Diff: EMAC/EmacRaw/crc32.c

Revision:

0:bf7b9fba3924

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/EMAC/EmacRaw/crc32.c	Sun Mar 20 05:38:56 2011 +0000
@@ -0,0 +1,100 @@
+/*****************************************************************************
+ *   crc32.c:  Ethernet CRC module file for NXP LPC230x Family Microprocessors
+ *
+ *   Copyright(C) 2006, NXP Semiconductor
+ *   All rights reserved.
+ *
+ *   History
+ *   2006.09.01  ver 1.00    Prelimnary version, first Release
+ *
+******************************************************************************/
+#include "lpc17xx_emac.h"                        /* LPC23xx/24xx definitions */
+#include "crc32.h"
+
+/******************************************************************************
+** Function name:		CRC_init
+**
+** Descriptions:		Begin CRC calculation.
+**
+** parameters:			pointer to the CRC area.
+** Returned value:		None
+**
+******************************************************************************/
+void crc32_init(uint32_t *pCRC)
+{
+    *pCRC = 0xffffffff;
+}
+
+/******************************************************************************
+** Function name:		CRC32_add
+**
+** Descriptions:		Calculate CRC value one at a time
+**
+** parameters:			pointer to the CRC area, and passing value to get the CRC
+** Returned value:		None
+**
+******************************************************************************/
+void crc32_add(uint32_t *pCRC, uint8_t val8)
+{
+    uint32_t i, poly;
+    uint32_t entry;
+    uint32_t crc_in;
+    uint32_t crc_out;
+
+    crc_in = *pCRC;
+    poly = 0xEDB88320L;
+    entry = (crc_in ^ ((uint32_t) val8)) & 0xFF;
+    for (i = 0; i < 8; i++)
+    {
+        if (entry & 1)
+            entry = (entry >> 1) ^ poly;
+        else
+            entry >>= 1;
+    }
+    crc_out = ((crc_in>>8) & 0x00FFFFFF) ^ entry;
+    *pCRC = crc_out;
+    return;
+}
+
+/******************************************************************************
+** Function name:		CRC32_end
+**
+** Descriptions:		Finish CRC calculation
+**
+** parameters:			pointer to the CRC area.
+** Returned value:		None
+**
+******************************************************************************/
+void crc32_end(uint32_t *pCRC)
+{
+    *pCRC ^= 0xffffffff;
+}
+
+/******************************************************************************
+** Function name:		CRC32_bfr
+**
+** Descriptions:		Get the CRC value based on size of the string.
+**
+** parameters:			Pointer to the string, size of the string.
+** Returned value:		CRC value
+**
+******************************************************************************/
+uint32_t crc32_bfr(void *pBfr, uint32_t size)
+{
+    uint32_t crc32;
+    uint8_t  *pu8;
+
+    crc32_init(&crc32);
+    pu8 = (uint8_t *) pBfr;
+    while (size-- != 0)
+    {
+        crc32_add(&crc32, *pu8);
+        pu8++ ;
+    }
+    crc32_end(&crc32);
+    return ( crc32 );
+}
+
+/*********************************************************************************
+**                            End Of File
+*********************************************************************************/