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_f16.c | 171 +++++++++++++++++++++
1 file changed, 171 insertions(+)
create mode 100644 Drivers/CMSIS/DSP/Source/FastMathFunctions/arm_atan2_f16.c
(limited to 'Drivers/CMSIS/DSP/Source/FastMathFunctions/arm_atan2_f16.c')
diff --git a/Drivers/CMSIS/DSP/Source/FastMathFunctions/arm_atan2_f16.c b/Drivers/CMSIS/DSP/Source/FastMathFunctions/arm_atan2_f16.c
new file mode 100644
index 0000000..b4a03a4
--- /dev/null
+++ b/Drivers/CMSIS/DSP/Source/FastMathFunctions/arm_atan2_f16.c
@@ -0,0 +1,171 @@
+/* ----------------------------------------------------------------------
+ * Project: CMSIS DSP Library
+ * Title: arm_atan2_f16.c
+ * Description: float16 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_f16.h"
+
+#if defined(ARM_FLOAT16_SUPPORTED)
+
+/*
+
+atan for argument between in [0, 1.0]
+
+
+*/
+
+#define PIF16 3.14f16
+#define PI16HALF 1.571f16
+
+#define ATANHALFF16 0.463648f16
+
+#define ATAN2_NB_COEFS_F16 5
+
+static const float16_t atan2_coefs_f16[ATAN2_NB_COEFS_F16]={0.f16
+,1.f16
+,0.f16
+,-0.367f16
+,0.152f16
+};
+
+__STATIC_FORCEINLINE float16_t arm_atan_limited_f16(float16_t x)
+{
+ float16_t res=atan2_coefs_f16[ATAN2_NB_COEFS_F16-1];
+ int i=1;
+ for(i=1;i<ATAN2_NB_COEFS_F16;i++)
+ {
+ res = (_Float16)x*(_Float16)res + (_Float16)atan2_coefs_f16[ATAN2_NB_COEFS_F16-1-i];
+ }
+
+
+ return(res);
+}
+
+__STATIC_FORCEINLINE float16_t arm_atan_f16(float16_t x)
+{
+ int sign=0;
+ float16_t res=0.0f16;
+
+ if ((_Float16)x < 0.0f16)
+ {
+ sign=1;
+ x=-(_Float16)x;
+ }
+
+ if ((_Float16)x > 1.0f16)
+ {
+ x = 1.0f16 / (_Float16)x;
+ res = (_Float16)PI16HALF - (_Float16)arm_atan_limited_f16(x);
+ }
+ else
+ {
+ res += (_Float16)arm_atan_limited_f16(x);
+ }
+
+
+ if (sign)
+ {
+ res = -(_Float16)res;
+ }
+
+ 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
+ @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_f16(float16_t y,float16_t x,float16_t *result)
+{
+ if ((_Float16)x > 0.0f16)
+ {
+ *result=arm_atan_f16((_Float16)y/(_Float16)x);
+ return(ARM_MATH_SUCCESS);
+ }
+ if ((_Float16)x < 0.0f16)
+ {
+ if ((_Float16)y > 0.0f16)
+ {
+ *result=(_Float16)arm_atan_f16((_Float16)y/(_Float16)x) + (_Float16)PIF16;
+ }
+ else if ((_Float16)y < 0.0f16)
+ {
+ *result=(_Float16)arm_atan_f16((_Float16)y/(_Float16)x) - (_Float16)PIF16;
+ }
+ else
+ {
+ if (signbit(y))
+ {
+ *result= -(_Float16)PIF16;
+ }
+ else
+ {
+ *result= PIF16;
+ }
+ }
+ return(ARM_MATH_SUCCESS);
+ }
+ if ((_Float16)x == 0.0f16)
+ {
+ if ((_Float16)y > 0.0f16)
+ {
+ *result=PI16HALF;
+ return(ARM_MATH_SUCCESS);
+ }
+ if ((_Float16)y < 0.0f16)
+ {
+ *result=-(_Float16)PI16HALF;
+ return(ARM_MATH_SUCCESS);
+ }
+ }
+
+
+ return(ARM_MATH_NANINF);
+
+}
+
+#endif /* #if defined(ARM_FLOAT16_SUPPORTED) */
+/**
+ @} end of atan2 group
+ */
--
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