add l476 implementationl476

1 files changed, 381 insertions, 381 deletions

diff --git a/Drivers/CMSIS/DSP/Source/TransformFunctions/arm_dct4_q15.c b/Drivers/CMSIS/DSP/Source/TransformFunctions/arm_dct4_q15.c
index a4650da..ba26300 100644
--- a/Drivers/CMSIS/DSP/Source/TransformFunctions/arm_dct4_q15.c
+++ b/Drivers/CMSIS/DSP/Source/TransformFunctions/arm_dct4_q15.c
@@ -1,381 +1,381 @@
-/* ----------------------------------------------------------------------
- * Project:      CMSIS DSP Library
- * Title:        arm_dct4_q15.c
- * Description:  Processing function of DCT4 & IDCT4 Q15
- *
- * $Date:        23 April 2021
- * $Revision:    V1.9.0
- *
- * Target Processor: Cortex-M and Cortex-A cores
- * -------------------------------------------------------------------- */
-/*
- * Copyright (C) 2010-2021 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/transform_functions.h"
-
-/**
-  @addtogroup DCT4_IDCT4
-  @{
- */
-
-/**
-  @brief         Processing function for the Q15 DCT4/IDCT4.
-  @param[in]     S             points to an instance of the Q15 DCT4 structure.
-  @param[in]     pState        points to state buffer.
-  @param[in,out] pInlineBuffer points to the in-place input and output buffer.
-  @return        none
- 
-  @par           Input an output formats
-                   Internally inputs are downscaled in the RFFT process function to avoid overflows.
-                   Number of bits downscaled, depends on the size of the transform. The input and output
-                   formats for different DCT sizes and number of bits to upscale are mentioned in the table below:
-
-                   \image html dct4FormatsQ15Table.gif
- */
-
-void arm_dct4_q15(
-  const arm_dct4_instance_q15 * S,
-        q15_t * pState,
-        q15_t * pInlineBuffer)
-{
-  const q15_t *weights = S->pTwiddle;                  /* Pointer to the Weights table */
-  const q15_t *cosFact = S->pCosFactor;                /* Pointer to the cos factors table */
-        q15_t *pS1, *pS2, *pbuff;                      /* Temporary pointers for input buffer and pState buffer */
-        q15_t in;                                      /* Temporary variable */
-        uint32_t i;                                    /* Loop counter */
-
-
-  /* DCT4 computation involves DCT2 (which is calculated using RFFT)
-   * along with some pre-processing and post-processing.
-   * Computational procedure is explained as follows:
-   * (a) Pre-processing involves multiplying input with cos factor,
-   *     r(n) = 2 * u(n) * cos(pi*(2*n+1)/(4*n))
-   *              where,
-   *                 r(n) -- output of preprocessing
-   *                 u(n) -- input to preprocessing(actual Source buffer)
-   * (b) Calculation of DCT2 using FFT is divided into three steps:
-   *                  Step1: Re-ordering of even and odd elements of input.
-   *                  Step2: Calculating FFT of the re-ordered input.
-   *                  Step3: Taking the real part of the product of FFT output and weights.
-   * (c) Post-processing - DCT4 can be obtained from DCT2 output using the following equation:
-   *                   Y4(k) = Y2(k) - Y4(k-1) and Y4(-1) = Y4(0)
-   *                        where,
-   *                           Y4 -- DCT4 output,   Y2 -- DCT2 output
-   * (d) Multiplying the output with the normalizing factor sqrt(2/N).
-   */
-
-  /*-------- Pre-processing ------------*/
-  /* Multiplying input with cos factor i.e. r(n) = 2 * x(n) * cos(pi*(2*n+1)/(4*n)) */
-  arm_mult_q15 (pInlineBuffer, cosFact, pInlineBuffer, S->N);
-  arm_shift_q15 (pInlineBuffer, 1, pInlineBuffer, S->N);
-
-  /* ----------------------------------------------------------------
-   * Step1: Re-ordering of even and odd elements as
-   *             pState[i] =  pInlineBuffer[2*i] and
-   *             pState[N-i-1] = pInlineBuffer[2*i+1] where i = 0 to N/2
-   ---------------------------------------------------------------------*/
-
-  /* pS1 initialized to pState */
-  pS1 = pState;
-
-  /* pS2 initialized to pState+N-1, so that it points to the end of the state buffer */
-  pS2 = pState + (S->N - 1U);
-
-  /* pbuff initialized to input buffer */
-  pbuff = pInlineBuffer;
-
