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Diffstat (limited to 'DSP_Lib/Source/FilteringFunctions/arm_fir_lattice_f32.c')
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diff --git a/DSP_Lib/Source/FilteringFunctions/arm_fir_lattice_f32.c b/DSP_Lib/Source/FilteringFunctions/arm_fir_lattice_f32.c new file mode 100644 index 0000000..4be468c --- /dev/null +++ b/DSP_Lib/Source/FilteringFunctions/arm_fir_lattice_f32.c @@ -0,0 +1,506 @@ +/* ---------------------------------------------------------------------- +* Copyright (C) 2010-2014 ARM Limited. All rights reserved. +* +* $Date: 19. March 2015 +* $Revision: V.1.4.5 +* +* Project: CMSIS DSP Library +* Title: arm_fir_lattice_f32.c +* +* Description: Processing function for the floating-point FIR Lattice filter. +* +* 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 FIR_Lattice Finite Impulse Response (FIR) Lattice Filters + * + * This set of functions implements Finite Impulse Response (FIR) lattice filters + * for Q15, Q31 and floating-point data types. Lattice filters are used in a + * variety of adaptive filter applications. The filter structure is feedforward and + * the net impulse response is finite length. + * The functions 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> and + * <code>pDst</code> point to input and output arrays containing <code>blockSize</code> values. + * + * \par Algorithm: + * \image html FIRLattice.gif "Finite Impulse Response Lattice filter" + * The following difference equation is implemented: + * <pre> + * f0[n] = g0[n] = x[n] + * fm[n] = fm-1[n] + km * gm-1[n-1] for m = 1, 2, ...M + * gm[n] = km * fm-1[n] + gm-1[n-1] for m = 1, 2, ...M + * y[n] = fM[n] + * </pre> + * \par + * <code>pCoeffs</code> points to tha array of reflection coefficients of size <code>numStages</code>. + * Reflection Coefficients are stored in the following order. + * \par + * <pre> + * {k1, k2, ..., kM} + * </pre> + * where M is number of stages + * \par + * <code>pState</code> points to a state array of size <code>numStages</code>. + * The state variables (g values) hold previous inputs and are stored in the following order. + * <pre> + * {g0[n], g1[n], g2[n] ...gM-1[n]} + * </pre> + * The state variables are updated after each block of data is processed; the coefficients are untouched. + * \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. + * There are separate instance structure declarations for each of the 3 supported data types. + * + * \par Initialization Functions + * There is also an associated initialization function for each data type. + * The initialization function performs the 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 and then manually initialize the instance structure as follows: + * <pre> + *arm_fir_lattice_instance_f32 S = {numStages, pState, pCoeffs}; + *arm_fir_lattice_instance_q31 S = {numStages, pState, pCoeffs}; + *arm_fir_lattice_instance_q15 S = {numStages, pState, pCoeffs}; + * </pre> + * \par + * where <code>numStages</code> is the number of stages in the filter; <code>pState</code> is the address of the state buffer; + * <code>pCoeffs</code> is the address of the coefficient buffer. + * \par Fixed-Point Behavior + * Care must be taken when using the fixed-point versions of the FIR Lattice filter functions. + * In particular, the overflow and saturation behavior