arm_fir_interpolate_q15.c
349 lines
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CLexer
r71 | /*----------------------------------------------------------------------------- | |||
* Copyright (C) 2010 ARM Limited. All rights reserved. | ||||
* | ||||
* $Date: 15. July 2011 | ||||
* $Revision: V1.0.10 | ||||
* | ||||
* Project: CMSIS DSP Library | ||||
* Title: arm_fir_interpolate_q15.c | ||||
* | ||||
* Description: Q15 FIR interpolation. | ||||
* | ||||
* Target Processor: Cortex-M4/Cortex-M3/Cortex-M0 | ||||
* | ||||
* Version 1.0.10 2011/7/15 | ||||
* Big Endian support added and Merged M0 and M3/M4 Source code. | ||||
* | ||||
* 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_Interpolate | ||||
* @{ | ||||
*/ | ||||
/** | ||||
* @brief Processing function for the Q15 FIR interpolator. | ||||
* @param[in] *S points to an instance of the Q15 FIR interpolator 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 input samples to process per call. | ||||
* @return none. | ||||
* | ||||
* <b>Scaling and Overflow Behavior:</b> | ||||
* \par | ||||
* The function is implemented using a 64-bit internal accumulator. | ||||
* Both coefficients and state variables are represented in 1.15 format and multiplications yield a 2.30 result. | ||||
* The 2.30 intermediate results are accumulated in a 64-bit accumulator in 34.30 format. | ||||
* There is no risk of internal overflow with this approach and the full precision of intermediate multiplications is preserved. | ||||
* After all additions have been performed, the accumulator is truncated to 34.15 format by discarding low 15 bits. | ||||
* Lastly, the accumulator is saturated to yield a result in 1.15 format. | ||||
*/ | ||||
void arm_fir_interpolate_q15( | ||||
const arm_fir_interpolate_instance_q15 * S, | ||||
q15_t * pSrc, | ||||
q15_t * pDst, | ||||
uint32_t blockSize) | ||||
{ | ||||
q15_t *pState = S->pState; /* State pointer */ | ||||
q15_t *pCoeffs = S->pCoeffs; /* Coefficient pointer */ | ||||
q15_t *pStateCurnt; /* Points to the current sample of the state */ | ||||
q15_t *ptr1, *ptr2; /* Temporary pointers for state and coefficient buffers */ | ||||
#ifndef ARM_MATH_CM0 | ||||
/* Run the below code for Cortex-M4 and Cortex-M3 */ | ||||
q63_t sum0; /* Accumulators */ | ||||
q15_t x0, c0, c1; /* Temporary variables to hold state and coefficient values */ | ||||
q31_t c, x; | ||||
uint32_t i, blkCnt, j, tapCnt; /* Loop counters */ | ||||
uint16_t phaseLen = S->phaseLength; /* Length of each polyphase filter component */ | ||||
/* S->pState buffer contains previous frame (phaseLen - 1) samples */ | ||||
/* pStateCurnt points to the location where the new input data should be written */ | ||||
pStateCurnt = S->pState + (phaseLen - 1u); | ||||
/* Total number of intput samples */ | ||||
blkCnt = blockSize; | ||||
/* Loop over the blockSize. */ | ||||
while(blkCnt > 0u) | ||||
{ | ||||
/* Copy new input sample into the state buffer */ | ||||
*pStateCurnt++ = *pSrc++; | ||||
/* Address modifier index of coefficient buffer */ | ||||
j = 1u; | ||||
/* Loop over the Interpolation factor. */ | ||||
i = S->L; | ||||
while(i > 0u) | ||||