-
-#if defined (ARM_MATH_LOOPUNROLL)
-
-  /* Initializing the loop counter to N/2 >> 2 for loop unrolling by 4 */
-  i = S->Nby2 >> 2U;
-
-  /* First part of the processing with loop unrolling.  Compute 4 outputs at a time.
-   ** a second loop below computes the remaining 1 to 3 samples. */
-  do
-  {
-    /* Re-ordering of even and odd elements */
-    /* pState[i] =  pInlineBuffer[2*i] */
-    *pS1++ = *pbuff++;
-    /* pState[N-i-1] = pInlineBuffer[2*i+1] */
-    *pS2-- = *pbuff++;
-
-    *pS1++ = *pbuff++;
-    *pS2-- = *pbuff++;
-
-    *pS1++ = *pbuff++;
-    *pS2-- = *pbuff++;
-
-    *pS1++ = *pbuff++;
-    *pS2-- = *pbuff++;
-
-    /* Decrement loop counter */
-    i--;
-  } while (i > 0U);
-
-  /* pbuff initialized to input buffer */
-  pbuff = pInlineBuffer;
-
-  /* pS1 initialized to pState */
-  pS1 = pState;
-
-  /* Initializing the loop counter to N/4 instead of N for loop unrolling */
-  i = S->N >> 2U;
-
-  /* Processing with loop unrolling 4 times as N is always multiple of 4.
-   * Compute 4 outputs at a time */
-  do
-  {
-    /* Writing the re-ordered output back to inplace input buffer */
-    *pbuff++ = *pS1++;
-    *pbuff++ = *pS1++;
-    *pbuff++ = *pS1++;
-    *pbuff++ = *pS1++;
-
-    /* Decrement the loop counter */
-    i--;
-  } while (i > 0U);
-
-
-  /* ---------------------------------------------------------
-   *     Step2: Calculate RFFT for N-point input
-   * ---------------------------------------------------------- */
-  /* pInlineBuffer is real input of length N , pState is the complex output of length 2N */
-  arm_rfft_q15 (S->pRfft, pInlineBuffer, pState);
-
-  /*----------------------------------------------------------------------
-   *  Step3: Multiply the FFT output with the weights.
-   *----------------------------------------------------------------------*/
-  arm_cmplx_mult_cmplx_q15 (pState, weights, pState, S->N);
-
-  /* The output of complex multiplication is in 3.13 format.
-   * Hence changing the format of N (i.e. 2*N elements) complex numbers to 1.15 format by shifting left by 2 bits. */
-  arm_shift_q15 (pState, 2, pState, S->N * 2);
-
-  /* ----------- Post-processing ---------- */
-  /* DCT-IV can be obtained from DCT-II by the equation,
-   *       Y4(k) = Y2(k) - Y4(k-1) and Y4(-1) = Y4(0)
-   *       Hence, Y4(0) = Y2(0)/2  */
-  /* Getting only real part from the output and Converting to DCT-IV */
-
-  /* Initializing the loop counter to N >> 2 for loop unrolling by 4 */
-  i = (S->N - 1U) >> 2U;
-
-  /* pbuff initialized to input buffer. */
-  pbuff = pInlineBuffer;
-
-  /* pS1 initialized to pState */
-  pS1 = pState;
-
-  /* Calculating Y4(0) from Y2(0) using Y4(0) = Y2(0)/2 */
-  in = *pS1++ >> 1U;
-  /* input buffer acts as inplace, so output values are stored in the input itself. */
-  *pbuff++ = in;
-
-  /* pState pointer is incremented twice as the real values are located alternatively in the array */
-  pS1++;
-
-  /* First part of the processing with loop unrolling.  Compute 4 outputs at a time.
-   ** a second loop below computes the remaining 1 to 3 samples. */
-  do
-  {
-    /* Calculating Y4(1) to Y4(N-1) from Y2 using equation Y4(k) = Y2(k) - Y4(k-1) */
-    /* pState pointer (pS1) is incremented twice as the real values are located alternatively in the array */
-    in = *pS1++ - in;
-    *pbuff++ = in;
-    /* points to the next real value */
-    pS1++;
-
-    in = *pS1++ - in;
-    *pbuff++ = in;
-    pS1++;
-
-    in = *pS1++ - in;
-    *pbuff++ = in;
-    pS1++;
-
-    in = *pS1++ - in;
-    *pbuff++ = in;
-    pS1++;
-
-    /* Decrement the loop counter */
-    i--;
-  } while (i > 0U);
-
-  /* If the blockSize is not a multiple of 4, compute any remaining output samples here.
-   ** No loop unrolling is used. */
-  i = (S->N - 1U) % 0x4U;
-
-  while (i > 0U)
-  {
-    /* Calculating Y4(1) to Y4(N-1) from Y2 using equation Y4(k) = Y2(k) - Y4(k-1) */
-    /* pState pointer (pS1) is incremented twice as the real values are located alternatively in the array */
-    in = *pS1++ - in;
-    *pbuff++ = in;
-
-    /* points to the next real value */
-    pS1++;
-
-    /* Decrement loop counter */
-    i--;
-  }
-
-
