00001 /* ---------------------------------------------------------------------- 00002 * Copyright (C) 2010 ARM Limited. All rights reserved. 00003 * 00004 * $Date: 15. July 2011 00005 * $Revision: V1.0.10 00006 * 00007 * Project: CMSIS DSP Library 00008 * Title: arm_fir_decimate_init_q31.c 00009 * 00010 * Description: Initialization function for Q31 FIR Decimation filter. 00011 * 00012 * Target Processor: Cortex-M4/Cortex-M3/Cortex-M0 00013 * 00014 * Version 1.0.10 2011/7/15 00015 * Big Endian support added and Merged M0 and M3/M4 Source code. 00016 * 00017 * Version 1.0.3 2010/11/29 00018 * Re-organized the CMSIS folders and updated documentation. 00019 * 00020 * Version 1.0.2 2010/11/11 00021 * Documentation updated. 00022 * 00023 * Version 1.0.1 2010/10/05 00024 * Production release and review comments incorporated. 00025 * 00026 * Version 1.0.0 2010/09/20 00027 * Production release and review comments incorporated 00028 * 00029 * Version 0.0.7 2010/06/10 00030 * Misra-C changes done 00031 * ------------------------------------------------------------------- */ 00032 00033 #include "arm_math.h" 00034 00067 arm_status arm_fir_decimate_init_q31( 00068 arm_fir_decimate_instance_q31 * S, 00069 uint16_t numTaps, 00070 uint8_t M, 00071 q31_t * pCoeffs, 00072 q31_t * pState, 00073 uint32_t blockSize) 00074 { 00075 arm_status status; 00076 00077 /* The size of the input block must be a multiple of the decimation factor */ 00078 if((blockSize % M) != 0u) 00079 { 00080 /* Set status as ARM_MATH_LENGTH_ERROR */ 00081 status = ARM_MATH_LENGTH_ERROR; 00082 } 00083 else 00084 { 00085 /* Assign filter taps */ 00086 S->numTaps = numTaps; 00087 00088 /* Assign coefficient pointer */ 00089 S->pCoeffs = pCoeffs; 00090 00091 /* Clear the state buffer. The size is always (blockSize + numTaps - 1) */ 00092 memset(pState, 0, (numTaps + (blockSize - 1)) * sizeof(q31_t)); 00093 00094 /* Assign state pointer */ 00095 S->pState = pState; 00096 00097 /* Assign Decimation factor */ 00098 S->M = M; 00099 00100 status = ARM_MATH_SUCCESS; 00101 } 00102 00103 return (status); 00104 00105 } 00106