diff options
Diffstat (limited to 'DSP_Lib/Source/FilteringFunctions/arm_biquad_cascade_stereo_df2T_f32.c')
-rw-r--r-- | DSP_Lib/Source/FilteringFunctions/arm_biquad_cascade_stereo_df2T_f32.c | 683 |
1 files changed, 683 insertions, 0 deletions
diff --git a/DSP_Lib/Source/FilteringFunctions/arm_biquad_cascade_stereo_df2T_f32.c b/DSP_Lib/Source/FilteringFunctions/arm_biquad_cascade_stereo_df2T_f32.c new file mode 100644 index 0000000..4811973 --- /dev/null +++ b/DSP_Lib/Source/FilteringFunctions/arm_biquad_cascade_stereo_df2T_f32.c @@ -0,0 +1,683 @@ +/* ---------------------------------------------------------------------- +* Copyright (C) 2010-2014 ARM Limited. All rights reserved. +* +* $Date: 19. March 2015 +* $Revision: V.1.4.5 +* +* Project: CMSIS DSP Library +* Title: arm_biquad_cascade_stereo_df2T_f32.c +* +* Description: Processing function for the floating-point transposed +* direct form II Biquad cascade filter. 2 channels +* +* Target Processor: Cortex-M4/Cortex-M3/Cortex-M0 +* +* Redistribution and use in source and binary forms, with or without +* modification, are permitted provided that the following conditions +* are met: +* - Redistributions of source code must retain the above copyright +* notice, this list of conditions and the following disclaimer. +* - Redistributions in binary form must reproduce the above copyright +* notice, this list of conditions and the following disclaimer in +* the documentation and/or other materials provided with the +* distribution. +* - Neither the name of ARM LIMITED nor the names of its contributors +* may be used to endorse or promote products derived from this +* software without specific prior written permission. +* +* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS +* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT +* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS +* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE +* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, +* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, +* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; +* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER +* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT +* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN +* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE +* POSSIBILITY OF SUCH DAMAGE. +* -------------------------------------------------------------------- */ + +#include "arm_math.h" + +/** +* @ingroup groupFilters +*/ + +/** +* @defgroup BiquadCascadeDF2T Biquad Cascade IIR Filters Using a Direct Form II Transposed Structure +* +* This set of functions implements arbitrary order recursive (IIR) filters using a transposed direct form II structure. +* The filters are implemented as a cascade of second order Biquad sections. +* These functions provide a slight memory savings as compared to the direct form I Biquad filter functions. +* Only floating-point data is supported. +* +* This function operate on blocks of input and output data and each call to the function +* processes <code>blockSize</code> samples through the filter. +* <code>pSrc</code> points to the array of input data and +* <code>pDst</code> points to the array of output data. +* Both arrays contain <code>blockSize</code> values. +* +* \par Algorithm +* Each