arm_min_q15.c

00001 /* ----------------------------------------------------------------------    
00002 * Copyright (C) 2010-2014 ARM Limited. All rights reserved.    
00003 *    
00004 * $Date:        12. March 2014
00005 * $Revision:    V1.4.3  
00006 *    
00007 * Project:      CMSIS DSP Library    
00008 * Title:        arm_min_q15.c    
00009 *    
00010 * Description:  Minimum value of a Q15 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 Q15 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_q15(
00065   q15_t * pSrc,
00066   uint32_t blockSize,
00067   q15_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   q15_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   /* Loop unrolling */
00084   blkCnt = (blockSize - 1u) >> 2u;
00085 
00086   while(blkCnt > 0)
00087   {
00088     /* Initialize minVal to the next consecutive values one by one */
00089     minVal1 = *pSrc++;
00090     minVal2 = *pSrc++;
00091 
00092     /* compare for the minimum value */
00093     if(out > minVal1)
00094     {
00095       /* Update the minimum value and its index */
00096       out = minVal1;
00097       outIndex = count + 1u;
00098     }
00099 
00100     minVal1 = *pSrc++;
00101 
00102     /* compare for the minimum value */
00103     if(out > minVal2)
00104     {
00105       /* Update the minimum value and its index */
00106       out = minVal2;
00107       outIndex = count + 2u;
00108     }
00109 
00110     minVal2 = *pSrc++;
00111 
00112     /* compare for the minimum value */
00113     if(out > minVal1)
00114     {
00115       /* Update the minimum value and its index */
00116       out = minVal1;
00117       outIndex = count + 3u;
00118     }
00119 
00120     /* compare for the minimum value */
00121     if(out > minVal2)
00122     {
00123       /* Update the minimum value and its index */
00124       out = minVal2;
00125       outIndex = count + 4u;
00126     }
00127 
00128     count += 4u;
00129 
00130     blkCnt--;
00131   }
00132 
00133   /* if (blockSize - 1u ) is not multiple of 4 */
00134   blkCnt = (blockSize - 1u) % 4u;
00135 
00136 #else
00137 
00138   /* Run the below code for Cortex-M0 */
00139   q15_t minVal1, out;                            /* Temporary variables to store the output value. */
00140   uint32_t blkCnt, outIndex;                     /* loop counter */
00141 
00142   blkCnt = (blockSize - 1u);
00143 
00144   /* Initialise the index value to zero. */
00145   outIndex = 0u;
00146   /* Load first input value that act as reference value for comparision */
00147   out = *pSrc++;
00148 
00149 #endif //      #ifndef ARM_MATH_CM0_FAMILY
00150 
00151   while(blkCnt > 0)
00152   {
00153     /* Initialize minVal to the next consecutive values one by one */
00154     minVal1 = *pSrc++;
00155 
00156     /* compare for the minimum value */
00157     if(out > minVal1)
00158     {
00159       /* Update the minimum value and it's index */
00160       out = minVal1;
00161       outIndex = blockSize - blkCnt;
00162     }
00163 
00164     blkCnt--;
00165 
00166   }
00167 
00168 
00169 
00170   /* Store the minimum value and its index into destination pointers */
00171   *pResult = out;
00172   *pIndex = outIndex;
00173 }
00174 
00175 /**    
00176  * @} end of Min group    
00177  */