-  /*------------ Normalizing the output by multiplying with the normalizing factor ----------*/
-
-  /* Initializing the loop counter to N/4 instead of N for loop unrolling */
-  i = S->N >> 2U;
-
-  /* pbuff initialized to the pInlineBuffer(now contains the output values) */
-  pbuff = pInlineBuffer;
-
-  /* Processing with loop unrolling 4 times as N is always multiple of 4.  Compute 4 outputs at a time */
-  do
-  {
-    /* Multiplying pInlineBuffer with the normalizing factor sqrt(2/N) */
-    in = *pbuff;
-    *pbuff++ = ((q15_t) (((q31_t) in * S->normalize) >> 15));
-
-    in = *pbuff;
-    *pbuff++ = ((q15_t) (((q31_t) in * S->normalize) >> 15));
-
-    in = *pbuff;
-    *pbuff++ = ((q15_t) (((q31_t) in * S->normalize) >> 15));
-
-    in = *pbuff;
-    *pbuff++ = ((q15_t) (((q31_t) in * S->normalize) >> 15));
-
-    /* Decrement loop counter */
-    i--;
-  } while (i > 0U);
-
-
-#else
-
-  /* Initializing the loop counter to N/2 */
-  i = S->Nby2;
-
-  do
-  {
-    /* Re-ordering of even and odd elements */
-    /* pState[i] =  pInlineBuffer[2*i] */
-    *pS1++ = *pbuff++;
-    /* pState[N-i-1] = pInlineBuffer[2*i+1] */
-    *pS2-- = *pbuff++;
-
-    /* Decrement the loop counter */
-    i--;
-  } while (i > 0U);
-
-  /* pbuff initialized to input buffer */
-  pbuff = pInlineBuffer;
-
-  /* pS1 initialized to pState */
-  pS1 = pState;
-
-  /* Initializing the loop counter */
-  i = S->N;
-
-  do
-  {
-    /* Writing the re-ordered output back to inplace input buffer */
-    *pbuff++ = *pS1++;
-
-    /* Decrement the loop counter */
-    i--;
-  } while (i > 0U);
-
-
-  /* ---------------------------------------------------------
-   *     Step2: Calculate RFFT for N-point input
-   * ---------------------------------------------------------- */
-  /* pInlineBuffer is real input of length N , pState is the complex output of length 2N */
-  arm_rfft_q15 (S->pRfft, pInlineBuffer, pState);
-
-  /*----------------------------------------------------------------------
-   *  Step3: Multiply the FFT output with the weights.
-   *----------------------------------------------------------------------*/
-  arm_cmplx_mult_cmplx_q15 (pState, weights, pState, S->N);
-
-  /* The output of complex multiplication is in 3.13 format.
-   * Hence changing the format of N (i.e. 2*N elements) complex numbers to 1.15 format by shifting left by 2 bits. */
-  arm_shift_q15 (pState, 2, pState, S->N * 2);
-
-  /* ----------- Post-processing ---------- */
-  /* DCT-IV can be obtained from DCT-II by the equation,
-   *       Y4(k) = Y2(k) - Y4(k-1) and Y4(-1) = Y4(0)
-   *       Hence, Y4(0) = Y2(0)/2  */
-  /* Getting only real part from the output and Converting to DCT-IV */
-
-  /* pbuff initialized to input buffer. */
-  pbuff = pInlineBuffer;
-
-  /* pS1 initialized to pState */
-  pS1 = pState;
-
-  /* Calculating Y4(0) from Y2(0) using Y4(0) = Y2(0)/2 */
-  in = *pS1++ >> 1U;
-  /* input buffer acts as inplace, so output values are stored in the input itself. */
-  *pbuff++ = in;
-
-  /* pState pointer is incremented twice as the real values are located alternatively in the array */
-  pS1++;
-
-  /* Initializing the loop counter */
-  i = (S->N - 1U);
-
-  do
-  {
-    /* Calculating Y4(1) to Y4(N-1) from Y2 using equation Y4(k) = Y2(k) - Y4(k-1) */
-    /* pState pointer (pS1) is incremented twice as the real values are located alternatively in the array */
-    in = *pS1++ - in;
-    *pbuff++ = in;
-
-    /* points to the next real value */
-    pS1++;
-
-    /* Decrement loop counter */
-    i--;
-  } while (i > 0U);
-
-  /*------------ Normalizing the output by multiplying with the normalizing factor ----------*/
-
-  /* Initializing loop counter */
-  i = S->N;
-
-  /* pbuff initialized to the pInlineBuffer (now contains the output values) */
-  pbuff = pInlineBuffer;
-
-  do
-  {
-    /* Multiplying pInlineBuffer with the normalizing factor sqrt(2/N) */
-    in = *pbuff;
-    *pbuff++ = ((q15_t) (((q31_t) in * S->normalize) >> 15));
-
-    /* Decrement loop counter */
-    i--;
-
-  } while (i > 0U);
-
-#endif /* #if defined (ARM_MATH_LOOPUNROLL) */
-
-}
-
-/**
-  @} end of DCT4_IDCT4 group
- */
+/* ----------------------------------------------------------------------

