| /* ---------------------------------------------------------------------- |
| * Project: CMSIS DSP Library |
| * Title: arm_fir_lattice_q15.c |
| * Description: Q15 FIR lattice filter processing function |
| * |
| * $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 FIR_Lattice |
| @{ |
| */ |
| |
| /** |
| @brief Processing function for 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, |
| const q15_t * pSrc, |
| q15_t * pDst, |
| uint32_t blockSize) |
| { |
| q15_t *pState = S->pState; /* State pointer */ |
| const q15_t *pCoeffs = S->pCoeffs; /* Coefficient pointer */ |
| q15_t *px; /* Temporary state pointer */ |
| const q15_t *pk; /* Temporary coefficient pointer */ |
| uint32_t numStages = S->numStages; /* Number of stages in the filter */ |
| uint32_t blkCnt, stageCnt; /* Loop counters */ |
| q31_t fcurr0, fnext0, gnext0, gcurr0; /* Temporary variables */ |
| |
| #if (1) |
| //#if !defined(ARM_MATH_CM0_FAMILY) |
| |
| #if defined (ARM_MATH_LOOPUNROLL) |
| q31_t fcurr1, fnext1, gnext1; /* Temporary variables for second sample in loop unrolling */ |
| q31_t fcurr2, fnext2, gnext2; /* Temporary variables for third sample in loop unrolling */ |
| q31_t fcurr3, fnext3, gnext3; /* Temporary variables for fourth sample in loop unrolling */ |
| #endif |
| |
| gcurr0 = 0; |
| |
| #if defined (ARM_MATH_LOOPUNROLL) |
| |
| /* Loop unrolling: Compute 4 outputs at a time */ |
| blkCnt = blockSize >> 2U; |
| |
| while (blkCnt > 0U) |
| { |
| /* Read two samples from input buffer */ |
| /* f0(n) = x(n) */ |
| fcurr0 = *pSrc++; |
| fcurr1 = *pSrc++; |
| |
| /* Initialize state pointer */ |
| px = pState; |
| |
| /* Initialize coeff pointer */ |
| pk = pCoeffs; |
| |
| /* Read g0(n-1) from state buffer */ |
| gcurr0 = *px; |
| |
| /* Process first sample for first tap */ |
| /* f1(n) = f0(n) + K1 * g0(n-1) */ |
| fnext0 = (q31_t) ((gcurr0 * (*pk)) >> 15U) + fcurr0; |
| fnext0 = __SSAT(fnext0, 16); |
| |
| /* g1(n) = f0(n) * K1 + g0(n-1) */ |
| gnext0 = (q31_t) ((fcurr0 * (*pk)) >> 15U) + gcurr0; |
| gnext0 = __SSAT(gnext0, 16); |
| |
| /* Process second sample for first tap */ |
| fnext1 = (q31_t) ((fcurr0 * (*pk)) >> 15U) + fcurr1; |
| fnext1 = __SSAT(fnext1, 16); |
| gnext1 = (q31_t) ((fcurr1 * (*pk)) >> 15U) + fcurr0; |
| gnext1 = __SSAT(gnext1, 16); |
| |
| /* Read next two samples from input buffer */ |
| /* f0(n+2) = x(n+2) */ |
| fcurr2 = *pSrc++; |
| fcurr3 = *pSrc++; |
| |
| /* Process third sample for first tap */ |
| fnext2 = (q31_t) ((fcurr1 * (*pk)) >> 15U) + fcurr2; |
| fnext2 = __SSAT(fnext2, 16); |
