From 3a0968cd3db127ca1e4e2983a72277a7ceb23444 Mon Sep 17 00:00:00 2001
From: Martin Budden <mjbudden@gmail.com>
Date: Thu, 13 Oct 2016 16:08:52 +0100
Subject: [PATCH] Added CRC_DVB_S2 calculation

---
 src/main/common/maths.c | 15 ++++++++++++++-
 1 file changed, 14 insertions(+), 1 deletion(-)

diff --git a/src/main/common/maths.c b/src/main/common/maths.c
index 1dd55519a1..8d43a4e125 100644
--- a/src/main/common/maths.c
+++ b/src/main/common/maths.c
@@ -339,7 +339,7 @@ fix12_t  qConstruct(int16_t num, int16_t den) {
 
 uint16_t crc16_ccitt(uint16_t crc, unsigned char a)
 {
-    crc ^= a << 8;
+    crc ^= (uint16_t)a << 8;
     for (int ii = 0; ii < 8; ++ii) {
         if (crc & 0x8000) {
             crc = (crc << 1) ^ 0x1021;
@@ -350,3 +350,16 @@ uint16_t crc16_ccitt(uint16_t crc, unsigned char a)
     return crc;
 }
 
+uint8_t crc8_dvb_s2(uint8_t crc, unsigned char a)
+{
+    crc ^= a;
+    for (int ii = 0; ii < 8; ++ii) {
+        if (crc & 0x80) {
+            crc = (crc << 1) ^ 0xD5;
+        } else {
+            crc = crc << 1;
+        }
+    }
+    return crc;
+}
+