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arm_iir_lattice_init_q31.c 3.3KB

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  1. /*-----------------------------------------------------------------------------
  2. * Copyright (C) 2010-2013 ARM Limited. All rights reserved.
  3. *
  4. * $Date: 17. January 2013
  5. * $Revision: V1.4.1
  6. *
  7. * Project: CMSIS DSP Library
  8. * Title: arm_iir_lattice_init_q31.c
  9. *
  10. * Description: Initialization function for the Q31 IIR lattice filter.
  11. *
  12. * Target Processor: Cortex-M4/Cortex-M3/Cortex-M0
  13. *
  14. * Redistribution and use in source and binary forms, with or without
  15. * modification, are permitted provided that the following conditions
  16. * are met:
  17. * - Redistributions of source code must retain the above copyright
  18. * notice, this list of conditions and the following disclaimer.
  19. * - Redistributions in binary form must reproduce the above copyright
  20. * notice, this list of conditions and the following disclaimer in
  21. * the documentation and/or other materials provided with the
  22. * distribution.
  23. * - Neither the name of ARM LIMITED nor the names of its contributors
  24. * may be used to endorse or promote products derived from this
  25. * software without specific prior written permission.
  26. *
  27. * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  28. * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  29. * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
  30. * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
  31. * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
  32. * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
  33. * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
  34. * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
  35. * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  36. * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
  37. * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  38. * POSSIBILITY OF SUCH DAMAGE.
  39. * ---------------------------------------------------------------------------*/
  40. #include "arm_math.h"
  41. /**
  42. * @ingroup groupFilters
  43. */
  44. /**
  45. * @addtogroup IIR_Lattice
  46. * @{
  47. */
  48. /**
  49. * @brief Initialization function for the Q31 IIR lattice filter.
  50. * @param[in] *S points to an instance of the Q31 IIR lattice structure.
  51. * @param[in] numStages number of stages in the filter.
  52. * @param[in] *pkCoeffs points to the reflection coefficient buffer. The array is of length numStages.
  53. * @param[in] *pvCoeffs points to the ladder coefficient buffer. The array is of length numStages+1.
  54. * @param[in] *pState points to the state buffer. The array is of length numStages+blockSize.
  55. * @param[in] blockSize number of samples to process.
  56. * @return none.
  57. */
  58. void arm_iir_lattice_init_q31(
  59. arm_iir_lattice_instance_q31 * S,
  60. uint16_t numStages,
  61. q31_t * pkCoeffs,
  62. q31_t * pvCoeffs,
  63. q31_t * pState,
  64. uint32_t blockSize)
  65. {
  66. /* Assign filter taps */
  67. S->numStages = numStages;
  68. /* Assign reflection coefficient pointer */
  69. S->pkCoeffs = pkCoeffs;
  70. /* Assign ladder coefficient pointer */
  71. S->pvCoeffs = pvCoeffs;
  72. /* Clear state buffer and size is always blockSize + numStages */
  73. memset(pState, 0, (numStages + blockSize) * sizeof(q31_t));
  74. /* Assign state pointer */
  75. S->pState = pState;
  76. }
  77. /**
  78. * @} end of IIR_Lattice group
  79. */