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Diffstat (limited to 'Drivers/CMSIS/DSP/Source/FilteringFunctions/arm_biquad_cascade_df2T_init_f32.c')
| -rw-r--r-- | Drivers/CMSIS/DSP/Source/FilteringFunctions/arm_biquad_cascade_df2T_init_f32.c | 211 |
1 files changed, 211 insertions, 0 deletions
diff --git a/Drivers/CMSIS/DSP/Source/FilteringFunctions/arm_biquad_cascade_df2T_init_f32.c b/Drivers/CMSIS/DSP/Source/FilteringFunctions/arm_biquad_cascade_df2T_init_f32.c new file mode 100644 index 0000000..1da7f3e --- /dev/null +++ b/Drivers/CMSIS/DSP/Source/FilteringFunctions/arm_biquad_cascade_df2T_init_f32.c @@ -0,0 +1,211 @@ +/* ----------------------------------------------------------------------
+ * Project: CMSIS DSP Library
+ * Title: arm_biquad_cascade_df2T_init_f32.c
+ * Description: Initialization function for floating-point transposed direct form II Biquad cascade filter
+ *
+ * $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"
+
+/**
+ @ingroup groupFilters
+ */
+
+/**
+ @addtogroup BiquadCascadeDF2T
+ @{
+ */
+
+/**
+ @brief Initialization function for the floating-point transposed direct form II Biquad cascade filter.
+ @param[in,out] S points to an instance of the filter data structure.
+ @param[in] numStages number of 2nd order stages in the filter.
+ @param[in] pCoeffs points to the filter coefficients.
+ @param[in] pState points to the state buffer.
+ @return none
+
+ @par Coefficient and State Ordering
+ The coefficients are stored in the array <code>pCoeffs</code> in the following order
+ in the not Neon version.
+ <pre>
+ {b10, b11, b12, a11, a12, b20, b21, b22, a21, a22, ...}
+ </pre>
+
+ @par
+ where <code>b1x</code> and <code>a1x</code> are the coefficients for the first stage,
+ <code>b2x</code> and <code>a2x</code> are the coefficients for the second stage,
+ and so on. The <code>pCoeffs</code> array contains a total of <code>5*numStages</code> values.
+
+ For Neon version, this array is bigger. If numstages = 4x + y, then the array has size:
+ 32*x + 5*y
+ and it must be initialized using the function
+ arm_biquad_cascade_df2T_compute_coefs_f32 which is taking the
+ standard array coefficient as parameters.
+
+ But, an array of 8*numstages is a good approximation.
+
+ Then, the initialization can be done with:
+ <pre>
+ arm_biquad_cascade_df2T_init_f32(&SNeon, nbCascade, neonCoefs, stateNeon);
+ arm_biquad_cascade_df2T_compute_coefs_f32(&SNeon,nbCascade,coefs);
+ </pre>
+
+ @par In this example, neonCoefs is a bigger array of size 8 * numStages.
+ coefs is the standard array:
+
+ <pre>
+ {b10, b11, b12, a11, a12, b20, b21, b22, a21, a22, ...}
+ </pre>
+
+
+ @par
+ The <code>pState</code> is a pointer to state array.
+ Each Biquad stage has 2 state variables <code>d1,</code> and <code>d2</code>.
+ The 2 state variables for stage 1 are first, then the 2 state variables for stage 2, and so on.
+ The state array has a total length of <code>2*numStages</code> values.
+ The state variables are updated after each block of data is processed; the coefficients are untouched.
+ */
+
+#if defined(ARM_MATH_NEON)
+/*
+
+Must be called after initializing the biquad instance.
+pCoeffs has size 5 * nbCascade
+Whereas the pCoeffs for the init has size (4*4 + 4*4)* nbCascade
+
+So this pCoeffs is the one which would be used for the not Neon version.
+The pCoeffs passed in init is bigger than the one for the not Neon version.
