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_q15_to_float.c 00009 * 00010 * Description: Converts the elements of the Q15 vector to floating-point vector. 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 00030 #include "arm_math.h" 00031 00066 void arm_q15_to_float( 00067 q15_t * pSrc, 00068 float32_t * pDst, 00069 uint32_t blockSize) 00070 { 00071 q15_t *pIn = pSrc; /* Src pointer */ 00072 uint32_t blkCnt; /* loop counter */ 00073 00074 00075 #ifndef ARM_MATH_CM0 00076 00077 /* Run the below code for Cortex-M4 and Cortex-M3 */ 00078 00079 /*loop Unrolling */ 00080 blkCnt = blockSize >> 2u; 00081 00082 /* First part of the processing with loop unrolling. Compute 4 outputs at a time. 00083 ** a second loop below computes the remaining 1 to 3 samples. */ 00084 while(blkCnt > 0u) 00085 { 00086 /* C = (float32_t) A / 32768 */ 00087 /* convert from q15 to float and then store the results in the destination buffer */ 00088 *pDst++ = ((float32_t) * pIn++ / 32768.0f); 00089 *pDst++ = ((float32_t) * pIn++ / 32768.0f); 00090 *pDst++ = ((float32_t) * pIn++ / 32768.0f); 00091 *pDst++ = ((float32_t) * pIn++ / 32768.0f); 00092 00093 /* Decrement the loop counter */ 00094 blkCnt--; 00095 } 00096 00097 /* If the blockSize is not a multiple of 4, compute any remaining output samples here. 00098 ** No loop unrolling is used. */ 00099 blkCnt = blockSize % 0x4u; 00100 00101 #else 00102 00103 /* Run the below code for Cortex-M0 */ 00104 00105 /* Loop over blockSize number of values */ 00106 blkCnt = blockSize; 00107 00108 #endif /* #ifndef ARM_MATH_CM0 */ 00109 00110 while(blkCnt > 0u) 00111 { 00112 /* C = (float32_t) A / 32768 */ 00113 /* convert from q15 to float and then store the results in the destination buffer */ 00114 *pDst++ = ((float32_t) * pIn++ / 32768.0f); 00115 00116 /* Decrement the loop counter */ 00117 blkCnt--; 00118 } 00119 } 00120