4 * This file is part of BeRTOS.
6 * Bertos is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License as published by
8 * the Free Software Foundation; either version 2 of the License, or
9 * (at your option) any later version.
11 * This program is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 * GNU General Public License for more details.
16 * You should have received a copy of the GNU General Public License
17 * along with this program; if not, write to the Free Software
18 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
20 * As a special exception, you may use this file as part of a free software
21 * library without restriction. Specifically, if other files instantiate
22 * templates or use macros or inline functions from this file, or you compile
23 * this file and link it with other files to produce an executable, this
24 * file does not by itself cause the resulting executable to be covered by
25 * the GNU General Public License. This exception does not however
26 * invalidate any other reasons why the executable file might be covered by
27 * the GNU General Public License.
29 * Copyright 2003, 2004 Develer S.r.l. (http://www.develer.com/)
33 * \brief Common and handy function macros
36 * \author Bernardo Innocenti <bernie@develer.com>
37 * \author Giovanni Bajo <rasky@develer.com>
42 #include <cfg/compiler.h>
44 /* avr-gcc does not seem to support libstdc++ */
45 #if defined(__cplusplus) && !CPU_AVR
46 /* Type-generic macros implemented with template functions. */
49 template<class T> inline T ABS(T n) { return n >= 0 ? n : -n; }
50 #define MIN(a,b) std::min(a, b)
51 #define MAX(a,b) std::max(a, b)
52 #define SWAP(a,b) std::swap(a, b)
53 #elif (COMPILER_STATEMENT_EXPRESSIONS && COMPILER_TYPEOF)
54 /* Type-generic macros implemented with statement expressions. */
57 (_n < 0) ? -_n : _n; \
62 ASSERT_TYPE_EQUAL(_a, _b); \
63 (_a < _b) ? _a : _b; \
68 ASSERT_TYPE_EQUAL(_a, _b); \
69 (_a > _b) ? _a : _b; \
71 #else /* !(COMPILER_STATEMENT_EXPRESSIONS && COMPILER_TYPEOF) */
72 /* Buggy macros for inferior compilers. */
73 #define ABS(a) (((a) < 0) ? -(a) : (a))
74 #define MIN(a,b) (((a) < (b)) ? (a) : (b))
75 #define MAX(a,b) (((a) > (b)) ? (a) : (b))
76 #endif /* !(COMPILER_STATEMENT_EXPRESSIONS && COMPILER_TYPEOF) */
78 /** Bound \a x between \a min and \a max. */
79 #define MINMAX(min,x,max) (MIN(MAX(min, x), max))
82 /* Use standard implementation from <algorithm> */
83 #define SWAP(a,b) std::swap(a, b)
86 * Type-generic macro to swap \a a with \a b.
88 * \note Arguments are evaluated multiple times.
93 ASSERT_TYPE_EQUAL(a, b); \
98 #else /* !COMPILER_TYPEOF */
99 /* Sub-optimal implementation that only works with integral types. */
107 #endif /* COMPILER_TYPEOF */
110 * Macro to swap \a a with \a b, with explicit type \a T for dumb C89 compilers.
112 * \note Arguments are evaluated multiple times.
114 #define SWAP_T(a, b, T) \
117 ASSERT_TYPE_IS(a, T); \
118 ASSERT_TYPE_IS(b, T); \
126 /** Convert a bit value to a binary flag. */
127 #define BV(x) (1<<(x))
130 /** Same as BV() but with 32 bit result */
131 #define BV32(x) ((uint32_t)1<<(x))
133 /** Same as BV() but with 16 bit result */
134 #define BV16(x) ((uint16_t)1<<(x))
136 /** Same as BV() but with 8 bit result */
137 #define BV8(x) ((uint8_t)1<<(x))
140 * Perform an integer division rounding the result to the nearest int value.
141 * \note \a divisor should preferibly be a costant, otherwise this macro generates
142 * 2 division. Also divisor is evaluated twice.
144 #define DIV_ROUND(dividend, divisor) (((dividend) + (divisor) / 2) / (divisor))
146 /** Round up \a x to an even multiple of the 2's power \a pad. */
147 #define ROUND_UP2(x, pad) (((x) + ((pad) - 1)) & ~((pad) - 1))
150 #define ROUND2 ROUND_UP2
153 * \name Integer round macros.
155 * Round \a x to a multiple of \a base.
156 * \note If \a x is signed these macros generate a lot of code.
159 #define ROUND_DOWN(x, base) ( (x) - ((x) % (base)) )
160 #define ROUND_UP(x, base) ( ((x) + (base) - 1) - (((x) + (base) - 1) % (base)) )
161 #define ROUND_NEAREST(x, base) ( ((x) + (base) / 2) - (((x) + (base) / 2) % (base)) )
164 /** Check if \a x is an integer power of 2. */
165 #define IS_POW2(x) (!(bool)((x) & ((x)-1)))
167 /** Calculate a compile-time log2 for a uint8_t */
168 #define UINT8_LOG2(x) \
175 ((x) < 128 ? 6 : 7)))))))
177 /** Calculate a compile-time log2 for a uint16_t */
178 #define UINT16_LOG2(x) \
179 ((x < 256) ? UINT8_LOG2(x) : UINT8_LOG2((x) >> 8) + 8)
181 /** Calculate a compile-time log2 for a uint32_t */
182 #define UINT32_LOG2(x) \
183 ((x < 65536UL) ? UINT16_LOG2(x) : UINT16_LOG2((x) >> 16) + 16)
185 #if COMPILER_VARIADIC_MACROS
186 /** Count the number of arguments (up to 16). */
187 #define PP_COUNT(...) \
188 PP_COUNT__(__VA_ARGS__,16,15,14,13,12,11,10,9,8,7,6,5,4,3,2,1,0)
189 #define PP_COUNT__(a0,a1,a2,a3,a4,a5,a6,a7,a8,a9,a10,a11,a12,a13,a14,a15,count,...) \
193 #if COMPILER_VARIADIC_MACROS
195 * \def BIT_CHANGE(reg, (mask, value), ...)
