CMSIS DSP Library from CMSIS 2.0. See http://www.onarm.com/cmsis/ for full details
Dependents: K22F_DSP_Matrix_least_square BNO055-ELEC3810 1BNO055 ECE4180Project--Slave2 ... more
Diff: src/Cortex-M4-M3/FilteringFunctions/arm_fir_lattice_q15.c
- Revision:
- 0:1014af42efd9
--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/src/Cortex-M4-M3/FilteringFunctions/arm_fir_lattice_q15.c Thu Mar 10 15:07:50 2011 +0000 @@ -0,0 +1,426 @@ +/* ---------------------------------------------------------------------- +* Copyright (C) 2010 ARM Limited. All rights reserved. +* +* $Date: 29. November 2010 +* $Revision: V1.0.3 +* +* Project: CMSIS DSP Library +* Title: arm_fir_lattice_q15.c +* +* Description: Q15 FIR lattice filter processing function. +* +* Target Processor: Cortex-M4/Cortex-M3 +* +* 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 + */ + +/** + * @addtogroup FIR_Lattice + * @{ + */ + + +/** + * @brief Processing function for the Q15 FIR lattice filter. + * @param[in] *S points to an instance of the Q15 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_q15( + const arm_fir_lattice_instance_q15 * S, + q15_t * pSrc, + q15_t * pDst, + uint32_t blockSize) +{ + q15_t *pState; /* State pointer */ + q15_t *pCoeffs = S->pCoeffs; /* Coefficient pointer */ + q15_t *px; /* temporary state pointer */ + q15_t *pk; /* temporary coefficient pointer */ + q31_t fcurnt1, fnext1, gcurnt1 = 0, gnext1; /* temporary variables for first sample in loop unrolling */ + q31_t fcurnt2, fnext2, gnext2; /* temporary variables for second sample in loop unrolling */ + q31_t fcurnt3, fnext3, gnext3; /* temporary variables for third sample in loop unrolling */ + q31_t fcurnt4, 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 */ + + pState = &S->pState[0]; + + blkCnt = 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(blkCnt > 0u) + { + + /* Read two samples from input buffer */ + /* f0(n) = x(n) */ + fcurnt1 = *pSrc++; + fcurnt2 = *pSrc++; + + /* Initialize coeff pointer */ + pk = (pCoeffs); + + /* Initialize state pointer */ + px = pState; + + /* Read g0(n-1) from state */ + gcurnt1 = *px; + + /* Process first sample for first tap */ + /* f1(n) = f0(n) + K1 * g0(n-1) */ + fnext1 = (q31_t) ((gcurnt1 * (*pk)) >> 15u) + fcurnt1; + fnext1 = __SSAT(fnext1, 16); + + /* g1(n) = f0(n) * K1 + g0(n-1) */ + gnext1 = (q31_t) ((fcurnt1 * (*pk)) >> 15u) + gcurnt1; + gnext1 = __SSAT(gnext1, 16); + + /* Process second sample for first tap */ + /* for sample 2 processing */ + fnext2 = (q31_t) ((fcurnt1 * (*pk)) >> 15u) + fcurnt2; + fnext2 = __SSAT(fnext2, 16); + + gnext2 = (q31_t) ((fcurnt2 * (*pk)) >> 15u) + fcurnt1; + gnext2 = __SSAT(gnext2, 16); + + + /* Read next two samples from input buffer */ + /* f0(n+2) = x(n+2) */ + fcurnt3 = *pSrc++; + fcurnt4 = *pSrc++; + + /* Copy only last input samples into the state buffer + which