of the accumulator used in each function must be considered. + * Refer to the function specific documentation below for usage guidelines. + */ + +/** + * @addtogroup FIR_Lattice + * @{ + */ + + + /** + * @brief Processing function for the floating-point FIR lattice filter. + * @param[in] *S points to an instance of the floating-point FIR lattice 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_fir_lattice_f32( + const arm_fir_lattice_instance_f32 * S, + float32_t * pSrc, + float32_t * pDst, + uint32_t blockSize) +{ + float32_t *pState; /* State pointer */ + float32_t *pCoeffs = S->pCoeffs; /* Coefficient pointer */ + float32_t *px; /* temporary state pointer */ + float32_t *pk; /* temporary coefficient pointer */ + + +#ifndef ARM_MATH_CM0_FAMILY + + /* Run the below code for Cortex-M4 and Cortex-M3 */ + + float32_t fcurr1, fnext1, gcurr1, gnext1; /* temporary variables for first sample in loop unrolling */ + float32_t fcurr2, fnext2, gnext2; /* temporary variables for second sample in loop unrolling */ + float32_t fcurr3, fnext3, gnext3; /* temporary variables for third sample in loop unrolling */ + float32_t fcurr4, fnext4, gnext4; /* temporary variables for fourth sample in loop unrolling */ + uint32_t numStages = S->numStages; /* Number of stages in the filter */ + uint32_t blkCnt, stageCnt; /* temporary variables for counts */ + + gcurr1 = 0.0f; + pState = &S->pState[0]; + + blkCnt = blockSize >> 2; + + /* 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(blkCnt > 0u) + { + + /* Read two samples from input buffer */ + /* f0(n) = x(n) */ + fcurr1 = *pSrc++; + fcurr2 = *pSrc++; + + /* Initialize coeff pointer */ + pk = (pCoeffs); + + /* Initialize state pointer */ + px = pState; + + /* Read g0(n-1) from state */ + gcurr1 = *px; + + /* Process first sample for first tap */ + /* f1(n) = f0(n) + K1 * g0(n-1) */ + fnext1 = fcurr1 + ((*pk) * gcurr1); + /* g1(n) = f0(n) * K1 + g0(n-1) */ + gnext1 = (fcurr1 * (*pk)) + gcurr1; + + /* Process second sample for first tap */ + /* for sample 2 processing */ + fnext2 = fcurr2 + ((*pk) * fcurr1); + gnext2 = (fcurr2 * (*pk)) + fcurr1; + + /* Read next two samples from input buffer */ + /* f0(n+2) = x(n+2) */ + fcurr3 = *pSrc++; + fcurr4 = *pSrc++; + + /* Copy only last input samples into the state buffer + which will be used for next four samples processing */ + *px++ = fcurr4; + + /* Process third sample for first tap */ + fnext3 = fcurr3 + ((*pk) * fcurr2); + gnext3 = (fcurr3 * (*pk)) + fcurr2; + + /* Process fourth sample for first tap */ + fnext4 = fcurr4 + ((*pk) * fcurr3); + gnext4 = (fcurr4 * (*pk++)) + fcurr3; + + /* Update of f values for next coefficient set processing */ + fcurr1 = fnext1; + fcurr2 = fnext2; + fcurr3 = fnext3; + fcurr4 = fnext4; + + /* Loop unrolling. Process 4 taps at a time . */ + stageCnt = (numStages - 1u) >> 2u; + + /* Loop over the number of taps. Unroll by a factor of 4. + ** Repeat until we've computed numStages-3 coefficients. */ + + /* Process 2nd, 3rd, 4th and 5th taps ... here */ + while(stageCnt > 0u) + { + /* Read g1(n-1), g3(n-1) .... from state */ + gcurr1 = *px; + + /* save g1(n) in state buffer */ + *px++ = gnext4; + + /* Process first sample for 2nd, 6th .. tap */ + /* Sample processing for K2, K6.... */ + /* f2(n) = f1(n) + K2 * g1(n-1) */ + fnext1 = fcurr1 + ((*pk) * gcurr1); + /* Process