| gnext2 = (q31_t) ((fcurr2 * (*pk)) >> 15U) + fcurr1; |
| gnext2 = __SSAT(gnext2, 16); |
| |
| /* Process fourth sample for first tap */ |
| fnext3 = (q31_t) ((fcurr2 * (*pk )) >> 15U) + fcurr3; |
| fnext3 = __SSAT(fnext3, 16); |
| gnext3 = (q31_t) ((fcurr3 * (*pk++)) >> 15U) + fcurr2; |
| gnext3 = __SSAT(gnext3, 16); |
| |
| /* Copy only last input sample into the state buffer |
| which will be used for next samples processing */ |
| *px++ = (q15_t) fcurr3; |
| |
| /* Update of f values for next coefficient set processing */ |
| fcurr0 = fnext0; |
| fcurr1 = fnext1; |
| fcurr2 = fnext2; |
| fcurr3 = fnext3; |
| |
| /* 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 */ |
| gcurr0 = *px; |
| |
| /* save g1(n) in state buffer */ |
| *px++ = (q15_t) gnext3; |
| |
| /* Process first sample for 2nd, 6th .. tap */ |
| /* Sample processing for K2, K6.... */ |
| /* f1(n) = f0(n) + K1 * g0(n-1) */ |
| fnext0 = (q31_t) ((gcurr0 * (*pk)) >> 15U) + fcurr0; |
| fnext0 = __SSAT(fnext0, 16); |
| |
| /* Process second sample for 2nd, 6th .. tap */ |
| /* for sample 2 processing */ |
| fnext1 = (q31_t) ((gnext0 * (*pk)) >> 15U) + fcurr1; |
| fnext1 = __SSAT(fnext1, 16); |
| |
| /* Process third sample for 2nd, 6th .. tap */ |
| fnext2 = (q31_t) ((gnext1 * (*pk)) >> 15U) + fcurr2; |
| fnext2 = __SSAT(fnext2, 16); |
| |
| /* Process fourth sample for 2nd, 6th .. tap */ |
| fnext3 = (q31_t) ((gnext2 * (*pk)) >> 15U) + fcurr3; |
| fnext3 = __SSAT(fnext3, 16); |
| |
| /* g1(n) = f0(n) * K1 + g0(n-1) */ |
| /* Calculation of state values for next stage */ |
| gnext3 = (q31_t) ((fcurr3 * (*pk)) >> 15U) + gnext2; |
| gnext3 = __SSAT(gnext3, 16); |
| |
| gnext2 = (q31_t) ((fcurr2 * (*pk)) >> 15U) + gnext1; |
| gnext2 = __SSAT(gnext2, 16); |
| |
| gnext1 = (q31_t) ((fcurr1 * (*pk)) >> 15U) + gnext0; |
| gnext1 = __SSAT(gnext1, 16); |
| |
| gnext0 = (q31_t) ((fcurr0 * (*pk++)) >> 15U) + gcurr0; |
| gnext0 = __SSAT(gnext0, 16); |
| |
| |
| /* Read g2(n-1), g4(n-1) .... from state */ |
| gcurr0 = *px; |
| |
| /* save g1(n) in state buffer */ |
| *px++ = (q15_t) gnext3; |
| |
| /* Sample processing for K3, K7.... */ |
| /* Process first sample for 3rd, 7th .. tap */ |
| /* f3(n) = f2(n) + K3 * g2(n-1) */ |
| fcurr0 = (q31_t) ((gcurr0 * (*pk)) >> 15U) + fnext0; |
| fcurr0 = __SSAT(fcurr0, 16); |
| |
| /* Process second sample for 3rd, 7th .. tap */ |
| fcurr1 = (q31_t) ((gnext0 * (*pk)) >> 15U) + fnext1; |
| fcurr1 = __SSAT(fcurr1, 16); |
| |
| /* Process third sample for 3rd, 7th .. tap */ |
| fcurr2 = (q31_t) ((gnext1 * (*pk)) >> 15U) + fnext2; |
| fcurr2 = __SSAT(fcurr2, 16); |
