| /* ---------------------------------------------------------------------- |
| * Copyright (C) 2010 ARM Limited. All rights reserved. |
| * |
| * $Date: 15. July 2011 |
| * $Revision: V1.0.10 |
| * |
| * Project: CMSIS DSP Library |
| * Title: arm_fir_sparse_q15.c |
| * |
| * Description: Q15 sparse FIR filter processing function. |
| * |
| * 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" |
| |
| /** |
| * @addtogroup FIR_Sparse |
| * @{ |
| */ |
| |
| /** |
| * @brief Processing function for the Q15 sparse FIR filter. |
| * @param[in] *S points to an instance of the Q15 sparse FIR structure. |
| * @param[in] *pSrc points to the block of input data. |
| * @param[out] *pDst points to the block of output data |
| * @param[in] *pScratchIn points to a temporary buffer of size blockSize. |
| * @param[in] *pScratchOut points to a temporary buffer of size blockSize. |
| * @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 an internal 32-bit accumulator. |
| * The 1.15 x 1.15 multiplications yield a 2.30 result and these are added to a 2.30 accumulator. |
| * Thus the full precision of the multiplications is maintained but there is only a single guard bit in the accumulator. |
| * If the accumulator result overflows it will wrap around rather than saturate. |
| * After all multiply-accumulates are performed, the 2.30 accumulator is truncated to 2.15 format and then saturated to 1.15 format. |
| * In order to avoid overflows the input signal or coefficients must be scaled down by log2(numTaps) bits. |
| */ |
| |
| |
| 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) |
| { |
| |
| q15_t *pState = S->pState; /* State pointer */ |
| q15_t *pIn = pSrc; /* Working pointer for input */ |
| q15_t *pOut = pDst; /* Working pointer for output */ |
| q15_t *pCoeffs = S->pCoeffs; /* Coefficient pointer */ |
| q15_t *px; /* Temporary pointers for scratch buffer */ |
| q15_t *pb = pScratchIn; /* Temporary pointers for scratch buffer */ |
| q15_t *py = pState; /* Temporary pointers for state buffer */ |
| int32_t *pTapDelay = S->pTapDelay; /* Pointer to the array containing offset of the non-zero tap values. */ |
| uint32_t delaySize = S->maxDelay + blockSize; /* state length */ |
| uint16_t numTaps = S->numTaps; /* Filter order */ |
| int32_t readIndex; /* Read index of the state buffer */ |
| uint32_t tapCnt, blkCnt; /* loop counters */ |
| q15_t coeff = *pCoeffs++; /* Read the first coefficient value */ |
| q31_t *pScr2 = pScratchOut; /* Working pointer for pScratchOut */ |
| |
| |
| #ifndef ARM_MATH_CM0 |
| |
| /* Run the below code for Cortex-M4 and Cortex-M3 */ |
| |
| q31_t in1, in2; /* Temporary variables */ |
| |
| |
| /* BlockSize of Input samples are copied into the state buffer */ |
| /* StateIndex points to the starting position to write in the state buffer */ |
| arm_circularWrite_q15(py, delaySize, &S->stateIndex, 1, pIn, 1, blockSize); |
| |
| /* Loop over the number of taps. */ |
| tapCnt = numTaps; |
| |
| /* Read Index, from where the state buffer should be read, is calculated. */ |
| readIndex = (S->stateIndex - blockSize) - *pTapDelay++; |
| |
| /* Wraparound of readIndex */ |
| if(readIndex < 0) |
| { |
| readIndex += (int32_t) delaySize; |
| } |
| |
| /* Working pointer for state buffer is updated */ |
| py = pState; |
| |
| /* blockSize samples are read from the state buffer */ |
| arm_circularRead_q15(py, delaySize, &readIndex, 1, |
| pb, pb, blockSize, 1, blockSize); |
| |
| /* Working pointer for the scratch buffer of state values */ |
| px = pb; |
| |
| /* Working pointer for scratch buffer of output values */ |
| pScratchOut = pScr2; |
| |
| /* Loop over the blockSize. Unroll by a factor of 4. |
