fixeria has uploaded this change for review. ( https://gerrit.osmocom.org/c/osmo-ttcn3-hacks/+/42915?usp=email )
Change subject: library: add f_gsm_fn_{sum,sub,diff}() ......................................................................
library: add f_gsm_fn_{sum,sub,diff}()
Change-Id: Ie91ccef5d3f170f4a341a6cf9d3323a896b299e6 --- M library/GSM_Types.ttcn 1 file changed, 22 insertions(+), 0 deletions(-)
git pull ssh://gerrit.osmocom.org:29418/osmo-ttcn3-hacks refs/changes/15/42915/1
diff --git a/library/GSM_Types.ttcn b/library/GSM_Types.ttcn index b3b6dc9..764b8ba 100644 --- a/library/GSM_Types.ttcn +++ b/library/GSM_Types.ttcn @@ -434,6 +434,28 @@ return (fn / 51) mod 8; }
+/* 45.002 4.3.3: TDMA frame number modular arithmetic */ + +/* Return the sum of two given TDMA frame numbers, wrapping around the hyperframe */ +function f_gsm_fn_sum(GsmFrameNumber a, GsmFrameNumber b) return GsmFrameNumber { + return (a + b) mod GsmMaxFrameNumber; +} + +/* Return the difference of two given TDMA frame numbers, wrapping around the hyperframe */ +function f_gsm_fn_sub(GsmFrameNumber a, GsmFrameNumber b) return GsmFrameNumber { + return (a - b + GsmMaxFrameNumber) mod GsmMaxFrameNumber; +} + +/* Return the *minimum* distance between two given TDMA frame numbers */ +function f_gsm_fn_diff(GsmFrameNumber a, GsmFrameNumber b) return GsmFrameNumber { + var GsmFrameNumber d1 := f_gsm_fn_sub(a, b); + var GsmFrameNumber d2 := f_gsm_fn_sub(b, a); + if (d1 < d2) { + return d1; + } + return d2; +} + type hexstring GsmBcdString with { variant "HEXORDER(low)" }; type GsmBcdString BcdMccMnc with { variant "FIELDLENGTH(6)" };
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fixeria