1 /*-
2 * Copyright (c) 2004-2005 David Schultz <das@FreeBSD.ORG>
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 *
14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24 * SUCH DAMAGE.
25 *
26 * $FreeBSD: src/lib/msun/amd64/fenv.c,v 1.3 2005/03/16 19:03:45 das Exp $
27 */
28
29 #include <sys/cdefs.h>
30 #include <sys/types.h>
31 #include <machine/fpu.h>
32 #include <fenv.h>
33
34 const fenv_t __fe_dfl_env = {
35 { 0xffff0000 | __INITIAL_FPUCW__,
36 0xffff0000,
37 0xffffffff,
38 { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
39 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0xff, 0xff }
40 },
41 __INITIAL_MXCSR__
42 };
43
44 int
fesetexceptflag(const fexcept_t * flagp,int excepts)45 fesetexceptflag(const fexcept_t *flagp, int excepts)
46 {
47 fenv_t env;
48
49 __fnstenv(&env.__x87);
50 env.__x87.__status &= ~excepts;
51 env.__x87.__status |= *flagp & excepts;
52 __fldenv(env.__x87);
53
54 __stmxcsr(&env.__mxcsr);
55 env.__mxcsr &= ~excepts;
56 env.__mxcsr |= *flagp & excepts;
57 __ldmxcsr(env.__mxcsr);
58
59 return (0);
60 }
61
62 int
feraiseexcept(int excepts)63 feraiseexcept(int excepts)
64 {
65 fexcept_t ex = excepts;
66
67 fesetexceptflag(&ex, excepts);
68 __fwait();
69 return (0);
70 }
71
72 int
fegetenv(fenv_t * envp)73 fegetenv(fenv_t *envp)
74 {
75 int control;
76
77 /*
78 * fnstenv masks all exceptions, so we need to save and
79 * restore the control word to avoid this side effect.
80 */
81 __fnstcw(&control);
82 __fnstenv(&envp->__x87);
83 __stmxcsr(&envp->__mxcsr);
84 __fldcw(control);
85 return (0);
86 }
87
88 int
feholdexcept(fenv_t * envp)89 feholdexcept(fenv_t *envp)
90 {
91 int mxcsr;
92
93 __stmxcsr(&mxcsr);
94 __fnstenv(&envp->__x87);
95 __fnclex();
96 envp->__mxcsr = mxcsr;
97 mxcsr &= ~FE_ALL_EXCEPT;
98 mxcsr |= FE_ALL_EXCEPT << _SSE_EMASK_SHIFT;
99 __ldmxcsr(mxcsr);
100 return (0);
101 }
102
103 int
feupdateenv(const fenv_t * envp)104 feupdateenv(const fenv_t *envp)
105 {
106 int mxcsr, status;
107
108 __fnstsw(&status);
109 __stmxcsr(&mxcsr);
110 fesetenv(envp);
111 feraiseexcept((mxcsr | status) & FE_ALL_EXCEPT);
112 return (0);
113 }
114
115 int
__feenableexcept(int mask)116 __feenableexcept(int mask)
117 {
118 int mxcsr, control, omask;
119
120 mask &= FE_ALL_EXCEPT;
121 __fnstcw(&control);
122 __stmxcsr(&mxcsr);
123 omask = (control | mxcsr >> _SSE_EMASK_SHIFT) & FE_ALL_EXCEPT;
124 control &= ~mask;
125 __fldcw(control);
126 mxcsr &= ~(mask << _SSE_EMASK_SHIFT);
127 __ldmxcsr(mxcsr);
128 return (~omask);
129 }
130
131 int
__fedisableexcept(int mask)132 __fedisableexcept(int mask)
133 {
134 int mxcsr, control, omask;
135
136 mask &= FE_ALL_EXCEPT;
137 __fnstcw(&control);
138 __stmxcsr(&mxcsr);
139 omask = (control | mxcsr >> _SSE_EMASK_SHIFT) & FE_ALL_EXCEPT;
140 control |= mask;
141 __fldcw(control);
142 mxcsr |= mask << _SSE_EMASK_SHIFT;
143 __ldmxcsr(mxcsr);
144 return (~omask);
145 }
146
147 __weak_reference(__feenableexcept, feenableexcept);
148 __weak_reference(__fedisableexcept, fedisableexcept);
149