diff options
Diffstat (limited to 'DSP_Lib/Source/FilteringFunctions/arm_fir_q31.c')
-rw-r--r-- | DSP_Lib/Source/FilteringFunctions/arm_fir_q31.c | 365 |
1 files changed, 0 insertions, 365 deletions
diff --git a/DSP_Lib/Source/FilteringFunctions/arm_fir_q31.c b/DSP_Lib/Source/FilteringFunctions/arm_fir_q31.c deleted file mode 100644 index 3536059..0000000 --- a/DSP_Lib/Source/FilteringFunctions/arm_fir_q31.c +++ /dev/null @@ -1,365 +0,0 @@ -/* ---------------------------------------------------------------------- -* Copyright (C) 2010-2014 ARM Limited. All rights reserved. -* -* $Date: 19. March 2015 -* $Revision: V.1.4.5 -* -* Project: CMSIS DSP Library -* Title: arm_fir_q31.c -* -* Description: Q31 FIR filter processing function. -* -* Target Processor: Cortex-M4/Cortex-M3/Cortex-M0 -* -* Redistribution and use in source and binary forms, with or without -* modification, are permitted provided that the following conditions -* are met: -* - Redistributions of source code must retain the above copyright -* notice, this list of conditions and the following disclaimer. -* - Redistributions in binary form must reproduce the above copyright -* notice, this list of conditions and the following disclaimer in -* the documentation and/or other materials provided with the -* distribution. -* - Neither the name of ARM LIMITED nor the names of its contributors -* may be used to endorse or promote products derived from this -* software without specific prior written permission. -* -* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS -* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT -* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS -* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE -* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, -* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, -* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; -* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER -* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT -* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN -* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE -* POSSIBILITY OF SUCH DAMAGE. -* -------------------------------------------------------------------- */ - -#include "arm_math.h" - -/** - * @ingroup groupFilters - */ - -/** - * @addtogroup FIR - * @{ - */ - -/** - * @param[in] *S points to an instance of the Q31 FIR filter 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 samples to process per call. - * @return none. - * - * @details - * <b>Scaling and Overflow Behavior:</b> - * \par - * The function is implemented using an internal 64-bit accumulator. - * The accumulator has a 2.62 format and maintains full precision of the intermediate multiplication results but provides only a single guard bit. - * Thus, if the accumulator result overflows it wraps around rather than clip. - * In order to avoid overflows completely the input signal must be scaled down by log2(numTaps) bits. - * After all multiply-accumulates are performed, the 2.62 accumulator is right shifted by 31 bits and saturated to 1.31 format to yield the final result. - * - * \par - * Refer to the function <code>arm_fir_fast_q31()</code> for a faster but less precise implementation of this filter for Cortex-M3 and Cortex-M4. - */ - -void arm_fir_q31( - const arm_fir_instance_q31 * S, - q31_t * pSrc, - q31_t * pDst, - uint32_t blockSize) -{ - q31_t *pState = S->pState; /* State pointer */ - q31_t *pCoeffs = S->pCoeffs; /* Coefficient pointer */ - q31_t *pStateCurnt; /* Points to the current