{ | ||||
/* Set accumulator to zero */ | ||||
sum0 = 0; | ||||
/* Initialize state pointer */ | ||||
ptr1 = pState; | ||||
/* Initialize coefficient pointer */ | ||||
ptr2 = pCoeffs + (S->L - j); | ||||
/* Loop over the polyPhase length. Unroll by a factor of 4. | ||||
** Repeat until we've computed numTaps-(4*S->L) coefficients. */ | ||||
tapCnt = (uint32_t) phaseLen >> 2u; | ||||
while(tapCnt > 0u) | ||||
{ | ||||
/* Read the coefficient */ | ||||
c0 = *(ptr2); | ||||
/* Upsampling is done by stuffing L-1 zeros between each sample. | ||||
* So instead of multiplying zeros with coefficients, | ||||
* Increment the coefficient pointer by interpolation factor times. */ | ||||
ptr2 += S->L; | ||||
/* Read the coefficient */ | ||||
c1 = *(ptr2); | ||||
/* Increment the coefficient pointer by interpolation factor times. */ | ||||
ptr2 += S->L; | ||||
/* Pack the coefficients */ | ||||
#ifndef ARM_MATH_BIG_ENDIAN | ||||
c = __PKHBT(c0, c1, 16); | ||||
#else | ||||
c = __PKHBT(c1, c0, 16); | ||||
#endif /* #ifndef ARM_MATH_BIG_ENDIAN */ | ||||
/* Read twp consecutive input samples */ | ||||
x = *__SIMD32(ptr1)++; | ||||
/* Perform the multiply-accumulate */ | ||||
sum0 = __SMLALD(x, c, sum0); | ||||
/* Read the coefficient */ | ||||
c0 = *(ptr2); | ||||
/* Upsampling is done by stuffing L-1 zeros between each sample. | ||||
* So insted of multiplying zeros with coefficients, | ||||
* Increment the coefficient pointer by interpolation factor times. */ | ||||
ptr2 += S->L; | ||||
/* Read the coefficient */ | ||||
c1 = *(ptr2); | ||||
/* Increment the coefficient pointer by interpolation factor times. */ | ||||
ptr2 += S->L; | ||||
/* Pack the coefficients */ | ||||
#ifndef ARM_MATH_BIG_ENDIAN | ||||
c = __PKHBT(c0, c1, 16); | ||||
#else | ||||
c = __PKHBT(c1, c0, 16); | ||||
#endif /* #ifndef ARM_MATH_BIG_ENDIAN */ | ||||
/* Read twp consecutive input samples */ | ||||
x = *__SIMD32(ptr1)++; | ||||
/* Perform the multiply-accumulate */ | ||||
sum0 = __SMLALD(x, c, sum0); | ||||
/* Decrement the loop counter */ | ||||
tapCnt--; | ||||
} | ||||
/* If the polyPhase length is not a multiple of 4, compute the remaining filter taps */ | ||||
tapCnt = (uint32_t) phaseLen & 0x3u; | ||||
while(tapCnt > 0u) | ||||
{ | ||||
/* Read the coefficient */ | ||||
c0 = *(ptr2); | ||||
/* Increment the coefficient pointer by interpolation factor times. */ | ||||
ptr2 += S->L; | ||||
/* Read the input sample */ | ||||
x0 = *(ptr1++); | ||||
/* Perform the multiply-accumulate */ | ||||
sum0 = __SMLALD(x0, c0, sum0); | ||||
/* Decrement the loop counter */ | ||||
tapCnt--; | ||||
} | ||||
/* The result is in the accumulator, store in the destination buffer. */ | ||||
*pDst++ = (q15_t) (__SSAT((sum0 >> 15), 16)); | ||||
/* Increment the address modifier index of coefficient buffer */ | ||||
j++; | ||||
/* Decrement the loop counter */ | ||||
i--; | ||||
} | ||||
/* Advance the state pointer by 1 | ||||
* to process the next group of interpolation factor number samples */ | ||||
pState = pState + 1; | ||||
/* Decrement the loop counter */ | ||||
blkCnt--; | ||||
} | ||||
/* Processing is complete. | ||||
