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1/*
2 * Copyright (c) 2002 Apple Computer, Inc. All rights reserved.
3 *
4 * @APPLE_LICENSE_HEADER_START@
5 *
6 * The contents of this file constitute Original Code as defined in and
7 * are subject to the Apple Public Source License Version 1.1 (the
8 * "License"). You may not use this file except in compliance with the
9 * License. Please obtain a copy of the License at
10 * http://www.apple.com/publicsource and read it before using this file.
11 *
12 * This Original Code and all software distributed under the License are
13 * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER
14 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
15 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
16 * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT. Please see the
17 * License for the specific language governing rights and limitations
18 * under the License.
19 *
20 * @APPLE_LICENSE_HEADER_END@
21 */
22
23/*******************************************************************************
24* *
25* File: fenv.h *
26* *
27* Contains: typedefs and prototypes for C99 floating point environment. *
28* *
29*******************************************************************************/
30
31#ifndef __FENV__
32#define __FENV__
33
34/* We require VFP for this set of interfaces to work */
35#if !defined(__VFP_FP__) || defined(__SOFTFP__)
36 #warning The <fenv.h> functions are not supported on platforms that do not have hardware floating-point.
37#else
38
39#ifdef __cplusplus
40extern "C" {
41#endif
42
43/*
44 A collection of functions designed to provide access to the floating
45 point environment for numerical programming. It is compliant with
46 the floating-point requirements in C99.
47
48 The file <fenv.h> declares many functions in support of numerical
49 programming. Programs that test flags or run under
50 non-default modes must do so under the effect of an enabling
51 "fenv_access" pragma:
52
53 #pragma STDC FENV_ACCESS on
54
55 Note that prior to iPhone OS 2.0, these interfaces did nothing.
56*/
57
58/********************************************************************************
59* *
60* fenv_t is a type for representing the entire floating-point *
61* environment in a single object. *
62* *
63* fexcept_t is a type for representing the floating-point *
64* exception flag state collectively. *
65* *
66********************************************************************************/
67
68
69
70typedef struct {
71 union
72 {
73 struct
74 {
75 unsigned int __fpscr;
76 unsigned int __reserved0;
77 unsigned int __reserved1;
78 unsigned int __reserved2;
79 };
80#if defined( __GNUC__ )
81 struct
82 {
83 unsigned int __fpscr_cmp_n : 1;
84 unsigned int __fpscr_cmp_z : 1;
85 unsigned int __fpscr_cmp_c : 1;
86 unsigned int __fpscr_cmp_v : 1;
87 unsigned int __fpscr_do_not_modify_1 : 2; /* Should be zero */
88 unsigned int __fpscr_default_nan_mode : 1;
89 unsigned int __fpscr_flush_to_zero : 1;
90 unsigned int __fpscr_rounding_mode : 2;
91 unsigned int __fpscr_stride : 2;
92 unsigned int __fpscr_do_not_modify_2 : 1; /* Should be zero */
93 unsigned int __fpscr_len : 3 ;
94 unsigned int __fpscr_trap_enable_subnormal : 1 ; /* Note: we run under "Run Fast Mode". Setting this bit has undefined results. */
95 unsigned int __fpscr_do_not_modfify_3 : 2; /* Should be zero */
96 unsigned int __fpscr_trap_enable_inexact : 1; /* Note: we run under "Run Fast Mode". Setting this bit has undefined results. */
97 unsigned int __fpscr_trap_enable_underflow : 1; /* Note: we run under "Run Fast Mode". Setting this bit has undefined results. */
98 unsigned int __fpscr_trap_enable_overflow : 1; /* Note: we run under "Run Fast Mode". Setting this bit has undefined results. */
99 unsigned int __fpscr_trap_enable_div_by_zero : 1; /* Note: we run under "Run Fast Mode". Setting this bit has undefined results. */
100 unsigned int __fpscr_trap_enable_invalid : 1; /* Note: we run under "Run Fast Mode". Setting this bit has undefined results. */
101 unsigned int __fpscr_fp_state_flag_subnormal : 1;
102 unsigned int __fpscr_do_not_modify_4 : 2; /* Should be zero */
103 unsigned int __fpscr_fp_state_flag_inexact : 1;
104 unsigned int __fpscr_fp_state_flag_underflow : 1;
105 unsigned int __fpscr_fp_state_flag_overflow : 1;
106 unsigned int __fpscr_fp_state_flag_div_by_zero : 1;
107 unsigned int __fpscr_fp_state_flag_invalid : 1;
108 } __attribute((packed));
109#endif
110 };
111} fenv_t;
112
113typedef unsigned short fexcept_t;
114
115/* Definitions of floating-point exception macros */
116#define FE_INEXACT 0x0010
117#define FE_UNDERFLOW 0x0008
118#define FE_OVERFLOW 0x0004
119#define FE_DIVBYZERO 0x0002
120#define FE_INVALID 0x0001
121#define FE_ALL_EXCEPT 0x001F
122
123/* Definitions of rounding direction macros */
124#define FE_TONEAREST 0x00000000
125#define FE_UPWARD 0x00400000
126#define FE_DOWNWARD 0x00800000
127#define FE_TOWARDZERO 0x00C00000
128
129/* default environment object */
130extern const fenv_t _FE_DFL_ENV;
131#define FE_DFL_ENV &_FE_DFL_ENV /* pointer to default environment */
132
133
134/*******************************************************************************
135* The following functions provide high level access to the exception flags.*
136* The "int" input argument can be constructed by bitwise ORs of the *
137* exception macros: for example: FE_OVERFLOW | FE_INEXACT. *
138*******************************************************************************/
139
140/*******************************************************************************
141* The function "feclearexcept" clears the supported floating point *
142* exceptions represented by its argument. *
143*******************************************************************************/
144
145extern int feclearexcept(int /*excepts*/);
146
147
148/*******************************************************************************
149* The function "fegetexceptflag" stores a implementation-defined *
150* representation of the states of the floating-point status flags indicated *
151* by its integer argument excepts in the object pointed to by the argument, *
