEVEL PATCH THAT GOT US HERE 394Srgrimes * -------------------- ----- ---------------------- 404Srgrimes * CURRENT PATCH LEVEL: 1 00154 414Srgrimes * -------------------- ----- ---------------------- 424Srgrimes * 434Srgrimes * 20 Apr 93 Bruce Evans New npx-0.5 code 444Srgrimes * 454Srgrimes */ 464Srgrimes 474Srgrimes/* 484Srgrimes * 287/387 NPX Coprocessor Data Structures and Constants 494Srgrimes * W. Jolitz 1/90 504Srgrimes */ 514Srgrimes 524Srgrimes#ifndef ___NPX87___ 534Srgrimes#define ___NPX87___ 544Srgrimes 554Srgrimes/* Environment information of floating point unit */ 564Srgrimesstruct env87 { 574Srgrimes long en_cw; /* control word (16bits) */ 584Srgrimes long en_sw; /* status word (16bits) */ 594Srgrimes long en_tw; /* tag word (16bits) */ 604Srgrimes long en_fip; /* floating point instruction pointer */ 614Srgrimes u_short en_fcs; /* floating code segment selector */ 624Srgrimes u_short en_opcode; /* opcode last executed (11 bits ) */ 634Srgrimes long en_foo; /* floating operand offset */ 644Srgrimes long en_fos; /* floating operand segment selector */ 654Srgrimes}; 664Srgrimes 674Srgrimes/* Contents of each floating point accumulator */ 684Srgrimesstruct fpacc87 { 694Srgrimes#ifdef dontdef /* too unportable */ 704Srgrimes u_long fp_mantlo; /* mantissa low (31:0) */ 714Srgrimes u_long fp_manthi; /* mantissa high (63:32) */ 724Srgrimes int fp_exp:15; /* exponent */ 734Srgrimes int fp_sgn:1; /* mantissa sign */ 744Srgrimes#else 754Srgrimes u_char fp_bytes[10]; 764Srgrimes#endif 774Srgrimes}; 784Srgrimes 794Srgrimes/* Floating point context */ 804Srgrimesstruct save87 { 814Srgrimes struct env87 sv_env; /* floating point control/status */ 824Srgrimes struct fpacc87 sv_ac[8]; /* accumulator contents, 0-7 */ 834Srgrimes#ifndef dontdef 844Srgrimes u_long sv_ex_sw; /* status word for last exception (was pad) */ 854Srgrimes u_long sv_ex_tw; /* tag word for last exception (was pad) */ 864Srgrimes u_char sv_pad[8 * 2 - 2 * 4]; /* bogus historical padding */ 874Srgrimes#endif 884Srgrimes}; 894Srgrimes 904Srgrimes/* Cyrix EMC memory - mapped coprocessor context switch information */ 914Srgrimesstruct emcsts { 924Srgrimes long em_msw; /* memory mapped status register when swtched */ 934Srgrimes long em_tar; /* memory mapped temp A register when swtched */ 944Srgrimes long em_dl; /* memory mapped D low register when swtched */ 954Srgrimes}; 964Srgrimes 974Srgrimes/* Intel prefers long real (53 bit) precision */ 984Srgrimes#define __iBCS_NPXCW__ 0x262 994Srgrimes/* wfj prefers temporary real (64 bit) precision */ 1004Srgrimes#define __386BSD_NPXCW__ 0x362 1014Srgrimes/* 1024Srgrimes * bde prefers 53 bit precision and all exceptions masked. 1034Srgrimes * 1044Srgrimes * The standard control word from finit is 0x37F, giving: 1054Srgrimes * 1064Srgrimes * round to nearest 1074Srgrimes * 64-bit precision 1084Srgrimes * all exceptions masked. 1094Srgrimes * 1104Srgrimes * Now I want: 1114Srgrimes * 1124Srgrimes * affine mode for 287's (if they work at all) (1 in bitfield 1<<12) 1134Srgrimes * 53-bit precision (2 in bitfield 3<<8) 1144Srgrimes * overflow exception unmasked (0 in bitfield 1<<3) 1154Srgrimes * zero divide exception unmasked (0 in bitfield 1<<2) 1164Srgrimes * invalid-operand exception unmasked (0 in bitfield 1<<0). 1174Srgrimes * 1184Srgrimes * 64-bit precision often gives bad results with high level languages 1194Srgrimes * because it makes the results of calculations depend on whether 1204Srgrimes * intermediate values are stored in memory or in FPU registers. 1214Srgrimes * 1224Srgrimes * The "Intel" and wfj control words have: 1234Srgrimes * 1244Srgrimes * underflow exception unmasked (0 in bitfield 1<<4) 1254Srgrimes * 1264Srgrimes * but that causes an unexpected exception in the test program 'paranoia' 1274Srgrimes * and makes denormals useless (DBL_MIN / 2 underflows). It doesn't make 1284Srgrimes * a lot of sense to trap underflow without trapping denormals. 1294Srgrimes * 1304Srgrimes * Later I will want the IEEE default of all exceptions masked. See the 1314Srgrimes * 0.0 math manpage for why this is better. The 0.1 math manpage is empty. 1324Srgrimes */ 1334Srgrimes#define __BDE_NPXCW__ 0x1272 1344Srgrimes#define __BETTER_BDE_NPXCW__ 0x127f 1354Srgrimes 1364Srgrimes#ifdef __BROKEN_NPXCW__ 1374Srgrimes#ifdef __386BSD__ 1384Srgrimes#define __INITIAL_NPXCW__ __386BSD_NPXCW__ 1394Srgrimes#else 1404Srgrimes#define __INITIAL_NPXCW__ __iBCS_NPXCW__ 1414Srgrimes#endif 1424Srgrimes#else 1434Srgrimes#define __INITIAL_NPXCW__ __BDE_NPXCW__ 1444Srgrimes#endif 1454Srgrimes 1464Srgrimes#endif ___NPX87___ 147