| /* ---------------------------------------------------------------------- |
| * Project: CMSIS DSP Library |
| * Title: arm_biquad_cascade_stereo_df2T_f32.c |
| * Description: Processing function for floating-point transposed direct form II Biquad cascade filter. 2 channels |
| * |
| * $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 Processing function for the floating-point transposed direct form II Biquad cascade filter. |
| @param[in] S points to an instance of the filter data structure |
| @param[in] pSrc points to the block of input data |
| @param[out] pDst points to the block of output data |
| @param[in] blockSize number of samples to process |
| @return none |
| */ |
| |
| LOW_OPTIMIZATION_ENTER |
| void arm_biquad_cascade_stereo_df2T_f32( |
| const arm_biquad_cascade_stereo_df2T_instance_f32 * S, |
| const float32_t * pSrc, |
| float32_t * pDst, |
| uint32_t blockSize) |
| { |
| const float32_t *pIn = pSrc; /* Source pointer */ |
| float32_t *pOut = pDst; /* Destination pointer */ |
| float32_t *pState = S->pState; /* State pointer */ |
| const float32_t *pCoeffs = S->pCoeffs; /* Coefficient pointer */ |
| float32_t acc1a, acc1b; /* Accumulator */ |
| float32_t b0, b1, b2, a1, a2; /* Filter coefficients */ |
| float32_t Xn1a, Xn1b; /* Temporary input */ |
| float32_t d1a, d2a, d1b, d2b; /* State variables */ |
| uint32_t sample, stage = S->numStages; /* Loop counters */ |
| |
| do |
| { |
| /* Reading the coefficients */ |
| b0 = pCoeffs[0]; |
| b1 = pCoeffs[1]; |
| b2 = pCoeffs[2]; |
| a1 = pCoeffs[3]; |
| a2 = pCoeffs[4]; |
| |
| /* Reading the state values */ |
| d1a = pState[0]; |
| d2a = pState[1]; |
| d1b = pState[2]; |
| d2b = pState[3]; |
| |
| pCoeffs += 5U; |
| |
| #if defined (ARM_MATH_LOOPUNROLL) |
| |
| /* Loop unrolling: Compute 8 outputs at a time */ |
| sample = blockSize >> 3U; |
| |
| while (sample > 0U) { |
| /* y[n] = b0 * x[n] + d1 */ |
| /* d1 = b1 * x[n] + a1 * y[n] + d2 */ |
| /* d2 = b2 * x[n] + a2 * y[n] */ |
| |
| /* 1 */ |
| Xn1a = *pIn++; /* Channel a */ |
| Xn1b = *pIn++; /* Channel b */ |
| |
| acc1a = (b0 * Xn1a) + d1a; |
| acc1b = (b0 * Xn1b) + d1b; |
| |
| *pOut++ = acc1a; |
| *pOut++ = acc1b; |
| |
| d1a = ((b1 * Xn1a) + (a1 * acc1a)) + d2a; |
| d1b = ((b1 * Xn1b) + (a1 * acc1b)) + d2b; |
| |
| d2a = (b2 * Xn1a) + (a2 * acc1a); |
| d2b = (b2 * Xn1b) + (a2 * acc1b); |
| |
| /* 2 */ |
| Xn1a = *pIn++; /* Channel a */ |
| Xn1b = *pIn++; /* Channel b */ |
| |
| acc1a = (b0 * Xn1a) + d1a; |
| acc1b = (b0 * Xn1b) + d1b; |
| |
| *pOut++ = acc1a; |
| *pOut++ = acc1b; |
| |
| d1a = ((b1 * Xn1a) + (a1 * acc1a)) + d2a; |
| d1b = ((b1 * Xn1b) + (a1 * acc1b)) + d2b; |
| |
| d2a = (b2 * Xn1a) + (a2 * acc1a); |
| d2b = (b2 * Xn1b) + (a2 * acc1b); |
| |
| /* 3 */ |
| Xn1a = *pIn++; /* Channel a */ |
| Xn1b = *pIn++; /* Channel b */ |
| |
| acc1a = (b0 * Xn1a) + d1a; |
| acc1b = (b0 * Xn1b) + d1b; |
| |
| *pOut++ = acc1a; |
| *pOut++ = acc1b; |
| |
| d1a = ((b1 * Xn1a) + (a1 * acc1a)) + d2a; |
| d1b = ((b1 * Xn1b) + (a1 * acc1b)) + d2b; |
| |
| d2a = (b2 * Xn1a) + (a2 * acc1a); |
| d2b = (b2 * Xn1b) + (a2 * acc1b); |
| |
| /* 4 */ |
| Xn1a = *pIn++; /* Channel a */ |
| Xn1b = *pIn++; /* Channel b */ |
| |
| acc1a = (b0 * Xn1a) + d1a; |
| acc1b = (b0 * Xn1b) + d1b; |