152* flagp. *
153*******************************************************************************/
154
155extern int fegetexceptflag(fexcept_t * /*flagp*/, int /*excepts*/);
156
157
158/*******************************************************************************
159* The function "feraiseexcept" raises the supported floating-point *
160* exceptions represented by its argument. The order in which these *
161* floating-point exceptions are raised is unspecified. *
162*******************************************************************************/
163
164extern int feraiseexcept(int /*excepts*/);
165
166
167/*******************************************************************************
168* The function "fesetexceptflag" sets or clears the floating point status *
169* flags indicated by the argument excepts to the states stored in the *
170* object pointed to by flagp. The value of the *flagp shall have been set *
171* by a previous call to fegetexceptflag whose second argument represented *
172* at least those floating-point exceptions represented by the argument *
173* excepts. This function does not raise floating-point exceptions; it just *
174* sets the state of the flags. *
175*******************************************************************************/
176
177extern int fesetexceptflag(const fexcept_t * /*flagp*/, int /*excepts*/);
178
179
180/*******************************************************************************
181* The function "fetestexcept" determines which of the specified subset of *
182* the floating-point exception flags are currently set. The excepts *
183* argument specifies the floating-point status flags to be queried. This *
184* function returns the value of the bitwise OR of the floating-point *
185* exception macros corresponding to the currently set floating-point *
186* exceptions included in excepts. *
187* *
188*******************************************************************************/
189
190extern int fetestexcept(int /*excepts*/);
191
192
193/*******************************************************************************
194* The following functions provide control of rounding direction modes. *
195*******************************************************************************/
196
197/*******************************************************************************
198* The function "fegetround" returns the value of the rounding direction *
199* macro which represents the current rounding direction, or a negative *
200* if there is no such rounding direction macro or the current rounding *
201* direction is not determinable. *
202*******************************************************************************/
203
204extern int fegetround(void);
205
206
207/*******************************************************************************
208* The function "fesetround" establishes the rounding direction represented *
209* by its argument "round". If the argument is not equal to the value of a *
210* rounding direction macro, the rounding direction is not changed. It *
211* returns zero if and only if the argument is equal to a rounding *
212* direction macro. *
213*******************************************************************************/
214
215extern int fesetround(int /*round*/);
216
217
218/*******************************************************************************
219* The following functions manage the floating-point environment, exception *
220* flags and dynamic modes, as one entity. *
221*******************************************************************************/
222
223/*******************************************************************************
224* The fegetenv function stores the current floating-point enviornment in *
225* the object pointed to by envp. *
226*******************************************************************************/
227extern int fegetenv(fenv_t * /*envp*/);
228
229/*******************************************************************************
230* The feholdexcept function saves the current floating-point environment in *
231* the object pointed to by envp, clears the floating-point status flags, *
232* and then installs a non-stop (continue on floating-point exceptions) *
233* mode, if available, for all floating-point exceptions. The feholdexcept *
234* function returns zero if and only if non-stop floating-point exceptions *
235* handling was successfully installed. *
236*******************************************************************************/
237extern int feholdexcept(fenv_t * /*envp*/);
238
239/*******************************************************************************
240* The fesetnv function establishes the floating-point environment *
241* represented by the object pointed to by envp. The argument envp shall *
242* point to an object set by a call to fegetenv or feholdexcept, or equal to *
243* a floating-point environment macro -- we define only *FE_DFL_ENV and *
244* FE_DISABLE_SSE_DENORMS_ENV -- to be C99 standard compliant and portable *
245* to other architectures. Note that fesetnv merely installs the state of *
246* the floating-point status flags represented through its argument, and *
247* does not raise these floating-point exceptions. *
248*******************************************************************************/
249extern int fesetenv(const fenv_t * /*envp*/);
250
251/*******************************************************************************
252* The feupdateenv function saves the currently raised floating-point *
253* exceptions in its automatic storage, installs the floating-point *
254* environment represented by the object pointed to by envp, and then raises *
255* the saved floating-point exceptions. The argument envp shall point to an *
256* object set by a call to feholdexcept or fegetenv or equal a *
257* floating-point environment macro. *
258*******************************************************************************/
259extern int feupdateenv(const fenv_t * /*envp*/);
260
261#ifdef __cplusplus
262}
263#endif
264
265#endif // HARDWARE FP
266
267#endif /* __FENV__ */
268