init

yaokon/Drivers/CMSIS/DSP/Source/FastMathFunctions/arm_sin_q15.c

@@ -0,0 +1,76 @@
+/* ----------------------------------------------------------------------
+ * Project:      CMSIS DSP Library
+ * Title:        arm_sin_q15.c
+ * Description:  Fast sine calculation for Q15 values
+ *
+ * $Date:        27. January 2017
+ * $Revision:    V.1.5.1
+ *
+ * Target Processor: Cortex-M cores
+ * -------------------------------------------------------------------- */
+/*
+ * Copyright (C) 2010-2017 ARM Limited or its affiliates. All rights reserved.
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * Licensed under the Apache License, Version 2.0 (the License); you may
+ * not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an AS IS BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "arm_math.h"
+#include "arm_common_tables.h"
+
+/**
+ * @ingroup groupFastMath
+ */
+
+ /**
+ * @addtogroup sin
+ * @{
+ */
+
+/**
+ * @brief Fast approximation to the trigonometric sine function for Q15 data.
+ * @param[in] x Scaled input value in radians.
+ * @return  sin(x).
+ *
+ * The Q15 input value is in the range [0 +0.9999] and is mapped to a radian value in the range [0 2*pi).
+ */
+
+q15_t arm_sin_q15(
+  q15_t x)
+{
+  q15_t sinVal;                                  /* Temporary variables for input, output */
+  int32_t index;                                 /* Index variables */
+  q15_t a, b;                                    /* Four nearest output values */
+  q15_t fract;                                   /* Temporary values for fractional values */
+
+  /* Calculate the nearest index */
+  index = (uint32_t)x >> FAST_MATH_Q15_SHIFT;
+
+  /* Calculation of fractional value */
+  fract = (x - (index << FAST_MATH_Q15_SHIFT)) << 9;
+
+  /* Read two nearest values of input value from the sin table */
+  a = sinTable_q15[index];
+  b = sinTable_q15[index+1];
+
+  /* Linear interpolation process */
+  sinVal = (q31_t)(0x8000-fract)*a >> 16;
+  sinVal = (q15_t)((((q31_t)sinVal << 16) + ((q31_t)fract*b)) >> 16);
+
+  return sinVal << 1;
+}
+
+/**
+ * @} end of sin group
+ */