CMSISDSP
Version 1.5.2
CMSIS DSP Software Library

Functions  
void  arm_fir_sparse_f32 (arm_fir_sparse_instance_f32 *S, float32_t *pSrc, float32_t *pDst, float32_t *pScratchIn, uint32_t blockSize) 
Processing function for the floatingpoint sparse FIR filter. More...  
void  arm_fir_sparse_init_f32 (arm_fir_sparse_instance_f32 *S, uint16_t numTaps, float32_t *pCoeffs, float32_t *pState, int32_t *pTapDelay, uint16_t maxDelay, uint32_t blockSize) 
Initialization function for the floatingpoint sparse FIR filter. More...  
void  arm_fir_sparse_init_q15 (arm_fir_sparse_instance_q15 *S, uint16_t numTaps, q15_t *pCoeffs, q15_t *pState, int32_t *pTapDelay, uint16_t maxDelay, uint32_t blockSize) 
Initialization function for the Q15 sparse FIR filter. More...  
void  arm_fir_sparse_init_q31 (arm_fir_sparse_instance_q31 *S, uint16_t numTaps, q31_t *pCoeffs, q31_t *pState, int32_t *pTapDelay, uint16_t maxDelay, uint32_t blockSize) 
Initialization function for the Q31 sparse FIR filter. More...  
void  arm_fir_sparse_init_q7 (arm_fir_sparse_instance_q7 *S, uint16_t numTaps, q7_t *pCoeffs, q7_t *pState, int32_t *pTapDelay, uint16_t maxDelay, uint32_t blockSize) 
Initialization function for the Q7 sparse FIR filter. More...  
void  arm_fir_sparse_q15 (arm_fir_sparse_instance_q15 *S, q15_t *pSrc, q15_t *pDst, q15_t *pScratchIn, q31_t *pScratchOut, uint32_t blockSize) 
Processing function for the Q15 sparse FIR filter. More...  
void  arm_fir_sparse_q31 (arm_fir_sparse_instance_q31 *S, q31_t *pSrc, q31_t *pDst, q31_t *pScratchIn, uint32_t blockSize) 
Processing function for the Q31 sparse FIR filter. More...  
void  arm_fir_sparse_q7 (arm_fir_sparse_instance_q7 *S, q7_t *pSrc, q7_t *pDst, q7_t *pScratchIn, q31_t *pScratchOut, uint32_t blockSize) 
Processing function for the Q7 sparse FIR filter. More...  
This group of functions implements sparse FIR filters. Sparse FIR filters are equivalent to standard FIR filters except that most of the coefficients are equal to zero. Sparse filters are used for simulating reflections in communications and audio applications.
There are separate functions for Q7, Q15, Q31, and floatingpoint data types. The functions operate on blocks of input and output data and each call to the function processes blockSize
samples through the filter. pSrc
and pDst
points to input and output arrays respectively containing blockSize
values.
pTapDelay
which specifies the locations of the nonzero coefficients. This is in addition to the coefficient array b
. The implementation essentially skips the multiplications by zero and leads to an efficient realization. y[n] = b[0] * x[npTapDelay[0]] + b[1] * x[npTapDelay[1]] + b[2] * x[npTapDelay[2]] + ...+ b[numTaps1] * x[npTapDelay[numTaps1]]
pCoeffs
points to a coefficient array of size numTaps
; pTapDelay
points to an array of nonzero indices and is also of size numTaps
; pState
points to a state array of size maxDelay + blockSize
, where maxDelay
is the largest offset value that is ever used in the pTapDelay
array. Some of the processing functions also require temporary working buffers.arm_fir_sparse_instance_f32 S = {numTaps, 0, pState, pCoeffs, maxDelay, pTapDelay}; arm_fir_sparse_instance_q31 S = {numTaps, 0, pState, pCoeffs, maxDelay, pTapDelay}; arm_fir_sparse_instance_q15 S = {numTaps, 0, pState, pCoeffs, maxDelay, pTapDelay}; arm_fir_sparse_instance_q7 S = {numTaps, 0, pState, pCoeffs, maxDelay, pTapDelay};
void arm_fir_sparse_f32  (  arm_fir_sparse_instance_f32 *  S, 
float32_t *  pSrc,  
float32_t *  pDst,  
float32_t *  pScratchIn,  
uint32_t  blockSize  
) 
[in]  *S  points to an instance of the floatingpoint sparse FIR structure. 
[in]  *pSrc  points to the block of input data. 
[out]  *pDst  points to the block of output data 
[in]  *pScratchIn  points to a temporary buffer of size blockSize. 