Biquad stage implements a second order filter using the difference equation: +* <pre> +* y[n] = b0 * x[n] + d1 +* d1 = b1 * x[n] + a1 * y[n] + d2 +* d2 = b2 * x[n] + a2 * y[n] +* </pre> +* where d1 and d2 represent the two state values. +* +* \par +* A Biquad filter using a transposed Direct Form II structure is shown below. +* \image html BiquadDF2Transposed.gif "Single transposed Direct Form II Biquad" +* Coefficients <code>b0, b1, and b2 </code> multiply the input signal <code>x[n]</code> and are referred to as the feedforward coefficients. +* Coefficients <code>a1</code> and <code>a2</code> multiply the output signal <code>y[n]</code> and are referred to as the feedback coefficients. +* Pay careful attention to the sign of the feedback coefficients. +* Some design tools flip the sign of the feedback coefficients: +* <pre> +* y[n] = b0 * x[n] + d1; +* d1 = b1 * x[n] - a1 * y[n] + d2; +* d2 = b2 * x[n] - a2 * y[n]; +* </pre> +* In this case the feedback coefficients <code>a1</code> and <code>a2</code> must be negated when used with the CMSIS DSP Library. +* +* \par +* Higher order filters are realized as a cascade of second order sections. +* <code>numStages</code> refers to the number of second order stages used. +* For example, an 8th order filter would be realized with <code>numStages=4</code> second order stages. +* A 9th order filter would be realized with <code>numStages=5</code> second order stages with the +* coefficients for one of the stages configured as a first order filter (<code>b2=0</code> and <code>a2=0</code>). +* +* \par +* <code>pState</code> points to the state variable array. +* Each Biquad stage has 2 state variables <code>d1</code> and <code>d2</code>. +* The state variables are arranged in the <code>pState</code> array as: +* <pre> +* {d11, d12, d21, d22, ...} +* </pre> +* where <code>d1x</code> refers to the state variables for the first Biquad and +* <code>d2x</code> refers to the state variables for the second Biquad. +* 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. +* +* \par +* The CMSIS library contains Biquad filters in both Direct Form I and transposed Direct Form II. +* The advantage of the Direct Form I structure is that it is numerically more robust for fixed-point data types. +* That is why the Direct Form I structure supports Q15 and Q31 data types. +* The transposed Direct Form II structure, on the other hand, requires a wide dynamic range for the state variables <code>d1</code> and <code>d2</code>. +* Because of this, the CMSIS library only has a floating-point version of the Direct Form II Biquad. +* The advantage of the Direct Form II Biquad is that it requires half the number of state variables, 2 rather than 4, per Biquad stage. +* +* \par Instance Structure +* The coefficients and state variables for a filter are stored together in an instance data structure. +* A separate instance structure must be defined for each filter. +* Coefficient arrays may be shared among several instances while state variable arrays cannot be shared. +* +* \par Init Functions +* There is also an associated initialization function. +* The initialization function performs following operations: +* - Sets the values of the internal structure fields. +* - Zeros out the values in the state buffer. +* To do this manually without