README change

1 files changed, 40 insertions, 0 deletions

diff --git a/gnuradio-core/src/lib/reed-solomon/fixed.h b/gnuradio-core/src/lib/reed-solomon/fixed.h
new file mode 100644
index 000000000..30091e7bf
--- /dev/null
+++ b/gnuradio-core/src/lib/reed-solomon/fixed.h
@@ -0,0 +1,40 @@
+/* Configure the RS codec with fixed parameters for CCSDS standard
+ * (255,223) code over GF(256). Note: the conventional basis is still
+ * used; the dual-basis mappings are performed in [en|de]code_rs_ccsds.c
+ *
+ * Copyright 2002 Phil Karn, KA9Q
+ * May be used under the terms of the GNU General Public License (GPL)
+ */
+#define DTYPE unsigned char
+
+#include <gr_core_api.h>
+
+static inline int mod255(int x){
+  while (x >= 255) {
+    x -= 255;
+    x = (x >> 8) + (x & 255);
+  }
+  return x;
+}
+#define MODNN(x) mod255(x)
+
+extern unsigned char CCSDS_alpha_to[];
+extern unsigned char CCSDS_index_of[];
+extern unsigned char CCSDS_poly[];
+
+#define MM 8
+#define NN 255
+#define ALPHA_TO CCSDS_alpha_to
+#define INDEX_OF CCSDS_index_of
+#define GENPOLY CCSDS_poly
+#define NROOTS 32
+#define FCR 112
+#define PRIM 11
+#define IPRIM 116
+#define A0 (NN)
+
+#define ENCODE_RS encode_rs_8
+#define DECODE_RS decode_rs_8
+
+GR_CORE_API void ENCODE_RS(DTYPE *data,DTYPE *parity);
+GR_CORE_API int DECODE_RS(DTYPE *data, int *eras_pos, int no_eras);
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