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#include "ref.h"
void ref_iir_lattice_f32(
const arm_iir_lattice_instance_f32 * S,
float32_t * pSrc,
float32_t * pDst,
uint32_t blockSize)
{
float32_t fcurr, fnext = 0, gcurr, gnext; /* Temporary variables for lattice stages */
float32_t acc; /* Accumlator */
uint32_t blkCnt, tapCnt; /* temporary variables for counts */
float32_t *px1, *px2, *pk, *pv; /* temporary pointers for state and coef */
uint32_t numStages = S->numStages; /* number of stages */
float32_t *pState; /* State pointer */
float32_t *pStateCurnt; /* State current pointer */
blkCnt = blockSize;
pState = &S->pState[0];
/* Sample processing */
while (blkCnt > 0U)
{
/* Read Sample from input buffer */
/* fN(n) = x(n) */
fcurr = *pSrc++;
/* Initialize state read pointer */
px1 = pState;
/* Initialize state write pointer */
px2 = pState;
/* Set accumulator to zero */
acc = 0.0f;
/* Initialize Ladder coeff pointer */
pv = &S->pvCoeffs[0];
/* Initialize Reflection coeff pointer */
pk = &S->pkCoeffs[0];
/* Process sample for numStages */
tapCnt = numStages;
while (tapCnt > 0U)
{
gcurr = *px1++;
/* Process sample for last taps */
fnext = fcurr - (*pk) * gcurr;
gnext = fnext * (*pk++) + gcurr;
/* Output samples for last taps */
acc += gnext * (*pv++);
*px2++ = gnext;
fcurr = fnext;
/* Decrementing loop counter */
tapCnt--;
}
/* y(n) += g0(n) * v0 */
acc += fnext * (*pv);
*px2++ = fnext;
/* write out into pDst */
*pDst++ = acc;
/* Advance the state pointer by 1 to process the next group of samples */
pState = pState + 1U;
blkCnt--;
}
/* Processing is complete. Now copy last S->numStages samples to start of the buffer
for the preperation of next frame process */
/* Points to the start of the state buffer */
pStateCurnt = &S->pState[0];
pState = &S->pState[blockSize];
tapCnt = numStages;
/* Copy the data */
while (tapCnt > 0U)
{
*pStateCurnt++ = *pState++;
/* Decrement the loop counter */
tapCnt--;
}
}
void ref_iir_lattice_q31(
const arm_iir_lattice_instance_q31 * S,
q31_t * pSrc,
q31_t * pDst,
uint32_t blockSize)
{
q31_t fcurr, fnext = 0, gcurr = 0, gnext; /* Temporary variables for lattice stages */
q63_t acc; /* Accumlator */
uint32_t blkCnt, tapCnt; /* Temporary variables for counts */
q31_t *px1, *px2, *pk, *pv; /* Temporary pointers for state and coef */
uint32_t numStages = S->numStages; /* number of stages */
q31_t *pState; /* State pointer */
q31_t *pStateCurnt; /* State current pointer */
blkCnt = blockSize;
pState = &S->pState[0];
/* Sample processing */
while (blkCnt > 0U)
{
/* Read Sample from input buffer */
/* fN(n) = x(n) */
fcurr = *pSrc++;
/* Initialize state read pointer */
px1 = pState;
/* Initialize state write pointer */
px2 = pState;
/* Set accumulator to zero */
acc = 0;
/* Initialize Ladder coeff pointer */
pv = &S->pvCoeffs[0];
/* Initialize Reflection coeff pointer */
pk = &S->pkCoeffs[0];
tapCnt = numStages;
while (tapCnt > 0U)
{
gcurr = *px1++;
/* Process sample */
/* fN-1(n) = fN(n) - kN * gN-1(n-1) */
fnext =
ref_sat_q31(((q63_t) fcurr -
((q31_t) (((q63_t) gcurr * (*pk)) >> 31))));
/* gN(n) = kN * fN-1(n) + gN-1(n-1) */
gnext =
ref_sat_q31(((q63_t) gcurr +
