1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
|
#ifndef CYGONCE_LIBC_STDLIB_DIV_INL
#define CYGONCE_LIBC_STDLIB_DIV_INL
/*===========================================================================
//
// div.inl
//
// Inline implementations for the ISO standard utility functions
// div() and ldiv()
//
//===========================================================================
// ####ECOSGPLCOPYRIGHTBEGIN####
// -------------------------------------------
// This file is part of eCos, the Embedded Configurable Operating System.
// Copyright (C) 1998, 1999, 2000, 2001, 2002 Free Software Foundation, Inc.
//
// eCos is free software; you can redistribute it and/or modify it under
// the terms of the GNU General Public License as published by the Free
// Software Foundation; either version 2 or (at your option) any later
// version.
//
// eCos is distributed in the hope that it will be useful, but WITHOUT
// ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
// FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
// for more details.
//
// You should have received a copy of the GNU General Public License
// along with eCos; if not, write to the Free Software Foundation, Inc.,
// 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
//
// As a special exception, if other files instantiate templates or use
// macros or inline functions from this file, or you compile this file
// and link it with other works to produce a work based on this file,
// this file does not by itself cause the resulting work to be covered by
// the GNU General Public License. However the source code for this file
// must still be made available in accordance with section (3) of the GNU
// General Public License v2.
//
// This exception does not invalidate any other reasons why a work based
// on this file might be covered by the GNU General Public License.
// -------------------------------------------
// ####ECOSGPLCOPYRIGHTEND####
//===========================================================================
//#####DESCRIPTIONBEGIN####
//
// Author(s): jlarmour
// Contributors:
// Date: 2000-04-28
// Purpose:
// Description:
// Usage: Do not include this file directly - include <stdlib.h> instead
//
//####DESCRIPTIONEND####
//
//=========================================================================*/
// CONFIGURATION
#include <pkgconf/libc_stdlib.h> // Configuration header
// INCLUDES
#include <cyg/infra/cyg_ass.h> // Assertion support
#include <cyg/infra/cyg_trac.h> // Tracing support
/* TYPE DEFINITIONS */
/* return type of the div() function */
typedef struct {
int quot; /* quotient */
int rem; /* remainder */
} div_t;
/* return type of the ldiv() function */
typedef struct {
long quot; /* quotient */
long rem; /* remainder */
} ldiv_t;
/* FUNCTION PROTOTYPES */
#ifdef __cplusplus
extern "C" {
#endif
extern div_t
div( int /* numerator */, int /* denominator */ ) __attribute__((__const__));
extern ldiv_t
ldiv( long /* numerator */, long /* denominator */ ) __attribute__((__const__));
#ifdef __cplusplus
} /* extern "C" */
#endif
/* FUNCTIONS */
#ifndef CYGPRI_LIBC_STDLIB_DIV_INLINE
# define CYGPRI_LIBC_STDLIB_DIV_INLINE extern __inline__
#endif
CYGPRI_LIBC_STDLIB_DIV_INLINE div_t
div( int __numer, int __denom )
{
div_t __ret;
CYG_REPORT_FUNCNAMETYPE( "div", "quotient: %d");
CYG_REPORT_FUNCARG2DV( __numer, __denom );
// FIXME: what if they want it handled with SIGFPE? Should have option
CYG_PRECONDITION(__denom != 0, "division by zero attempted!");
__ret.quot = __numer / __denom;
__ret.rem = __numer % __denom;
// But the modulo is implementation-defined for -ve numbers (ISO C 6.3.5)
// and we are required to "round" to zero (ISO C 7.10.6.2)
//
// The cases we have to deal with are inexact division of:
// a) + div +
// b) + div -
// c) - div +
// d) - div -
//
// a) can never go wrong and the quotient and remainder are always positive
// b) only goes wrong if the negative quotient has been "rounded" to
// -infinity - if so then the remainder will be negative when it
// should be positive or zero
// c) only goes wrong if the negative quotient has been "rounded" to
// -infinity - if so then the remainder will be positive when it
// should be negative or zero
// d) only goes wrong if the positive quotient has been rounded to
// +infinity - if so then the remainder will be positive when it
// should be negative or zero
//
// So the correct sign of the remainder corresponds to the sign of the
// numerator. Which means we can say that the result needs adjusting
// iff the sign of the numerator is different from the sign of the
// remainder.
//
// You may be interested to know that the Berkeley version of div()
// would get this wrong for e.g. (c) and (d) on some targets.
// e.g. for (-5)/4 it could leave the result as -2R3
if ((__ret.rem < 0) && (__numer > 0)) {
++__ret.quot;
__ret.rem -= __denom;
} else if ((__ret.rem > 0) && (__numer < 0)) {
--__ret.quot;
__ret.rem += __denom;
} // else
CYG_REPORT_RETVAL( __ret.quot );
return __ret;
} // div()
CYGPRI_LIBC_STDLIB_DIV_INLINE ldiv_t
ldiv( long __numer, long __denom )
{
ldiv_t __ret;
CYG_REPORT_FUNCNAMETYPE( "ldiv", "quotient: %d");
CYG_REPORT_FUNCARG2DV( __numer, __denom );
// FIXME: what if they want it handled with SIGFPE? Should have option
CYG_PRECONDITION(__denom != 0, "division by zero attempted!");
__ret.quot = __numer / __denom;
__ret.rem = __numer % __denom;
// But the modulo is implementation-defined for -ve numbers (ISO C 6.3.5)
// and we are required to "round" to zero (ISO C 7.10.6.2)
//
// The cases we have to deal with are inexact division of:
// a) + div +
// b) + div -
// c) - div +
// d) - div -
//
// a) can never go wrong and the quotient and remainder are always positive
// b) only goes wrong if the negative quotient has been "rounded" to
// -infinity - if so then the remainder will be negative when it
// should be positive or zero
// c) only goes wrong if the negative quotient has been "rounded" to
// -infinity - if so then the remainder will be positive when it
// should be negative or zero
// d) only goes wrong if the positive quotient has been rounded to
// +infinity - if so then the remainder will be positive when it
// should be negative or zero
//
// So the correct sign of the remainder corresponds to the sign of the
// numerator. Which means we can say that the result needs adjusting
// iff the sign of the numerator is different from the sign of the
// remainder.
//
// You may be interested to know that the Berkeley version of ldiv()
// would get this wrong for e.g. (c) and (d) on some targets.
// e.g. for (-5)/4 it could leave the result as -2R3
if ((__ret.rem < 0) && (__numer > 0)) {
++__ret.quot;
__ret.rem -= __denom;
} else if ((__ret.rem > 0) && (__numer < 0)) {
--__ret.quot;
__ret.rem += __denom;
} // else
CYG_REPORT_RETVAL( __ret.quot );
return __ret;
} // ldiv()
#endif // CYGONCE_LIBC_STDLIB_DIV_INL multiple inclusion protection
// EOF div.inl
|