** Now copy the last phaseLen - 1 samples to the satrt of the state buffer. | ||||
** This prepares the state buffer for the next function call. */ | ||||
/* Points to the start of the state buffer */ | ||||
pStateCurnt = S->pState; | ||||
i = ((uint32_t) phaseLen - 1u) >> 2u; | ||||
/* copy data */ | ||||
while(i > 0u) | ||||
{ | ||||
*__SIMD32(pStateCurnt)++ = *__SIMD32(pState)++; | ||||
*__SIMD32(pStateCurnt)++ = *__SIMD32(pState)++; | ||||
/* Decrement the loop counter */ | ||||
i--; | ||||
} | ||||
i = ((uint32_t) phaseLen - 1u) % 0x04u; | ||||
while(i > 0u) | ||||
{ | ||||
*pStateCurnt++ = *pState++; | ||||
/* Decrement the loop counter */ | ||||
i--; | ||||
} | ||||
#else | ||||
/* Run the below code for Cortex-M0 */ | ||||
q63_t sum; /* Accumulator */ | ||||
q15_t x0, c0; /* Temporary variables to hold state and coefficient values */ | ||||
uint32_t i, blkCnt, tapCnt; /* Loop counters */ | ||||
uint16_t phaseLen = S->phaseLength; /* Length of each polyphase filter component */ | ||||
/* S->pState buffer contains previous frame (phaseLen - 1) samples */ | ||||
/* pStateCurnt points to the location where the new input data should be written */ | ||||
pStateCurnt = S->pState + (phaseLen - 1u); | ||||
/* Total number of intput samples */ | ||||
blkCnt = blockSize; | ||||
/* Loop over the blockSize. */ | ||||
while(blkCnt > 0u) | ||||
{ | ||||
/* Copy new input sample into the state buffer */ | ||||
*pStateCurnt++ = *pSrc++; | ||||
/* Loop over the Interpolation factor. */ | ||||
i = S->L; | ||||
while(i > 0u) | ||||
{ | ||||
/* Set accumulator to zero */ | ||||
sum = 0; | ||||
/* Initialize state pointer */ | ||||
ptr1 = pState; | ||||
/* Initialize coefficient pointer */ | ||||
ptr2 = pCoeffs + (i - 1u); | ||||
/* Loop over the polyPhase length */ | ||||
tapCnt = (uint32_t) phaseLen; | ||||
while(tapCnt > 0u) | ||||
{ | ||||
/* Read the coefficient */ | ||||
c0 = *ptr2; | ||||
/* Increment the coefficient pointer by interpolation factor times. */ | ||||
ptr2 += S->L; | ||||
/* Read the input sample */ | ||||
x0 = *ptr1++; | ||||
/* Perform the multiply-accumulate */ | ||||
sum += ((q31_t) x0 * c0); | ||||
/* Decrement the loop counter */ | ||||
tapCnt--; | ||||
} | ||||
/* Store the result after converting to 1.15 format in the destination buffer */ | ||||
*pDst++ = (q15_t) (__SSAT((sum >> 15), 16)); | ||||
/* Decrement the loop counter */ | ||||
i--; | ||||
} | ||||
/* Advance the state pointer by 1 | ||||
* to process the next group of interpolation factor number samples */ | ||||
pState = pState + 1; | ||||
/* Decrement the loop counter */ | ||||
blkCnt--; | ||||
} | ||||
/* Processing is complete. | ||||
** Now copy the last phaseLen - 1 samples to the start of the state buffer. | ||||
** This prepares the state buffer for the next function call. */ | ||||
/* Points to the start of the state buffer */ | ||||
pStateCurnt = S->pState; | ||||
i = (uint32_t) phaseLen - 1u; | ||||
while(i > 0u) | ||||
{ | ||||
*pStateCurnt++ = *pState++; | ||||
/* Decrement the loop counter */ | ||||
i--; | ||||
} | ||||
#endif /* #ifndef ARM_MATH_CM0 */ | ||||
} | ||||
/** | ||||
* @} end of FIR_Interpolate group | ||||
*/ | ||||