arm_cmplx_mult_real_q31.c

00001 /* ----------------------------------------------------------------------    
00002 * Copyright (C) 2010-2013 ARM Limited. All rights reserved.    
00003 *    
00004 * $Date:        17. January 2013
00005 * $Revision:    V1.4.1
00006 *    
00007 * Project:      CMSIS DSP Library    
00008 * Title:        arm_cmplx_mult_real_q31.c    
00009 *    
00010 * Description:  Q31 complex by real multiplication    
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 CmplxByRealMult    
00049  * @{    
00050  */
00051 
00052 
00053 /**    
00054  * @brief  Q31 complex-by-real multiplication    
00055  * @param[in]  *pSrcCmplx points to the complex input vector    
00056  * @param[in]  *pSrcReal points to the real input vector    
00057  * @param[out]  *pCmplxDst points to the complex output vector    
00058  * @param[in]  numSamples number of samples in each vector    
00059  * @return none.    
00060  *    
00061  * <b>Scaling and Overflow Behavior:</b>    
00062  * \par    
00063  * The function uses saturating arithmetic.    
00064  * Results outside of the allowable Q31 range[0x80000000 0x7FFFFFFF] will be saturated.    
00065  */
00066 
00067 void arm_cmplx_mult_real_q31(
00068   q31_t * pSrcCmplx,
00069   q31_t * pSrcReal,
00070   q31_t * pCmplxDst,
00071   uint32_t numSamples)
00072 {
00073   q31_t inA1;                                    /* Temporary variable to store input value */
00074 
00075 #ifndef ARM_MATH_CM0_FAMILY
00076 
00077   /* Run the below code for Cortex-M4 and Cortex-M3 */
00078   uint32_t blkCnt;                               /* loop counters */
00079   q31_t inA2, inA3, inA4;                        /* Temporary variables to hold input data */
00080   q31_t inB1, inB2;                              /* Temporary variabels to hold input data */
00081   q31_t out1, out2, out3, out4;                  /* Temporary variables to hold output data */
00082 
00083   /* loop Unrolling */
00084   blkCnt = numSamples >> 2u;
00085 
00086   /* First part of the processing with loop unrolling.  Compute 4 outputs at a time.    
00087    ** a second loop below computes the remaining 1 to 3 samples. */
00088   while(blkCnt > 0u)
00089   {
00090     /* C[2 * i] = A[2 * i] * B[i].            */
00091     /* C[2 * i + 1] = A[2 * i + 1] * B[i].        */
00092     /* read real input from complex input buffer */
00093     inA1 = *pSrcCmplx++;
00094     inA2 = *pSrcCmplx++;
00095     /* read input from real input bufer */
00096     inB1 = *pSrcReal++;
00097     inB2 = *pSrcReal++;
00098     /* read imaginary input from complex input buffer */
00099     inA3 = *pSrcCmplx++;
00100     inA4 = *pSrcCmplx++;
00101 
00102     /* multiply complex input with real input */
00103     out1 = ((q63_t) inA1 * inB1) >> 32;
00104     out2 = ((q63_t) inA2 * inB1) >> 32;
00105     out3 = ((q63_t) inA3 * inB2) >> 32;
00106     out4 = ((q63_t) inA4 * inB2) >> 32;
00107 
00108     /* sature the result */
00109     out1 = __SSAT(out1, 31);
00110     out2 = __SSAT(out2, 31);
00111     out3 = __SSAT(out3, 31);
00112     out4 = __SSAT(out4, 31);
00113 
00114     /* get result in 1.31 format */
00115     out1 = out1 << 1;
00116     out2 = out2 << 1;
00117     out3 = out3 << 1;
00118     out4 = out4 << 1;
00119 
