diff options
| author | Pau Espin Pedrol <pespin@sysmocom.de> | 2020-07-07 17:20:59 +0200 |
|---|---|---|
| committer | Pau Espin Pedrol <pespin@sysmocom.de> | 2020-07-09 13:36:47 +0200 |
| commit | 732373d7b442568620261f2930d07d535b7155ba (patch) | |
| tree | 98292602b6e713ce560ca167999f8e6fc96e5947 /src/encoding.cpp | |
| parent | 26743ac4f94437f383fb4082976235149c8b2d96 (diff) | |
encoding: Encode TA as unsigned and check validty against GSM48_TA_INVALID
According to 3GPP TS 44.018 sec 10.5.2.40, Timing Advance value is 8 bit
and range is 0-63 (0-219 on GSM400). Unsigned value (uint8_t) is used
everywhere else, so avoid using a signed one here, and simply check for
GSM48_TA_INVALID here, which we use everywhere else to initialize when the
value is not known. Ideally we should check for value based on band, but
it makes more sense to check that when receiving the data and storing in
in set_ta().
Change-Id: I82b13561d0fe5ebafb5c3a8b9a501045c29809bc
Diffstat (limited to 'src/encoding.cpp')
| -rw-r--r-- | src/encoding.cpp | 6 |
1 files changed, 3 insertions, 3 deletions
diff --git a/src/encoding.cpp b/src/encoding.cpp index 89cc5f21..32358c33 100644 --- a/src/encoding.cpp +++ b/src/encoding.cpp @@ -142,9 +142,9 @@ static inline bool write_tai(bitvec *dest, unsigned& wp, int8_t tai) } /* { 0 | 1 < TIMING_ADVANCE_VALUE : bit (6) > } */ -static inline void write_ta(bitvec *dest, unsigned& wp, int8_t ta) +static inline void write_ta(bitvec *dest, unsigned& wp, uint8_t ta) { - if (ta < 0) /* No TIMING_ADVANCE_VALUE: */ + if (ta >= GSM48_TA_INVALID) /* No TIMING_ADVANCE_VALUE: */ bitvec_write_field(dest, &wp, 0, 1); else { /* TIMING_ADVANCE_VALUE: */ bitvec_write_field(dest, &wp, 1, 1); @@ -174,7 +174,7 @@ static inline void write_ws(bitvec *dest, unsigned int *write_index, uint16_t ws < TIMING_ADVANCE_TIMESLOT_NUMBER : bit (3) > } */ static inline void write_ta_ie(bitvec *dest, unsigned& wp, - int8_t ta, int8_t tai, uint8_t ts) + uint8_t ta, int8_t tai, uint8_t ts) { write_ta(dest, wp, ta); if (write_tai(dest, wp, tai)) /* TIMING_ADVANCE_TIMESLOT_NUMBER: */ |