TRX: Cleanup of channel transcoding

1 files changed, 65 insertions, 0 deletions

diff --git a/src/osmo-bts-trx/gsm0503_mapping.c b/src/osmo-bts-trx/gsm0503_mapping.c
new file mode 100644
index 00000000..e5ee9206
--- /dev/null
+++ b/src/osmo-bts-trx/gsm0503_mapping.c
@@ -0,0 +1,65 @@
+
+#include <stdint.h>
+#include <string.h>
+
+#include <osmocom/core/bits.h>
+
+#include "gsm0503_mapping.h"
+
+void gsm0503_xcch_burst_unmap(sbit_t *iB, sbit_t *eB, sbit_t *hl, sbit_t *hn)
+{
+	memcpy(iB,    eB,    57);
+	memcpy(iB+57, eB+59, 57);
+
+	if (hl)
+		*hl = eB[57];
+
+	if (hn)
+		*hn = eB[58];
+}
+
+void gsm0503_xcch_burst_map(ubit_t *iB, ubit_t *eB, const ubit_t *hl,
+	const ubit_t *hn)
+{
+	memcpy(eB,    iB,    57);
+	memcpy(eB+59, iB+57, 57);
+
+	if (hl)
+		eB[57] = *hl;
+	if (hn)
+		eB[58] = *hn;
+}
+
+void gsm0503_tch_fr_burst_unmap(sbit_t *iB, sbit_t *eB, sbit_t *h, int odd)
+{
+	int i;
+
+	/* brainfuck: only copy even or odd bits */
+	for (i=odd; i<57; i+=2)
+		iB[i] = eB[i];
+	for (i=58-odd; i<114; i+=2)
+		iB[i] = eB[i+2];
+
+	if (h && !odd)
+		*h = eB[58];
+
+	if (h && odd)
+		*h = eB[57];
+}
+
+void gsm0503_tch_fr_burst_map(ubit_t *iB, ubit_t *eB, const ubit_t *h, int odd)
+{
+	int i;
+
+	/* brainfuck: only copy even or odd bits */
+	for (i=odd; i<57; i+=2)
+		eB[i] = iB[i];
+	for (i=58-odd; i<114; i+=2)
+		eB[i+2] = iB[i];
+
+	if (h && !odd)
+		eB[58] = *h;
+	if (h && odd)
+		eB[57] = *h;
+}
+