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Diffstat (limited to 'tmk_core/tool/mbed/mbed-sdk/libraries/dsp/cmsis_dsp/FilteringFunctions/arm_biquad_cascade_df1_f32.c')
-rw-r--r-- | tmk_core/tool/mbed/mbed-sdk/libraries/dsp/cmsis_dsp/FilteringFunctions/arm_biquad_cascade_df1_f32.c | 425 |
1 files changed, 0 insertions, 425 deletions
diff --git a/tmk_core/tool/mbed/mbed-sdk/libraries/dsp/cmsis_dsp/FilteringFunctions/arm_biquad_cascade_df1_f32.c b/tmk_core/tool/mbed/mbed-sdk/libraries/dsp/cmsis_dsp/FilteringFunctions/arm_biquad_cascade_df1_f32.c deleted file mode 100644 index f3002bb3e2..0000000000 --- a/tmk_core/tool/mbed/mbed-sdk/libraries/dsp/cmsis_dsp/FilteringFunctions/arm_biquad_cascade_df1_f32.c +++ /dev/null @@ -1,425 +0,0 @@ -/* ---------------------------------------------------------------------- -* 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_f32.c -* -* Description: Processing function for the -* floating-point Biquad cascade DirectFormI(DF1) 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 - */ - -/** - * @defgroup BiquadCascadeDF1 Biquad Cascade IIR Filters Using Direct Form I Structure - * - * This set of functions implements arbitrary order recursive (IIR) filters. - * The filters are implemented as a cascade of second order Biquad sections. - * The functions support Q15, Q31 and floating-point data types. - * Fast version of Q15 and Q31 also supported on CortexM4 and Cortex-M3. - * - * The functions operate on blocks of input and output data and each call to the function - * processes <code>blockSize</code> samples through the filter. - * <code>pSrc</code> points to the array of input data and - * <code>pDst</code> points to the array of output data. - * Both arrays contain <code>blockSize</code> values. - * - * \par Algorithm - * Each Biquad stage implements a second order filter using the difference equation: - * <pre> - * y[n] = b0 * x[n] + b1 * x[n-1] + b2 * x[n-2] + a1 * y[n-1] + a2 * y[n-2] - * </pre> - * A Direct Form I algorithm is used with 5 coefficients and 4 state variables per stage. - * \image html Biquad.gif "Single Biquad filter stage" - * Coefficients <code>b0, b1 and b2 </code> multiply the input signal <code>x[n]</code> and are referred to as the feedforward coefficients. - * Coefficients <code>a1</code> and <code>a2</code> multiply the output signal <code>y[n]</code> and are referred to as the feedback coefficients. - * Pay careful attention to the sign of the feedback coefficients. - * Some design tools use the difference equation - * <pre> - * y[n] = b0 * x[n] + b1 * x[n-1] + b2 * x[n-2] - a1 * y[n-1] - a2 * y[n-2] - * </pre> - * In this case the feedback coefficients <code>a1</code> and <code>a2</code> must be negated when used with the CMSIS DSP Library. - * - * \par - * Higher order filters are realized as a cascade of second order sections. - * <code>numStages</code> refers to the number of second order stages used. - * For example, an 8th order filter would be realized with <code>numStages=4</code> second order stages. - * \image html BiquadCascade.gif "8th order filter using a cascade of Biquad stages" - * A 9th order filter would be realized with <code>numStages=5</code> second order stages with the coefficients for one of the stages configured as a first order filter (<code>b2=0</code> and <code>a2=0</code>). - * - * \par - * The <code>pState</code> points to state variables array. - * Each Biquad stage has 4 state variables <code>x[n-1], x[n-2], y[n-1],</code> and <code>y[n-2]</code>. - * The state variables are arranged in the <code>pState</code> array as: - * <pre> - * {x[n-1], x[n-2], y[n-1], y[n-2]} - * </pre> - * - * \par - * The 4 state variables for stage 1 are first, then the 4 state variables for stage 2, and so on. - * The state array has a total length of <code>4*numStages</code> values. - * The state variables are updated after each block of data is processed, the coefficients are untouched. - * - * \par Instance Structure - * The coefficients and state variables for a filter are stored together in an instance data structure. - * A separate instance structure must be defined for each filter. - * Coefficient arrays may be shared among several instances while state variable arrays cannot be shared. - * There are separate instance structure declarations for each of the 3 supported data types. - * - * \par Init Functions - * There is also an associated initialization function for each data type. - * The initialization function performs following operations: - * - Sets the values of the internal structure fields. - * - Zeros out the values in the state buffer. - * To do this manually without calling the init function, assign the follow subfields of the instance structure: - * numStages, pCoeffs, pState. Also set all of the values in pState to zero. - * - * \par - * Use of the initialization function is optional. - * However, if the initialization function is used, then the instance structure cannot be placed into a const data section. - * To place an instance structure into a const data section, the instance structure must be manually initialized. - * Set the values in the state buffer to zeros before static initialization. - * The code below statically initializes each of the 3 different data type filter instance structures - * <pre> - * arm_biquad_casd_df1_inst_f32 S1 = {numStages, pState, pCoeffs}; - * arm_biquad_casd_df1_inst_q15 S2 = {numStages, pState, pCoeffs, postShift}; - * arm_biquad_casd_df1_inst_q31 S3 = {numStages, pState, pCoeffs, postShift}; - * </pre> - * where <code>numStages</code> is the number of Biquad stages in the filter; <code>pState</code> is the address of the state buffer; - * <code>pCoeffs</code> is the address of the coefficient buffer; <code>postShift</code> shift to be applied. - * - * \par Fixed-Point Behavior - * Care must be taken when using the Q15 and Q31 versions of the Biquad Cascade filter functions. - * Following issues must be considered: - * - Scaling of coefficients - * - Filter gain - * - Overflow and saturation - * - * \par - * <b>Scaling of coefficients: </b> - * Filter coefficients are represented as fractional values and - * coefficients are restricted to lie in the range <code>[-1 +1)</code>. - * The fixed-point functions have an additional scaling parameter <code>postShift</code> - * which allow the filter coefficients to exceed the range <code>[+1 -1)</code>. - * At the output of the filter's accumulator is a shift register which shifts the result by <code>postShift</code> bits. - * \image html BiquadPostshift.gif "Fixed-point Biquad with shift by postShift bits after accumulator" - * This essentially scales the filter coefficients by <code>2^postShift</code>. - * For example, to realize the coefficients - * <pre> - * {1.5, -0.8, 1.2, 1.6, -0.9} - * </pre> - * set the pCoeffs array to: - * <pre> - * {0.75, -0.4, 0.6, 0.8, -0.45} - * </pre> - * and set <code>postShift=1</code> - * - * \par - * <b>Filter gain: </b> - * The frequency response of a Biquad filter is a function of its coefficients. - * It is possible for the gain through the filter to exceed 1.0 meaning that the filter increases the amplitude of certain frequencies. - * This means that an input signal with amplitude < 1.0 may result in an output > 1.0 and these are saturated or overflowed based on the implementation of the filter. - * To avoid this behavior the filter needs to be scaled down such that its peak gain < 1.0 or the input signal must be scaled down so that the combination of input and filter are never overflowed. - * - * \par - * <b>Overflow and saturation: </b> - * For Q15 and Q31 versions, it is described separately as part of the function specific documentation below. - */ - -/** - * @addtogroup BiquadCascadeDF1 - * @{ - */ - -/** - * @param[in] *S points to an instance of the floating-point 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. - * - */ - -void arm_biquad_cascade_df1_f32( - const