second sample for 2nd, 6th .. tap */ + /* for sample 2 processing */ + fnext2 = fcurr2 + ((*pk) * gnext1); + /* Process third sample for 2nd, 6th .. tap */ + fnext3 = fcurr3 + ((*pk) * gnext2); + /* Process fourth sample for 2nd, 6th .. tap */ + fnext4 = fcurr4 + ((*pk) * gnext3); + + /* g2(n) = f1(n) * K2 + g1(n-1) */ + /* Calculation of state values for next stage */ + gnext4 = (fcurr4 * (*pk)) + gnext3; + gnext3 = (fcurr3 * (*pk)) + gnext2; + gnext2 = (fcurr2 * (*pk)) + gnext1; + gnext1 = (fcurr1 * (*pk++)) + gcurr1; + + + /* Read g2(n-1), g4(n-1) .... from state */ + gcurr1 = *px; + + /* save g2(n) in state buffer */ + *px++ = gnext4; + + /* Sample processing for K3, K7.... */ + /* Process first sample for 3rd, 7th .. tap */ + /* f3(n) = f2(n) + K3 * g2(n-1) */ + fcurr1 = fnext1 + ((*pk) * gcurr1); + /* Process second sample for 3rd, 7th .. tap */ + fcurr2 = fnext2 + ((*pk) * gnext1); + /* Process third sample for 3rd, 7th .. tap */ + fcurr3 = fnext3 + ((*pk) * gnext2); + /* Process fourth sample for 3rd, 7th .. tap */ + fcurr4 = fnext4 + ((*pk) * gnext3); + + /* Calculation of state values for next stage */ + /* g3(n) = f2(n) * K3 + g2(n-1) */ + gnext4 = (fnext4 * (*pk)) + gnext3; + gnext3 = (fnext3 * (*pk)) + gnext2; + gnext2 = (fnext2 * (*pk)) + gnext1; + gnext1 = (fnext1 * (*pk++)) + gcurr1; + + + /* Read g1(n-1), g3(n-1) .... from state */ + gcurr1 = *px; + + /* save g3(n) in state buffer */ + *px++ = gnext4; + + /* Sample processing for K4, K8.... */ + /* Process first sample for 4th, 8th .. tap */ + /* f4(n) = f3(n) + K4 * g3(n-1) */ + fnext1 = fcurr1 + ((*pk) * gcurr1); + /* Process second sample for 4th, 8th .. tap */ + /* for sample 2 processing */ + fnext2 = fcurr2 + ((*pk) * gnext1); + /* Process third sample for 4th, 8th .. tap */ + fnext3 = fcurr3 + ((*pk) * gnext2); + /* Process fourth sample for 4th, 8th .. tap */ + fnext4 = fcurr4 + ((*pk) * gnext3); + + /* g4(n) = f3(n) * K4 + g3(n-1) */ + /* Calculation of state values for next stage */ + gnext4 = (fcurr4 * (*pk)) + gnext3; + gnext3 = (fcurr3 * (*pk)) + gnext2; + gnext2 = (fcurr2 * (*pk)) + gnext1; + gnext1 = (fcurr1 * (*pk++)) + gcurr1; + + /* Read g2(n-1), g4(n-1) .... from state */ + gcurr1 = *px; + + /* save g4(n) in state buffer */ + *px++ = gnext4; + + /* Sample processing for K5, K9.... */ + /* Process first sample for 5th, 9th .. tap */ + /* f5(n) = f4(n) + K5 * g4(n-1) */ + fcurr1 = fnext1 + ((*pk) * gcurr1); + /* Process second sample for 5th, 9th .. tap */ + fcurr2 = fnext2 + ((*pk) * gnext1); + /* Process third sample for 5th, 9th .. tap */ + fcurr3 = fnext3 + ((*pk) * gnext2); + /* Process fourth sample for 5th, 9th .. tap */ + fcurr4 = fnext4 + ((*pk) * gnext3); + + /* Calculation of state values for next stage */ + /* g5(n) = f4(n) * K5 + g4(n-1) */ + gnext4 = (fnext4 * (*pk)) + gnext3; + gnext3 = (fnext3 * (*pk)) + gnext2; + gnext2 = (fnext2 * (*pk)) + gnext1; + gnext1 = (fnext1 * (*pk++)) + gcurr1; + + stageCnt--; + } + + /* If the (filter length -1) is not a multiple of 4, compute the remaining filter taps */ + stageCnt = (numStages - 1u) % 0x4u; + + while(stageCnt > 0u) + { + gcurr1 = *px; + + /* save g value in state buffer */ + *px++ = gnext4; + + /* Process four samples for last three taps here */ + fnext1 = fcurr1 + ((*pk) * gcurr1); + fnext2 = fcurr2 + ((*pk) * gnext1); + fnext3 = fcurr3 + ((*pk) * gnext2); + fnext4 = fcurr4 + ((*pk) * gnext3); + + /* g1(n) = f0(n) * K1 + g0(n-1) */ + gnext4 = (fcurr4 * (*pk)) + gnext3; + gnext3 = (fcurr3 * (*pk)) + gnext2; + gnext2 = (fcurr2 * (*pk)) + gnext1; + gnext1 = (fcurr1 * (*pk++)) + gcurr1; + + /* Update of f values for next coefficient set processing */ + fcurr1 = fnext1; + fcurr2 = fnext2; + fcurr3 = fnext3; + fcurr4 = fnext4; + + stageCnt--; + + } + + /* The results in the 4 accumulators, store in the destination buffer. */ + /* y(n) = fN(n) */ + *pDst++ = fcurr1; + *pDst++ = fcurr2; + *pDst++ = fcurr3; + *pDst++ = fcurr4; + + blkCnt--; + } + + /* If the blockSize is not a multiple of 4, compute any remaining output samples here. + ** No loop unrolling is used. */ + blkCnt = blockSize % 0x4u; + + while(blkCnt > 0u) + { + /* f0(n) = x(n) */ + fcurr1 = *pSrc++; + + /* Initialize coeff pointer */ + pk = (pCoeffs); + + /* Initialize state pointer */ + px = pState; + + /* read g2(n) from state buffer */ + gcurr1 = *px; + + /* for sample 1 processing */ + /* f1(n) = f0(n) + K1 * g0(n-1) */ + fnext1 = fcurr1 + ((*pk) * gcurr1); + /* g1(n) = f0(n) * K1 + g0(n-1) */ + gnext1 = (fcurr1 * (*pk++)) + gcurr1; + + /* save g1(n) in state buffer */ + *px++ = fcurr1; + + /* f1(n) is saved in fcurr1 + for next stage processing */ + fcurr1 = fnext1; + + stageCnt = (numStages - 1u); + + /* stage loop */ + while(stageCnt > 0u) + { + /* read g2(n) from state buffer */ + gcurr1 = *px; + + /* save g1(n) in state buffer */ + *px++ = gnext1; + + /* Sample processing for K2, K3.... */ + /* f2(n) = f1(n) + K2 * g1(n-1) */ + fnext1 = fcurr1 + ((*pk) * gcurr1); + /* g2(n) = f1(n) * K2 + g1(n-1) */ + gnext1 = (fcurr1 * (*pk++)) + gcurr1; + + /* f1(n) is saved in fcurr1 + for next stage processing */ + fcurr1 = fnext1; + + stageCnt--; + + } + + /* y(n) = fN(n) */ + *pDst++ = fcurr1; + + blkCnt--; + + } + +#else + + /* Run the below code for Cortex-M0 */ + + float32_t fcurr, fnext, gcurr, gnext; /* temporary variables */ + uint32_t numStages = S->numStages; /* Length of the filter */ + uint32_t blkCnt, stageCnt; /* temporary variables for counts */ + + pState = &S->pState[0]; + + blkCnt = blockSize; + + while(blkCnt > 0u) + { + /* f0(n) = x(n) */ + fcurr = *pSrc++; + + /* Initialize coeff pointer */ + pk = pCoeffs; + + /* Initialize state pointer */ + px = pState; + + /* read g0(n-1) from state buffer */ + gcurr = *px; + + /* for sample 1 processing */ + /* f1(n) = f0(n) + K1 * g0(n-1) */ + fnext = fcurr + ((*pk) * gcurr); + /* g1(n) = f0(n) * K1 + g0(n-1) */ + gnext = (fcurr * (*pk++)) + gcurr; + + /* save f0(n) in state buffer */ + *px++ = fcurr; + + /* f1(n) is saved in fcurr + for next stage processing */ + fcurr = fnext; + + stageCnt = (numStages - 1u); + + /* stage loop */ + while(stageCnt > 0u) + { + /* read g2(n) from state buffer */ + gcurr = *px; + + /* save g1(n) in state buffer */ + *px++ = gnext; + + /* Sample processing for K2, K3.... */ + /* f2(n) = f1(n) + K2 * g1(n-1) */ + fnext = fcurr + ((*pk) * gcurr); + /* g2(n) = f1(n) * K2 + g1(n-1) */ + gnext = (fcurr * (*pk++)) + gcurr; + + /* f1(n) is saved in fcurr1 + for next stage processing */ + fcurr = fnext; + + stageCnt--; + + } + + /* y(n) = fN(n) */ + *pDst++ = fcurr; + + blkCnt--; + + } + +#endif /* #ifndef ARM_MATH_CM0_FAMILY */ + +} + +/** + * @} end of FIR_Lattice group + */ |