is used for next four samples processing */ + *px++ = (q15_t) fcurnt4; + + /* Process third sample for first tap */ + fnext3 = (q31_t) ((fcurnt2 * (*pk)) >> 15u) + fcurnt3; + fnext3 = __SSAT(fnext3, 16); + gnext3 = (q31_t) ((fcurnt3 * (*pk)) >> 15u) + fcurnt2; + gnext3 = __SSAT(gnext3, 16); + + /* Process fourth sample for first tap */ + fnext4 = (q31_t) ((fcurnt3 * (*pk)) >> 15u) + fcurnt4; + fnext4 = __SSAT(fnext4, 16); + gnext4 = (q31_t) ((fcurnt4 * (*pk++)) >> 15u) + fcurnt3; + gnext4 = __SSAT(gnext4, 16); + + /* Update of f values for next coefficient set processing */ + fcurnt1 = fnext1; + fcurnt2 = fnext2; + fcurnt3 = fnext3; + fcurnt4 = fnext4; + + + /* Loop unrolling. Process 4 taps at a time . */ + stageCnt = (numStages - 1u) >> 2; + + + /* 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 */ + gcurnt1 = *px; + + /* save g1(n) in state buffer */ + *px++ = (q15_t) gnext4; + + /* Process first sample for 2nd, 6th .. tap */ + /* Sample processing for K2, K6.... */ + /* f1(n) = f0(n) + K1 * g0(n-1) */ + fnext1 = (q31_t) ((gcurnt1 * (*pk)) >> 15u) + fcurnt1; + fnext1 = __SSAT(fnext1, 16); + + + /* Process second sample for 2nd, 6th .. tap */ + /* for sample 2 processing */ + fnext2 = (q31_t) ((gnext1 * (*pk)) >> 15u) + fcurnt2; + fnext2 = __SSAT(fnext2, 16); + /* Process third sample for 2nd, 6th .. tap */ + fnext3 = (q31_t) ((gnext2 * (*pk)) >> 15u) + fcurnt3; + fnext3 = __SSAT(fnext3, 16); + /* Process fourth sample for 2nd, 6th .. tap */ + /* fnext4 = fcurnt4 + (*pk) * gnext3; */ + fnext4 = (q31_t) ((gnext3 * (*pk)) >> 15u) + fcurnt4; + fnext4 = __SSAT(fnext4, 16); + + /* g1(n) = f0(n) * K1 + g0(n-1) */ + /* Calculation of state values for next stage */ + gnext4 = (q31_t) ((fcurnt4 * (*pk)) >> 15u) + gnext3; + gnext4 = __SSAT(gnext4, 16); + gnext3 = (q31_t) ((fcurnt3 * (*pk)) >> 15u) + gnext2; + gnext3 = __SSAT(gnext3, 16); + + gnext2 = (q31_t) ((fcurnt2 * (*pk)) >> 15u) + gnext1; + gnext2 = __SSAT(gnext2, 16); + + gnext1 = (q31_t) ((fcurnt1 * (*pk++)) >> 15u) + gcurnt1; + gnext1 = __SSAT(gnext1, 16); + + + /* Read g2(n-1), g4(n-1) .... from state */ + gcurnt1 = *px; + + /* save g1(n) in state buffer */ + *px++ = (q15_t) gnext4; + + /* Sample processing for K3, K7.... */ + /* Process first sample for 3rd, 7th .. tap */ + /* f3(n) = f2(n) + K3 * g2(n-1) */ + fcurnt1 = (q31_t) ((gcurnt1 * (*pk)) >> 15u) + fnext1; + fcurnt1 = __SSAT(fcurnt1, 16); + + /* Process second sample for 3rd, 7th .. tap */ + fcurnt2 = (q31_t) ((gnext1 * (*pk)) >> 15u) + fnext2; + fcurnt2 = __SSAT(fcurnt2, 16); + + /* Process third sample for 3rd, 7th .. tap */ + fcurnt3 = (q31_t) ((gnext2 * (*pk)) >> 15u) + fnext3; + fcurnt3 = __SSAT(fcurnt3, 16); + + /* Process fourth sample for 3rd, 7th .. tap */ + fcurnt4 = (q31_t) ((gnext3 * (*pk)) >> 15u) + fnext4; + fcurnt4 = __SSAT(fcurnt4, 16); + + /* Calculation of state