00120     /* store the result to destination buffer */
00121     *pCmplxDst++ = out1;
00122     *pCmplxDst++ = out2;
00123     *pCmplxDst++ = out3;
00124     *pCmplxDst++ = out4;
00125 
00126     /* read real input from complex input buffer */
00127     inA1 = *pSrcCmplx++;
00128     inA2 = *pSrcCmplx++;
00129     /* read input from real input bufer */
00130     inB1 = *pSrcReal++;
00131     inB2 = *pSrcReal++;
00132     /* read imaginary input from complex input buffer */
00133     inA3 = *pSrcCmplx++;
00134     inA4 = *pSrcCmplx++;
00135 
00136     /* multiply complex input with real input */
00137     out1 = ((q63_t) inA1 * inB1) >> 32;
00138     out2 = ((q63_t) inA2 * inB1) >> 32;
00139     out3 = ((q63_t) inA3 * inB2) >> 32;
00140     out4 = ((q63_t) inA4 * inB2) >> 32;
00141 
00142     /* sature the result */
00143     out1 = __SSAT(out1, 31);
00144     out2 = __SSAT(out2, 31);
00145     out3 = __SSAT(out3, 31);
00146     out4 = __SSAT(out4, 31);
00147 
00148     /* get result in 1.31 format */
00149     out1 = out1 << 1;
00150     out2 = out2 << 1;
00151     out3 = out3 << 1;
00152     out4 = out4 << 1;
00153 
00154     /* store the result to destination buffer */
00155     *pCmplxDst++ = out1;
00156     *pCmplxDst++ = out2;
00157     *pCmplxDst++ = out3;
00158     *pCmplxDst++ = out4;
00159 
00160     /* Decrement the numSamples loop counter */
00161     blkCnt--;
00162   }
00163 
00164   /* If the numSamples is not a multiple of 4, compute any remaining output samples here.    
00165    ** No loop unrolling is used. */
00166   blkCnt = numSamples % 0x4u;
00167 
00168   while(blkCnt > 0u)
00169   {
00170     /* C[2 * i] = A[2 * i] * B[i].            */
00171     /* C[2 * i + 1] = A[2 * i + 1] * B[i].        */
00172     /* read real input from complex input buffer */
00173     inA1 = *pSrcCmplx++;
00174     inA2 = *pSrcCmplx++;
00175     /* read input from real input bufer */
00176     inB1 = *pSrcReal++;
00177 
00178     /* multiply complex input with real input */
00179     out1 = ((q63_t) inA1 * inB1) >> 32;
00180     out2 = ((q63_t) inA2 * inB1) >> 32;
00181 
00182     /* sature the result */
00183     out1 = __SSAT(out1, 31);
00184     out2 = __SSAT(out2, 31);
00185 
00186     /* get result in 1.31 format */
00187     out1 = out1 << 1;
00188     out2 = out2 << 1;
00189 
00190     /* store the result to destination buffer */
00191     *pCmplxDst++ = out1;
00192     *pCmplxDst++ = out2;
00193 
00194     /* Decrement the numSamples loop counter */
00195     blkCnt--;
00196   }
00197 
00198 #else
00199 
00200   /* Run the below code for Cortex-M0 */
00201 
00202   while(numSamples > 0u)
00203   {
00204     /* realOut = realA * realB.            */
00205     /* imagReal = imagA * realB.               */
00206     inA1 = *pSrcReal++;
00207     /* store the result in the destination buffer. */
00208     *pCmplxDst++ =
00209       (q31_t) clip_q63_to_q31(((q63_t) * pSrcCmplx++ * inA1) >> 31);
00210     *pCmplxDst++ =
00211       (q31_t) clip_q63_to_q31(((q63_t) * pSrcCmplx++ * inA1) >> 31);
00212 
00213     /* Decrement the numSamples loop counter */
00214     numSamples--;
00215   }
00216 
00217 #endif /* #ifndef ARM_MATH_CM0_FAMILY */
00218 
00219 }
00220 
00221 /**    
00222  * @} end of CmplxByRealMult group    
00223  */