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#include "ref.h"
void ref_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 */
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--;
}
}
void ref_fir_lattice_q31(
const arm_fir_lattice_instance_q31 * S,
q31_t * pSrc,
q31_t * pDst,
uint32_t blockSize)
{
q31_t *pState; /* State pointer */
q31_t *pCoeffs = S->pCoeffs; /* Coefficient pointer */
q31_t *px; /* temporary state pointer */
q31_t *pk; /* temporary coefficient pointer */
q31_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 = (q31_t) (((q63_t) gcurr * (*pk)) >> 31) + fcurr;
/* g1(n) = f0(n) * K1 + g0(n-1) */
gnext = (q31_t) (((q63_t) fcurr * (*pk++)) >> 31) + gcurr;
/* save g1(n) in state buffer */
*px++ = fcurr;
/* f1(n) is saved in fcurr1
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 = (q31_t) (((q63_t) gcurr * (*pk)) >> 31) + fcurr;
/* g2(n) = f1(n) * K2 + g1(n-1) */
gnext = (q31_t) (((q63_t) fcurr * (*pk++)) >> 31) + gcurr;
/* f1(n) is saved in fcurr1
for next stage processing */
fcurr = fnext;
stageCnt--;
}
/* y(n) = fN(n) */
*pDst++ = fcurr;
blkCnt--;
}
}
void ref_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 fcurnt, fnext, gcurnt, 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) */
fcurnt = *pSrc++;
/* Initialize coeff pointer */
pk = (pCoeffs);
/* Initialize state pointer */
px = pState;
/* read g0(n-1) from state buffer */
gcurnt = *px;
/* for sample 1 processing */
/* f1(n) = f0(n) + K1 * g0(n-1) */
fnext = ((gcurnt * (*pk)) >> 15U) + fcurnt;
fnext = ref_sat_q15(fnext);
/* g1(n) = f0(n) * K1 + g0(n-1) */
gnext = ((fcurnt * (*pk++)) >> 15U) + gcurnt;
gnext = ref_sat_q15(gnext);
/* save f0(n) in state buffer */
*px++ = (q15_t) fcurnt;
/* f1(n) is saved in fcurnt
for next stage processing */
fcurnt = fnext;
stageCnt = (numStages - 1U);
/* stage loop */
while (stageCnt > 0U)
{
/* read g1(n-1) from state buffer */
gcurnt = *px;
/* save g0(n-1) in state buffer */
*px++ = (q15_t) gnext;
/* Sample processing for K2, K3.... */
/* f2(n) = f1(n) + K2 * g1(n-1) */
fnext = ((gcurnt * (*pk)) >> 15U) + fcurnt;
fnext = ref_sat_q15(fnext);
/* g2(n) = f1(n) * K2 + g1(n-1) */
gnext = ((fcurnt * (*pk++)) >> 15U) + gcurnt;
gnext = ref_sat_q15(gnext);
/* f1(n) is saved in fcurnt
for next stage processing */
fcurnt = fnext;
stageCnt--;
}
/* y(n) = fN(n) */
*pDst++ = ref_sat_q15(fcurnt);
blkCnt--;
}
}
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