1 /*-
2 * Copyright (c) 1993 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: @(#) floatingpoint.h 1.0 (Berkeley) 9/23/93
34 * $FreeBSD: src/sys/i386/include/floatingpoint.h,v 1.6.12.1 1999/09/05 08:11:48 peter Exp $
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 */
63 static __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 */
90 static __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_ */
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