| * Compute 4 multiplications at a time. */ |
| blkCnt = blockSize >> 2; |
| |
| while(blkCnt > 0u) |
| { |
| /* Perform multiplication and store in the scratch buffer */ |
| *pScratchOut++ = ((q31_t) * px++ * coeff); |
| *pScratchOut++ = ((q31_t) * px++ * coeff); |
| *pScratchOut++ = ((q31_t) * px++ * coeff); |
| *pScratchOut++ = ((q31_t) * px++ * coeff); |
| |
| /* Decrement the loop counter */ |
| blkCnt--; |
| } |
| |
| /* If the blockSize is not a multiple of 4, |
| * compute the remaining samples */ |
| blkCnt = blockSize % 0x4u; |
| |
| while(blkCnt > 0u) |
| { |
| /* Perform multiplication and store in the scratch buffer */ |
| *pScratchOut++ = ((q31_t) * px++ * coeff); |
| |
| /* Decrement the loop counter */ |
| blkCnt--; |
| } |
| |
| /* Load the coefficient value and |
| * increment the coefficient buffer for the next set of state values */ |
| coeff = *pCoeffs++; |
| |
| /* Read Index, from where the state buffer should be read, is calculated. */ |
| readIndex = (S->stateIndex - blockSize) - *pTapDelay++; |
| |
| /* Wraparound of readIndex */ |
| if(readIndex < 0) |
| { |
| readIndex += (int32_t) delaySize; |
| } |
| |
| /* Loop over the number of taps. */ |
| tapCnt = (uint32_t) numTaps - 1u; |
| |
| while(tapCnt > 0u) |
| { |
| /* Working pointer for state buffer is updated */ |
| py = pState; |
| |
| /* blockSize samples are read from the state buffer */ |
| arm_circularRead_q15(py, delaySize, &readIndex, 1, |
| pb, pb, blockSize, 1, blockSize); |
| |
| /* Working pointer for the scratch buffer of state values */ |
| px = pb; |
| |
| /* Working pointer for scratch buffer of output values */ |
| pScratchOut = pScr2; |
| |
| /* Loop over the blockSize. Unroll by a factor of 4. |
| * Compute 4 MACS at a time. */ |
| blkCnt = blockSize >> 2; |
| |
| while(blkCnt > 0u) |
| { |
| /* Perform Multiply-Accumulate */ |
| *pScratchOut++ += (q31_t) * px++ * coeff; |
| *pScratchOut++ += (q31_t) * px++ * coeff; |
| *pScratchOut++ += (q31_t) * px++ * coeff; |
| *pScratchOut++ += (q31_t) * px++ * coeff; |
| |
| /* Decrement the loop counter */ |
| blkCnt--; |
| } |
| |
| /* If the blockSize is not a multiple of 4, |
| * compute the remaining samples */ |
| blkCnt = blockSize % 0x4u; |
| |
| while(blkCnt > 0u) |
| { |
| /* Perform Multiply-Accumulate */ |
| *pScratchOut++ += (q31_t) * px++ * coeff; |
| |
| /* Decrement the loop counter */ |
| blkCnt--; |
| } |
| |
| /* Load the coefficient value and |
| * increment the coefficient buffer for the next set of state values */ |
| coeff = *pCoeffs++; |
| |
| /* Read Index, from where the state buffer should be read, is calculated. */ |
| readIndex = (S->stateIndex - blockSize) - *pTapDelay++; |
| |
| /* Wraparound of readIndex */ |
| if(readIndex < 0) |
| { |
| readIndex += (int32_t) delaySize; |
| } |
| |
| /* Decrement the tap loop counter */ |
| tapCnt--; |
| } |
| |
| /* All the output values are in pScratchOut buffer. |
| Convert them into 1.15 format, saturate and store in the destination buffer. */ |
| /* Loop over the blockSize. */ |
| blkCnt = blockSize >> 2; |
| |
| while(blkCnt > 0u) |
| { |
| in1 = *pScr2++; |
| in2 = *pScr2++; |
| |
| #ifndef ARM_MATH_BIG_ENDIAN |
| |
| *__SIMD32(pOut)++ = |
| __PKHBT((q15_t) __SSAT(in1 >> 15, 16), (q15_t) __SSAT(in2 >> 15, 16), |
| 16); |
| |
| #else |
| *__SIMD32(pOut)++ = |
| __PKHBT((q15_t) __SSAT(in2 >> 15, 16), (q15_t) __SSAT(in1 >> 15, 16), |
| 16); |
| |
| #endif /* #ifndef ARM_MATH_BIG_ENDIAN */ |
| |
| in1 = *pScr2++; |
| |
| in2 = *pScr2++; |
| |
| #ifndef ARM_MATH_BIG_ENDIAN |
| |
| *__SIMD32(pOut)++ = |
| __PKHBT((q15_t) __SSAT(in1 >> 15, 16), (q15_t) __SSAT(in2 >> 15, 16), |
| 16); |
| |
| #else |
