yaffs: Update year to 2011 in copyrights etc.

[yaffs2.git] / yaffs_ecc.c

diff --git a/yaffs_ecc.c b/yaffs_ecc.c
index 0ea0305e5ceb10025f9e4016c439930631ac9a79..0f41ec761b18ac5128035d435faca0ade68959ef 100644 (file)
--- a/yaffs_ecc.c
+++ b/yaffs_ecc.c
@@ -1,7 +1,7 @@
 /*
  * YAFFS: Yet Another Flash File System. A NAND-flash specific file system.
  *
- * Copyright (C) 2002-2010 Aleph One Ltd.
+ * Copyright (C) 2002-2011 Aleph One Ltd.
  *   for Toby Churchill Ltd and Brightstar Engineering
  *
  * Created by Charles Manning <charles@aleph1.co.uk>
@@ -16,22 +16,22 @@
  *
  * The ECC comprises 22 bits of parity information and is stuffed into 3 bytes.
  * The two unused bit are set to 1.
- * The ECC can correct single bit errors in a 256-byte page of data. Thus, two such ECC
- * blocks are used on a 512-byte NAND page.
+ * The ECC can correct single bit errors in a 256-byte page of data. Thus, two
+ * such ECC blocks are used on a 512-byte NAND page.
  *
  */
 
+#include "yportenv.h"
+
+#include "yaffs_ecc.h"
+
 /* Table generated by gen-ecc.c
  * Using a table means we do not have to calculate p1..p4 and p1'..p4'
  * for each byte of data. These are instead provided in a table in bits7..2.
- * Bit 0 of each entry indicates whether the entry has an odd or even parity, and therefore
- * this bytes influence on the line parity.
+ * Bit 0 of each entry indicates whether the entry has an odd or even parity,
+ * and therefore this bytes influence on the line parity.
  */
 
-#include "yportenv.h"
-
-#include "yaffs_ecc.h"
-
 static const unsigned char column_parity_table[] = {
        0x00, 0x55, 0x59, 0x0c, 0x65, 0x30, 0x3c, 0x69,
        0x69, 0x3c, 0x30, 0x65, 0x0c, 0x59, 0x55, 0x00,
@@ -67,35 +67,11 @@ static const unsigned char column_parity_table[] = {
        0x69, 0x3c, 0x30, 0x65, 0x0c, 0x59, 0x55, 0x00,
 };
 
-/* Count the bits in an unsigned char or a U32 */
-
-static int yaffs_count_bits(unsigned char x)
-{
-       int r = 0;
-       while (x) {
-               if (x & 1)
-                       r++;
-               x >>= 1;
-       }
-       return r;
-}
-
-static int yaffs_count_bits32(unsigned x)
-{
-       int r = 0;
-       while (x) {
-               if (x & 1)
-                       r++;
-               x >>= 1;
-       }
-       return r;
-}
 
 /* Calculate the ECC for a 256-byte block of data */
 void yaffs_ecc_cacl(const unsigned char *data, unsigned char *ecc)
 {
        unsigned int i;
-
        unsigned char col_parity = 0;
        unsigned char line_parity = 0;
        unsigned char line_parity_prime = 0;
@@ -222,8 +198,7 @@ int yaffs_ecc_correct(unsigned char *data, unsigned char *read_ecc,
                return 1;       /* Corrected the error */
        }
 
-       if ((yaffs_count_bits(d0) +
-            yaffs_count_bits(d1) + yaffs_count_bits(d2)) == 1) {
+       if ((hweight8(d0) + hweight8(d1) + hweight8(d2)) == 1) {
                /* Reccoverable error in ecc */
 
                read_ecc[0] = test_ecc[0];
@@ -246,7 +221,6 @@ void yaffs_ecc_calc_other(const unsigned char *data, unsigned n_bytes,
                          struct yaffs_ecc_other *ecc_other)
 {
        unsigned int i;
-
        unsigned char col_parity = 0;
        unsigned line_parity = 0;
        unsigned line_parity_prime = 0;
@@ -307,9 +281,9 @@ int yaffs_ecc_correct_other(unsigned char *data, unsigned n_bytes,
                return 1;       /* corrected */
        }
 
-       if ((yaffs_count_bits32(delta_line) +
-            yaffs_count_bits32(delta_line_prime) +
-            yaffs_count_bits(delta_col)) == 1) {
+       if ((hweight32(delta_line) +
+            hweight32(delta_line_prime) +
+            hweight8(delta_col)) == 1) {
                /* Reccoverable error in ecc */
 
                *read_ecc = *test_ecc;