1 files changed, 55 insertions, 0 deletions
diff --git a/src/ao_convert.c b/src/ao_convert.c
new file mode 100644
index 00000000..57ed7370
--- /dev/null
+++ b/src/ao_convert.c
@@ -0,0 +1,55 @@
+/*
+ * Copyright © 2009 Keith Packard <keithp@keithp.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; version 2 of the License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
+ */
+
+#include "ao.h"
+
+static const int16_t altitude_table[2048] = {
+#include "altitude.h"
+};
+
+int16_t
+ao_pres_to_altitude(int16_t pres) __reentrant
+{
+	pres = pres >> 4;
+	if (pres < 0) pres = 0;
+	if (pres > 2047) pres = 2047;
+	return altitude_table[pres];
+}
+
+int16_t
+ao_altitude_to_pres(int16_t alt) __reentrant
+{
+	int16_t pres;
+
+	for (pres = 0; pres < 2047; pres++)
+		if (altitude_table[pres] <= alt)
+			break;
+	return pres << 4;
+}
+
+static __xdata uint8_t	ao_temp_mutex;
+
+int16_t
+ao_temp_to_dC(int16_t temp) __reentrant
+{
+	int16_t	ret;
+
+	ao_mutex_get(&ao_temp_mutex);
+	ret = (int16_t) ((temp >> 4) * 3300L / 2047L) - 500;
+	ao_mutex_put(&ao_temp_mutex);
+	return ret;
+}