+ * Project:      CMSIS DSP Library

+ * Title:        arm_dct4_q15.c

+ * Description:  Processing function of DCT4 & IDCT4 Q15

+ *

+ * $Date:        18. March 2019

+ * $Revision:    V1.6.0

+ *

+ * Target Processor: Cortex-M cores

+ * -------------------------------------------------------------------- */

+/*

+ * Copyright (C) 2010-2019 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"

+

+/**

+  @addtogroup DCT4_IDCT4

+  @{

+ */

+

+/**

+  @brief         Processing function for the Q15 DCT4/IDCT4.

+  @param[in]     S             points to an instance of the Q15 DCT4 structure.

+  @param[in]     pState        points to state buffer.

+  @param[in,out] pInlineBuffer points to the in-place input and output buffer.

+  @return        none

+ 

+  @par           Input an output formats

+                   Internally inputs are downscaled in the RFFT process function to avoid overflows.

+                   Number of bits downscaled, depends on the size of the transform. The input and output

+                   formats for different DCT sizes and number of bits to upscale are mentioned in the table below:

+

+                   \image html dct4FormatsQ15Table.gif

+ */

+

+void arm_dct4_q15(

+  const arm_dct4_instance_q15 * S,

+        q15_t * pState,

+        q15_t * pInlineBuffer)

+{

+  const q15_t *weights = S->pTwiddle;                  /* Pointer to the Weights table */

+  const q15_t *cosFact = S->pCosFactor;                /* Pointer to the cos factors table */

+        q15_t *pS1, *pS2, *pbuff;                      /* Temporary pointers for input buffer and pState buffer */

+        q15_t in;                                      /* Temporary variable */

+        uint32_t i;                                    /* Loop counter */

+

+

+  /* DCT4 computation involves DCT2 (which is calculated using RFFT)

+   * along with some pre-processing and post-processing.

