floatingpoint.h revision 21673
128762Sbde/*- 228762Sbde * Copyright (c) 1993 Andrew Moore, Talke Studio 314331Speter * All rights reserved. 428762Sbde * 514331Speter * Redistribution and use in source and binary forms, with or without 628762Sbde * modification, are permitted provided that the following conditions 714331Speter * are met: 814331Speter * 1. Redistributions of source code must retain the above copyright 928762Sbde * notice, this list of conditions and the following disclaimer. 1014331Speter * 2. Redistributions in binary form must reproduce the above copyright 1114331Speter * notice, this list of conditions and the following disclaimer in the 1214331Speter * documentation and/or other materials provided with the distribution. 1314331Speter * 3. All advertising materials mentioning features or use of this software 1414331Speter * must display the following acknowledgement: 1514331Speter * This product includes software developed by the University of 1614331Speter * California, Berkeley and its contributors. 1714331Speter * 4. Neither the name of the University nor the names of its contributors 1814331Speter * may be used to endorse or promote products derived from this software 1914331Speter * without specific prior written permission. 2014331Speter * 2114331Speter * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 2214331Speter * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 2314331Speter * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 2414331Speter * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 31 * SUCH DAMAGE. 32 * 33 * from: @(#) floatingpoint.h 1.0 (Berkeley) 9/23/93 34 * $FreeBSD: head/sys/i386/include/floatingpoint.h 21673 1997-01-14 07:20:47Z jkh $ 35 */ 36 37#ifndef _FLOATINGPOINT_H_ 38#define _FLOATINGPOINT_H_ 39 40/* 41 * IEEE floating point structure and function definitions 42 */ 43 44/*- 45 * XXX the following undocumented pollution is exported: 46 * fpsetsticky(). 47 * FP*FLD, FP*OFF and FP*REG from <machine/ieeefp.h> 48 */ 49 50#include <sys/cdefs.h> 51#include <machine/ieeefp.h> 52 53#ifdef __GNUC__ 54 55#define __fldenv(addr) __asm __volatile("fldenv %0" : : "m" (*(addr))) 56#define __fnstenv(addr) __asm __volatile("fnstenv %0" : "=m" (*(addr))) 57#define __fnstcw(addr) __asm __volatile("fnstcw %0" : "=m" (*(addr))) 58#define __fnstsw(addr) __asm __volatile("fnstsw %0" : "=m" (*(addr))) 59 60/* 61 * return the contents of a FP register 62 */ 63static __inline__ int 64__fpgetreg(int _reg) 65{ 66 unsigned short _mem; 67 68 /*- 69 * This is more efficient than it looks. The switch gets optimized 70 * away if _reg is constant. 71 * 72 * The default case only supports _reg == 0. We could handle more 73 * registers (e.g., tags) using fnstenv, but the interface doesn't 74 * support more. 75 */ 76 switch(_reg) { 77 default: 78 __fnstcw(&_mem); 79 break; 80 case FP_STKY_REG: 81 __fnstsw(&_mem); 82 break; 83 } 84 return _mem; 85} 86 87/* 88 * set a FP mode; return previous mode 89 */ 90static __inline__ int 91__fpsetreg(int _m, int _reg, int _fld, int _off) 92{ 93 unsigned _env[7]; 94 unsigned _p; 95 96 /* 97 * _reg == 0 could be handled better using fnstcw/fldcw. 98 */ 99 __fnstenv(_env); 100 _p = (_env[_reg] & _fld) >> _off; 101 _env[_reg] = (_env[_reg] & ~_fld) | (_m << _off & _fld); 102 __fldenv(_env); 103 return _p; 104} 105 106#endif /* __GNUC__ */ 107 108/* 109 * SysV/386 FP control interface 110 */ 111#define fpgetround() ((__fpgetreg(FP_RND_REG) & FP_RND_FLD) >> FP_RND_OFF) 112#define fpsetround(m) __fpsetreg((m), FP_RND_REG, FP_RND_FLD, FP_RND_OFF) 113#define fpgetprec() ((__fpgetreg(FP_PRC_REG) & FP_PRC_FLD) >> FP_PRC_OFF) 114#define fpsetprec(m) __fpsetreg((m), FP_PRC_REG, FP_PRC_FLD, FP_PRC_OFF) 115#define fpgetmask() ((~__fpgetreg(FP_MSKS_REG) & FP_MSKS_FLD) >> FP_MSKS_OFF) 116#define fpsetmask(m) __fpsetreg(~(m), FP_MSKS_REG, FP_MSKS_FLD, FP_MSKS_OFF) 117#define fpgetsticky() ((__fpgetreg(FP_STKY_REG) & FP_STKY_FLD) >> FP_STKY_OFF) 118#define fpresetsticky(m) __fpsetreg(0, FP_STKY_REG, (m), FP_STKY_OFF) 119#define fpsetsticky(m) fpresetsticky(m) 120 121#endif /* !_FLOATINGPOINT_H_ */ 122