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diff --git a/apps/mathlib/CMSIS/DSP_Lib/Source/FilteringFunctions/arm_biquad_cascade_df2T_f32.c b/apps/mathlib/CMSIS/DSP_Lib/Source/FilteringFunctions/arm_biquad_cascade_df2T_f32.c new file mode 100644 index 000000000..a8cb0c98c --- /dev/null +++ b/apps/mathlib/CMSIS/DSP_Lib/Source/FilteringFunctions/arm_biquad_cascade_df2T_f32.c @@ -0,0 +1,377 @@ +/* ----------------------------------------------------------------------
+* Copyright (C) 2010 ARM Limited. All rights reserved.
+*
+* $Date: 15. February 2012
+* $Revision: V1.1.0
+*
+* Project: CMSIS DSP Library
+* Title: arm_biquad_cascade_df2T_f32.c
+*
+* Description: Processing function for the floating-point transposed
+* direct form II Biquad cascade filter.
+*
+* Target Processor: Cortex-M4/Cortex-M3/Cortex-M0
+*
+* Version 1.1.0 2012/02/15
+* Updated with more optimizations, bug fixes and minor API changes.
+*
+* Version 1.0.10 2011/7/15
+* Big Endian support added and Merged M0 and M3/M4 Source code.
+*
+* Version 1.0.3 2010/11/29
+* Re-organized the CMSIS folders and updated documentation.
+*
+* Version 1.0.2 2010/11/11
+* Documentation updated.
+*
+* Version 1.0.1 2010/10/05
+* Production release and review comments incorporated.
+*
+* Version 1.0.0 2010/09/20
+* Production release and review comments incorporated
+*
+* Version 0.0.7 2010/06/10
+* Misra-C changes done
+* -------------------------------------------------------------------- */
+
+#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.
+ *
+ * \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.
+ */
+
+void arm_biquad_cascade_df2T_f32(
+ const arm_biquad_cascade_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 acc0; /* accumulator */
+ float32_t b0, b1, b2, a1, a2; /* Filter coefficients */
+ float32_t Xn; /* temporary input */
+ float32_t d1, d2; /* state variables */
+ uint32_t sample, stage = S->numStages; /* loop counters */
+
+#ifndef ARM_MATH_CM0
+
+ float32_t Xn1, Xn2; /* Input State variables */
+ float32_t acc1; /* accumulator */
+
+
+
+ /* 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 */
+ d1 = pState[0];
+ d2 = pState[1];
+
+ /* 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 first input */
+ Xn1 = *pIn++;
+
+ /* y[n] = b0 * x[n] + d1 */
+ acc0 = (b0 * Xn1) + d1;
+
+ /* d1 = b1 * x[n] + d2 */
+ d1 = (b1 * Xn1) + d2;
+
+ /* d2 = b2 * x[n] */
+ d2 = (b2 * Xn1);
+
+ /* Read the second input */
+ Xn2 = *pIn++;
+
+ /* d1 = b1 * x[n] + a1 * y[n] */
+ d1 = (a1 * acc0) + d1;
+
+ /* Store the result in the accumulator in the destination buffer. */
+ *pOut++ = acc0;
+
+ d2 = (a2 * acc0) + d2;
+
+ /* y[n] = b0 * x[n] + d1 */
+ acc1 = (b0 * Xn2) + d1;
+
+ /* Read the third input */
+ Xn1 = *pIn++;
+
+ d1 = (b1 * Xn2) + d2;
+
+ d2 = (b2 * Xn2);
+
+ /* Store the result in the accumulator in the destination buffer. */
+ *pOut++ = acc1;
+
+ d1 = (a1 * acc1) + d1;
+
+ d2 = (a2 * acc1) + d2;
+
+ /* y[n] = b0 * x[n] + d1 */
+ acc0 = (b0 * Xn1) + d1;
+
+ d1 = (b1 * Xn1) + d2;
+
+ d2 = (b2 * Xn1);
+
+ /* Read the fourth input */
+ Xn2 = *pIn++;
+
+ d1 = (a1 * acc0) + d1;
+
+ /* Store the result in the accumulator in the destination buffer. */
+ *pOut++ = acc0;
+
+ d2 = (a2 * acc0) + d2;
+
+ /* y[n] = b0 * x[n] + d1 */
+ acc1 = (b0 * Xn2) + d1;
+
+ d1 = (b1 * Xn2) + d2;
+
+ d2 = (b2 * Xn2);
+
+ /* Store the result in the accumulator in the destination buffer. */
+ *pOut++ = acc1;
+
+ d1 = (a1 * acc1) + d1;
+
+ d2 = (a2 * acc1) + d2;
+
+ /* decrement the loop counter */
+ sample--;
+
+ }
+
+ /* If the blockSize is not a multiple of 4, compute any remaining output samples here.
+ ** No loop unrolling is used. */
+ sample = blockSize & 0x3u;
+
+ while(sample > 0u)
+ {
+ /* Read the input */
+ Xn = *pIn++;
+
+ /* y[n] = b0 * x[n] + d1 */
+ acc0 = (b0 * Xn) + d1;
+
+ /* Store the result in the accumulator in the destination buffer. */
+ *pOut++ = acc0;
+
+ /* Every time after the output is computed state should be updated. */
+ /* d1 = b1 * x[n] + a1 * y[n] + d2 */
+ d1 = ((b1 * Xn) + (a1 * acc0)) + d2;
+
+ /* d2 = b2 * x[n] + a2 * y[n] */
+ d2 = (b2 * Xn) + (a2 * acc0);
+
+ /* decrement the loop counter */
+ sample--;
+ }
+
+ /* Store the updated state variables back into the state array */
+ *pState++ = d1;
+ *pState++ = d2;
+
+ /* 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
+
+ /* 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 */
+ d1 = pState[0];
+ d2 = pState[1];
+
+
+ sample = blockSize;
+
+ while(sample > 0u)
+ {
+ /* Read the input */
+ Xn = *pIn++;
+
+ /* y[n] = b0 * x[n] + d1 */
+ acc0 = (b0 * Xn) + d1;
+
+ /* Store the result in the accumulator in the destination buffer. */
+ *pOut++ = acc0;
+
+ /* Every time after the output is computed state should be updated. */
+ /* d1 = b1 * x[n] + a1 * y[n] + d2 */
+ d1 = ((b1 * Xn) + (a1 * acc0)) + d2;
+
+ /* d2 = b2 * x[n] + a2 * y[n] */
+ d2 = (b2 * Xn) + (a2 * acc0);
+
+ /* decrement the loop counter */
+ sample--;
+ }
+
+ /* Store the updated state variables back into the state array */
+ *pState++ = d1;
+ *pState++ = d2;
+
+ /* 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 /* #ifndef ARM_MATH_CM0 */
+
+}
+
+
+ /**
+ * @} end of BiquadCascadeDF2T group
+ */
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