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author | JanHenrik <janhenrik@janhenrik.org> | 2020-04-01 00:40:03 +0200 |
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committer | JanHenrik <janhenrik@janhenrik.org> | 2020-04-01 00:40:03 +0200 |
commit | f7de54fc6fa6b40dfa2dfbe4c2a8ee933affa126 (patch) | |
tree | 78465e38a01011dc9f17eb73416011310532017f /cdc-dials/Drivers/CMSIS/DSP/Source/FastMathFunctions/arm_cos_q31.c | |
parent | 3ec13d81e70e52246545c720abe756ccf09fb231 (diff) | |
download | minikbd-f7de54fc6fa6b40dfa2dfbe4c2a8ee933affa126.tar.gz minikbd-f7de54fc6fa6b40dfa2dfbe4c2a8ee933affa126.tar.bz2 minikbd-f7de54fc6fa6b40dfa2dfbe4c2a8ee933affa126.zip |
added files
Diffstat (limited to 'cdc-dials/Drivers/CMSIS/DSP/Source/FastMathFunctions/arm_cos_q31.c')
-rw-r--r-- | cdc-dials/Drivers/CMSIS/DSP/Source/FastMathFunctions/arm_cos_q31.c | 84 |
1 files changed, 84 insertions, 0 deletions
diff --git a/cdc-dials/Drivers/CMSIS/DSP/Source/FastMathFunctions/arm_cos_q31.c b/cdc-dials/Drivers/CMSIS/DSP/Source/FastMathFunctions/arm_cos_q31.c new file mode 100644 index 0000000..105addb --- /dev/null +++ b/cdc-dials/Drivers/CMSIS/DSP/Source/FastMathFunctions/arm_cos_q31.c @@ -0,0 +1,84 @@ +/* ----------------------------------------------------------------------
+ * Project: CMSIS DSP Library
+ * Title: arm_cos_q31.c
+ * Description: Fast cosine calculation for Q31 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 cos
+ * @{
+ */
+
+/**
+ * @brief Fast approximation to the trigonometric cosine function for Q31 data.
+ * @param[in] x Scaled input value in radians.
+ * @return cos(x).
+ *
+ * The Q31 input value is in the range [0 +0.9999] and is mapped to a radian
+ * value in the range [0 2*pi).
+ */
+
+q31_t arm_cos_q31(
+ q31_t x)
+{
+ q31_t cosVal; /* Temporary variables for input, output */
+ int32_t index; /* Index variables */
+ q31_t a, b; /* Four nearest output values */
+ q31_t fract; /* Temporary values for fractional values */
+
+ /* add 0.25 (pi/2) to read sine table */
+ x = (uint32_t)x + 0x20000000;
+ if (x < 0)
+ { /* convert negative numbers to corresponding positive ones */
+ x = (uint32_t)x + 0x80000000;
+ }
+
+ /* Calculate the nearest index */
+ index = (uint32_t)x >> FAST_MATH_Q31_SHIFT;
+
+ /* Calculation of fractional value */
+ fract = (x - (index << FAST_MATH_Q31_SHIFT)) << 9;
+
+ /* Read two nearest values of input value from the sin table */
+ a = sinTable_q31[index];
+ b = sinTable_q31[index+1];
+
+ /* Linear interpolation process */
+ cosVal = (q63_t)(0x80000000-fract)*a >> 32;
+ cosVal = (q31_t)((((q63_t)cosVal << 32) + ((q63_t)fract*b)) >> 32);
+
+ return cosVal << 1;
+}
+
+/**
+ * @} end of cos group
+ */
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