| |
| /* Process fourth sample for 3rd, 7th .. tap */ |
| fcurr3 = (q31_t) ((gnext2 * (*pk)) >> 15U) + fnext3; |
| fcurr3 = __SSAT(fcurr3, 16); |
| |
| /* Calculation of state values for next stage */ |
| /* g3(n) = f2(n) * K3 + g2(n-1) */ |
| 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) + gnext0; |
| gnext1 = __SSAT(gnext1, 16); |
| |
| gnext0 = (q31_t) ((fnext0 * (*pk++)) >> 15U) + gcurr0; |
| gnext0 = __SSAT(gnext0, 16); |
| |
| /* Read g1(n-1), g3(n-1) .... from state */ |
| gcurr0 = *px; |
| |
| /* save g1(n) in state buffer */ |
| *px++ = (q15_t) gnext3; |
| |
| /* Sample processing for K4, K8.... */ |
| /* Process first sample for 4th, 8th .. tap */ |
| /* f4(n) = f3(n) + K4 * g3(n-1) */ |
| fnext0 = (q31_t) ((gcurr0 * (*pk)) >> 15U) + fcurr0; |
| fnext0 = __SSAT(fnext0, 16); |
| |
| /* Process second sample for 4th, 8th .. tap */ |
| /* for sample 2 processing */ |
| fnext1 = (q31_t) ((gnext0 * (*pk)) >> 15U) + fcurr1; |
| fnext1 = __SSAT(fnext1, 16); |
| |
| /* Process third sample for 4th, 8th .. tap */ |
| fnext2 = (q31_t) ((gnext1 * (*pk)) >> 15U) + fcurr2; |
| fnext2 = __SSAT(fnext2, 16); |
| |
| /* Process fourth sample for 4th, 8th .. tap */ |
| fnext3 = (q31_t) ((gnext2 * (*pk)) >> 15U) + fcurr3; |
| fnext3 = __SSAT(fnext3, 16); |
| |
| /* g4(n) = f3(n) * K4 + g3(n-1) */ |
| /* Calculation of state values for next stage */ |
| gnext3 = (q31_t) ((fcurr3 * (*pk)) >> 15U) + gnext2; |
| gnext3 = __SSAT(gnext3, 16); |
| |
| gnext2 = (q31_t) ((fcurr2 * (*pk)) >> 15U) + gnext1; |
| gnext2 = __SSAT(gnext2, 16); |
| |
| gnext1 = (q31_t) ((fcurr1 * (*pk)) >> 15U) + gnext0; |
| gnext1 = __SSAT(gnext1, 16); |
| |
| gnext0 = (q31_t) ((fcurr0 * (*pk++)) >> 15U) + gcurr0; |
| gnext0 = __SSAT(gnext0, 16); |
| |
| /* Read g2(n-1), g4(n-1) .... from state */ |
| gcurr0 = *px; |
| |
| /* save g4(n) in state buffer */ |
| *px++ = (q15_t) gnext3; |
| |
| /* Sample processing for K5, K9.... */ |
| /* Process first sample for 5th, 9th .. tap */ |
| /* f5(n) = f4(n) + K5 * g4(n-1) */ |
| fcurr0 = (q31_t) ((gcurr0 * (*pk)) >> 15U) + fnext0; |
| fcurr0 = __SSAT(fcurr0, 16); |
| |
| /* Process second sample for 5th, 9th .. tap */ |
| fcurr1 = (q31_t) ((gnext0 * (*pk)) >> 15U) + fnext1; |
| fcurr1 = __SSAT(fcurr1, 16); |
| |
| /* Process third sample for 5th, 9th .. tap */ |
| fcurr2 = (q31_t) ((gnext1 * (*pk)) >> 15U) + fnext2; |
| fcurr2 = __SSAT(fcurr2, 16); |
| |
| /* Process fourth sample for 5th, 9th .. tap */ |
| fcurr3 = (q31_t) ((gnext2 * (*pk)) >> 15U) + fnext3; |
| fcurr3 = __SSAT(fcurr3, 16); |
| |
| /* Calculation of state values for next stage */ |
