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Diffstat (limited to 'tmk_core/tool/mbed/mbed-sdk/libraries/dsp/cmsis_dsp/FilteringFunctions/arm_biquad_cascade_df1_q31.c')
| -rw-r--r-- | tmk_core/tool/mbed/mbed-sdk/libraries/dsp/cmsis_dsp/FilteringFunctions/arm_biquad_cascade_df1_q31.c | 402 |
1 files changed, 402 insertions, 0 deletions
diff --git a/tmk_core/tool/mbed/mbed-sdk/libraries/dsp/cmsis_dsp/FilteringFunctions/arm_biquad_cascade_df1_q31.c b/tmk_core/tool/mbed/mbed-sdk/libraries/dsp/cmsis_dsp/FilteringFunctions/arm_biquad_cascade_df1_q31.c new file mode 100644 index 0000000000..174398b9d2 --- /dev/null +++ b/tmk_core/tool/mbed/mbed-sdk/libraries/dsp/cmsis_dsp/FilteringFunctions/arm_biquad_cascade_df1_q31.c @@ -0,0 +1,402 @@ +/* ---------------------------------------------------------------------- +* Copyright (C) 2010-2013 ARM Limited. All rights reserved. +* +* $Date: 17. January 2013 +* $Revision: V1.4.1 +* +* Project: CMSIS DSP Library +* Title: arm_biquad_cascade_df1_q31.c +* +* Description: Processing function for the +* Q31 Biquad cascade filter +* +* 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 BiquadCascadeDF1 + * @{ + */ + +/** + * @brief Processing function for the Q31 Biquad cascade filter. + * @param[in] *S points to an instance of the Q31 Biquad cascade 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. + * + * <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 2 bits and lie in the range [-0.25 +0.25). + * After all 5 multiply-accumulates are performed, the 2.62 accumulator is shifted by <code>postShift</code> bits and the result truncated to + * 1.31 format by discarding the low 32 bits. + * + * \par + * Refer to the function <code>arm_biquad_cascade_df1_fast_q31()</code> for a faster but less precise implementation of this filter for Cortex-M3 and Cortex-M4. + */ + +void arm_biquad_cascade_df1_q31( + const arm_biquad_casd_df1_inst_q31 * S, + q31_t * pSrc, + q31_t * pDst, + uint32_t blockSize) +{ + q63_t acc; /* accumulator */ + uint32_t uShift = ((uint32_t) S->postShift + 1u); + uint32_t lShift = 32u - uShift; /* Shift to be applied to the output */ + q31_t *pIn = pSrc; /* input pointer initialization */ + q31_t *pOut = pDst; /* output pointer initialization */ + q31_t *pState = S->pState; /* pState pointer initialization */ + q31_t *pCoeffs = S->pCoeffs; /* coeff pointer initialization */ + q31_t Xn1, Xn2, Yn1, Yn2; /* Filter state variables */ + q31_t b0, b1, b2, a1, a2; /* Filter coefficients */ + q31_t Xn; /* temporary input */ + uint32_t sample, stage = S->numStages; /* loop counters */ + + +#ifndef ARM_MATH_CM0_FAMILY + + q31_t acc_l, acc_h; /* temporary output variables */ + + /* Run the below code for Cortex-M4 and Cortex-M3 */ + + do + { + /* Reading the coefficients */ + b0 = *pCoeffs++; + b1 = *pCoeffs++; + b2 = *pCoeffs++; + a1 = *pCoeffs++; + a2 = *pCoeffs++; + + /* Reading the state values */ + Xn1 = pState[0]; + Xn2 = pState[1]; + Yn1 = pState[2]; + Yn2 = pState[3]; + + /* Apply loop unrolling and compute 4 output values simultaneously. */ + /* The variable acc hold output values that are being computed: + * + * acc = b0 * x[n] + b1 * x[n-1] + b2 * x[n-2] + a1 * y[n-1] + a2 * y[n-2] + */ + + sample = blockSize >> 2u; + + /* 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(sample > 0u) + { + /* Read the input */ + Xn = *pIn++; + + /* acc = b0 * x[n] + b1 * x[n-1] + b2 * x[n-2] + a1 * y[n-1] + a2 * y[n-2] */ + + /* acc = b0 * x[n] */ + acc = (q63_t) b0 *Xn; + /* acc += b1 * x[n-1] */ + acc += (q63_t) b1 *Xn1; + /* acc += b[2] * x[n-2] */ + acc += (q63_t) b2 *Xn2; + /* acc += a1 * y[n-1] */ + acc += (q63_t) a1 *Yn1; + /* acc += a2 * y[n-2] */ + acc += (q63_t) a2 *Yn2; + + /* The result is converted to 1.31 , Yn2 variable is reused */ + + /* Calc lower part of acc */ + acc_l = acc & 0xffffffff; + + /* Calc upper part of acc */ + acc_h = (acc >> 32) & 0xffffffff; + + /* Apply shift for lower part of acc and upper part of acc */ + Yn2 = (uint32_t) acc_l >> lShift | acc_h << uShift; + + /* Store the output in the destination buffer. */ + *pOut++ = Yn2; + + /* Read the second input */ + Xn2 = *pIn++; + + /* acc = b0 * x[n] + b1 * x[n-1] + b2 * x[n-2] + a1 * y[n-1] + a2 * y[n-2] */ + + /* acc = b0 * x[n] */ + acc = (q63_t) b0 *Xn2; + /* acc += b1 * x[n-1] */ + acc += (q63_t) b1 *Xn; + /* acc += b[2] * x[n-2] */ + acc += (q63_t) b2 *Xn1; + /* acc += a1 * y[n-1] */ + acc += (q63_t) a1 *Yn2; + /* acc += a2 * y[n-2] */ + acc += (q63_t) a2 *Yn1; + + + /* The result is converted to 1.31, Yn1 variable is reused */ + + /* Calc lower part of acc */ + acc_l = acc & 0xffffffff; + + /* Calc upper part of acc */ + acc_h = (acc >> 32) & 0xffffffff; + + + /* Apply shift for lower part of acc and upper part of acc */ + Yn1 = (uint32_t) acc_l >> lShift | acc_h << uShift; + + /* Store the output in the destination buffer. */ + *pOut++ = Yn1; + + /* Read the third input */ + Xn1 = *pIn++; + + /* acc = b0 * x[n] + b1 * x[n-1] + b2 * x[n-2] + a1 * y[n-1] + a2 * y[n-2] */ + + /* acc = b0 * x[n] */ + acc = (q63_t) b0 *Xn1; + /* acc += b1 * x[n-1] */ + acc += (q63_t) b1 *Xn2; + /* acc += b[2] * x[n-2] */ + acc += (q63_t) b2 *Xn; + /* acc += a1 * y[n-1] */ + acc += (q63_t) a1 *Yn1; + /* acc += a2 * y[n-2] */ + acc += (q63_t) a2 *Yn2; + + /* The result is converted to 1.31, Yn2 variable is reused */ + /* Calc lower part of acc */ + acc_l = acc & 0xffffffff; + + /* Calc upper part of acc */ + acc_h = (acc >> 32) & 0xffffffff; + + + /* Apply shift for lower part of acc and upper part of acc */ + Yn2 = (uint32_t) acc_l >> lShift | acc_h << uShift; + + /* Store the output in the destination buffer. */ + *pOut++ = Yn2; + + /* Read the forth input */ + Xn = *pIn++; + + /* acc = b0 * x[n] + b1 * x[n-1] + b2 * x[n-2] + a1 * y[n-1] + a2 * y[n-2] */ + + /* acc = b0 * x[n] */ + acc = (q63_t) b0 *Xn; + /* acc += b1 * x[n-1] */ + acc += (q63_t) b1 *Xn1; + /* acc += b[2] * x[n-2] */ + acc += (q63_t) b2 *Xn2; + /* acc += a1 * y[n-1] */ + acc += (q63_t) a1 *Yn2; + /* acc += a2 * y[n-2] */ + acc += (q63_t) a2 *Yn1; + + /* The result is converted to 1.31, Yn1 variable is reused */ + /* Calc lower part of acc */ + acc_l = acc & 0xffffffff; + + /* Calc upper part of acc */ + acc_h = (acc >> 32) & 0xffffffff; + + /* Apply shift for lower part of acc and upper part of acc */ + Yn1 = (uint32_t) acc_l >> lShift | acc_h << uShift; + + /* Every time after the output is computed state should be updated. */ + /* The states should be updated as: */ + /* Xn2 = Xn1 */ + /* Xn1 = Xn */ + /* Yn2 = Yn1 */ + /* Yn1 = acc */ + Xn2 = Xn1; + Xn1 = Xn; + + /* Store