From 5b81bc8ccbd342b8566d88fc9f17a73aec03b5b6 Mon Sep 17 00:00:00 2001
From: Clyne Sullivan <clyne@bitgloo.com>
Date: Wed, 29 Jan 2025 21:34:25 -0500
Subject: initial commit
---
.../DSP/Source/FastMathFunctions/arm_atan2_q15.c | 201 +++++++++++++++++++++
1 file changed, 201 insertions(+)
create mode 100644 Drivers/CMSIS/DSP/Source/FastMathFunctions/arm_atan2_q15.c
(limited to 'Drivers/CMSIS/DSP/Source/FastMathFunctions/arm_atan2_q15.c')
diff --git a/Drivers/CMSIS/DSP/Source/FastMathFunctions/arm_atan2_q15.c b/Drivers/CMSIS/DSP/Source/FastMathFunctions/arm_atan2_q15.c
new file mode 100644
index 0000000..ddf98d8
--- /dev/null
+++ b/Drivers/CMSIS/DSP/Source/FastMathFunctions/arm_atan2_q15.c
@@ -0,0 +1,201 @@
+/* ----------------------------------------------------------------------
+ * Project: CMSIS DSP Library
+ * Title: arm_atan2_q15.c
+ * Description: float32 Arc tangent of y/x
+ *
+ * $Date: 22 April 2022
+ * $Revision: V1.10.0
+ *
+ * Target Processor: Cortex-M and Cortex-A cores
+ * -------------------------------------------------------------------- */
+/*
+ * Copyright (C) 2010-2022 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 "dsp/fast_math_functions.h"
+#include "dsp/utils.h"
+
+/*
+
+atan for argument between in [0, 1.0]
+
+*/
+
+
+/* Q2.13 */
+#define ATANHALFQ13 0xed6
+#define PIHALFQ13 0x3244
+#define PIQ13 0x6488
+
+#define ATAN2_NB_COEFS_Q15 10
+
+static const q15_t atan2_coefs_q15[ATAN2_NB_COEFS_Q15]={0x0000
+,0x7fff
+,0xffff
+,0xd567
+,0xff70
+,0x1bad
+,0xfd58
+,0xe9a9
+,0x1129
+,0xfbdb
+};
+
+__STATIC_FORCEINLINE q15_t arm_atan_limited_q15(q15_t x)
+{
+ q31_t res=(q31_t)atan2_coefs_q15[ATAN2_NB_COEFS_Q15-1];
+ int i=1;
+ for(i=1;i<ATAN2_NB_COEFS_Q15;i++)
+ {
+ res = ((q31_t) x * res) >> 15U;
+ res = res + ((q31_t) atan2_coefs_q15[ATAN2_NB_COEFS_Q15-1-i]) ;
+ }
+
+ res = __SSAT(res>>2,16);
+
+
+ return(res);
+}
+
+
+__STATIC_FORCEINLINE q15_t arm_atan_q15(q15_t y,q15_t x)
+{
+ int sign=0;
+ q15_t res=0;
+
+ if (y<0)
+ {
+ arm_negate_q15(&y,&y,1);
+ sign=1-sign;
+ }
+
+ if (x < 0)
+ {
+ sign=1 - sign;
+ arm_negate_q15(&x,&x,1);
+ }
+
+ if (y > x)
+ {
+ q15_t ratio;
+ int16_t shift;
+
+ arm_divide_q15(x,y,&ratio,&shift);
+
+ arm_shift_q15(&ratio,shift,&ratio,1);
+
+ res = PIHALFQ13 - arm_atan_limited_q15(ratio);
+
+ }
+ else
+ {
+ q15_t ratio;
+ int16_t shift;
+
+ arm_divide_q15(y,x,&ratio,&shift);
+
+ arm_shift_q15(&ratio,shift,&ratio,1);
+
+ res = arm_atan_limited_q15(ratio);
+
+ }
+
+
+ if (sign)
+ {
+ arm_negate_q15(&res,&res,1);
+ }
+
+ return(res);
+}
+
+
+/**
+ @ingroup groupFastMath
+ */
+
+
+/**
+ @addtogroup atan2
+ @{
+ */
+
+/**
+ @brief Arc Tangent of y/x using sign of y and x to get right quadrant
+ @param[in] y y coordinate
+ @param[in] x x coordinate
+ @param[out] result Result in Q2.13
+ @return error status.
+
+ @par Compute the Arc tangent of y/x:
+ The sign of y and x are used to determine the right quadrant
+ and compute the right angle.
+*/
+
+
+arm_status arm_atan2_q15(q15_t y,q15_t x,q15_t *result)
+{
+ if (x > 0)
+ {
+ *result=arm_atan_q15(y,x);
+ return(ARM_MATH_SUCCESS);
+ }
+ if (x < 0)
+ {
+ if (y > 0)
+ {
+ *result=arm_atan_q15(y,x) + PIQ13;
+ }
+ else if (y < 0)
+ {
+ *result=arm_atan_q15(y,x) - PIQ13;
+ }
+ else
+ {
+ if (y<0)
+ {
+ *result= -PIQ13;
+ }
+ else
+ {
+ *result= PIQ13;
+ }
+ }
+ return(ARM_MATH_SUCCESS);
+ }
+ if (x == 0)
+ {
+ if (y > 0)
+ {
+ *result=PIHALFQ13;
+ return(ARM_MATH_SUCCESS);
+ }
+ if (y < 0)
+ {
+ *result=-PIHALFQ13;
+ return(ARM_MATH_SUCCESS);
+ }
+ }
+
+
+ return(ARM_MATH_NANINF);
+
+}
+
+/**
+ @} end of atan2 group
+ */
--
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