[in]  blockSize  number of input samples to process per call. 
References arm_circularRead_f32(), arm_circularWrite_f32(), blockSize, arm_fir_sparse_instance_f32::maxDelay, arm_fir_sparse_instance_f32::numTaps, arm_fir_sparse_instance_f32::pCoeffs, arm_fir_sparse_instance_f32::pState, arm_fir_sparse_instance_f32::pTapDelay, and arm_fir_sparse_instance_f32::stateIndex.
void arm_fir_sparse_init_f32  (  arm_fir_sparse_instance_f32 *  S, 
uint16_t  numTaps,  
float32_t *  pCoeffs,  
float32_t *  pState,  
int32_t *  pTapDelay,  
uint16_t  maxDelay,  
uint32_t  blockSize  
) 
[in,out]  *S  points to an instance of the floatingpoint sparse FIR structure. 
[in]  numTaps  number of nonzero coefficients in the filter. 
[in]  *pCoeffs  points to the array of filter coefficients. 
[in]  *pState  points to the state buffer. 
[in]  *pTapDelay  points to the array of offset times. 
[in]  maxDelay  maximum offset time supported. 
[in]  blockSize  number of samples that will be processed per block. 
Description:
pCoeffs
holds the filter coefficients and has length numTaps
. pState
holds the filter's state variables and must be of length maxDelay + blockSize
, where maxDelay
is the maximum number of delay line values. blockSize
is the number of samples processed by the arm_fir_sparse_f32()
function. References arm_fir_sparse_instance_f32::maxDelay, arm_fir_sparse_instance_f32::numTaps, arm_fir_sparse_instance_f32::pCoeffs, arm_fir_sparse_instance_f32::pState, arm_fir_sparse_instance_f32::pTapDelay, and arm_fir_sparse_instance_f32::stateIndex.
void arm_fir_sparse_init_q15  (  arm_fir_sparse_instance_q15 *  S, 
uint16_t  numTaps,  
q15_t *  pCoeffs,  
q15_t *  pState,  
int32_t *  pTapDelay,  
uint16_t  maxDelay,  
uint32_t  blockSize  
) 
[in,out]  *S  points to an instance of the Q15 sparse FIR structure. 
[in]  numTaps  number of nonzero coefficients in the filter. 
[in]  *pCoeffs  points to the array of filter coefficients. 
[in]  *pState  points to the state buffer. 
[in]  *pTapDelay  points to the array of offset times. 
[in]  maxDelay  maximum offset time supported. 
[in]  blockSize  number of samples that will be processed per block. 
Description:
pCoeffs
holds the filter coefficients and has length numTaps
. pState
holds the filter's state variables and must be of length maxDelay + blockSize
, where maxDelay
is the maximum number of delay line values. blockSize
is the number of words processed by arm_fir_sparse_q15()
function. References arm_fir_sparse_instance_q15::maxDelay, arm_fir_sparse_instance_q15::numTaps, arm_fir_sparse_instance_q15::pCoeffs, arm_fir_sparse_instance_q15::pState, arm_fir_sparse_instance_q15::pTapDelay, and arm_fir_sparse_instance_q15::stateIndex.
void arm_fir_sparse_init_q31  (  arm_fir_sparse_instance_q31 *  S, 
uint16_t  numTaps,  
q31_t *  pCoeffs,  
q31_t *  pState,  
int32_t *  pTapDelay,  
uint16_t  maxDelay,  
uint32_t  blockSize  
) 
[in,out]  *S  points to an instance of the Q31 sparse FIR structure. 
[in]  numTaps  number of nonzero coefficients in the filter. 
[in]  *pCoeffs  points to the array of filter coefficients. 
[in]  *pState  points to the state buffer. 
[in]  *pTapDelay  points to the array of offset times. 
[in]  maxDelay  maximum offset time supported. 
[in]  blockSize  number of samples that will be processed per block. 
Description:
pCoeffs
holds the filter coefficients and has length numTaps
. pState
holds the filter's state variables and must be of length maxDelay + blockSize
, where maxDelay
is the maximum number of delay line values. blockSize
is the number of words processed by arm_fir_sparse_q31()
function. References arm_fir_sparse_instance_q31::maxDelay, arm_fir_sparse_instance_q31::numTaps, arm_fir_sparse_instance_q31::pCoeffs, arm_fir_sparse_instance_q31::pState, arm_fir_sparse_instance_q31::pTapDelay, and arm_fir_sparse_instance_q31::stateIndex.
void arm_fir_sparse_init_q7  (  arm_fir_sparse_instance_q7 *  S, 
uint16_t  numTaps,  
q7_t *  pCoeffs,  
q7_t *  pState,  
int32_t *  pTapDelay,  
uint16_t  maxDelay,  
uint32_t  blockSize  
) 
[in,out]  *S  points to an instance of the Q7 sparse FIR structure. 