197 * This macro allows for efficient and compact bit toggling in a hardware
198 * register. It is meant to replace hand-coded cruft which toggles bits
201 * It is possible to specify an unlimited pair of (mask, value) parameters.
205 * void set_timer(bool start)
207 * BIT_CHANGE(REG_CTRL_TIMER,
208 * (TIMER_MODE, MODE_COUNT),
216 * The macro expansion will be roughly the following:
219 * REG_CTRL_TIMER = (REG_CTRL_TIMER & ~(TIMER_MODE|OVL_IRQ|CMP_IRQ|START)
220 * | (MODE_COUNT|OVL_IRQ|CMP_IRQ|(start ? START : 0));
223 * It is up to the compiler to produce the optimal code. We checked that GCC produces
224 * the best code in most cases. We preferred this expansion over the use of a block
225 * with a local variable because CodeWarrior 6.1 was not able to remove completely the
226 * allocation of the local from the stack.
228 * \note This macro is available only in C99 because it makes use of variadic macros.
229 * It would be possible to make up an implementation with a slightly different syntax
230 * for use with C90 compilers, through Boost Preprocessor.
234 * \def BIT_CHANGE_BV(reg, (bit, value), ...)
236 * Similar to BIT_CHANGE(), but get bits instead of masks (and applies BV() to convert
240 #define BIT_EXTRACT_FLAG_0(bit, value) bit
241 #define BIT_EXTRACT_FLAG_1(bit, value) BV(bit)
242 #define BIT_EXTRACT_VALUE__(bit, value) value
244 #define BIT_MASK_SINGLE__(use_bv, index, max, arg) \
245 ((index < max) ? (PP_CAT(BIT_EXTRACT_FLAG_, use_bv) arg) : 0) \
248 #define BIT_MASK_IF_SINGLE__(use_bv, index, max, arg) \
249 (((index < max) && (BIT_EXTRACT_VALUE__ arg)) ? (PP_CAT(BIT_EXTRACT_FLAG_, use_bv) arg) : 0) \
252 #define BIT_ITER__2(macro, use_bv, max, a0,a1,a2,a3,a4,a5,a6,a7,a8,a9,a10,a11,a12,a13,a14,a15, ...) \
253 (macro(use_bv, 0, max, a0) | \
254 macro(use_bv, 1, max, a1) | \
255 macro(use_bv, 2, max, a2) | \
256 macro(use_bv, 3, max, a3) | \
257 macro(use_bv, 4, max, a4) | \
258 macro(use_bv, 5, max, a5) | \
259 macro(use_bv, 6, max, a6) | \
260 macro(use_bv, 7, max, a7) | \
261 macro(use_bv, 8, max, a8) | \
262 macro(use_bv, 9, max, a9) | \
263 macro(use_bv, 10, max, a10) | \
264 macro(use_bv, 11, max, a11) | \
265 macro(use_bv, 12, max, a12) | \
266 macro(use_bv, 13, max, a13) | \
267 macro(use_bv, 14, max, a14) | \
268 macro(use_bv, 15, max, a15)) \
271 #define BIT_ITER__(macro, use_bv, ...) \
272 BIT_ITER__2(macro, use_bv, PP_COUNT(__VA_ARGS__), __VA_ARGS__, (0,1),(0,1),(0,1),(0,1),(0,1),(0,1),(0,1),(0,1),(0,1),(0,1),(0,1),(0,1),(0,1),(0,1),(0,1),(0,1)) \
275 #define BIT_MASKS__(use_bv, ...) \
276 BIT_ITER__(BIT_MASK_SINGLE__, use_bv, __VA_ARGS__)
279 #define BIT_MASKS_CONDITIONAL__(use_bv, ...) \
280 BIT_ITER__(BIT_MASK_IF_SINGLE__, use_bv, __VA_ARGS__)
283 #define BIT_CHANGE__(reg, use_bv, ...) \
284 ((reg) = ((reg) & ~BIT_MASKS__(use_bv, __VA_ARGS__)) | BIT_MASKS_CONDITIONAL__(use_bv, __VA_ARGS__)) \
287 #define BIT_CHANGE(reg, ...) BIT_CHANGE__(reg, 0, __VA_ARGS__)
288 #define BIT_CHANGE_BV(reg, ...) BIT_CHANGE__(reg, 1, __VA_ARGS__)
290 #endif /* COMPILER_VARIADIC_MACROS */
293 * Macro for rotating bit left or right.
296 #define ROTR(var, rot) (((var) >> (rot)) | ((var) << ((sizeof(var) * 8) - (rot))))
297 #define ROTL(var, rot) (((var) << (rot)) | ((var) >> ((sizeof(var) * 8) - (rot))))
300 #endif /* MACROS_H */