| |
| *__SIMD32(pOut)++ = |
| __PKHBT((q15_t) __SSAT(in2 >> 15, 16), (q15_t) __SSAT(in1 >> 15, 16), |
| 16); |
| |
| #endif /* #ifndef ARM_MATH_BIG_ENDIAN */ |
| |
| |
| blkCnt--; |
| |
| } |
| |
| /* If the blockSize is not a multiple of 4, |
| remaining samples are processed in the below loop */ |
| blkCnt = blockSize % 0x4u; |
| |
| while(blkCnt > 0u) |
| { |
| *pOut++ = (q15_t) __SSAT(*pScr2++ >> 15, 16); |
| blkCnt--; |
| } |
| |
| #else |
| |
| /* Run the below code for Cortex-M0 */ |
| |
| /* BlockSize of Input samples are copied into the state buffer */ |
| /* StateIndex points to the starting position to write in the state buffer */ |
| arm_circularWrite_q15(py, delaySize, &S->stateIndex, 1, pIn, 1, blockSize); |
| |
| /* Loop over the number of taps. */ |
| tapCnt = numTaps; |
| |
| /* Read Index, from where the state buffer should be read, is calculated. */ |
| readIndex = (S->stateIndex - blockSize) - *pTapDelay++; |
| |
| /* Wraparound of readIndex */ |
| if(readIndex < 0) |
| { |
| readIndex += (int32_t) delaySize; |
| } |
| |
| /* Working pointer for state buffer is updated */ |
| py = pState; |
| |
| /* blockSize samples are read from the state buffer */ |
| arm_circularRead_q15(py, delaySize, &readIndex, 1, |
| pb, pb, blockSize, 1, blockSize); |
| |
| /* Working pointer for the scratch buffer of state values */ |
| px = pb; |
| |
| /* Working pointer for scratch buffer of output values */ |
| pScratchOut = pScr2; |
| |
| blkCnt = blockSize; |
| |
| while(blkCnt > 0u) |
| { |
| /* Perform multiplication and store in the scratch buffer */ |
| *pScratchOut++ = ((q31_t) * px++ * coeff); |
| |
| /* Decrement the loop counter */ |
| blkCnt--; |
| } |
| |
| /* Load the coefficient value and |
| * increment the coefficient buffer for the next set of state values */ |
| coeff = *pCoeffs++; |
| |
| /* Read Index, from where the state buffer should be read, is calculated. */ |
| readIndex = (S->stateIndex - blockSize) - *pTapDelay++; |
| |
| /* Wraparound of readIndex */ |
| if(readIndex < 0) |
| { |
| readIndex += (int32_t) delaySize; |
| } |
| |
| /* Loop over the number of taps. */ |
| tapCnt = (uint32_t) numTaps - 1u; |
| |
| while(tapCnt > 0u) |
| { |
| /* Working pointer for state buffer is updated */ |
| py = pState; |
| |
| /* blockSize samples are read from the state buffer */ |
| arm_circularRead_q15(py, delaySize, &readIndex, 1, |
| pb, pb, blockSize, 1, blockSize); |
| |
| /* Working pointer for the scratch buffer of state values */ |
| px = pb; |
| |
| /* Working pointer for scratch buffer of output values */ |
| pScratchOut = pScr2; |
| |
| blkCnt = blockSize; |
| |
| while(blkCnt > 0u) |
| { |
| /* Perform Multiply-Accumulate */ |
| *pScratchOut++ += (q31_t) * px++ * coeff; |
| |
| /* Decrement the loop counter */ |
| blkCnt--; |
| } |
| |
| /* Load the coefficient value and |
| * increment the coefficient buffer for the next set of state values */ |
| coeff = *pCoeffs++; |
| |
| /* Read Index, from where the state buffer should be read, is calculated. */ |
| readIndex = (S->stateIndex - blockSize) - *pTapDelay++; |
| |
| /* Wraparound of readIndex */ |
| if(readIndex < 0) |
| { |
| readIndex += (int32_t) delaySize; |
| } |
| |
| /* Decrement the tap loop counter */ |
| tapCnt--; |
| } |
| |
| /* All the output values are in pScratchOut buffer. |
| Convert them into 1.15 format, saturate and store in the destination buffer. */ |
| /* Loop over the blockSize. */ |
| blkCnt = blockSize; |
| |
| while(blkCnt > 0u) |
| { |
| *pOut++ = (q15_t) __SSAT(*pScr2++ >> 15, 16); |
| blkCnt--; |
| } |
| |
| #endif /* #ifndef ARM_MATH_CM0 */ |
| |
| } |
| |
| /** |
| * @} end of FIR_Sparse group |
| */ |