| /* g5(n) = f4(n) * K5 + g4(n-1) */ |
| 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) + gnext0; |
| gnext1 = __SSAT(gnext1, 16); |
| |
| gnext0 = (q31_t) ((fnext0 * (*pk++)) >> 15U) + gcurr0; |
| gnext0 = __SSAT(gnext0, 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) |
| { |
| gcurr0 = *px; |
| |
| /* save g value in state buffer */ |
| *px++ = (q15_t) gnext3; |
| |
| /* Process four samples for last three taps here */ |
| fnext0 = (q31_t) ((gcurr0 * (*pk)) >> 15U) + fcurr0; |
| fnext0 = __SSAT(fnext0, 16); |
| |
| fnext1 = (q31_t) ((gnext0 * (*pk)) >> 15U) + fcurr1; |
| fnext1 = __SSAT(fnext1, 16); |
| |
| fnext2 = (q31_t) ((gnext1 * (*pk)) >> 15U) + fcurr2; |
| fnext2 = __SSAT(fnext2, 16); |
| |
| fnext3 = (q31_t) ((gnext2 * (*pk)) >> 15U) + fcurr3; |
| fnext3 = __SSAT(fnext3, 16); |
| |
| /* g1(n) = f0(n) * K1 + g0(n-1) */ |
| gnext3 = (q31_t) ((fcurr3 * (*pk)) >> 15U) + gnext2; |
| gnext3 = __SSAT(gnext3, 16); |
| |
| gnext2 = (q31_t) ((fcurr2 * (*pk)) >> 15U) + gnext1; |
| gnext2 = __SSAT(gnext2, 16); |
| |
| gnext1 = (q31_t) ((fcurr1 * (*pk)) >> 15U) + gnext0; |
| gnext1 = __SSAT(gnext1, 16); |
| |
| gnext0 = (q31_t) ((fcurr0 * (*pk++)) >> 15U) + gcurr0; |
| gnext0 = __SSAT(gnext0, 16); |
| |
| /* Update of f values for next coefficient set processing */ |
| fcurr0 = fnext0; |
| fcurr1 = fnext1; |
| fcurr2 = fnext2; |
| fcurr3 = fnext3; |
| |
| stageCnt--; |
| } |
| |
| /* The results in the 4 accumulators, store in the destination buffer. */ |
| /* y(n) = fN(n) */ |
| |
| #ifndef ARM_MATH_BIG_ENDIAN |
| write_q15x2_ia (&pDst, __PKHBT(fcurr0, fcurr1, 16)); |
| write_q15x2_ia (&pDst, __PKHBT(fcurr2, fcurr3, 16)); |
| #else |
| write_q15x2_ia (&pDst, __PKHBT(fcurr1, fcurr0, 16)); |
| write_q15x2_ia (&pDst, __PKHBT(fcurr3, fcurr2, 16)); |
| #endif /* #ifndef ARM_MATH_BIG_ENDIAN */ |
| |
| blkCnt--; |
| } |
| |
| /* Loop unrolling: Compute remaining outputs */ |
| blkCnt = blockSize % 0x4U; |
| |
| #else |
| |
| /* Initialize blkCnt with number of samples */ |
| blkCnt = blockSize; |
| |
| #endif /* #if defined (ARM_MATH_LOOPUNROLL) */ |
| |
| while (blkCnt > 0U) |
| { |
| /* f0(n) = x(n) */ |
| fcurr0 = *pSrc++; |
| |
| /* Initialize state pointer */ |
| px = pState; |
| |
| /* Initialize coeff pointer */ |
| pk = pCoeffs; |
| |
| /* read g2(n) from state buffer */ |
| gcurr0 = *px; |
| |
| /* for sample 1 processing */ |
| /* f1(n) = f0(n) + K1 * g0(n-1) */ |
| fnext0 = (((q31_t) gcurr0 * (*pk)) >> 15U) + fcurr0; |
| fnext0 = __SSAT(fnext0, 16); |
| |
| /* g1(n) = f0(n) * K1 + g0(n-1) */ |