calling the init function, assign the follow subfields of the instance structure: +* numStages, pCoeffs, pState. Also set all of the values in pState to zero. +* +* \par +* Use of the initialization function is optional. +* However, if the initialization function is used, then the instance structure cannot be placed into a const data section. +* To place an instance structure into a const data section, the instance structure must be manually initialized. +* Set the values in the state buffer to zeros before static initialization. +* For example, to statically initialize the instance structure use +* <pre> +* arm_biquad_cascade_df2T_instance_f32 S1 = {numStages, pState, pCoeffs}; +* </pre> +* where <code>numStages</code> is the number of Biquad stages in the filter; <code>pState</code> is the address of the state buffer. +* <code>pCoeffs</code> is the address of the coefficient buffer; +* +*/ + +/** +* @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, +float32_t * pSrc, +float32_t * pDst, +uint32_t blockSize) +{ + + float32_t *pIn = pSrc; /* source pointer */ + float32_t *pOut = pDst; /* destination pointer */ + float32_t *pState = S->pState; /* State pointer */ + 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 */ + +#if defined(ARM_MATH_CM7) + + float32_t Xn2a, Xn3a, Xn4a, Xn5a, Xn6a, Xn7a, Xn8a; /* Input State variables */ + float32_t Xn2b, Xn3b, Xn4b, Xn5b, Xn6b, Xn7b, Xn8b; /* Input State variables */ + float32_t acc2a, acc3a, acc4a, acc5a, acc6a, acc7a, acc8a; /* Simulates the accumulator */ + float32_t acc2b, acc3b, acc4b, acc5b, acc6b, acc7b, acc8b; /* Simulates the accumulator */ + + do + { + /* Reading the coefficients */ + b0 = pCoeffs[0]; + b1 = pCoeffs[1]; + b2 = pCoeffs[2]; + a1 = pCoeffs[3]; + /* Apply loop unrolling and compute 8 output values simultaneously. */ + sample = blockSize >> 3u; + a2 = pCoeffs[4]; + + /*Reading the state values */ + d1a = pState[0]; + d2a = pState[1]; + d1b = pState[2]; + d2b = pState[3]; + + pCoeffs += 5u; + + /* First part of the processing with loop unrolling. Compute 8 outputs at a time. + ** a second loop below computes the remaining 1 to 7 samples. */ + while(sample > 0u) { + + /* y[n] = b0 * x[n] + d1 */ + /* d1 = b1 * x[n] + a1 * y[n] + d2 */ + /* d2 = b2 * x[n] + a2 * y[n] */ + + /* Read the first 2 inputs. 2 cycles */ + Xn1a = pIn[0 ]; + Xn1b = pIn[1 ]; + + /* Sample 1. 5 cycles */ + Xn2a = pIn[2 ]; + acc1a = b0 * Xn1a + d1a; + + Xn2b = pIn[3 ]; + d1a = b1 * Xn1a + d2a; + + Xn3a = pIn[4 ]; + d2a = b2 * Xn1a; + + Xn3b = pIn[5 ]; + d1a += a1 * acc1a; + + Xn4a = pIn[6 ]; + d2a += a2 * acc1a; + + /* Sample 2. 5 cycles */ + Xn4b = pIn[7 ]; + acc1b = b0 * Xn1b + d1b; + + Xn5a = pIn[8 ]; + d1b = b1 * Xn1b + d2b; + + Xn5b = pIn[9 ]; + d2b = b2 * Xn1b; + + Xn6a = pIn[10]; + d1b += a1 * acc1b; + + Xn6b = pIn[11]; + d2b += a2 * acc1b; + + /* Sample 3. 5 cycles */ + Xn7a = pIn[12]; + acc2a = b0 * Xn2a + d1a; + + Xn7b = pIn[13]; + d1a = b1 * Xn2a + d2a; + + Xn8a = pIn[14]; + d2a = b2 * Xn2a; + + Xn8b = pIn[15]; + d1a += a1 * acc2a; + + pIn += 16; + d2a += a2 * acc2a; + + /* Sample 4. 5 cycles */ + acc2b = b0 * Xn2b + d1b; + d1b = b1 * Xn2b + d2b; + d2b = b2 * Xn2b; + d1b += a1 * acc2b; + d2b += a2 * acc2b; + + /* Sample 5. 5 cycles */ + acc3a = b0 * Xn3a + d1a; + d1a = b1 * Xn3a + d2a; + d2a = b2 * Xn3a; + d1a += a1 * acc3a; + d2a += a2 * acc3a; + + /* Sample 6. 