+   * Computational procedure is explained as follows:

+   * (a) Pre-processing involves multiplying input with cos factor,

+   *     r(n) = 2 * u(n) * cos(pi*(2*n+1)/(4*n))

+   *              where,

+   *                 r(n) -- output of preprocessing

+   *                 u(n) -- input to preprocessing(actual Source buffer)

+   * (b) Calculation of DCT2 using FFT is divided into three steps:

+   *                  Step1: Re-ordering of even and odd elements of input.

+   *                  Step2: Calculating FFT of the re-ordered input.

+   *                  Step3: Taking the real part of the product of FFT output and weights.

+   * (c) Post-processing - DCT4 can be obtained from DCT2 output using the following equation:

+   *                   Y4(k) = Y2(k) - Y4(k-1) and Y4(-1) = Y4(0)

+   *                        where,

+   *                           Y4 -- DCT4 output,   Y2 -- DCT2 output

+   * (d) Multiplying the output with the normalizing factor sqrt(2/N).

+   */

+

+  /*-------- Pre-processing ------------*/

+  /* Multiplying input with cos factor i.e. r(n) = 2 * x(n) * cos(pi*(2*n+1)/(4*n)) */

+  arm_mult_q15 (pInlineBuffer, cosFact, pInlineBuffer, S->N);

+  arm_shift_q15 (pInlineBuffer, 1, pInlineBuffer, S->N);

+

+  /* ----------------------------------------------------------------

+   * Step1: Re-ordering of even and odd elements as

+   *             pState[i] =  pInlineBuffer[2*i] and

+   *             pState[N-i-1] = pInlineBuffer[2*i+1] where i = 0 to N/2

+   ---------------------------------------------------------------------*/

+

+  /* pS1 initialized to pState */

+  pS1 = pState;

+

+  /* pS2 initialized to pState+N-1, so that it points to the end of the state buffer */

+  pS2 = pState + (S->N - 1U);

+

+  /* pbuff initialized to input buffer */

+  pbuff = pInlineBuffer;

+

+

+#if defined (ARM_MATH_LOOPUNROLL)

+

+  /* Initializing the loop counter to N/2 >> 2 for loop unrolling by 4 */

+  i = S->Nby2 >> 2U;

+

+  /* First part of the processing with loop unrolling.  Compute 4 outputs at a time.

+   ** a second loop below computes the remaining 1 to 3 samples. */

+  do

+  {

+    /* Re-ordering of even and odd elements */

+    /* pState[i] =  pInlineBuffer[2*i] */

+    *pS1++ = *pbuff++;

+    /* pState[N-i-1] = pInlineBuffer[2*i+1] */

+    *pS2-- = *pbuff++;

+

+    *pS1++ = *pbuff++;

+    *pS2-- = *pbuff++;

+

+    *pS1++ = *pbuff++;

+    *pS2-- = *pbuff++;

+

+    *pS1++ = *pbuff++;

+    *pS2-- = *pbuff++;

+

+    /* Decrement loop counter */

+    i--;

+  } while (i > 0U);

+

+  /* pbuff initialized to input buffer */

+  pbuff = pInlineBuffer;

+

+  /* pS1 initialized to pState */

+  pS1 = pState;

+

+  /* Initializing the loop counter to N/4 instead of N for loop unrolling */

+  i = S->N >> 2U;

+

+  /* Processing with loop unrolling 4 times as N is always multiple of 4.

+   * Compute 4 outputs at a time */

+  do

+  {

+    /* Writing the re-ordered output back to inplace input buffer */

+    *pbuff++ = *pS1++;

+    *pbuff++ = *pS1++;

+    *pbuff++ = *pS1++;

+    *pbuff++ = *pS1++;

+

+    /* Decrement the loop counter */

+    i--;

+  } while (i > 0U);

+

+

+  /* ---------------------------------------------------------

+   *     Step2: Calculate RFFT for N-point input

+   * ---------------------------------------------------------- */

+  /* pInlineBuffer is real input of length N , pState is the complex output of length 2N */

+  arm_rfft_q15 (S->pRfft, pInlineBuffer, pState);

+

+  /*----------------------------------------------------------------------

+   *  Step3: Multiply the FFT output with the weights.

