diff options
Diffstat (limited to 'src/osmo-bts-trx/gsm0503_parity.c')
-rw-r--r-- | src/osmo-bts-trx/gsm0503_parity.c | 103 |
1 files changed, 103 insertions, 0 deletions
diff --git a/src/osmo-bts-trx/gsm0503_parity.c b/src/osmo-bts-trx/gsm0503_parity.c new file mode 100644 index 00000000..ba2e144a --- /dev/null +++ b/src/osmo-bts-trx/gsm0503_parity.c @@ -0,0 +1,103 @@ + +#include <stdint.h> + +#include <osmocom/core/crcgen.h> + +#include "gsm0503_parity.h" + +/* + * GSM (SACCH) parity (FIRE code) + * + * g(x) = (x^23 + 1)(x^17 + x^3 + 1) + * = x^40 + x^26 + x^23 + x^17 + x^3 + a1 + */ + +const struct osmo_crc64gen_code gsm0503_fire_crc40 = { + .bits = 40, + .poly = 0x0004820009ULL, + .init = 0x0000000000ULL, + .remainder = 0xffffffffffULL, +}; + + +/* + * GSM PDTCH CS-2, CS-3, CS-4 parity + * + * g(x) = x^16 + x^12 + x^5 + 1 + */ + +const struct osmo_crc16gen_code gsm0503_cs234_crc16 = { + .bits = 16, + .poly = 0x1021, + .init = 0x0000, + .remainder = 0xffff, +}; + + +/* + * GSM RACH parity + * + * g(x) = x^6 + x^5 + x^3 + x^2 + x^1 + 1 + */ + +const struct osmo_crc8gen_code gsm0503_rach_crc6 = { + .bits = 6, + .poly = 0x2f, + .init = 0x00, + .remainder = 0x3f, +}; + + +/* + * GSM SCH parity + * + * g(x) = x^10 + x^8 + x^6 + x^5 + x^4 + x^2 + 1 + */ + +const struct osmo_crc16gen_code gsm0503_sch_crc10 = { + .bits = 10, + .poly = 0x175, + .init = 0x000, + .remainder = 0x3ff, +}; + + +/* + * GSM TCH FR/HR/EFR parity + * + * g(x) = x^3 + x + 1 + */ + +const struct osmo_crc8gen_code gsm0503_tch_fr_crc3 = { + .bits = 3, + .poly = 0x3, + .init = 0x0, + .remainder = 0x7, +}; + +/* + * GSM TCH EFR parity + * + * g(x) = x^8 + x^4 + x^3 + x^2 + 1 + */ + +const struct osmo_crc8gen_code gsm0503_tch_efr_crc8 = { + .bits = 8, + .poly = 0x1d, + .init = 0x00, + .remainder = 0x00, +}; + +/* + * GSM AMR parity + * + * g(x) = x^6 + x^5 + x^3 + x^2 + x^1 + 1 + */ + +const struct osmo_crc8gen_code gsm0503_amr_crc6 = { + .bits = 6, + .poly = 0x2f, + .init = 0x00, + .remainder = 0x3f, +}; + |