5 cycles */ + acc3b = b0 * Xn3b + d1b; + d1b = b1 * Xn3b + d2b; + d2b = b2 * Xn3b; + d1b += a1 * acc3b; + d2b += a2 * acc3b; + + /* Sample 7. 5 cycles */ + acc4a = b0 * Xn4a + d1a; + d1a = b1 * Xn4a + d2a; + d2a = b2 * Xn4a; + d1a += a1 * acc4a; + d2a += a2 * acc4a; + + /* Sample 8. 5 cycles */ + acc4b = b0 * Xn4b + d1b; + d1b = b1 * Xn4b + d2b; + d2b = b2 * Xn4b; + d1b += a1 * acc4b; + d2b += a2 * acc4b; + + /* Sample 9. 5 cycles */ + acc5a = b0 * Xn5a + d1a; + d1a = b1 * Xn5a + d2a; + d2a = b2 * Xn5a; + d1a += a1 * acc5a; + d2a += a2 * acc5a; + + /* Sample 10. 5 cycles */ + acc5b = b0 * Xn5b + d1b; + d1b = b1 * Xn5b + d2b; + d2b = b2 * Xn5b; + d1b += a1 * acc5b; + d2b += a2 * acc5b; + + /* Sample 11. 5 cycles */ + acc6a = b0 * Xn6a + d1a; + d1a = b1 * Xn6a + d2a; + d2a = b2 * Xn6a; + d1a += a1 * acc6a; + d2a += a2 * acc6a; + + /* Sample 12. 5 cycles */ + acc6b = b0 * Xn6b + d1b; + d1b = b1 * Xn6b + d2b; + d2b = b2 * Xn6b; + d1b += a1 * acc6b; + d2b += a2 * acc6b; + + /* Sample 13. 5 cycles */ + acc7a = b0 * Xn7a + d1a; + d1a = b1 * Xn7a + d2a; + + pOut[0 ] = acc1a ; + d2a = b2 * Xn7a; + + pOut[1 ] = acc1b ; + d1a += a1 * acc7a; + + pOut[2 ] = acc2a ; + d2a += a2 * acc7a; + + /* Sample 14. 5 cycles */ + pOut[3 ] = acc2b ; + acc7b = b0 * Xn7b + d1b; + + pOut[4 ] = acc3a ; + d1b = b1 * Xn7b + d2b; + + pOut[5 ] = acc3b ; + d2b = b2 * Xn7b; + + pOut[6 ] = acc4a ; + d1b += a1 * acc7b; + + pOut[7 ] = acc4b ; + d2b += a2 * acc7b; + + /* Sample 15. 5 cycles */ + pOut[8 ] = acc5a ; + acc8a = b0 * Xn8a + d1a; + + pOut[9 ] = acc5b; + d1a = b1 * Xn8a + d2a; + + pOut[10] = acc6a; + d2a = b2 * Xn8a; + + pOut[11] = acc6b; + d1a += a1 * acc8a; + + pOut[12] = acc7a; + d2a += a2 * acc8a; + + /* Sample 16. 5 cycles */ + pOut[13] = acc7b; + acc8b = b0 * Xn8b + d1b; + + pOut[14] = acc8a; + d1b = b1 * Xn8b + d2b; + + pOut[15] = acc8b; + d2b = b2 * Xn8b; + + sample--; + d1b += a1 * acc8b; + + pOut += 16; + d2b += a2 * acc8b; + } + + sample = blockSize & 0x7u; + 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); + + sample--; + } + + /* Store the updated state variables back into the state array */ + pState[0] = d1a; + pState[1] = d2a; + + pState[2] = d1b; + pState[3] = d2b; + + /* The current stage input is given as the output to the next stage */ + pIn = pDst; + /* decrement the loop counter */ + stage--; + + pState += 4u; + /*Reset the output working pointer */ + pOut = pDst; + + } while(stage > 0u); + +#elif defined(ARM_MATH_CM0_FAMILY) + + /* Run the below code for Cortex-M0 */ + + do + { + /* Reading the coefficients */ + b0 = *pCoeffs++; + b1 = *pCoeffs++; + b2 = *pCoeffs++; + a1 = *pCoeffs++; + a2 = *pCoeffs++; + + /*Reading the state values */ + d1a = pState[0]; + d2a = pState[1]; + d1b = pState[2]; + d2b = pState[3]; + + + sample = blockSize; + + 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 the loop counter */ + sample--; + } + + /* Store the updated state variables back into the state array */ + *pState++ = d1a; + *pState++ = d2a; + *pState++ = d1b; + *pState++ = d2b; + + /* 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); + +#else + + float32_t Xn2a, Xn3a, Xn4a; /* Input State variables */ + float32_t Xn2b, Xn3b, Xn4b; /* Input State variables */ + float32_t acc2a, acc3a, acc4a; /* accumulator */ + float32_t acc2b, acc3b, acc4b; /* accumulator */ + float32_t p0a, p1a, p2a, p3a, p4a, A1a; + float32_t p0b, p1b, p2b, p3b, p4b, A1b; + + /* Run the below code for Cortex-M4 and Cortex-M3 */ + do + { + /* Reading the coefficients */ + b0 = *pCoeffs++; + b1 = *pCoeffs++; + b2 = *pCoeffs++; + a1 = *pCoeffs++; + a2 = *pCoeffs++; + + /*Reading the state values */ + d1a = pState[0]; + d2a = pState[1]; + d1b = pState[2]; + d2b = pState[3]; + + /* Apply loop unrolling and compute 4 output values simultaneously. */ + sample = blockSize >> 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. */ + while(sample > 0u) { + + /* y[n] = b0 * x[n] + d1 */ + /* d1 = b1 * x[n] + a1 * y[n] + d2 */ + /* d2 = b2 * x[n] + a2 * y[n] */ + + /* Read the four inputs */ + Xn1a = pIn[0]; + Xn1b = pIn[1]; + Xn2a = pIn[2]; + Xn2b = pIn[3]; + Xn3a = pIn[4]; + Xn3b = pIn[5]; + Xn4a = pIn[6]; + Xn4b = pIn[7]; + pIn += 8; + + p0a = b0 * Xn1a; + p0b = b0 * Xn1b; + p1a = b1 * Xn1a; + p1b = b1 * Xn1b; + acc1a = p0a + d1a; + acc1b = p0b + d1b; + p0a = b0 * Xn2a; + p0b = b0 * Xn2b; + p3a = a1 * acc1a; + p3b = a1 * acc1b; + p2a = b2 * Xn1a; + p2b = b2 * Xn1b; + A1a = p1a + p3a; + A1b = p1b + p3b; + p4a = a2 * acc1a; + p4b = a2 * acc1b; + d1a = A1a + d2a; + d1b = A1b + d2b; + d2a = p2a + p4a; + d2b = p2b + p4b; + + p1a = b1 * Xn2a; + p1b = b1 * Xn2b; + acc2a = p0a + d1a; + acc2b = p0b + d1b; + p0a = b0 * Xn3a; + p0b = b0 * Xn3b; + p3a = a1 * acc2a; + p3b = a1 * acc2b; + p2a = b2 * Xn2a; + p2b = b2 * Xn2b; + A1a = p1a + p3a; + A1b = p1b + p3b; + p4a = a2 * acc2a; + p4b = a2 * acc2b; + d1a = A1a + d2a; + d1b = A1b + d2b; + d2a = p2a + p4a; + d2b = p2b + p4b; + + p1a = b1 * Xn3a; + p1b = b1 * Xn3b; + acc3a = p0a + d1a; + acc3b = p0b + d1b; + p0a = b0 * Xn4a; + p0b = b0 * Xn4b; + p3a = a1 * acc3a; + p3b = a1 * acc3b; + p2a = b2 * Xn3a; + p2b = b2 * Xn3b; + A1a = p1a + p3a; + A1b = p1b + p3b; + p4a = a2 * acc3a; + p4b = a2 * acc3b; + d1a = A1a + d2a; + d1b = A1b + d2b; + d2a = p2a + p4a; + d2b = p2b + p4b; + + acc4a = p0a + d1a; + acc4b = p0b + d1b; + p1a = b1 * Xn4a; + p1b = b1 * Xn4b; + p3a = a1 * acc4a; + p3b = a1 * acc4b; + p2a = b2 * Xn4a; + p2b = b2 * Xn4b; + A1a = p1a + p3a; + A1b = p1b + p3b; + p4a = a2 * acc4a; + p4b = a2 * acc4b; + d1a = A1a + d2a; + d1b = A1b + d2b; + d2a = p2a + p4a; + d2b = p2b + p4b; + + pOut[0] = acc1a; + pOut[1] = acc1b; + pOut[2] = acc2a; + pOut[3] = acc2b; + pOut[4] = acc3a; + pOut[5] = acc3b; + pOut[6] = acc4a; + pOut[7] = acc4b; + pOut += 8; + + sample--; + } + + sample = blockSize & 0x3u; + while(sample > 0u) { + Xn1a = *pIn++; + Xn1b = *pIn++; + + p0a = b0 * Xn1a; + p0b = b0 * Xn1b; + p1a = b1 * Xn1a; + p1b = b1 * Xn1b; + acc1a = p0a + d1a; + acc1b = p0b + d1b; + p3a = a1 * acc1a; + p3b = a1 * acc1b; + p2a = b2 * Xn1a; + p2b = b2 * Xn1b; + A1a = p1a + p3a; + A1b = p1b + p3b; + p4a = a2 * acc1a; + p4b = a2 * acc1b; + d1a = A1a + d2a; + d1b = A1b + d2b; + d2a = p2a + p4a; + d2b = p2b + p4b; + + *pOut++ = acc1a; + *pOut++ = acc1b; + + sample--; + } + + /* Store the updated state variables back into the state array */ + *pState++ = d1a; + *pState++ = d2a; + *pState++ = d1b; + *pState++ = d2b; + + /* 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); + +#endif + +} +LOW_OPTIMIZATION_EXIT + +/** + * @} end of BiquadCascadeDF2T group + */ |