| gnext0 = (((q31_t) fcurr0 * (*pk++)) >> 15U) + gcurr0; |
| gnext0 = __SSAT(gnext0, 16); |
| |
| /* save g1(n) in state buffer */ |
| *px++ = (q15_t) fcurr0; |
| |
| /* f1(n) is saved in fcurr0 for next stage processing */ |
| fcurr0 = fnext0; |
| |
| stageCnt = (numStages - 1U); |
| |
| /* stage loop */ |
| while (stageCnt > 0U) |
| { |
| /* read g2(n) from state buffer */ |
| gcurr0 = *px; |
| |
| /* save g1(n) in state buffer */ |
| *px++ = (q15_t) gnext0; |
| |
| /* Sample processing for K2, K3.... */ |
| /* f2(n) = f1(n) + K2 * g1(n-1) */ |
| fnext0 = (((q31_t) gcurr0 * (*pk)) >> 15U) + fcurr0; |
| fnext0 = __SSAT(fnext0, 16); |
| |
| /* g2(n) = f1(n) * K2 + g1(n-1) */ |
| gnext0 = (((q31_t) fcurr0 * (*pk++)) >> 15U) + gcurr0; |
| gnext0 = __SSAT(gnext0, 16); |
| |
| /* f1(n) is saved in fcurr0 for next stage processing */ |
| fcurr0 = fnext0; |
| |
| stageCnt--; |
| } |
| |
| /* y(n) = fN(n) */ |
| *pDst++ = __SSAT(fcurr0, 16); |
| |
| blkCnt--; |
| } |
| |
| #else |
| /* alternate version for CM0_FAMILY */ |
| |
| blkCnt = blockSize; |
| |
| while (blkCnt > 0U) |
| { |
| /* f0(n) = x(n) */ |
| fcurr0 = *pSrc++; |
| |
| /* Initialize state pointer */ |
| px = pState; |
| |
| /* Initialize coeff pointer */ |
| pk = pCoeffs; |
| |
| /* read g0(n-1) from state buffer */ |
| gcurr0 = *px; |
| |
| /* for sample 1 processing */ |
| /* f1(n) = f0(n) + K1 * g0(n-1) */ |
| fnext0 = ((gcurr0 * (*pk)) >> 15U) + fcurr0; |
| fnext0 = __SSAT(fnext, 16); |
| |
| /* g1(n) = f0(n) * K1 + g0(n-1) */ |
| gnext0 = ((fcurr0 * (*pk++)) >> 15U) + gcurr0; |
| gnext0 = __SSAT(gnext0, 16); |
| |
| /* save f0(n) in state buffer */ |
| *px++ = (q15_t) fcurr0; |
| |
| /* f1(n) is saved in fcurr for next stage processing */ |
| fcurr0 = fnext0; |
| |
| stageCnt = (numStages - 1U); |
| |
| /* stage loop */ |
| while (stageCnt > 0U) |
| { |
| /* read g1(n-1) from state buffer */ |
| gcurr0 = *px; |
| |
| /* save g0(n-1) in state buffer */ |
| *px++ = (q15_t) gnext0; |
| |
| /* Sample processing for K2, K3.... */ |
| /* f2(n) = f1(n) + K2 * g1(n-1) */ |
| fnext0 = ((gcurr0 * (*pk)) >> 15U) + fcurr0; |
| fnext0 = __SSAT(fnext0, 16); |
| |
| /* g2(n) = f1(n) * K2 + g1(n-1) */ |
| gnext0 = ((fcurr0 * (*pk++)) >> 15U) + gcurr0; |
| gnext0 = __SSAT(gnext0, 16); |
| |
| /* f1(n) is saved in fcurr0 for next stage processing */ |
| fcurr0 = fnext0; |
| |
| stageCnt--; |
| } |
| |
| /* y(n) = fN(n) */ |
| *pDst++ = __SSAT(fcurr0, 16); |
| |
| blkCnt--; |
| } |
| |
| #endif /* #if !defined(ARM_MATH_CM0_FAMILY) */ |
| |
| } |
| |
| /** |
| @} end of FIR_Lattice group |
| */ |