values for next stage */ + /* g3(n) = f2(n) * K3 + g2(n-1) */ + gnext4 = (q31_t) ((fnext4 * (*pk)) >> 15u) + gnext3; + gnext4 = __SSAT(gnext4, 16); + + gnext3 = (q31_t) ((fnext3 * (*pk)) >> 15u) + gnext2; + gnext3 = __SSAT(gnext3, 16); + + gnext2 = (q31_t) ((fnext2 * (*pk)) >> 15u) + gnext1; + gnext2 = __SSAT(gnext2, 16); + + gnext1 = (q31_t) ((fnext1 * (*pk++)) >> 15u) + gcurnt1; + gnext1 = __SSAT(gnext1, 16); + + /* Read g1(n-1), g3(n-1) .... from state */ + gcurnt1 = *px; + + /* save g1(n) in state buffer */ + *px++ = (q15_t) gnext4; + + /* Sample processing for K4, K8.... */ + /* Process first sample for 4th, 8th .. tap */ + /* f4(n) = f3(n) + K4 * g3(n-1) */ + fnext1 = (q31_t) ((gcurnt1 * (*pk)) >> 15u) + fcurnt1; + fnext1 = __SSAT(fnext1, 16); + + /* Process second sample for 4th, 8th .. tap */ + /* for sample 2 processing */ + fnext2 = (q31_t) ((gnext1 * (*pk)) >> 15u) + fcurnt2; + fnext2 = __SSAT(fnext2, 16); + + /* Process third sample for 4th, 8th .. tap */ + fnext3 = (q31_t) ((gnext2 * (*pk)) >> 15u) + fcurnt3; + fnext3 = __SSAT(fnext3, 16); + + /* Process fourth sample for 4th, 8th .. tap */ + fnext4 = (q31_t) ((gnext3 * (*pk)) >> 15u) + fcurnt4; + fnext4 = __SSAT(fnext4, 16); + + /* g4(n) = f3(n) * K4 + g3(n-1) */ + /* Calculation of state values for next stage */ + gnext4 = (q31_t) ((fcurnt4 * (*pk)) >> 15u) + gnext3; + gnext4 = __SSAT(gnext4, 16); + + gnext3 = (q31_t) ((fcurnt3 * (*pk)) >> 15u) + gnext2; + gnext3 = __SSAT(gnext3, 16); + + gnext2 = (q31_t) ((fcurnt2 * (*pk)) >> 15u) + gnext1; + gnext2 = __SSAT(gnext2, 16); + gnext1 = (q31_t) ((fcurnt1 * (*pk++)) >> 15u) + gcurnt1; + gnext1 = __SSAT(gnext1, 16); + + + /* Read g2(n-1), g4(n-1) .... from state */ + gcurnt1 = *px; + + /* save g4(n) in state buffer */ + *px++ = (q15_t) gnext4; + + /* Sample processing for K5, K9.... */ + /* Process first sample for 5th, 9th .. tap */ + /* f5(n) = f4(n) + K5 * g4(n-1) */ + fcurnt1 = (q31_t) ((gcurnt1 * (*pk)) >> 15u) + fnext1; + fcurnt1 = __SSAT(fcurnt1, 16); + + /* Process second sample for 5th, 9th .. tap */ + fcurnt2 = (q31_t) ((gnext1 * (*pk)) >> 15u) + fnext2; + fcurnt2 = __SSAT(fcurnt2, 16); + + /* Process third sample for 5th, 9th .. tap */ + fcurnt3 = (q31_t) ((gnext2 * (*pk)) >> 15u) + fnext3; + fcurnt3 = __SSAT(fcurnt3, 16); + + /* Process fourth sample for 5th, 9th .. tap */ + fcurnt4 = (q31_t) ((gnext3 * (*pk)) >> 15u) + fnext4; + fcurnt4 = __SSAT(fcurnt4, 16); + + /* Calculation of state values for next stage */ + /* g5(n) = f4(n) * K5 + g4(n-1) */ + gnext4 = (q31_t) ((fnext4 * (*pk)) >> 15u) + gnext3; + gnext4 = __SSAT(gnext4, 16); + gnext3 = (q31_t) ((fnext3 * (*pk)) >> 15u) + gnext2; + gnext3 = __SSAT(gnext3, 16); + gnext2 = (q31_t) ((fnext2 * (*pk)) >> 15u) + gnext1; + gnext2 = __SSAT(gnext2, 16); + gnext1 = (q31_t) ((fnext1 * (*pk++)) >> 15u) + gcurnt1; + gnext1 = __SSAT(gnext1, 