the output in the destination buffer. */ + *pOut++ = Yn1; + + /* decrement the loop counter */ + sample--; + } + + /* If the blockSize is not a multiple of 4, compute any remaining output samples here. + ** No loop unrolling is used. */ + sample = (blockSize & 0x3u); + + while(sample > 0u) + { + /* Read the input */ + Xn = *pIn++; + + /* acc = b0 * x[n] + b1 * x[n-1] + b2 * x[n-2] + a1 * y[n-1] + a2 * y[n-2] */ + + /* acc = b0 * x[n] */ + acc = (q63_t) b0 *Xn; + /* acc += b1 * x[n-1] */ + acc += (q63_t) b1 *Xn1; + /* acc += b[2] * x[n-2] */ + acc += (q63_t) b2 *Xn2; + /* acc += a1 * y[n-1] */ + acc += (q63_t) a1 *Yn1; + /* acc += a2 * y[n-2] */ + acc += (q63_t) a2 *Yn2; + + /* The result is converted to 1.31 */ + acc = acc >> lShift; + + /* Every time after the output is computed state should be updated. */ + /* The states should be updated as: */ + /* Xn2 = Xn1 */ + /* Xn1 = Xn */ + /* Yn2 = Yn1 */ + /* Yn1 = acc */ + Xn2 = Xn1; + Xn1 = Xn; + Yn2 = Yn1; + Yn1 = (q31_t) acc; + + /* Store the output in the destination buffer. */ + *pOut++ = (q31_t) acc; + + /* decrement the loop counter */ + sample--; + } + + /* The first stage goes from the input buffer to the output buffer. */ + /* Subsequent stages occur in-place in the output buffer */ + pIn = pDst; + + /* Reset to destination pointer */ + pOut = pDst; + + /* Store the updated state variables back into the pState array */ + *pState++ = Xn1; + *pState++ = Xn2; + *pState++ = Yn1; + *pState++ = Yn2; + + } while(--stage); + +#else + + /* Run the below code for Cortex-M0 */ + + do + { + /* Reading the coefficients */ + b0 = *pCoeffs++; + b1 = *pCoeffs++; + b2 = *pCoeffs++; + a1 = *pCoeffs++; + a2 = *pCoeffs++; + + /* Reading the state values */ + Xn1 = pState[0]; + Xn2 = pState[1]; + Yn1 = pState[2]; + Yn2 = pState[3]; + + /* The variables acc holds the output value that is computed: + * acc = b0 * x[n] + b1 * x[n-1] + b2 * x[n-2] + a1 * y[n-1] + a2 * y[n-2] + */ + + sample = blockSize; + + while(sample > 0u) + { + /* Read the input */ + Xn = *pIn++; + + /* acc = b0 * x[n] + b1 * x[n-1] + b2 * x[n-2] + a1 * y[n-1] + a2 * y[n-2] */ + /* acc = b0 * x[n] */ + acc = (q63_t) b0 *Xn; + + /* acc += b1 * x[n-1] */ + acc += (q63_t) b1 *Xn1; + /* acc += b[2] * x[n-2] */ + acc += (q63_t) b2 *Xn2; + /* acc += a1 * y[n-1] */ + acc += (q63_t) a1 *Yn1; + /* acc += a2 * y[n-2] */ + acc += (q63_t) a2 *Yn2; + + /* The result is converted to 1.31 */ + acc = acc >> lShift; + + /* Every time after the output is computed state should be updated. */ + /* The states should be updated as: */ + /* Xn2 = Xn1 */ + /* Xn1 = Xn */ + /* Yn2 = Yn1 */ + /* Yn1 = acc */ + Xn2 = Xn1; + Xn1 = Xn; + Yn2 = Yn1; + Yn1 = (q31_t) acc; + + /* Store the output in the destination buffer. */ + *pOut++ = (q31_t) acc; + + /* decrement the loop counter */ + sample--; + } + + /* The first stage goes from the input buffer to the output buffer. */ + /* Subsequent stages occur in-place in the output buffer */ + pIn = pDst; + + /* Reset to destination pointer */ + pOut = pDst; + + /* Store the updated state variables back into the pState array */ + *pState++ = Xn1; + *pState++ = Xn2; + *pState++ = Yn1; + *pState++ = Yn2; + + } while(--stage); + +#endif /* #ifndef ARM_MATH_CM0_FAMILY */ +} + +/** + * @} end of BiquadCascadeDF1 group + */ |