altos: Rename 'core' to 'kernel'

[fw/altos] / src / kernel / ao_fec.h

diff --git a/src/kernel/ao_fec.h b/src/kernel/ao_fec.h
new file mode 100644 (file)
index 0000000..618756c
--- /dev/null
+++ b/src/kernel/ao_fec.h
@@ -0,0 +1,84 @@
+/*
+ * Copyright © 2012 Keith Packard <keithp@keithp.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; version 2 of the License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
+ */
+
+#ifndef _AO_FEC_H_
+#define _AO_FEC_H_
+
+#include <stdint.h>
+
+#define AO_FEC_CRC_INIT                        0xffff
+#define AO_FEC_TRELLIS_TERMINATOR      0x0b
+#define AO_FEC_PREPARE_EXTRA           4
+
+extern const uint8_t ao_fec_whiten_table[];
+
+#if AO_FEC_DEBUG
+void
+ao_fec_dump_bytes(const uint8_t *bytes, uint16_t len, const char *name);
+#endif
+
+static inline uint16_t
+ao_fec_crc_byte(uint8_t byte, uint16_t crc)
+{
+       uint8_t bit;
+
+       for (bit = 0; bit < 8; bit++) {
+               if (((crc & 0x8000) >> 8) ^ (byte & 0x80))
+                       crc = (crc << 1) ^ 0x8005;
+               else
+                       crc = (crc << 1);
+               byte <<= 1;
+       }
+       return crc;
+}
+
+uint16_t
+ao_fec_crc(const uint8_t *bytes, uint8_t len);
+
+/*
+ * 'len' is the length of the original data; 'bytes'
+ * must  be four bytes longer than that, and the first
+ * two after 'len' must be the received crc
+ */
+uint8_t
+ao_fec_check_crc(const uint8_t *bytes, uint8_t len);
+
+/*
+ * Compute CRC, whiten, convolve and interleave data. 'out' must be (len + 4) * 2 bytes long
+ */
+uint8_t
+ao_fec_encode(const uint8_t *in, uint8_t len, uint8_t *out);
+
+/*
+ * Decode data. 'in' is one byte per bit, soft decision
+ * 'out' must be len/8 bytes long
+ */
+
+#define AO_FEC_DECODE_BLOCK    (32)    /* callback must return multiples of this many bits */
+
+#define AO_FEC_DECODE_CRC_OK   0x80    /* stored in out[out_len-1] */
+
+uint8_t
+ao_fec_decode(const uint8_t *in, uint16_t in_len, uint8_t *out, uint8_t out_len, uint16_t (*callback)(void));
+
+/*
+ * Interleave data packed in bytes. 'out' must be 'len' bytes long.
+ */
+uint16_t
+ao_fec_interleave_bytes(uint8_t *in, uint16_t len, uint8_t *out);
+
+#endif /* _AO_FEC_H_ */