((q31_t) (((q63_t) fnext * (*pk++)) >> 31))));
/* Output samples */
/* y(n) += gN(n) * vN */
acc += ((q63_t) gnext * *pv++);
/* write gN-1(n-1) into state for next sample processing */
*px2++ = gnext;
/* Update f values for next coefficient processing */
fcurr = fnext;
tapCnt--;
}
/* y(n) += g0(n) * v0 */
acc += (q63_t) fnext *(*pv++);
*px2++ = fnext;
/* write out into pDst */
*pDst++ = (q31_t) (acc >> 31U);
/* Advance the state pointer by 1 to process the next group of samples */
pState = pState + 1U;
blkCnt--;
}
/* Processing is complete. Now copy last S->numStages samples to start of the buffer
for the preperation of next frame process */
/* Points to the start of the state buffer */
pStateCurnt = &S->pState[0];
pState = &S->pState[blockSize];
tapCnt = numStages;
/* Copy the remaining q31_t data */
while (tapCnt > 0U)
{
*pStateCurnt++ = *pState++;
/* Decrement the loop counter */
tapCnt--;
}
}
void ref_iir_lattice_q15(
const arm_iir_lattice_instance_q15 * S,
q15_t * pSrc,
q15_t * pDst,
uint32_t blockSize)
{
q31_t fcurr, fnext = 0, gcurr = 0, gnext; /* Temporary variables for lattice stages */
uint32_t stgCnt; /* Temporary variables for counts */
q63_t acc; /* Accumlator */
uint32_t blkCnt, tapCnt; /* Temporary variables for counts */
q15_t *px1, *px2, *pk, *pv; /* temporary pointers for state and coef */
uint32_t numStages = S->numStages; /* number of stages */
q15_t *pState; /* State pointer */
q15_t *pStateCurnt; /* State current pointer */
q15_t out; /* Temporary variable for output */
blkCnt = blockSize;
pState = &S->pState[0];
/* Sample processing */
while (blkCnt > 0U)
{
/* Read Sample from input buffer */
/* fN(n) = x(n) */
fcurr = *pSrc++;
/* Initialize state read pointer */
px1 = pState;
/* Initialize state write pointer */
px2 = pState;
/* Set accumulator to zero */
acc = 0;
/* Initialize Ladder coeff pointer */
pv = &S->pvCoeffs[0];
/* Initialize Reflection coeff pointer */
pk = &S->pkCoeffs[0];
tapCnt = numStages;
while (tapCnt > 0U)
{
gcurr = *px1++;
/* Process sample */
/* fN-1(n) = fN(n) - kN * gN-1(n-1) */
fnext = fcurr - ((gcurr * (*pk)) >> 15);
fnext = ref_sat_q15(fnext);
/* gN(n) = kN * fN-1(n) + gN-1(n-1) */
gnext = ((fnext * (*pk++)) >> 15) + gcurr;
gnext = ref_sat_q15(gnext);
/* Output samples */
/* y(n) += gN(n) * vN */
acc += (q31_t) ((gnext * (*pv++)));
/* write gN(n) into state for next sample processing */
*px2++ = (q15_t) gnext;
/* Update f values for next coefficient processing */
fcurr = fnext;
tapCnt--;
}
/* y(n) += g0(n) * v0 */
acc += (q31_t) ((fnext * (*pv++)));
out = ref_sat_q15(acc >> 15);
*px2++ = (q15_t) fnext;
/* write out into pDst */
*pDst++ = out;
/* Advance the state pointer by 1 to process the next group of samples */
pState = pState + 1U;
blkCnt--;
}
/* Processing is complete. Now copy last S->numStages samples to start of the buffer
for the preperation of next frame process */
/* Points to the start of the state buffer */
pStateCurnt = &S->pState[0];
pState = &S->pState[blockSize];
stgCnt = numStages;
/* copy data */
while (stgCnt > 0U)
{
*pStateCurnt++ = *pState++;
/* Decrement the loop counter */
stgCnt--;
}
}
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