Add some doc;add init value;extend RAM occupation optimization to all harvard processors.

[bertos.git] / bertos / algo / crc.h

diff --git a/bertos/algo/crc.h b/bertos/algo/crc.h
index d6a1f45de21ca688c7b83615d3287b15a85a4a9a..b64d140feb16adcb33f002120d16cbf35661b19b 100644 (file)
--- a/bertos/algo/crc.h
+++ b/bertos/algo/crc.h
@@ -27,11 +27,11 @@
  * the GNU General Public License.
  *
  * Copyright 2003, 2004 Develer S.r.l. (http://www.develer.com/)
- * Copyright 1999 Bernardo Innocenti <bernie@develer.com>
+ * Copyright 1999 Bernie Innocenti <bernie@codewiz.org>
  *
  * -->
  *
- * \brief XModem-CRC16 algorithm (interface)
+ * \brief Cyclic Redundancy Check 16 (CRC). This algorithm is the one used by the XMODEM protocol.
  *
  * \note This algorithm is incompatible with the CCITT-CRC16.
  *
@@ -44,18 +44,18 @@
  * Omen Technology.
  *
  * \version $Id$
- * \author Bernardo Innocenti <bernie@develer.com>
+ * \author Bernie Innocenti <bernie@codewiz.org>
+ *
+ * $WIZ$ module_name = "crc16"
  */
 
 #ifndef ALGO_CRC_H
 #define ALGO_CRC_H
 
 #include <cfg/compiler.h>
+#include <cpu/pgm.h>
 
-#ifdef __cplusplus
-extern "C" {
-#endif /* __cplusplus */
-
+EXTERN_C_BEGIN
 
 /* CRC table */
 extern const uint16_t crc16tab[256];
@@ -70,16 +70,26 @@ extern const uint16_t crc16tab[256];
  * \param c New octet (range 0-255)
  * \param oldcrc Previous CRC16 value (referenced twice, beware of side effects)
  */
-#define UPDCRC16(c, oldcrc) (crc16tab[((oldcrc) >> 8) ^ ((unsigned char)(c))] ^ ((oldcrc) << 8))
+#if CPU_HARVARD
+       #define UPDCRC16(c, oldcrc) (pgm_read_uint16_t(&crc16tab[((oldcrc) >> 8) ^ ((unsigned char)(c))]) ^ ((oldcrc) << 8))
+#else
+       #define UPDCRC16(c, oldcrc) ((crc16tab[((oldcrc) >> 8) ^ ((unsigned char)(c))]) ^ ((oldcrc) << 8))
+#endif
 
+/** CRC-16 init value */
+#define CRC16_INIT_VAL ((uint16_t)0)
 
 #ifdef INLINE
 /**
- * \brief Compute the updated CRC16 value for one octet (macro version)
+ * \brief Compute the updated CRC16 value for one octet (inline version)
  */
 INLINE uint16_t updcrc16(uint8_t c, uint16_t oldcrc)
 {
+#if CPU_HARVARD
+       return pgm_read_uint16_t(&crc16tab[(oldcrc >> 8) ^ c]) ^ (oldcrc << 8);
+#else
        return crc16tab[(oldcrc >> 8) ^ c] ^ (oldcrc << 8);
+#endif
 }
 #endif // INLINE
 
@@ -95,8 +105,6 @@ INLINE uint16_t updcrc16(uint8_t c, uint16_t oldcrc)
  */
 extern uint16_t crc16(uint16_t crc, const void *buf, size_t len);
 
-#ifdef __cplusplus
-}
-#endif /* __cplusplus */
+EXTERN_C_END
 
 #endif /* ALGO_CRC_H */