Pasto.

[bertos.git] / bertos / cfg / macros.h

diff --git a/bertos/cfg/macros.h b/bertos/cfg/macros.h
index 4f77b21e6c6c7227492156dea2329e59b9e6f6cf..073ad55fc84a30ad3ea952d4aa4f15a04414e27a 100644 (file)
--- a/bertos/cfg/macros.h
+++ b/bertos/cfg/macros.h
@@ -30,9 +30,12 @@
  *
  * -->
  *
+ * \defgroup macros General purpose macros
+ * \ingroup core
+ * \{
+ *
  * \brief Common and handy function macros
  *
- * \version $Id$
  * \author Bernie Innocenti <bernie@codewiz.org>
  * \author Giovanni Bajo <rasky@develer.com>
  */
@@ -95,6 +98,11 @@
        #define MAX(a,b)        (((a) > (b)) ? (a) : (b))
 #endif /* !(COMPILER_STATEMENT_EXPRESSIONS && COMPILER_TYPEOF) */
 
+/** Align \p value to the next \p align boundary */
+#define ALIGN_UP(value, align) (((value) & ((align) - 1)) ? \
+                               (((value) + ((align) - 1)) & ~((align) - 1)) : \
+                               (value))
+
 /** Bound \a x between \a min and \a max. */
 #define MINMAX(min,x,max)  (MIN(MAX(min, x), max))
 
@@ -182,6 +190,48 @@
  */
 #define DIV_ROUND(dividend, divisor)  (((dividend) + (divisor) / 2) / (divisor))
 
+/**
+ * Perform an integer division rounding the result to the upper int value.
+ * \note \a divisor is evaluated twice.
+ */
+#define DIV_ROUNDUP(dividend, divisor)  (((dividend) + (divisor) - 1) / (divisor))
+
+
+/**
+ * Perform a multiply between the integer \a a and the float constant \a f.
+ *
+ * This macro can be used in order to avoid floating point arithmetics
+ * in expressions like this:
+ * \code
+ * int a, b;
+ * a = b * 0.5579652750;
+ * \endcode
+ *
+ * This macro rounds the floating point constant to a fraction,
+ * usign (2 ^ prec) as the denominator.
+ * For instance, with prec = 8, the constant 0.5579652750 will be rounded to:
+ * (143 / 256) = 0.55859375
+ * So, the former code will be transformed to:
+ * \code
+ * a = b * 143 / 256;
+ * \endcode
+ *
+ * Since the denominator is a power of 2, we rely on the compiler to optimize
+ * this to a right shift.
+ * So, when you have to multiply an integer by a float constant, this macro
+ * will not use the floating point arithmentics.
+ * The operation will be converted to a mul + shift, with a huge performance boost.
+ *
+ * \note \a f MUST be a constant in order gain performance benefits.
+ *
+ * \param a integer you want to multiply
+ * \param f floating point constant which you want to multply with \a a
+ * \param prec conversion precision, ranges from 1 to the number of bits in a long.
+ *             The higher, the better the approximation of the float constant will be.
+ */
+#define INT_MULT(a, f, prec) (((a) * (long)((f) * (1 << (prec)) + 0.5)) >> (prec))
+
+
 /** Round up \a x to an even multiple of the 2's power \a pad. */
 #define ROUND_UP2(x, pad) (((x) + ((pad) - 1)) & ~((pad) - 1))
 
@@ -348,5 +398,15 @@
  */
 typedef uint32_t id_t;
 
+/**
+ * Check if a pointer is aligned to a certain power-of-2 size
+ */
+INLINE bool is_aligned(const void *addr, size_t size)
+{
+       return ((size_t)addr & (size - 1)) == 0;
+}
+
+/** \} */ //defgroup macros
+
 #endif /* MACROS_H */