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_q15.c 00009 * 00010 * Description: Initialization function for the Q15 FIR Decimator. 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 00068 arm_status arm_fir_decimate_init_q15( 00069 arm_fir_decimate_instance_q15 * S, 00070 uint16_t numTaps, 00071 uint8_t M, 00072 q15_t * pCoeffs, 00073 q15_t * pState, 00074 uint32_t blockSize) 00075 { 00076 00077 arm_status status; 00078 00079 /* The size of the input block must be a multiple of the decimation factor */ 00080 if((blockSize % M) != 0u) 00081 { 00082 /* Set status as ARM_MATH_LENGTH_ERROR */ 00083 status = ARM_MATH_LENGTH_ERROR; 00084 } 00085 else 00086 { 00087 /* Assign filter taps */ 00088 S->numTaps = numTaps; 00089 00090 /* Assign coefficient pointer */ 00091 S->pCoeffs = pCoeffs; 00092 00093 /* Clear the state buffer. The size of buffer is always (blockSize + numTaps - 1) */ 00094 memset(pState, 0, (numTaps + (blockSize - 1u)) * sizeof(q15_t)); 00095 00096 /* Assign state pointer */ 00097 S->pState = pState; 00098 00099 /* Assign Decimation factor */ 00100 S->M = M; 00101 00102 status = ARM_MATH_SUCCESS; 00103 } 00104 00105 return (status); 00106 00107 } 00108