Move crc16tab in PROGMEM for AVR chips (Thanks to M. Cialdi, Powersoft).

Save some RAM bytes by moving crc table into PROGMEM.

git-svn-id: https://src.develer.com/svnoss/bertos/trunk@2770 38d2e660-2303-0410-9eaa-f027e97ec537

diff --git a/bertos/algo/crc.c b/bertos/algo/crc.c
index 684ddbd9c1868041d893cb1917b8fdca78df90a1..96007addc049b3890a125709f16c643b3e189b27 100644 (file)
--- a/bertos/algo/crc.c
+++ b/bertos/algo/crc.c
@@ -42,7 +42,7 @@
 /**
  * crctab calculated by Mark G. Mendel, Network Systems Corporation
  */
-const uint16_t crc16tab[256] = {
+const uint16_t PROGMEM crc16tab[256] = {
        0x0000, 0x1021, 0x2042, 0x3063, 0x4084, 0x50a5, 0x60c6, 0x70e7,
        0x8108, 0x9129, 0xa14a, 0xb16b, 0xc18c, 0xd1ad, 0xe1ce, 0xf1ef,
        0x1231, 0x0210, 0x3273, 0x2252, 0x52b5, 0x4294, 0x72f7, 0x62d6,

diff --git a/bertos/algo/crc.h b/bertos/algo/crc.h
index 483f2192cf29916ba0e366ab604286b5c3e0d2a3..81a0c9265a2b6bb7996618a3566c5cde34ab3465 100644 (file)
--- a/bertos/algo/crc.h
+++ b/bertos/algo/crc.h
@@ -53,6 +53,8 @@
 #define ALGO_CRC_H
 
 #include <cfg/compiler.h>
+#include <cpu/pgm.h>
+
 
 #ifdef __cplusplus
 extern "C" {
@@ -60,7 +62,7 @@ extern "C" {
 
 
 /* CRC table */
-extern const uint16_t crc16tab[256];
+const uint16_t crc16tab[256];
 
 
 /**
@@ -72,7 +74,11 @@ 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_AVR
+       #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
 
 
 #ifdef INLINE
@@ -81,7 +87,11 @@ extern const uint16_t crc16tab[256];
  */
 INLINE uint16_t updcrc16(uint8_t c, uint16_t oldcrc)
 {
+#if CPU_AVR
+       return pgm_read_uint16_t(&crc16tab[(oldcrc >> 8) ^ c]) ^ (oldcrc << 8);
+#else
        return crc16tab[(oldcrc >> 8) ^ c] ^ (oldcrc << 8);
+#endif
 }
 #endif // INLINE