[in]  numTaps  number of nonzero coefficients in the filter. 
[in]  *pCoeffs  points to the array of filter coefficients. 
[in]  *pState  points to the state buffer. 
[in]  *pTapDelay  points to the array of offset times. 
[in]  maxDelay  maximum offset time supported. 
[in]  blockSize  number of samples that will be processed per block. 
Description:
pCoeffs
holds the filter coefficients and has length numTaps
. pState
holds the filter's state variables and must be of length maxDelay + blockSize
, where maxDelay
is the maximum number of delay line values. blockSize
is the number of samples processed by the arm_fir_sparse_q7()
function. References arm_fir_sparse_instance_q7::maxDelay, arm_fir_sparse_instance_q7::numTaps, arm_fir_sparse_instance_q7::pCoeffs, arm_fir_sparse_instance_q7::pState, arm_fir_sparse_instance_q7::pTapDelay, and arm_fir_sparse_instance_q7::stateIndex.
void arm_fir_sparse_q15  (  arm_fir_sparse_instance_q15 *  S, 
q15_t *  pSrc,  
q15_t *  pDst,  
q15_t *  pScratchIn,  
q31_t *  pScratchOut,  
uint32_t  blockSize  
) 
[in]  *S  points to an instance of the Q15 sparse FIR structure. 
[in]  *pSrc  points to the block of input data. 
[out]  *pDst  points to the block of output data 
[in]  *pScratchIn  points to a temporary buffer of size blockSize. 
[in]  *pScratchOut  points to a temporary buffer of size blockSize. 
[in]  blockSize  number of input samples to process per call. 
Scaling and Overflow Behavior:
References __PKHBT, __SIMD32, arm_circularRead_q15(), arm_circularWrite_q15(), blockSize, arm_fir_sparse_instance_q15::maxDelay, arm_fir_sparse_instance_q15::numTaps, arm_fir_sparse_instance_q15::pCoeffs, arm_fir_sparse_instance_q15::pState, arm_fir_sparse_instance_q15::pTapDelay, and arm_fir_sparse_instance_q15::stateIndex.
void arm_fir_sparse_q31  (  arm_fir_sparse_instance_q31 *  S, 
q31_t *  pSrc,  
q31_t *  pDst,  
q31_t *  pScratchIn,  
uint32_t  blockSize  
) 
[in]  *S  points to an instance of the Q31 sparse FIR structure. 
[in]  *pSrc  points to the block of input data. 
[out]  *pDst  points to the block of output data 
[in]  *pScratchIn  points to a temporary buffer of size blockSize. 
[in]  blockSize  number of input samples to process per call. 
Scaling and Overflow Behavior:
References arm_circularRead_f32(), arm_circularWrite_f32(), blockSize, arm_fir_sparse_instance_q31::maxDelay, arm_fir_sparse_instance_q31::numTaps, arm_fir_sparse_instance_q31::pCoeffs, arm_fir_sparse_instance_q31::pState, arm_fir_sparse_instance_q31::pTapDelay, and arm_fir_sparse_instance_q31::stateIndex.
void arm_fir_sparse_q7  (  arm_fir_sparse_instance_q7 *  S, 
q7_t *  pSrc,  
q7_t *  pDst,  
q7_t *  pScratchIn,  
q31_t *  pScratchOut,  
uint32_t  blockSize  
) 
[in]  *S  points to an instance of the Q7 sparse FIR structure. 
[in]  *pSrc  points to the block of input data. 
[out]  *pDst  points to the block of output data 
[in]  *pScratchIn  points to a temporary buffer of size blockSize. 
[in]  *pScratchOut  points to a temporary buffer of size blockSize. 
[in]  blockSize  number of input samples to process per call. 
Scaling and Overflow Behavior:
References __PACKq7, __SIMD32, arm_circularRead_q7(), arm_circularWrite_q7(), blockSize, arm_fir_sparse_instance_q7::maxDelay, arm_fir_sparse_instance_q7::numTaps, arm_fir_sparse_instance_q7::pCoeffs, arm_fir_sparse_instance_q7::pState, arm_fir_sparse_instance_q7::pTapDelay, and arm_fir_sparse_instance_q7::stateIndex.