sample of the state */ - - -#ifndef ARM_MATH_CM0_FAMILY - - /* Run the below code for Cortex-M4 and Cortex-M3 */ - - q31_t x0, x1, x2; /* Temporary variables to hold state */ - q31_t c0; /* Temporary variable to hold coefficient value */ - q31_t *px; /* Temporary pointer for state */ - q31_t *pb; /* Temporary pointer for coefficient buffer */ - q63_t acc0, acc1, acc2; /* Accumulators */ - uint32_t numTaps = S->numTaps; /* Number of filter coefficients in the filter */ - uint32_t i, tapCnt, blkCnt, tapCntN3; /* Loop counters */ - - /* S->pState points to state array which contains previous frame (numTaps - 1) samples */ - /* pStateCurnt points to the location where the new input data should be written */ - pStateCurnt = &(S->pState[(numTaps - 1u)]); - - /* Apply loop unrolling and compute 4 output values simultaneously. - * The variables acc0 ... acc3 hold output values that are being computed: - * - * acc0 = b[numTaps-1] * x[n-numTaps-1] + b[numTaps-2] * x[n-numTaps-2] + b[numTaps-3] * x[n-numTaps-3] +...+ b[0] * x[0] - * acc1 = b[numTaps-1] * x[n-numTaps] + b[numTaps-2] * x[n-numTaps-1] + b[numTaps-3] * x[n-numTaps-2] +...+ b[0] * x[1] - * acc2 = b[numTaps-1] * x[n-numTaps+1] + b[numTaps-2] * x[n-numTaps] + b[numTaps-3] * x[n-numTaps-1] +...+ b[0] * x[2] - * acc3 = b[numTaps-1] * x[n-numTaps+2] + b[numTaps-2] * x[n-numTaps+1] + b[numTaps-3] * x[n-numTaps] +...+ b[0] * x[3] - */ - blkCnt = blockSize / 3; - blockSize = blockSize - (3 * blkCnt); - - tapCnt = numTaps / 3; - tapCntN3 = numTaps - (3 * tapCnt); - - /* First part of the processing with loop unrolling. Compute 4 outputs at a time. - ** a second loop below computes the remaining 1 to 3 samples. */ - while(blkCnt > 0u) - { - /* Copy three new input samples into the state buffer */ - *pStateCurnt++ = *pSrc++; - *pStateCurnt++ = *pSrc++; - *pStateCurnt++ = *pSrc++; - - /* Set all accumulators to zero */ - acc0 = 0; - acc1 = 0; - acc2 = 0; - - /* Initialize state pointer */ - px = pState; - - /* Initialize coefficient pointer */ - pb = pCoeffs; - - /* Read the first two samples from the state buffer: - * x[n-numTaps], x[n-numTaps-1] */ - x0 = *(px++); - x1 = *(px++); - - /* Loop unrolling. Process 3 taps at a time. */ - i = tapCnt; - - while(i > 0u) - { - /* Read the b[numTaps] coefficient */ - c0 = *pb; - - /* Read x[n-numTaps-2] sample */ - x2 = *(px++); - - /* Perform the multiply-accumulates */ - acc0 += ((q63_t) x0 * c0); - acc1 += ((q63_t) x1 * c0); - acc2 += ((q63_t) x2 * c0); - - /* Read the coefficient and state */ - c0 = *(pb + 1u); - x0 = *(px++); - - /* Perform the multiply-accumulates */ - acc0 += ((q63_t) x1 * c0); - acc1 += ((q63_t) x2 * c0); - acc2 += ((q63_t) x0 * c0); - - /* Read the coefficient and state */ - c0 = *(pb + 2u); - x1 = *(px++); - - /* update coefficient pointer */ - pb += 3u; - - /* Perform the multiply-accumulates */ - acc0 += ((q63_t) x2 * c0); - acc1 += ((q63_t) x0 * c0); - acc2 += ((q63_t) x1 * c0); - - /* Decrement the loop counter */ - i--; - } - - /* If the filter length is not a multiple of 3, compute the remaining filter taps */ - - i = tapCntN3; - - while(i > 0u) - { - /* Read coefficients */ - c0 = *(pb++); - - /* Fetch 1 state variable */ - x2 = *(px++); - - /* Perform the multiply-accumulates */ - acc0 += ((q63_t) x0 * c0); - acc1 += ((q63_t) x1 * c0); - acc2 += ((q63_t) x2 * c0); - - /* Reuse the present sample states for next sample */ - x0 = x1; - x1 = x2; - - /* Decrement the loop counter */ - i--; - } - - /* Advance the state pointer by 3 to process the next group of 3 samples */ - pState = pState + 3; - - /* The results in the 3 accumulators are in 2.30 format. Convert to 1.31 - ** Then store the 3 outputs in the destination buffer. */ - *pDst++ = (q31_t) (acc0 >> 31u); - *pDst++ = (q31_t) (acc1 >> 31u); - *pDst++ = (q31_t) (acc2 >> 31u); - - /* Decrement the samples loop counter */ - blkCnt--; - } - - /* If the blockSize is not a multiple of 3, compute any remaining output samples here. - ** No loop unrolling is used. */ - - while(blockSize > 0u) - { - /* Copy one sample at a time into state buffer */ - *pStateCurnt++ = *pSrc++; - - /* Set the accumulator to zero */ - acc0 = 0; - - /* Initialize state pointer */ - px = pState; - - /* Initialize Coefficient pointer */ - pb = (pCoeffs); - - i = numTaps; - - /* Perform the multiply-accumulates */ - do - { - acc0 += (q63_t) * (px++) * (*(pb++)); - i--; - } while(i > 0u); - - /* The result is in 2.62 format. Convert to 1.31 - ** Then store the output in the destination buffer. */ - *pDst++ = (q31_t) (acc0 >> 31u); - - /* Advance state pointer by 1 for the next sample */ - pState = pState + 1; - - /* Decrement the samples loop counter */ - blockSize--; - } - - /* Processing is complete. - ** Now copy the last numTaps - 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; - - tapCnt = (numTaps - 1u) >> 2u; - - /* copy data */ - while(tapCnt > 0u) - { - *pStateCurnt++ = *pState++; - *pStateCurnt++ = *pState++; - *pStateCurnt++ = *pState++; - *pStateCurnt++ = *pState++; - - /* Decrement the loop counter */ - tapCnt--; - } - - /* Calculate remaining number of copies */ - tapCnt = (numTaps - 1u) % 0x4u; - - /* Copy the remaining q31_t data */ - while(tapCnt > 0u) - { - *pStateCurnt++ = *pState++; - - /* Decrement the loop counter */ - tapCnt--; - } - -#else - -/* Run the below code for Cortex-M0 */ - - q31_t *px; /* Temporary pointer for state */ - q31_t *pb; /* Temporary pointer for coefficient buffer */ - q63_t acc; /* Accumulator */ - uint32_t numTaps = S->numTaps; /* Length of the filter */ - uint32_t i, tapCnt, blkCnt; /* Loop counters */ - - /* S->pState buffer contains previous frame (numTaps - 1) samples */ - /* pStateCurnt points to the location where the new input data should be written */ - pStateCurnt = &(S->pState[(numTaps - 1u)]); - - /* Initialize blkCnt with blockSize */ - blkCnt = blockSize; - - while(blkCnt > 0u) - { - /* Copy one sample at a time into state buffer */ - *pStateCurnt++ = *pSrc++; - - /* Set the accumulator to zero */ - acc = 0; - - /* Initialize state pointer */ - px = pState; - - /* Initialize Coefficient pointer */ - pb = pCoeffs; - - i = numTaps; - - /* Perform the multiply-accumulates */ - do - { - /* acc = b[numTaps-1] * x[n-numTaps-1] + b[numTaps-2] * x[n-numTaps-2] + b[numTaps-3] * x[n-numTaps-3] +...+ b[0] * x[0] */ - acc += (q63_t) * px++ * *pb++; - i--; - } while(i > 0u); - - /* The result is in 2.62 format. Convert to 1.31 - ** Then store the output in the destination buffer. */ - *pDst++ = (q31_t) (acc >> 31u); - - /* Advance state pointer by 1 for the next sample */ - pState = pState + 1; - - /* Decrement the samples loop counter */ - blkCnt--; - } - - /* Processing is complete. - ** Now copy the last numTaps - 1 samples to the starting 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; - - /* Copy numTaps number of values */ - tapCnt = numTaps - 1u; - - /* Copy the data */ - while(tapCnt > 0u) - { - *pStateCurnt++ = *pState++; - - /* Decrement the loop counter */ - tapCnt--; - } - - -#endif /* #ifndef ARM_MATH_CM0_FAMILY */ - -} - -/** - * @} end of FIR group - */ |