+   *----------------------------------------------------------------------*/

+  arm_cmplx_mult_cmplx_q15 (pState, weights, pState, S->N);

+

+  /* The output of complex multiplication is in 3.13 format.

+   * Hence changing the format of N (i.e. 2*N elements) complex numbers to 1.15 format by shifting left by 2 bits. */

+  arm_shift_q15 (pState, 2, pState, S->N * 2);

+

+  /* ----------- Post-processing ---------- */

+  /* DCT-IV can be obtained from DCT-II by the equation,

+   *       Y4(k) = Y2(k) - Y4(k-1) and Y4(-1) = Y4(0)

+   *       Hence, Y4(0) = Y2(0)/2  */

+  /* Getting only real part from the output and Converting to DCT-IV */

+

+  /* Initializing the loop counter to N >> 2 for loop unrolling by 4 */

+  i = (S->N - 1U) >> 2U;

+

+  /* pbuff initialized to input buffer. */

+  pbuff = pInlineBuffer;

+

+  /* pS1 initialized to pState */

+  pS1 = pState;

+

+  /* Calculating Y4(0) from Y2(0) using Y4(0) = Y2(0)/2 */

+  in = *pS1++ >> 1U;

+  /* input buffer acts as inplace, so output values are stored in the input itself. */

+  *pbuff++ = in;

+

+  /* pState pointer is incremented twice as the real values are located alternatively in the array */

+  pS1++;

+

+  /* First part of the processing with loop unrolling.  Compute 4 outputs at a time.

+   ** a second loop below computes the remaining 1 to 3 samples. */

+  do

+  {

+    /* Calculating Y4(1) to Y4(N-1) from Y2 using equation Y4(k) = Y2(k) - Y4(k-1) */

+    /* pState pointer (pS1) is incremented twice as the real values are located alternatively in the array */

+    in = *pS1++ - in;

+    *pbuff++ = in;

+    /* points to the next real value */

+    pS1++;

+

+    in = *pS1++ - in;

+    *pbuff++ = in;

+    pS1++;

+

+    in = *pS1++ - in;

+    *pbuff++ = in;

+    pS1++;

+

+    in = *pS1++ - in;

+    *pbuff++ = in;

+    pS1++;

+

+    /* Decrement the loop counter */

+    i--;

+  } while (i > 0U);

+

+  /* If the blockSize is not a multiple of 4, compute any remaining output samples here.

+   ** No loop unrolling is used. */

+  i = (S->N - 1U) % 0x4U;

+

+  while (i > 0U)

+  {

+    /* Calculating Y4(1) to Y4(N-1) from Y2 using equation Y4(k) = Y2(k) - Y4(k-1) */

+    /* pState pointer (pS1) is incremented twice as the real values are located alternatively in the array */

+    in = *pS1++ - in;

+    *pbuff++ = in;

+

+    /* points to the next real value */

+    pS1++;

+

+    /* Decrement loop counter */

+    i--;

+  }

+

+

+  /*------------ Normalizing the output by multiplying with the normalizing factor ----------*/

+

+  /* Initializing the loop counter to N/4 instead of N for loop unrolling */

+  i = S->N >> 2U;

+

+  /* pbuff initialized to the pInlineBuffer(now contains the output values) */

+  pbuff = pInlineBuffer;

+

+  /* Processing with loop unrolling 4 times as N is always multiple of 4.  Compute 4 outputs at a time */

+  do

+  {

+    /* Multiplying pInlineBuffer with the normalizing factor sqrt(2/N) */

+    in = *pbuff;

+    *pbuff++ = ((q15_t) (((q31_t) in * S->normalize) >> 15));

+

+    in = *pbuff;

+    *pbuff++ = ((q15_t) (((q31_t) in * S->normalize) >> 15));

+

+    in = *pbuff;

+    *pbuff++ = ((q15_t) (((q31_t) in * S->normalize) >> 15));

+

+    in = *pbuff;

