arm_cmplx_mag_squared_q31.c

00001 /* ----------------------------------------------------------------------    
00002 * Copyright (C) 2010-2014 ARM Limited. All rights reserved.    
00003 *    
00004 * $Date:        19. March 2015
00005 * $Revision:    V.1.4.5
00006 *    
00007 * Project:      CMSIS DSP Library    
00008 * Title:        arm_cmplx_mag_squared_q31.c    
00009 *    
00010 * Description:  Q31 complex magnitude squared.    
00011 *    
00012 * Target Processor: Cortex-M4/Cortex-M3/Cortex-M0
00013 *  
00014 * Redistribution and use in source and binary forms, with or without 
00015 * modification, are permitted provided that the following conditions
00016 * are met:
00017 *   - Redistributions of source code must retain the above copyright
00018 *     notice, this list of conditions and the following disclaimer.
00019 *   - Redistributions in binary form must reproduce the above copyright
00020 *     notice, this list of conditions and the following disclaimer in
00021 *     the documentation and/or other materials provided with the 
00022 *     distribution.
00023 *   - Neither the name of ARM LIMITED nor the names of its contributors
00024 *     may be used to endorse or promote products derived from this
00025 *     software without specific prior written permission.
00026 *
00027 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
00028 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
00029 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
00030 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE 
00031 * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
00032 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
00033 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
00034 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
00035 * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
00036 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
00037 * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
00038 * POSSIBILITY OF SUCH DAMAGE. 
00039 * ---------------------------------------------------------------------------- */
00040 
00041 #include "arm_math.h"
00042 
00043 /**    
00044  * @ingroup groupCmplxMath    
00045  */
00046 
00047 /**    
00048  * @addtogroup cmplx_mag_squared    
00049  * @{    
00050  */
00051 
00052 
00053 /**    
00054  * @brief  Q31 complex magnitude squared    
00055  * @param  *pSrc points to the complex input vector    
00056  * @param  *pDst points to the real output vector    
00057  * @param  numSamples number of complex samples in the input vector    
00058  * @return none.    
00059  *    
00060  * <b>Scaling and Overflow Behavior:</b>    
00061  * \par    
00062  * The function implements 1.31 by 1.31 multiplications and finally output is converted into 3.29 format.    
00063  * Input down scaling is not required.    
00064  */
00065 
00066 void arm_cmplx_mag_squared_q31(
00067   q31_t * pSrc,
00068   q31_t * pDst,
00069   uint32_t numSamples)
00070 {
00071   q31_t real, imag;                              /* Temporary variables to store real and imaginary values */
00072   q31_t acc0, acc1;                              /* Accumulators */
00073 
00074 #ifndef ARM_MATH_CM0_FAMILY
00075 
00076   /* Run the below code for Cortex-M4 and Cortex-M3 */
00077   uint32_t blkCnt;                               /* loop counter */
00078 
00079   /* loop Unrolling */
00080   blkCnt = numSamples >> 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[0] = (A[0] * A[0] + A[1] * A[1]) */
00087     real = *pSrc++;
00088     imag = *pSrc++;
00089     acc0 = (q31_t) (((q63_t) real * real) >> 33);
00090     acc1 = (q31_t) (((q63_t) imag * imag) >> 33);
00091     /* store the result in 3.29 format in the destination buffer. */
00092     *pDst++ = acc0 + acc1;
00093 
00094     real = *pSrc++;
00095     imag = *pSrc++;
00096     acc0 = (q31_t) (((q63_t) real * real) >> 33);
00097     acc1 = (q31_t) (((q63_t) imag * imag) >> 33);
00098     /* store the result in 3.29 format in the destination buffer. */
00099     *pDst++ = acc0 + acc1;
00100 
00101     real = *pSrc++;
00102     imag = *pSrc++;
00103     acc0 = (q31_t) (((q63_t) real * real) >> 33);
00104     acc1 = (q31_t) (((q63_t) imag * imag) >> 33);
00105     /* store the result in 3.29 format in the destination buffer. */
00106     *pDst++ = acc0 + acc1;
00107 
00108     real = *pSrc++;
00109     imag = *pSrc++;
00110     acc0 = (q31_t) (((q63_t) real * real) >> 33);
00111     acc1 = (q31_t) (((q63_t) imag * imag) >> 33);
00112     /* store the result in 3.29 format in the destination buffer. */
00113     *pDst++ = acc0 + acc1;
00114 
00115     /* Decrement the loop counter */
00116     blkCnt--;
00117   }
00118 
00119   /* If the numSamples is not a multiple of 4, compute any remaining output samples here.    
00120    ** No loop unrolling is used. */
00121   blkCnt = numSamples % 0x4u;
00122 
00123   while(blkCnt > 0u)
00124   {
00125     /* C[0] = (A[0] * A[0] + A[1] * A[1]) */
00126     real = *pSrc++;
00127     imag = *pSrc++;
00128     acc0 = (q31_t) (((q63_t) real * real) >> 33);
00129     acc1 = (q31_t) (((q63_t) imag * imag) >> 33);
00130     /* store the result in 3.29 format in the destination buffer. */
00131     *pDst++ = acc0 + acc1;
00132 
00133     /* Decrement the loop counter */
00134     blkCnt--;
00135   }
00136 
00137 #else
00138 
00139   /* Run the below code for Cortex-M0 */
00140 
00141   while(numSamples > 0u)
00142   {
00143     /* out = ((real * real) + (imag * imag)) */
00144     real = *pSrc++;
00145     imag = *pSrc++;
00146     acc0 = (q31_t) (((q63_t) real * real) >> 33);
00147     acc1 = (q31_t) (((q63_t) imag * imag) >> 33);
00148     /* store the result in 3.29 format in the destination buffer. */
00149     *pDst++ = acc0 + acc1;
00150 
00151     /* Decrement the loop counter */
00152     numSamples--;
00153   }
00154 
00155 #endif /* #ifndef ARM_MATH_CM0_FAMILY */
00156 
00157 }
00158 
00159 /**    
00160  * @} end of cmplx_mag_squared group    
00161  */