arm_biquad_casd_df1_inst_f32 * S, - float32_t * pSrc, - float32_t * pDst, - uint32_t blockSize) -{ - float32_t *pIn = pSrc; /* source pointer */ - float32_t *pOut = pDst; /* destination pointer */ - float32_t *pState = S->pState; /* pState pointer */ - float32_t *pCoeffs = S->pCoeffs; /* coefficient pointer */ - float32_t acc; /* Simulates the accumulator */ - float32_t b0, b1, b2, a1, a2; /* Filter coefficients */ - float32_t Xn1, Xn2, Yn1, Yn2; /* Filter pState variables */ - float32_t Xn; /* temporary input */ - uint32_t sample, stage = S->numStages; /* loop counters */ - - -#ifndef ARM_MATH_CM0_FAMILY - - /* 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 pState 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] - * acc = b0 * x[n] + b1 * x[n-1] + b2 * x[n-2] + a1 * y[n-1] + a2 * y[n-2] - * acc = b0 * x[n] + b1 * x[n-1] + b2 * x[n-2] + a1 * y[n-1] + a2 * y[n-2] - * 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 first input */ - Xn = *pIn++; - - /* acc = b0 * x[n] + b1 * x[n-1] + b2 * x[n-2] + a1 * y[n-1] + a2 * y[n-2] */ - Yn2 = (b0 * Xn) + (b1 * Xn1) + (b2 * Xn2) + (a1 * Yn1) + (a2 * Yn2); - - /* Store the result in the accumulator in the destination buffer. */ - *pOut++ = Yn2; - - /* 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 */ - - /* 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] */ - Yn1 = (b0 * Xn2) + (b1 * Xn) + (b2 * Xn1) + (a1 * Yn2) + (a2 * Yn1); - - /* Store the result in the accumulator in the destination buffer. */ - *pOut++ = Yn1; - - /* 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 */ - - /* 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] */ - Yn2 = (b0 * Xn1) + (b1 * Xn2) + (b2 * Xn) + (a1 * Yn1) + (a2 * Yn2); - - /* Store the result in the accumulator in the destination buffer. */ - *pOut++ = Yn2; - - /* 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 */ - - /* 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] */ - Yn1 = (b0 * Xn) + (b1 * Xn1) + (b2 * Xn2) + (a1 * Yn2) + (a2 * Yn1); - - /* Store the result in the accumulator in the destination buffer. */ - *pOut++ = Yn1; - - /* 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; - - /* 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 * Xn) + (b1 * Xn1) + (b2 * Xn2) + (a1 * Yn1) + (a2 * Yn2); - - /* Store the result in the accumulator in the destination buffer. */ - *pOut++ = acc; - - /* 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 = acc; - - /* decrement the loop counter */ - sample--; - - } - - /* Store the updated state variables back into the pState array */ - *pState++ = Xn1; - *pState++ = Xn2; - *pState++ = Yn1; - *pState++ = Yn2; - - /* The first stage goes from the input buffer to the output buffer. */ - /* Subsequent numStages occur in-place in the output buffer */ - pIn = pDst; - - /* Reset the output pointer */ - pOut = pDst; - - /* decrement the loop counter */ - stage--; - - } while(stage > 0u); - -#else - - /* Run the below code for Cortex-M0 */ - - do - { - /* Reading the coefficients */ - b0 = *pCoeffs++; - b1 = *pCoeffs++; - b2 = *pCoeffs++; - a1 = *pCoeffs++; - a2 = *pCoeffs++; - - /* Reading the pState 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 * Xn) + (b1 * Xn1) + (b2 * Xn2) + (a1 * Yn1) + (a2 * Yn2); - - /* Store the result in the accumulator in the destination buffer. */ - *pOut++ = acc; - - /* 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 = acc; - - /* decrement the loop counter */ - sample--; - } - - /* Store the updated state variables back into the pState array */ - *pState++ = Xn1; - *pState++ = Xn2; - *pState++ = Yn1; - *pState++ = Yn2; - - /* The first stage goes from the input buffer to the output buffer. */ - /* Subsequent numStages occur in-place in the output buffer */ - pIn = pDst; - - /* Reset the output pointer */ - pOut = pDst; - - /* decrement the loop counter */ - stage--; - - } while(stage > 0u); - -#endif /* #ifndef ARM_MATH_CM0_FAMILY */ - -} - - - /** - * @} end of BiquadCascadeDF1 group - */ |