16); + + stageCnt--; + } + + /* If the (filter length -1) is not a multiple of 4, compute the remaining filter taps */ + stageCnt = (numStages - 1u) % 0x4u; + + while(stageCnt > 0u) + { + gcurnt1 = *px; + + /* save g value in state buffer */ + *px++ = (q15_t) gnext4; + + /* Process four samples for last three taps here */ + fnext1 = (q31_t) ((gcurnt1 * (*pk)) >> 15u) + fcurnt1; + fnext1 = __SSAT(fnext1, 16); + fnext2 = (q31_t) ((gnext1 * (*pk)) >> 15u) + fcurnt2; + fnext2 = __SSAT(fnext2, 16); + + fnext3 = (q31_t) ((gnext2 * (*pk)) >> 15u) + fcurnt3; + fnext3 = __SSAT(fnext3, 16); + + fnext4 = (q31_t) ((gnext3 * (*pk)) >> 15u) + fcurnt4; + fnext4 = __SSAT(fnext4, 16); + + /* g1(n) = f0(n) * K1 + g0(n-1) */ + gnext4 = (q31_t) ((fcurnt4 * (*pk)) >> 15u) + gnext3; + gnext4 = __SSAT(gnext4, 16); + gnext3 = (q31_t) ((fcurnt3 * (*pk)) >> 15u) + gnext2; + gnext3 = __SSAT(gnext3, 16); + gnext2 = (q31_t) ((fcurnt2 * (*pk)) >> 15u) + gnext1; + gnext2 = __SSAT(gnext2, 16); + gnext1 = (q31_t) ((fcurnt1 * (*pk++)) >> 15u) + gcurnt1; + gnext1 = __SSAT(gnext1, 16); + + /* Update of f values for next coefficient set processing */ + fcurnt1 = fnext1; + fcurnt2 = fnext2; + fcurnt3 = fnext3; + fcurnt4 = fnext4; + + stageCnt--; + + } + + /* The results in the 4 accumulators, store in the destination buffer. */ + /* y(n) = fN(n) */ + *__SIMD32(pDst)++ = __PKHBT(fcurnt1, fcurnt2, 16); + *__SIMD32(pDst)++ = __PKHBT(fcurnt3, fcurnt4, 16); + + 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) */ + fcurnt1 = *pSrc++; + + /* Initialize coeff pointer */ + pk = (pCoeffs); + + /* Initialize state pointer */ + px = pState; + + /* read g2(n) from state buffer */ + gcurnt1 = *px; + + /* for sample 1 processing */ + /* f1(n) = f0(n) + K1 * g0(n-1) */ + fnext1 = (((q31_t) gcurnt1 * (*pk)) >> 15u) + fcurnt1; + fnext1 = __SSAT(fnext1, 16); + + + /* g1(n) = f0(n) * K1 + g0(n-1) */ + gnext1 = (((q31_t) fcurnt1 * (*pk++)) >> 15u) + gcurnt1; + gnext1 = __SSAT(gnext1, 16); + + /* save g1(n) in state buffer */ + *px++ = (q15_t) fcurnt1; + + /* f1(n) is saved in fcurnt1 + for next stage processing */ + fcurnt1 = fnext1; + + stageCnt = (numStages - 1u); + + /* stage loop */ + while(stageCnt > 0u) + { + /* read g2(n) from state buffer */ + gcurnt1 = *px; + + /* save g1(n) in state buffer */ + *px++ = (q15_t) gnext1; + + /* Sample processing for K2, K3.... */ + /* f2(n) = f1(n) + K2 * g1(n-1) */ + fnext1 = (((q31_t) gcurnt1 * (*pk)) >> 15u) + fcurnt1; + fnext1 = __SSAT(fnext1, 16); + + /* g2(n) = f1(n) * K2 + g1(n-1) */ + gnext1 = (((q31_t) fcurnt1 * (*pk++)) >> 15u) + gcurnt1; + gnext1 = __SSAT(gnext1, 16); + + + /* f1(n) is saved in fcurnt1 + for next stage processing */ + fcurnt1 = fnext1; + + stageCnt--; + + } + + /* y(n) = fN(n) */ + *pDst++ = __SSAT(fcurnt1, 16); + + + blkCnt--; + + } +} + +/** + * @} end of FIR_Lattice group + */