123 lines
3.5 KiB
C
123 lines
3.5 KiB
C
/*! \file bits.h
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* Osmocom bit level support code.
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*
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*/
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#pragma once
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#include <stdint.h>
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#include <stddef.h>
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#include <osmocom/core/bit16gen.h>
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#include <osmocom/core/bit32gen.h>
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#include <osmocom/core/bit64gen.h>
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/*! \defgroup bits soft, unpacked and packed bits
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* @{
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* \file bits.h */
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/*! soft bit with value (-127...127), as commonly used in
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* communications receivers such as [viterbi] decoders */
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typedef int8_t sbit_t;
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/*! unpacked bit (0 or 1): 1 bit per byte */
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typedef uint8_t ubit_t;
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/*! packed bits (8 bits in a byte).
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* NOTE on the endian-ness of \ref pbit_t:
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* - Bits in a \ref pbit_t are ordered MSB first, i.e. 0x80 is the first bit.
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* - Bit i in a \ref pbit_t array is array[i/8] & (1<<(7-i%8)) */
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typedef uint8_t pbit_t;
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/*! determine how many bytes we would need for \a num_bits packed bits
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* \param[in] num_bits Number of packed bits
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* \returns number of bytes needed for \a num_bits packed bits
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*/
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static inline unsigned int osmo_pbit_bytesize(unsigned int num_bits)
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{
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unsigned int pbit_bytesize = num_bits / 8;
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if (num_bits % 8)
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pbit_bytesize++;
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return pbit_bytesize;
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}
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int osmo_ubit2pbit(pbit_t *out, const ubit_t *in, unsigned int num_bits);
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int osmo_pbit2ubit(ubit_t *out, const pbit_t *in, unsigned int num_bits);
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void osmo_nibble_shift_right(uint8_t *out, const uint8_t *in,
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unsigned int num_nibbles);
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void osmo_nibble_shift_left_unal(uint8_t *out, const uint8_t *in,
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unsigned int num_nibbles);
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void osmo_ubit2sbit(sbit_t *out, const ubit_t *in, unsigned int num_bits);
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void osmo_sbit2ubit(ubit_t *out, const sbit_t *in, unsigned int num_bits);
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int osmo_ubit2pbit_ext(pbit_t *out, unsigned int out_ofs,
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const ubit_t *in, unsigned int in_ofs,
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unsigned int num_bits, int lsb_mode);
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int osmo_pbit2ubit_ext(ubit_t *out, unsigned int out_ofs,
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const pbit_t *in, unsigned int in_ofs,
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unsigned int num_bits, int lsb_mode);
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#define OSMO_BIN_SPEC "%d%d%d%d%d%d%d%d"
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#define OSMO_BIN_PRINT(byte) \
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(byte & 0x80 ? 1 : 0), \
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(byte & 0x40 ? 1 : 0), \
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(byte & 0x20 ? 1 : 0), \
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(byte & 0x10 ? 1 : 0), \
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(byte & 0x08 ? 1 : 0), \
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(byte & 0x04 ? 1 : 0), \
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(byte & 0x02 ? 1 : 0), \
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(byte & 0x01 ? 1 : 0)
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#define OSMO_BIT_SPEC "%c%c%c%c%c%c%c%c"
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#define OSMO_BIT_PRINT_EX(byte, ch) \
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(byte & 0x80 ? ch : '.'), \
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(byte & 0x40 ? ch : '.'), \
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(byte & 0x20 ? ch : '.'), \
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(byte & 0x10 ? ch : '.'), \
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(byte & 0x08 ? ch : '.'), \
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(byte & 0x04 ? ch : '.'), \
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(byte & 0x02 ? ch : '.'), \
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(byte & 0x01 ? ch : '.')
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#define OSMO_BIT_PRINT(byte) OSMO_BIT_PRINT_EX(byte, '1')
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/* BIT REVERSAL */
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/*! bit-reversal mode for osmo_bit_reversal() */
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enum osmo_br_mode {
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/*! reverse all bits in a 32bit dword */
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OSMO_BR_BITS_IN_DWORD = 31,
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/*! reverse byte order in a 32bit dword */
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OSMO_BR_BYTES_IN_DWORD = 24,
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/*! reverse bits of each byte in a 32bit dword */
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OSMO_BR_BITS_IN_BYTE = 7,
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/*! swap the two 16bit words in a 32bit dword */
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OSMO_BR_WORD_SWAP = 16,
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};
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uint32_t osmo_bit_reversal(uint32_t x, enum osmo_br_mode k);
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uint32_t osmo_revbytebits_32(uint32_t x);
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uint32_t osmo_revbytebits_8(uint8_t x);
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void osmo_revbytebits_buf(uint8_t *buf, int len);
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/*! left circular shift
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* \param[in] in The 16 bit unsigned integer to be rotated
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* \param[in] shift Number of bits to shift \a in to, [0;16] bits
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* \returns shifted value
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*/
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static inline uint16_t osmo_rol16(uint16_t in, unsigned shift)
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{
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return (in << shift) | (in >> (16 - shift));
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}
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/*! @} */
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