ieeefp.h revision 143658
1/*- 2 * Copyright (c) 1990 Andrew Moore, Talke Studio 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 3. All advertising materials mentioning features or use of this software 14 * must display the following acknowledgement: 15 * This product includes software developed by the University of 16 * California, Berkeley and its contributors. 17 * 4. Neither the name of the University nor the names of its contributors 18 * may be used to endorse or promote products derived from this software 19 * without specific prior written permission. 20 * 21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 24 * 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: @(#) ieeefp.h 1.0 (Berkeley) 9/23/93 34 * $FreeBSD: head/sys/i386/include/ieeefp.h 143658 2005-03-15 15:53:39Z das $ 35 */ 36 37/* 38 * IEEE floating point type and constant definitions. 39 */ 40 41#ifndef _MACHINE_IEEEFP_H_ 42#define _MACHINE_IEEEFP_H_ 43 44#ifndef _SYS_CDEFS_H_ 45#error this file needs sys/cdefs.h as a prerequisite 46#endif 47 48/* 49 * FP rounding modes 50 */ 51typedef enum { 52 FP_RN=0, /* round to nearest */ 53 FP_RM, /* round down to minus infinity */ 54 FP_RP, /* round up to plus infinity */ 55 FP_RZ /* truncate */ 56} fp_rnd_t; 57 58/* 59 * FP precision modes 60 */ 61typedef enum { 62 FP_PS=0, /* 24 bit (single-precision) */ 63 FP_PRS, /* reserved */ 64 FP_PD, /* 53 bit (double-precision) */ 65 FP_PE /* 64 bit (extended-precision) */ 66} fp_prec_t; 67 68#define fp_except_t int 69 70/* 71 * FP exception masks 72 */ 73#define FP_X_INV 0x01 /* invalid operation */ 74#define FP_X_DNML 0x02 /* denormal */ 75#define FP_X_DZ 0x04 /* zero divide */ 76#define FP_X_OFL 0x08 /* overflow */ 77#define FP_X_UFL 0x10 /* underflow */ 78#define FP_X_IMP 0x20 /* (im)precision */ 79#define FP_X_STK 0x40 /* stack fault */ 80 81/* 82 * FP registers 83 */ 84#define FP_MSKS_REG 0 /* exception masks */ 85#define FP_PRC_REG 0 /* precision */ 86#define FP_RND_REG 0 /* direction */ 87#define FP_STKY_REG 1 /* sticky flags */ 88 89/* 90 * FP register bit field masks 91 */ 92#define FP_MSKS_FLD 0x3f /* exception masks field */ 93#define FP_PRC_FLD 0x300 /* precision control field */ 94#define FP_RND_FLD 0xc00 /* round control field */ 95#define FP_STKY_FLD 0x3f /* sticky flags field */ 96 97/* 98 * FP register bit field offsets 99 */ 100#define FP_MSKS_OFF 0 /* exception masks offset */ 101#define FP_PRC_OFF 8 /* precision control offset */ 102#define FP_RND_OFF 10 /* round control offset */ 103#define FP_STKY_OFF 0 /* sticky flags offset */ 104 105#ifdef __GNUCLIKE_ASM 106 107#define __fldenv(addr) __asm __volatile("fldenv %0" : : "m" (*(addr))) 108#define __fnstenv(addr) __asm __volatile("fnstenv %0" : "=m" (*(addr))) 109#define __fnstcw(addr) __asm __volatile("fnstcw %0" : "=m" (*(addr))) 110#define __fnstsw(addr) __asm __volatile("fnstsw %0" : "=m" (*(addr))) 111 112/* 113 * return the contents of a FP register 114 */ 115static __inline__ int 116__fpgetreg(int _reg) 117{ 118 unsigned short _mem; 119 120 /*- 121 * This is more efficient than it looks. The switch gets optimized 122 * away if _reg is constant. 123 * 124 * The default case only supports _reg == 0. We could handle more 125 * registers (e.g., tags) using fnstenv, but the interface doesn't 126 * support more. 127 */ 128 switch(_reg) { 129 default: 130 __fnstcw(&_mem); 131 break; 132 case FP_STKY_REG: 133 __fnstsw(&_mem); 134 break; 135 } 136 return _mem; 137} 138 139/* 140 * set a FP mode; return previous mode 141 */ 142static __inline__ int 143__fpsetreg(int _m, int _reg, int _fld, int _off) 144{ 145 unsigned _env[7]; 146 unsigned _p; 147 148 /* 149 * _reg == 0 could be handled better using fnstcw/fldcw. 150 */ 151 __fnstenv(_env); 152 _p = (_env[_reg] & _fld) >> _off; 153 _env[_reg] = (_env[_reg] & ~_fld) | (_m << _off & _fld); 154 __fldenv(_env); 155 return _p; 156} 157 158#endif /* __GNUCLIKE_ASM */ 159 160/* 161 * SysV/386 FP control interface 162 */ 163#define fpgetround() ((fp_rnd_t) \ 164 ((__fpgetreg(FP_RND_REG) & FP_RND_FLD) >> FP_RND_OFF)) 165#define fpsetround(m) ((fp_rnd_t) \ 166 __fpsetreg((m), FP_RND_REG, FP_RND_FLD, FP_RND_OFF)) 167#define fpgetprec() ((fp_prec_t) \ 168 ((__fpgetreg(FP_PRC_REG) & FP_PRC_FLD) >> FP_PRC_OFF)) 169#define fpsetprec(m) ((fp_prec_t) \ 170 __fpsetreg((m), FP_PRC_REG, FP_PRC_FLD, FP_PRC_OFF)) 171#define fpgetmask() ((fp_except_t) \ 172 ((~__fpgetreg(FP_MSKS_REG) & FP_MSKS_FLD) >> FP_MSKS_OFF)) 173#define fpsetmask(m) ((fp_except_t) \ 174 (~__fpsetreg(~(m), FP_MSKS_REG, FP_MSKS_FLD, FP_MSKS_OFF)) & \ 175 (FP_MSKS_FLD >> FP_MSKS_OFF)) 176#define fpgetsticky() ((fp_except_t) \ 177 ((__fpgetreg(FP_STKY_REG) & FP_STKY_FLD) >> FP_STKY_OFF)) 178#define fpresetsticky(m) ((fp_except_t) \ 179 __fpsetreg(0, FP_STKY_REG, (m), FP_STKY_OFF)) 180 181/* Suppress prototypes in the MI header. */ 182#define _IEEEFP_INLINED_ 1 183 184#endif /* !_MACHINE_IEEEFP_H_ */ 185