gsm: add gsm0502_fn_compare() for comparing TDMA FNs
We need this function in:
* osmocom-bb.git for trxcon and l1gprs,
* osmo-pcu.git replacing fn_cmp().
Change-Id: I9590f2e836fc48650decf1564b6ab46306c4fe2d
Related: OS#5500
diff --git a/tests/gsm0502/gsm0502_test.c b/tests/gsm0502/gsm0502_test.c
index e9deaa9..d78a94d 100644
--- a/tests/gsm0502/gsm0502_test.c
+++ b/tests/gsm0502/gsm0502_test.c
@@ -148,8 +148,28 @@
printf("\n");
}
+static void test_gsm0502_fn_compare(void)
+{
+ OSMO_ASSERT(gsm0502_fn_compare(1337, 1337) == 0);
+ OSMO_ASSERT(gsm0502_fn_compare(42, 1337) == -1);
+ OSMO_ASSERT(gsm0502_fn_compare(1337, 42) == 1);
+ OSMO_ASSERT(gsm0502_fn_compare(42, 0) == 1);
+
+ /* 2715642 is very close to the Fn period (GSM_TDMA_HYPERFRAME) */
+ OSMO_ASSERT(gsm0502_fn_compare(2715642, 42) == -1);
+ OSMO_ASSERT(gsm0502_fn_compare(42, 2715642) == 1);
+ OSMO_ASSERT(gsm0502_fn_compare(0, 2715642) == 1);
+
+ /* 1357824 is half of the Fn period (GSM_TDMA_HYPERFRAME) */
+ OSMO_ASSERT(gsm0502_fn_compare(1357820, 1357824) == -1);
+ OSMO_ASSERT(gsm0502_fn_compare(1357820, 1357825) == -1);
+ OSMO_ASSERT(gsm0502_fn_compare(1357824, 1357820) == 1);
+ OSMO_ASSERT(gsm0502_fn_compare(1357825, 1357820) == 1);
+}
+
int main(int argc, char **argv)
{
test_gsm0502_fn_remap();
+ test_gsm0502_fn_compare();
return EXIT_SUCCESS;
}