Diff: functions/TransformFunctions/arm_cfft_radix4_init_q15.c

Revision:

1:24714b45cd1b

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/functions/TransformFunctions/arm_cfft_radix4_init_q15.c	Wed Jun 20 11:21:31 2018 +0000
@@ -0,0 +1,140 @@
+/* ----------------------------------------------------------------------
+ * Project:      CMSIS DSP Library
+ * Title:        arm_cfft_radix4_init_q15.c
+ * Description:  Radix-4 Decimation in Frequency Q15 FFT & IFFT initialization function
+ *
+ * $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 groupTransforms
+ */
+
+
+/**
+ * @addtogroup ComplexFFT
+ * @{
+ */
+
+
+/**
+* @brief Initialization function for the Q15 CFFT/CIFFT.
+* @deprecated Do not use this function.  It has been superseded by \ref arm_cfft_q15 and will be removed
+* @param[in,out] *S             points to an instance of the Q15 CFFT/CIFFT structure.
+* @param[in]     fftLen         length of the FFT.
+* @param[in]     ifftFlag       flag that selects forward (ifftFlag=0) or inverse (ifftFlag=1) transform.
+* @param[in]     bitReverseFlag flag that enables (bitReverseFlag=1) or disables (bitReverseFlag=0) bit reversal of output.
+* @return        The function returns ARM_MATH_SUCCESS if initialization is successful or ARM_MATH_ARGUMENT_ERROR if <code>fftLen</code> is not a supported value.
+*
+* \par Description:
+* \par
+* The parameter <code>ifftFlag</code> controls whether a forward or inverse transform is computed.
+* Set(=1) ifftFlag for calculation of CIFFT otherwise  CFFT is calculated
+* \par
+* The parameter <code>bitReverseFlag</code> controls whether output is in normal order or bit reversed order.
+* Set(=1) bitReverseFlag for output to be in normal order otherwise output is in bit reversed order.
+* \par
+* The parameter <code>fftLen</code>	Specifies length of CFFT/CIFFT process. Supported FFT Lengths are 16, 64, 256, 1024.
+* \par
+* This Function also initializes Twiddle factor table pointer and Bit reversal table pointer.
+*/
+
+arm_status arm_cfft_radix4_init_q15(
+  arm_cfft_radix4_instance_q15 * S,
+  uint16_t fftLen,
+  uint8_t ifftFlag,
+  uint8_t bitReverseFlag)
+{
+  /*  Initialise the default arm status */
+  arm_status status = ARM_MATH_SUCCESS;
+  /*  Initialise the FFT length */
+  S->fftLen = fftLen;
+  /*  Initialise the Twiddle coefficient pointer */
+  S->pTwiddle = (q15_t *) twiddleCoef_4096_q15;
+  /*  Initialise the Flag for selection of CFFT or CIFFT */
+  S->ifftFlag = ifftFlag;
+  /*  Initialise the Flag for calculation Bit reversal or not */
+  S->bitReverseFlag = bitReverseFlag;
+
+  /*  Initializations of structure parameters depending on the FFT length */
+  switch (S->fftLen)
+  {
+  case 4096U:
+    /*  Initializations of structure parameters for 4096 point FFT */
+
+    /*  Initialise the twiddle coef modifier value */
+    S->twidCoefModifier = 1U;
+    /*  Initialise the bit reversal table modifier */
+    S->bitRevFactor = 1U;
+    /*  Initialise the bit reversal table pointer */
+    S->pBitRevTable = (uint16_t *) armBitRevTable;
+
+    break;
+
+  case 1024U:
+    /*  Initializations of structure parameters for 1024 point FFT */
+    S->twidCoefModifier = 4U;
+    S->bitRevFactor = 4U;
+    S->pBitRevTable = (uint16_t *) & armBitRevTable[3];
+
+    break;
+
+  case 256U:
+    /*  Initializations of structure parameters for 256 point FFT */
+    S->twidCoefModifier = 16U;
+    S->bitRevFactor = 16U;
+    S->pBitRevTable = (uint16_t *) & armBitRevTable[15];
+
+    break;
+
+  case 64U:
+    /*  Initializations of structure parameters for 64 point FFT */
+    S->twidCoefModifier = 64U;
+    S->bitRevFactor = 64U;
+    S->pBitRevTable = (uint16_t *) & armBitRevTable[63];
+
+    break;
+
+  case 16U:
+    /*  Initializations of structure parameters for 16 point FFT */
+    S->twidCoefModifier = 256U;
+    S->bitRevFactor = 256U;
+    S->pBitRevTable = (uint16_t *) & armBitRevTable[255];
+
+    break;
+
+  default:
+    /*  Reporting argument error if fftSize is not valid value */
+    status = ARM_MATH_ARGUMENT_ERROR;
+    break;
+  }
+
+  return (status);
+}
+
+/**
+ * @} end of ComplexFFT group
+ */