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Diffstat (limited to 'tmk_core/tool/mbed/mbed-sdk/libraries/dsp/cmsis_dsp/FilteringFunctions/arm_biquad_cascade_df1_init_q31.c')
| -rw-r--r-- | tmk_core/tool/mbed/mbed-sdk/libraries/dsp/cmsis_dsp/FilteringFunctions/arm_biquad_cascade_df1_init_q31.c | 111 |
1 files changed, 111 insertions, 0 deletions
diff --git a/tmk_core/tool/mbed/mbed-sdk/libraries/dsp/cmsis_dsp/FilteringFunctions/arm_biquad_cascade_df1_init_q31.c b/tmk_core/tool/mbed/mbed-sdk/libraries/dsp/cmsis_dsp/FilteringFunctions/arm_biquad_cascade_df1_init_q31.c new file mode 100644 index 0000000000..89b2477fc5 --- /dev/null +++ b/tmk_core/tool/mbed/mbed-sdk/libraries/dsp/cmsis_dsp/FilteringFunctions/arm_biquad_cascade_df1_init_q31.c @@ -0,0 +1,111 @@ +/* ---------------------------------------------------------------------- +* 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_init_q31.c +* +* Description: Q31 Biquad cascade DirectFormI(DF1) filter initialization 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 BiquadCascadeDF1 + * @{ + */ + +/** + * @details + * + * @param[in,out] *S points to an instance of the Q31 Biquad cascade structure. + * @param[in] numStages number of 2nd order stages in the filter. + * @param[in] *pCoeffs points to the filter coefficients buffer. + * @param[in] *pState points to the state buffer. + * @param[in] postShift Shift to be applied after the accumulator. Varies according to the coefficients format + * @return none + * + * <b>Coefficient and State Ordering:</b> + * + * \par + * The coefficients are stored in the array <code>pCoeffs</code> in the following order: + * <pre> + * {b10, b11, b12, a11, a12, b20, b21, b22, a21, a22, ...} + * </pre> + * where <code>b1x</code> and <code>a1x</code> are the coefficients for the first stage, + * <code>b2x</code> and <code>a2x</code> are the coefficients for the second stage, + * and so on. The <code>pCoeffs</code> array contains a total of <code>5*numStages</code> values. + * + * \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> + * 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. + */ + +void arm_biquad_cascade_df1_init_q31( + arm_biquad_casd_df1_inst_q31 * S, + uint8_t numStages, + q31_t * pCoeffs, + q31_t * pState, + int8_t postShift) +{ + /* Assign filter stages */ + S->numStages = numStages; + + /* Assign postShift to be applied to the output */ + S->postShift = postShift; + + /* Assign coefficient pointer */ + S->pCoeffs = pCoeffs; + + /* Clear state buffer and size is always 4 * numStages */ + memset(pState, 0, (4u * (uint32_t) numStages) * sizeof(q31_t)); + + /* Assign state pointer */ + S->pState = pState; +} + +/** + * @} end of BiquadCascadeDF1 group + */ |