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authorHarald Welte <laforge@gnumonks.org>2017-10-16 14:18:17 +0200
committerHarald Welte <laforge@gnumonks.org>2017-10-16 14:19:12 +0200
commitef7a44e33d52ab2e046efdd2535c9428796fc09e (patch)
tree1dd78086912cf2a37351c5e8fc64bbfec3cd055d
parent53de0d31698e8c598e36ccad9d864c450da343b9 (diff)
[doc] bits.c: Better / more Doxygen documentation
Change-Id: If824a5c8d8ee6e3dc96a3fddeb105786c0c027c1
-rw-r--r--include/osmocom/core/bits.h22
-rw-r--r--src/bits.c5
2 files changed, 17 insertions, 10 deletions
diff --git a/include/osmocom/core/bits.h b/include/osmocom/core/bits.h
index c6a142f8..b1b80406 100644
--- a/include/osmocom/core/bits.h
+++ b/include/osmocom/core/bits.h
@@ -1,9 +1,6 @@
/*! \file bits.h
* Osmocom bit level support code.
*
- * NOTE on the endianess of pbit_t:
- * Bits in a pbit_t are ordered MSB first, i.e. 0x80 is the first bit.
- * Bit i in a pbit_t array is array[i/8] & (1<<(7-i%8))
*/
#pragma once
@@ -19,9 +16,18 @@
* @{
* \file bits.h */
-typedef int8_t sbit_t; /*!< soft bit (-127...127) */
-typedef uint8_t ubit_t; /*!< unpacked bit (0 or 1) */
-typedef uint8_t pbit_t; /*!< packed bis (8 bits in a byte) */
+/*! soft bit with value (-127...127), as commonly used in
+ * communications receivers such as [viterbi] decoders */
+typedef int8_t sbit_t;
+
+/*! unpacked bit (0 or 1): 1 bit per byte */
+typedef uint8_t ubit_t;
+
+/*! packed bits (8 bits in a byte).
+ * NOTE on the endian-ness of \ref pbit_t:
+ * - Bits in a \ref pbit_t are ordered MSB first, i.e. 0x80 is the first bit.
+ * - Bit i in a \ref pbit_t array is array[i/8] & (1<<(7-i%8)) */
+typedef uint8_t pbit_t;
/*! determine how many bytes we would need for \a num_bits packed bits
* \param[in] num_bits Number of packed bits
@@ -95,16 +101,12 @@ enum osmo_br_mode {
OSMO_BR_WORD_SWAP = 16,
};
-/*! generic bit reversal function */
uint32_t osmo_bit_reversal(uint32_t x, enum osmo_br_mode k);
-/* reverse the bits within each byte of a 32bit word */
uint32_t osmo_revbytebits_32(uint32_t x);
-/* reverse the bits within a byte */
uint32_t osmo_revbytebits_8(uint8_t x);
-/* reverse the bits of each byte in a given buffer */
void osmo_revbytebits_buf(uint8_t *buf, int len);
/*! left circular shift
diff --git a/src/bits.c b/src/bits.c
index af09441a..fa917b07 100644
--- a/src/bits.c
+++ b/src/bits.c
@@ -28,6 +28,11 @@
* @{
* Osmocom bit level support code.
*
+ * This module implements the notion of different bit-fields, such as
+ * - unpacked bits (\ref ubit_t), i.e. 1 bit per byte
+ * - packed bits (\ref pbit_t), i.e. 8 bits per byte
+ * - soft bits (\ref sbit_t), 1 bit per byte from -127 to 127
+ *
* \file bits.c */
/*! convert unpacked bits to packed bits, return length in bytes