1 /*- 2 * SPDX-License-Identifier: BSD-4-Clause 3 * 4 * Copyright (c) 2003 Peter Wemm. 5 * Copyright (c) 1990 Andrew Moore, Talke Studio 6 * All rights reserved. 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: @(#) ieeefp.h 1.0 (Berkeley) 9/23/93 37 */ 38 39 #ifndef _X86_X86_IEEEFP_H_ 40 #define _X86_X86_IEEEFP_H_ 41 42 /* Deprecated historical FPU control interface */ 43 44 /* 45 * IEEE floating point type, constant and function definitions. 46 * XXX: {FP,SSE}*FLD and {FP,SSE}*OFF are undocumented pollution. 47 */ 48 49 /* 50 * Rounding modes. 51 */ 52 typedef enum { 53 FP_RN=0, /* round to nearest */ 54 FP_RM, /* round down towards minus infinity */ 55 FP_RP, /* round up towards plus infinity */ 56 FP_RZ /* truncate */ 57 } fp_rnd_t; 58 59 /* 60 * Precision (i.e., rounding precision) modes. 61 */ 62 typedef enum { 63 FP_PS=0, /* 24 bit (single-precision) */ 64 FP_PRS, /* reserved */ 65 FP_PD, /* 53 bit (double-precision) */ 66 FP_PE /* 64 bit (extended-precision) */ 67 } fp_prec_t; 68 69 #define fp_except_t int 70 71 /* 72 * Exception bit masks. 73 */ 74 #define FP_X_INV 0x01 /* invalid operation */ 75 #define FP_X_DNML 0x02 /* denormal */ 76 #define FP_X_DZ 0x04 /* zero divide */ 77 #define FP_X_OFL 0x08 /* overflow */ 78 #define FP_X_UFL 0x10 /* underflow */ 79 #define FP_X_IMP 0x20 /* (im)precision */ 80 #define FP_X_STK 0x40 /* stack fault */ 81 82 /* 83 * FPU control word bit-field masks. 84 */ 85 #define FP_MSKS_FLD 0x3f /* exception masks field */ 86 #define FP_PRC_FLD 0x300 /* precision control field */ 87 #define FP_RND_FLD 0xc00 /* rounding control field */ 88 89 /* 90 * FPU status word bit-field masks. 91 */ 92 #define FP_STKY_FLD 0x3f /* sticky flags field */ 93 94 /* 95 * FPU control word bit-field offsets (shift counts). 96 */ 97 #define FP_MSKS_OFF 0 /* exception masks offset */ 98 #define FP_PRC_OFF 8 /* precision control offset */ 99 #define FP_RND_OFF 10 /* rounding control offset */ 100 101 /* 102 * FPU status word bit-field offsets (shift counts). 103 */ 104 #define FP_STKY_OFF 0 /* sticky flags offset */ 105 106 #define __fldcw(addr) __asm __volatile("fldcw %0" : : "m" (*(addr))) 107 #define __fldenv(addr) __asm __volatile("fldenv %0" : : "m" (*(addr))) 108 #define __fnclex() __asm __volatile("fnclex") 109 #define __fnstcw(addr) __asm __volatile("fnstcw %0" : "=m" (*(addr))) 110 #define __fnstenv(addr) __asm __volatile("fnstenv %0" : "=m" (*(addr))) 111 #define __fnstsw(addr) __asm __volatile("fnstsw %0" : "=m" (*(addr))) 112 #define __ldmxcsr(addr) __asm __volatile("ldmxcsr %0" : : "m" (*(addr))) 113 #define __stmxcsr(addr) __asm __volatile("stmxcsr %0" : "=m" (*(addr))) 114 115 /* 116 * Load the control word. Be careful not to trap if there is a currently 117 * unmasked exception (ones that will become freshly unmasked are not a 118 * problem). This case must be handled by a save/restore of the 119 * environment or even of the full x87 state. Accessing the environment 120 * is very inefficient, so only do it when necessary. 121 */ 122 static __inline void 123 __fnldcw(unsigned short _cw, unsigned short _newcw) 124 { 125 struct { 126 unsigned _cw; 127 unsigned _other[6]; 128 } _env; 129 unsigned short _sw; 130 131 if ((_cw & FP_MSKS_FLD) != FP_MSKS_FLD) { 132 __fnstsw(&_sw); 133 if (((_sw & ~_cw) & FP_STKY_FLD) != 0) { 134 __fnstenv(&_env); 135 _env._cw = _newcw; 136 __fldenv(&_env); 137 return; 138 } 139 } 140 __fldcw(&_newcw); 141 } 142 143 #endif/* _X86_X86_IEEEFP_H_ */ 144