# HG changeset patch
# User John Tsiombikas <nuclear@member.fsf.org>
# Date 1402700218 -10800
# Node ID 8e9225853d7518c09fe529099e7cd43ffe1fd384
# Parent  5143908d0220a9b89abde9157bd82937188ba256
added sincos luts

diff -r 5143908d0220 -r 8e9225853d75 src/sincos.c
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/sincos.c	Sat Jun 14 01:56:58 2014 +0300
@@ -0,0 +1,42 @@
+#include <math.h>
+#include "sincos.h"
+#include "logger.h"
+
+void sincos_init(void)
+{
+	int i;
+
+	logmsg(LOG_ALL, "calculating sin/cos lut...\n");
+
+	for(i=0; i<SINLUT_SIZE; i++) {
+		float angle = 2.0 * M_PI * ((float)i / (float)SINLUT_SIZE);
+		float val = sin(angle);
+		sinlut[i] = (int16_t)(val * SINLUT_SCALE);
+	}
+}
+
+int16_t sin_int(int16_t norm_angle)
+{
+	norm_angle %= SINLUT_SIZE;
+	if(norm_angle < 0) {
+		norm_angle += SINLUT_SIZE;
+	}
+	return sinlut[norm_angle];
+}
+
+int16_t cos_int(int16_t norm_angle)
+{
+	return sin_int(norm_angle + SINLUT_SIZE / 4);
+}
+
+int32_t sin_x16(int32_t radians)
+{
+	int32_t na = (radians << 16) / (M_PI_X16 * 2);
+	return sin_int((na >> 8) * (SINLUT_SIZE << 8));
+}
+
+int32_t cos_x16(int32_t radians)
+{
+	int32_t na = (radians << 16) / (M_PI_X16 * 2);
+	return cos_int((na >> 8) * (SINLUT_SIZE << 8));
+}
diff -r 5143908d0220 -r 8e9225853d75 src/sincos.h
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/sincos.h	Sat Jun 14 01:56:58 2014 +0300
@@ -0,0 +1,27 @@
+#ifndef SINCOS_H_
+#define SINCOS_H_
+
+#include <stdint.h>
+
+#define M_PI_X16	(int32_t)(M_PI * 65536.0)
+/*#define M_PI_X16	(int32_t)((31416 << 16) / 10000)*/
+
+#define SINLUT_SCALE	512
+#define SINLUT_SIZE		512
+int16_t sinlut[SINLUT_SIZE];
+
+void sincos_init(void);
+
+/* takes angle in [0, SINLUT_SIZE] and returns:
+ * sin(2 * angle / SINLUT_SIZE / pi) * SINLUT_SCALE
+ */
+int16_t sin_int(int16_t norm_angle);
+int16_t cos_int(int16_t norm_angle);
+
+/* takes angle in fixed point 16.16 radians [0, 2pi << 16]
+ * and returns 16.16 fixed point in [-1 << 16, 1 << 16]
+ */
+int32_t sin_x16(int32_t radians);
+int32_t cos_x16(int32_t radians);
+
+#endif	/* SINCOS_H_ */