+    *pbuff++ = ((q15_t) (((q31_t) in * S->normalize) >> 15));

+

+    /* Decrement loop counter */

+    i--;

+  } while (i > 0U);

+

+

+#else

+

+  /* Initializing the loop counter to N/2 */

+  i = S->Nby2;

+

+  do

+  {

+    /* Re-ordering of even and odd elements */

+    /* pState[i] =  pInlineBuffer[2*i] */

+    *pS1++ = *pbuff++;

+    /* pState[N-i-1] = pInlineBuffer[2*i+1] */

+    *pS2-- = *pbuff++;

+

+    /* Decrement the loop counter */

+    i--;

+  } while (i > 0U);

+

+  /* pbuff initialized to input buffer */

+  pbuff = pInlineBuffer;

+

+  /* pS1 initialized to pState */

+  pS1 = pState;

+

+  /* Initializing the loop counter */

+  i = S->N;

+

+  do

+  {

+    /* Writing the re-ordered output back to inplace input buffer */

+    *pbuff++ = *pS1++;

+

+    /* Decrement the loop counter */

+    i--;

+  } while (i > 0U);

+

+

+  /* ---------------------------------------------------------

+   *     Step2: Calculate RFFT for N-point input

+   * ---------------------------------------------------------- */

+  /* pInlineBuffer is real input of length N , pState is the complex output of length 2N */

+  arm_rfft_q15 (S->pRfft, pInlineBuffer, pState);

+

+  /*----------------------------------------------------------------------

+   *  Step3: Multiply the FFT output with the weights.

+   *----------------------------------------------------------------------*/

+  arm_cmplx_mult_cmplx_q15 (pState, weights, pState, S->N);

+

+  /* The output of complex multiplication is in 3.13 format.

+   * Hence changing the format of N (i.e. 2*N elements) complex numbers to 1.15 format by shifting left by 2 bits. */

+  arm_shift_q15 (pState, 2, pState, S->N * 2);

+

+  /* ----------- Post-processing ---------- */

+  /* DCT-IV can be obtained from DCT-II by the equation,

+   *       Y4(k) = Y2(k) - Y4(k-1) and Y4(-1) = Y4(0)

+   *       Hence, Y4(0) = Y2(0)/2  */

+  /* Getting only real part from the output and Converting to DCT-IV */

+

+  /* pbuff initialized to input buffer. */

+  pbuff = pInlineBuffer;

+

+  /* pS1 initialized to pState */

+  pS1 = pState;

+

+  /* Calculating Y4(0) from Y2(0) using Y4(0) = Y2(0)/2 */

+  in = *pS1++ >> 1U;

+  /* input buffer acts as inplace, so output values are stored in the input itself. */

+  *pbuff++ = in;

+

+  /* pState pointer is incremented twice as the real values are located alternatively in the array */

+  pS1++;

+

+  /* Initializing the loop counter */

+  i = (S->N - 1U);

+

+  do

+  {

+    /* Calculating Y4(1) to Y4(N-1) from Y2 using equation Y4(k) = Y2(k) - Y4(k-1) */

+    /* pState pointer (pS1) is incremented twice as the real values are located alternatively in the array */

+    in = *pS1++ - in;

+    *pbuff++ = in;

+

+    /* points to the next real value */

+    pS1++;

+

+    /* Decrement loop counter */

+    i--;

+  } while (i > 0U);

+

+  /*------------ Normalizing the output by multiplying with the normalizing factor ----------*/

+

+  /* Initializing loop counter */

+  i = S->N;

+

+  /* pbuff initialized to the pInlineBuffer (now contains the output values) */

+  pbuff = pInlineBuffer;

+

+  do

+  {

+    /* Multiplying pInlineBuffer with the normalizing factor sqrt(2/N) */

+    in = *pbuff;

+    *pbuff++ = ((q15_t) (((q31_t) in * S->normalize) >> 15));

+

+    /* Decrement loop counter */

+    i--;

+

+  } while (i > 0U);

+

+#endif /* #if defined (ARM_MATH_LOOPUNROLL) */

+

+}

+

+/**

+  @} end of DCT4_IDCT4 group

+ */