| |
| *pOut++ = acc1a; |
| *pOut++ = acc1b; |
| |
| d1a = ((b1 * Xn1a) + (a1 * acc1a)) + d2a; |
| d1b = ((b1 * Xn1b) + (a1 * acc1b)) + d2b; |
| |
| d2a = (b2 * Xn1a) + (a2 * acc1a); |
| d2b = (b2 * Xn1b) + (a2 * acc1b); |
| |
| /* 5 */ |
| Xn1a = *pIn++; /* Channel a */ |
| Xn1b = *pIn++; /* Channel b */ |
| |
| acc1a = (b0 * Xn1a) + d1a; |
| acc1b = (b0 * Xn1b) + d1b; |
| |
| *pOut++ = acc1a; |
| *pOut++ = acc1b; |
| |
| d1a = ((b1 * Xn1a) + (a1 * acc1a)) + d2a; |
| d1b = ((b1 * Xn1b) + (a1 * acc1b)) + d2b; |
| |
| d2a = (b2 * Xn1a) + (a2 * acc1a); |
| d2b = (b2 * Xn1b) + (a2 * acc1b); |
| |
| /* 6 */ |
| Xn1a = *pIn++; /* Channel a */ |
| Xn1b = *pIn++; /* Channel b */ |
| |
| acc1a = (b0 * Xn1a) + d1a; |
| acc1b = (b0 * Xn1b) + d1b; |
| |
| *pOut++ = acc1a; |
| *pOut++ = acc1b; |
| |
| d1a = ((b1 * Xn1a) + (a1 * acc1a)) + d2a; |
| d1b = ((b1 * Xn1b) + (a1 * acc1b)) + d2b; |
| |
| d2a = (b2 * Xn1a) + (a2 * acc1a); |
| d2b = (b2 * Xn1b) + (a2 * acc1b); |
| |
| /* 7 */ |
| Xn1a = *pIn++; /* Channel a */ |
| Xn1b = *pIn++; /* Channel b */ |
| |
| acc1a = (b0 * Xn1a) + d1a; |
| acc1b = (b0 * Xn1b) + d1b; |
| |
| *pOut++ = acc1a; |
| *pOut++ = acc1b; |
| |
| d1a = ((b1 * Xn1a) + (a1 * acc1a)) + d2a; |
| d1b = ((b1 * Xn1b) + (a1 * acc1b)) + d2b; |
| |
| d2a = (b2 * Xn1a) + (a2 * acc1a); |
| d2b = (b2 * Xn1b) + (a2 * acc1b); |
| |
| /* 8 */ |
| Xn1a = *pIn++; /* Channel a */ |
| Xn1b = *pIn++; /* Channel b */ |
| |
| acc1a = (b0 * Xn1a) + d1a; |
| acc1b = (b0 * Xn1b) + d1b; |
| |
| *pOut++ = acc1a; |
| *pOut++ = acc1b; |
| |
| d1a = ((b1 * Xn1a) + (a1 * acc1a)) + d2a; |
| d1b = ((b1 * Xn1b) + (a1 * acc1b)) + d2b; |
| |
| d2a = (b2 * Xn1a) + (a2 * acc1a); |
| d2b = (b2 * Xn1b) + (a2 * acc1b); |
| |
| /* decrement loop counter */ |
| sample--; |
| } |
| |
| /* Loop unrolling: Compute remaining outputs */ |
| sample = blockSize & 0x7U; |
| |
| #else |
| |
| /* Initialize blkCnt with number of samples */ |
| sample = blockSize; |
| |
| #endif /* #if defined (ARM_MATH_LOOPUNROLL) */ |
| |
| while (sample > 0U) { |
| /* Read the input */ |
| Xn1a = *pIn++; /* Channel a */ |
| Xn1b = *pIn++; /* Channel b */ |
| |
| /* y[n] = b0 * x[n] + d1 */ |
| acc1a = (b0 * Xn1a) + d1a; |
| acc1b = (b0 * Xn1b) + d1b; |
| |
| /* Store the result in the accumulator in the destination buffer. */ |
| *pOut++ = acc1a; |
| *pOut++ = acc1b; |
| |
| /* Every time after the output is computed state should be updated. */ |
| /* d1 = b1 * x[n] + a1 * y[n] + d2 */ |
| d1a = ((b1 * Xn1a) + (a1 * acc1a)) + d2a; |
| d1b = ((b1 * Xn1b) + (a1 * acc1b)) + d2b; |
| |
| /* d2 = b2 * x[n] + a2 * y[n] */ |
| d2a = (b2 * Xn1a) + (a2 * acc1a); |
| d2b = (b2 * Xn1b) + (a2 * acc1b); |
| |
| /* decrement loop counter */ |
| sample--; |
| } |
| |
| /* Store the updated state variables back into the state array */ |
| pState[0] = d1a; |
| pState[1] = d2a; |
| |
| pState[2] = d1b; |
| pState[3] = d2b; |
| |
| pState += 4U; |
| |
| /* The current stage input is given as the output to the next stage */ |
| pIn = pDst; |
| |
| /* Reset the output working pointer */ |
| pOut = pDst; |
| |
| /* Decrement the loop counter */ |
| stage--; |
| |
| } while (stage > 0U); |
| |
| } |
| LOW_OPTIMIZATION_EXIT |
| /** |
| @} end of BiquadCascadeDF2T group |
| */ |