From 5cfffbfa62aaf425ec6b309f7054b8b3c7d6ef28 Mon Sep 17 00:00:00 2001
From: "Paul A. Patience" <paul-a.patience@polymtl.ca>
Date: Fri, 10 Jun 2016 11:41:11 -0400
Subject: [PATCH] crc64: fix error

---
 include/crc64.h       | 22 ++++++++++++++++++++++
 libc/misc/lib_crc64.c | 15 +++++++--------
 2 files changed, 29 insertions(+), 8 deletions(-)

diff --git a/include/crc64.h b/include/crc64.h
index 8db458ad66..e08183327a 100644
--- a/include/crc64.h
+++ b/include/crc64.h
@@ -43,6 +43,28 @@
 #include <sys/types.h>
 #include <stdint.h>
 
+/****************************************************************************
+ * Pre-processor Definitions
+ ****************************************************************************/
+
+/*
+ * CRC64_CHECK is the CRC64 of the string "123456789" without the null byte.
+ *
+ *   const uint8_t checkbuf[] =
+ *   {
+ *     '1', '2', '3', '4', '5', '6', '7', '8', '9'
+ *   };
+ *
+ *   assert(crc64(checkbuf, sizeof(checkbuf)) == CRC64_CHECK);
+ */
+
+/* CRC-64/WE */
+
+#define CRC64_POLY   ((uint64_t)0x42f0e1eba9ea3693)
+#define CRC64_INIT   ((uint64_t)0xffffffffffffffff)
+#define CRC64_XOROUT ((uint64_t)0xffffffffffffffff)
+#define CRC64_CHECK  ((uint64_t)0x62ec59e3f1a4f00a)
+
 /****************************************************************************
  * Public Function Prototypes
  ****************************************************************************/
diff --git a/libc/misc/lib_crc64.c b/libc/misc/lib_crc64.c
index 4b0374c554..8faf0193d1 100644
--- a/libc/misc/lib_crc64.c
+++ b/libc/misc/lib_crc64.c
@@ -54,8 +54,8 @@
  *   #include <stdint.h>
  *   #include <stdio.h>
  *
- *   #define CRC64_POLYNOMIAL ((uint64_t)0x42f0e1eba9ea3693)
- *   #define CRC64_TABLEN     ((size_t)256)
+ *   #define CRC64_POLY   ((uint64_t)0x42f0e1eba9ea3693)
+ *   #define CRC64_TABLEN ((size_t)256)
  *
  *   int main(void)
  *   {
@@ -73,7 +73,7 @@
  *           {
  *             if ((crc64val & ((uint64_t)1 << 63)) != 0)
  *               {
- *                 crc64val = (crc64val << 1) ^ CRC64_POLYNOMIAL;
+ *                 crc64val = (crc64val << 1) ^ CRC64_POLY;
  *               }
  *             else
  *               {
@@ -234,8 +234,6 @@ static const uint64_t crc64_tab[256] =
   0x5dedc41a34bbeeb2, 0x1f1d25f19d51d821,
   0xd80c07cd676f8394, 0x9afce626ce85b507
 };
-#else
-#  define CRC64_POLYNOMIAL ((uint64_t)0x42f0e1eba9ea3693)
 #endif
 
 /****************************************************************************
@@ -257,7 +255,8 @@ uint64_t crc64part(FAR const uint8_t *src, size_t len, uint64_t crc64val)
 
   for (i = 0; i < len; i++)
     {
-      crc64val = crc64_tab[((crc64val >> 56) & 0xff) ^ src[i]] ^ (crc64val << 8);
+      crc64val = crc64_tab[((crc64val >> 56) & 0xff) ^ src[i]] ^
+                 (crc64val << 8);
     }
 
   return crc64val;
@@ -275,7 +274,7 @@ uint64_t crc64part(FAR const uint8_t *src, size_t len, uint64_t crc64val)
         {
           if ((crc64val & ((uint64_t)1 << 63)) != 0)
             {
-              crc64val = (crc64val << 1) ^ CRC64_POLYNOMIAL;
+              crc64val = (crc64val << 1) ^ CRC64_POLY;
             }
           else
             {
@@ -298,5 +297,5 @@ uint64_t crc64part(FAR const uint8_t *src, size_t len, uint64_t crc64val)
 
 uint64_t crc64(FAR const uint8_t *src, size_t len)
 {
-  return crc64part(src, len, ~(uint64_t)0);
+  return crc64part(src, len, CRC64_INIT) ^ CRC64_XOROUT;
 }