arm_dot_prod_q7.c

00001 /* ----------------------------------------------------------------------  
00002 * Copyright (C) 2010 ARM Limited. All rights reserved.  
00003 *  
00004 * $Date:        29. November 2010  
00005 * $Revision:    V1.0.3  
00006 *  
00007 * Project:      CMSIS DSP Library  
00008 * Title:        arm_dot_prod_q7.c  
00009 *  
00010 * Description:  Q7 dot product.  
00011 *  
00012 * Target Processor: Cortex-M4/Cortex-M3
00013 *  
00014 * Version 1.0.3 2010/11/29 
00015 *    Re-organized the CMSIS folders and updated documentation.  
00016 *   
00017 * Version 1.0.2 2010/11/11  
00018 *    Documentation updated.   
00019 *  
00020 * Version 1.0.1 2010/10/05   
00021 *    Production release and review comments incorporated.  
00022 *  
00023 * Version 1.0.0 2010/09/20   
00024 *    Production release and review comments incorporated.  
00025 *  
00026 * Version 0.0.7  2010/06/10   
00027 *    Misra-C changes done  
00028 * -------------------------------------------------------------------- */ 
00029  
00030 #include "arm_math.h" 
00031  
00032 /**  
00033  * @ingroup groupMath  
00034  */ 
00035  
00036 /**  
00037  * @addtogroup dot_prod  
00038  * @{  
00039  */ 
00040  
00041 /**  
00042  * @brief Dot product of Q7 vectors.  
00043  * @param[in]       *pSrcA points to the first input vector  
00044  * @param[in]       *pSrcB points to the second input vector  
00045  * @param[in]       blockSize number of samples in each vector  
00046  * @param[out]      *result output result returned here  
00047  * @return none.  
00048  *  
00049  * <b>Scaling and Overflow Behavior:</b>  
00050  * \par  
00051  * The intermediate multiplications are in 1.7 x 1.7 = 2.14 format and these  
00052  * results are added to an accumulator in 18.14 format.  
00053  * Nonsaturating additions are used and there is no danger of wrap around as long as  
00054  * the vectors are less than 2^18 elements long.  
00055  * The return result is in 18.14 format.  
00056  */ 
00057  
00058 void arm_dot_prod_q7( 
00059   q7_t * pSrcA, 
00060   q7_t * pSrcB, 
00061   uint32_t blockSize, 
00062   q31_t * result) 
00063 { 
00064   q31_t input1, input2;                          /* Temporary variables to store input */ 
00065   q15_t in1, in2;                                /* Temporary variables to store input */ 
00066   q31_t sum = 0;                                 /* Temporary variables to store output */ 
00067   uint32_t blkCnt;                               /* loop counter */ 
00068  
00069  
00070  
00071   /*loop Unrolling */ 
00072   blkCnt = blockSize >> 2u; 
00073  
00074   /* First part of the processing with loop unrolling.  Compute 4 outputs at a time.  
00075    ** a second loop below computes the remaining 1 to 3 samples. */ 
00076   while(blkCnt > 0u) 
00077   { 
00078     /* Reading two inputs of SrcA buffer and packing */ 
00079     in1 = (q15_t) * pSrcA++; 
00080     in2 = (q15_t) * pSrcA++; 
00081     input1 = ((q31_t) in1 & 0x0000FFFF) | ((q31_t) in2 << 16); 
00082  
00083     /* Reading two inputs of SrcB buffer and packing */ 
00084     in1 = (q15_t) * pSrcB++; 
00085     in2 = (q15_t) * pSrcB++; 
00086     input2 = ((q31_t) in1 & 0x0000FFFF) | ((q31_t) in2 << 16); 
00087  
00088     /* C = A[0]* B[0] + A[1]* B[1] + A[2]* B[2] + .....+ A[blockSize-1]* B[blockSize-1] */ 
00089     /* Perform Dot product of 2 packed inputs using SMLALD and store the result in a temporary variable. */ 
00090     sum = __SMLAD(input1, input2, sum); 
00091  
00092     /* Reading two inputs of SrcA buffer and packing */ 
00093     in1 = (q15_t) * pSrcA++; 
00094     in2 = (q15_t) * pSrcA++; 
00095     input1 = ((q31_t) in1 & 0x0000FFFF) | ((q31_t) in2 << 16); 
00096  
00097     /* Reading two inputs of SrcB buffer and packing */ 
00098     in1 = (q15_t) * pSrcB++; 
00099     in2 = (q15_t) * pSrcB++; 
00100     input2 = ((q31_t) in1 & 0x0000FFFF) | ((q31_t) in2 << 16); 
00101  
00102     /* C = A[0]* B[0] + A[1]* B[1] + A[2]* B[2] + .....+ A[blockSize-1]* B[blockSize-1] */ 
00103     /* Perform Dot product of 2 packed inputs using SMLALD and store the result in a temporary variable. */ 
00104     sum = __SMLAD(input1, input2, sum); 
00105  
00106  
00107  
00108     /* Decrement the loop counter */ 
00109     blkCnt--; 
00110   } 
00111  
00112   /* If the blockSize is not a multiple of 4, compute any remaining output samples here.  
00113    ** No loop unrolling is used. */ 
00114   blkCnt = blockSize % 0x4u; 
00115  
00116   while(blkCnt > 0u) 
00117   { 
00118     /* C = A[0]* B[0] + A[1]* B[1] + A[2]* B[2] + .....+ A[blockSize-1]* B[blockSize-1] */ 
00119     /* Dot product and then store the results in a temporary buffer. */ 
00120     sum = __SMLAD(*pSrcA++, *pSrcB++, sum); 
00121  
00122     /* Decrement the loop counter */ 
00123     blkCnt--; 
00124   } 
00125  
00126   /* Store the result in the destination buffer in 18.14 format */ 
00127   *result = sum; 
00128 } 
00129  
00130 /**  
00131  * @} end of dot_prod group  
00132  */