#include "ref.h"
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void ref_fir_lattice_f32(
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const arm_fir_lattice_instance_f32 * S,
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float32_t * pSrc,
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float32_t * pDst,
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uint32_t blockSize)
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{
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float32_t *pState; /* State pointer */
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float32_t *pCoeffs = S->pCoeffs; /* Coefficient pointer */
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float32_t *px; /* temporary state pointer */
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float32_t *pk; /* temporary coefficient pointer */
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float32_t fcurr, fnext, gcurr, gnext; /* temporary variables */
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uint32_t numStages = S->numStages; /* Length of the filter */
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uint32_t blkCnt, stageCnt; /* temporary variables for counts */
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pState = &S->pState[0];
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blkCnt = blockSize;
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while (blkCnt > 0U)
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{
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/* f0(n) = x(n) */
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fcurr = *pSrc++;
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/* Initialize coeff pointer */
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pk = pCoeffs;
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/* Initialize state pointer */
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px = pState;
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/* read g0(n-1) from state buffer */
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gcurr = *px;
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/* for sample 1 processing */
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/* f1(n) = f0(n) + K1 * g0(n-1) */
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fnext = fcurr + ((*pk) * gcurr);
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/* g1(n) = f0(n) * K1 + g0(n-1) */
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gnext = (fcurr * (*pk++)) + gcurr;
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/* save f0(n) in state buffer */
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*px++ = fcurr;
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/* f1(n) is saved in fcurr
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for next stage processing */
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fcurr = fnext;
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stageCnt = (numStages - 1U);
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/* stage loop */
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while (stageCnt > 0U)
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{
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/* read g2(n) from state buffer */
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gcurr = *px;
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/* save g1(n) in state buffer */
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*px++ = gnext;
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/* Sample processing for K2, K3.... */
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/* f2(n) = f1(n) + K2 * g1(n-1) */
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fnext = fcurr + ((*pk) * gcurr);
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/* g2(n) = f1(n) * K2 + g1(n-1) */
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gnext = (fcurr * (*pk++)) + gcurr;
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/* f1(n) is saved in fcurr1
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for next stage processing */
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fcurr = fnext;
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stageCnt--;
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}
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/* y(n) = fN(n) */
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*pDst++ = fcurr;
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blkCnt--;
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}
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}
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void ref_fir_lattice_q31(
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const arm_fir_lattice_instance_q31 * S,
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q31_t * pSrc,
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q31_t * pDst,
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uint32_t blockSize)
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{
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q31_t *pState; /* State pointer */
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q31_t *pCoeffs = S->pCoeffs; /* Coefficient pointer */
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q31_t *px; /* temporary state pointer */
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q31_t *pk; /* temporary coefficient pointer */
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q31_t fcurr, fnext, gcurr, gnext; /* temporary variables */
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uint32_t numStages = S->numStages; /* Length of the filter */
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uint32_t blkCnt, stageCnt; /* temporary variables for counts */
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pState = &S->pState[0];
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blkCnt = blockSize;
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while (blkCnt > 0U)
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{
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/* f0(n) = x(n) */
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fcurr = *pSrc++;
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/* Initialize coeff pointer */
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pk = pCoeffs;
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/* Initialize state pointer */
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px = pState;
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/* read g0(n-1) from state buffer */
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gcurr = *px;
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/* for sample 1 processing */
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/* f1(n) = f0(n) + K1 * g0(n-1) */
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fnext = (q31_t) (((q63_t) gcurr * (*pk)) >> 31) + fcurr;
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/* g1(n) = f0(n) * K1 + g0(n-1) */
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gnext = (q31_t) (((q63_t) fcurr * (*pk++)) >> 31) + gcurr;
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/* save g1(n) in state buffer */
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*px++ = fcurr;
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/* f1(n) is saved in fcurr1
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for next stage processing */
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fcurr = fnext;
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stageCnt = (numStages - 1U);
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/* stage loop */
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while (stageCnt > 0U)
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{
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/* read g2(n) from state buffer */
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gcurr = *px;
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/* save g1(n) in state buffer */
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*px++ = gnext;
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/* Sample processing for K2, K3.... */
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/* f2(n) = f1(n) + K2 * g1(n-1) */
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fnext = (q31_t) (((q63_t) gcurr * (*pk)) >> 31) + fcurr;
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/* g2(n) = f1(n) * K2 + g1(n-1) */
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gnext = (q31_t) (((q63_t) fcurr * (*pk++)) >> 31) + gcurr;
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/* f1(n) is saved in fcurr1
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for next stage processing */
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fcurr = fnext;
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stageCnt--;
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}
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/* y(n) = fN(n) */
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*pDst++ = fcurr;
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blkCnt--;
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}
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}
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void ref_fir_lattice_q15(
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const arm_fir_lattice_instance_q15 * S,
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q15_t * pSrc,
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q15_t * pDst,
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uint32_t blockSize)
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{
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q15_t *pState; /* State pointer */
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q15_t *pCoeffs = S->pCoeffs; /* Coefficient pointer */
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q15_t *px; /* temporary state pointer */
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q15_t *pk; /* temporary coefficient pointer */
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q31_t fcurnt, fnext, gcurnt, gnext; /* temporary variables */
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uint32_t numStages = S->numStages; /* Length of the filter */
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uint32_t blkCnt, stageCnt; /* temporary variables for counts */
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pState = &S->pState[0];
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blkCnt = blockSize;
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while (blkCnt > 0U)
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{
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/* f0(n) = x(n) */
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fcurnt = *pSrc++;
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/* Initialize coeff pointer */
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pk = (pCoeffs);
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/* Initialize state pointer */
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px = pState;
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/* read g0(n-1) from state buffer */
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gcurnt = *px;
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/* for sample 1 processing */
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/* f1(n) = f0(n) + K1 * g0(n-1) */
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fnext = ((gcurnt * (*pk)) >> 15U) + fcurnt;
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fnext = ref_sat_q15(fnext);
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/* g1(n) = f0(n) * K1 + g0(n-1) */
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gnext = ((fcurnt * (*pk++)) >> 15U) + gcurnt;
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gnext = ref_sat_q15(gnext);
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/* save f0(n) in state buffer */
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*px++ = (q15_t) fcurnt;
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/* f1(n) is saved in fcurnt
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for next stage processing */
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fcurnt = fnext;
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stageCnt = (numStages - 1U);
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/* stage loop */
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while (stageCnt > 0U)
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{
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/* read g1(n-1) from state buffer */
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gcurnt = *px;
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/* save g0(n-1) in state buffer */
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*px++ = (q15_t) gnext;
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/* Sample processing for K2, K3.... */
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/* f2(n) = f1(n) + K2 * g1(n-1) */
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fnext = ((gcurnt * (*pk)) >> 15U) + fcurnt;
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fnext = ref_sat_q15(fnext);
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/* g2(n) = f1(n) * K2 + g1(n-1) */
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gnext = ((fcurnt * (*pk++)) >> 15U) + gcurnt;
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gnext = ref_sat_q15(gnext);
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/* f1(n) is saved in fcurnt
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for next stage processing */
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fcurnt = fnext;
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stageCnt--;
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}
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/* y(n) = fN(n) */
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*pDst++ = ref_sat_q15(fcurnt);
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blkCnt--;
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}
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}
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