arm_min_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_min_q31.c    
00009 *    
00010 * Description:  Minimum value of a Q31 vector.    
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 groupStats    
00045  */
00046 
00047 
00048 /**    
00049  * @addtogroup Min    
00050  * @{    
00051  */
00052 
00053 
00054 /**    
00055  * @brief Minimum value of a Q31 vector.    
00056  * @param[in]       *pSrc points to the input vector    
00057  * @param[in]       blockSize length of the input vector    
00058  * @param[out]      *pResult minimum value returned here    
00059  * @param[out]      *pIndex index of minimum value returned here    
00060  * @return none.    
00061  *    
00062  */
00063 
00064 void arm_min_q31(
00065   q31_t * pSrc,
00066   uint32_t blockSize,
00067   q31_t * pResult,
00068   uint32_t * pIndex)
00069 {
00070 #ifndef ARM_MATH_CM0_FAMILY
00071 
00072   /* Run the below code for Cortex-M4 and Cortex-M3 */
00073   q31_t minVal1, minVal2, out;                   /* Temporary variables to store the output value. */
00074   uint32_t blkCnt, outIndex, count;              /* loop counter */
00075 
00076   /* Initialise the count value. */
00077   count = 0u;
00078   /* Initialise the index value to zero. */
00079   outIndex = 0u;
00080   /* Load first input value that act as reference value for comparision */
00081   out = *pSrc++;
00082 
00083 
00084   /* Loop unrolling */
00085   blkCnt = (blockSize - 1u) >> 2u;
00086 
00087   while(blkCnt > 0)
00088   {
00089     /* Initialize minVal to the next consecutive values one by one */
00090     minVal1 = *pSrc++;
00091     minVal2 = *pSrc++;
00092 
00093     /* compare for the minimum value */
00094     if(out > minVal1)
00095     {
00096       /* Update the minimum value and its index */
00097       out = minVal1;
00098       outIndex = count + 1u;
00099     }
00100 
00101     minVal1 = *pSrc++;
00102 
00103     /* compare for the minimum value */
00104     if(out > minVal2)
00105     {
00106       /* Update the minimum value and its index */
00107       out = minVal2;
00108       outIndex = count + 2u;
00109     }
00110 
00111     minVal2 = *pSrc++;
00112 
00113     /* compare for the minimum value */
00114     if(out > minVal1)
00115     {
00116       /* Update the minimum value and its index */
00117       out = minVal1;
00118       outIndex = count + 3u;
00119     }
00120 
00121     /* compare for the minimum value */
00122     if(out > minVal2)
00123     {
00124       /* Update the minimum value and its index */
00125       out = minVal2;
00126       outIndex = count + 4u;
00127     }
00128 
00129     count += 4u;
00130 
00131     blkCnt--;
00132   }
00133 
00134   /* if (blockSize - 1u ) is not multiple of 4 */
00135   blkCnt = (blockSize - 1u) % 4u;
00136 
00137 #else
00138 
00139   /* Run the below code for Cortex-M0 */
00140   q31_t minVal1, out;                            /* Temporary variables to store the output value. */
00141   uint32_t blkCnt, outIndex;                     /* loop counter */
00142 
00143   blkCnt = (blockSize - 1u);
00144 
00145   /* Initialise the index value to zero. */
00146   outIndex = 0u;
00147   /* Load first input value that act as reference value for comparision */
00148   out = *pSrc++;
00149 
00150 #endif //      #ifndef ARM_MATH_CM0_FAMILY
00151 
00152   while(blkCnt > 0)
00153   {
00154     /* Initialize minVal to the next consecutive values one by one */
00155     minVal1 = *pSrc++;
00156 
00157     /* compare for the minimum value */
00158     if(out > minVal1)
00159     {
00160       /* Update the minimum value and it's index */
00161       out = minVal1;
00162       outIndex = blockSize - blkCnt;
00163     }
00164 
00165     blkCnt--;
00166 
00167   }
00168 
00169   /* Store the minimum value and its index into destination pointers */
00170   *pResult = out;
00171   *pIndex = outIndex;
00172 }
00173 
00174 /**    
00175  * @} end of Min group    
00176  */