+
+*/
+void arm_biquad_cascade_df2T_compute_coefs_f32(
+ arm_biquad_cascade_df2T_instance_f32 * S,
+ uint8_t numStages,
+ float32_t * pCoeffs)
+{
+ uint8_t cnt;
+ float32_t *pDstCoeffs;
+ float32_t b0[4],b1[4],b2[4],a1[4],a2[4];
+
+ pDstCoeffs = S->pCoeffs;
+
+ cnt = numStages >> 2;
+ while(cnt > 0)
+ {
+ for(int i=0;i<4;i++)
+ {
+ b0[i] = pCoeffs[0];
+ b1[i] = pCoeffs[1];
+ b2[i] = pCoeffs[2];
+ a1[i] = pCoeffs[3];
+ a2[i] = pCoeffs[4];
+ pCoeffs += 5;
+ }
+
+ /* Vec 1 */
+ *pDstCoeffs++ = 0;
+ *pDstCoeffs++ = b0[1];
+ *pDstCoeffs++ = b0[2];
+ *pDstCoeffs++ = b0[3];
+
+ /* Vec 2 */
+ *pDstCoeffs++ = 0;
+ *pDstCoeffs++ = 0;
+ *pDstCoeffs++ = b0[1] * b0[2];
+ *pDstCoeffs++ = b0[2] * b0[3];
+
+ /* Vec 3 */
+ *pDstCoeffs++ = 0;
+ *pDstCoeffs++ = 0;
+ *pDstCoeffs++ = 0;
+ *pDstCoeffs++ = b0[1] * b0[2] * b0[3];
+
+ /* Vec 4 */
+ *pDstCoeffs++ = b0[0];
+ *pDstCoeffs++ = b0[0] * b0[1];
+ *pDstCoeffs++ = b0[0] * b0[1] * b0[2];
+ *pDstCoeffs++ = b0[0] * b0[1] * b0[2] * b0[3];
+
+ /* Vec 5 */
+ *pDstCoeffs++ = b1[0];
+ *pDstCoeffs++ = b1[1];
+ *pDstCoeffs++ = b1[2];
+ *pDstCoeffs++ = b1[3];
+
+ /* Vec 6 */
+ *pDstCoeffs++ = b2[0];
+ *pDstCoeffs++ = b2[1];
+ *pDstCoeffs++ = b2[2];
+ *pDstCoeffs++ = b2[3];
+
+ /* Vec 7 */
+ *pDstCoeffs++ = a1[0];
+ *pDstCoeffs++ = a1[1];
+ *pDstCoeffs++ = a1[2];
+ *pDstCoeffs++ = a1[3];
+
+ /* Vec 8 */
+ *pDstCoeffs++ = a2[0];
+ *pDstCoeffs++ = a2[1];
+ *pDstCoeffs++ = a2[2];
+ *pDstCoeffs++ = a2[3];
+
+ cnt--;
+ }
+
+ cnt = numStages & 0x3;
+ while(cnt > 0)
+ {
+ *pDstCoeffs++ = *pCoeffs++;
+ *pDstCoeffs++ = *pCoeffs++;
+ *pDstCoeffs++ = *pCoeffs++;
+ *pDstCoeffs++ = *pCoeffs++;
+ *pDstCoeffs++ = *pCoeffs++;
+ cnt--;
+ }
+
+}
+#endif
+
+void arm_biquad_cascade_df2T_init_f32(
+ arm_biquad_cascade_df2T_instance_f32 * S,
+ uint8_t numStages,
+ const float32_t * pCoeffs,
+ float32_t * pState)
+{
+ /* Assign filter stages */
+ S->numStages = numStages;
+
+ /* Assign coefficient pointer */
+ S->pCoeffs = pCoeffs;
+
+ /* Clear state buffer and size is always 2 * numStages */
+ memset(pState, 0, (2U * (uint32_t) numStages) * sizeof(float32_t));
+
+ /* Assign state pointer */
+ S->pState = pState;
+}
+
+/**
+ @} end of BiquadCascadeDF2T group
+ */
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