arm_q7_to_q15.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_q7_to_q15.c    
00009 *    
00010 * Description:  Converts the elements of the Q7 vector to 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 groupSupport    
00045  */
00046 
00047 /**    
00048  * @addtogroup q7_to_x    
00049  * @{    
00050  */
00051 
00052 
00053 
00054 
00055 /**    
00056  * @brief Converts the elements of the Q7 vector to Q15 vector.    
00057  * @param[in]       *pSrc points to the Q7 input vector    
00058  * @param[out]      *pDst points to the Q15 output vector   
00059  * @param[in]       blockSize length of the input vector    
00060  * @return none.    
00061  *    
00062  * \par Description:    
00063  *    
00064  * The equation used for the conversion process is:    
00065  *   
00066  * <pre>    
00067  *  pDst[n] = (q15_t) pSrc[n] << 8;   0 <= n < blockSize.    
00068  * </pre>    
00069  *   
00070  */
00071 
00072 
00073 void arm_q7_to_q15(
00074   q7_t * pSrc,
00075   q15_t * pDst,
00076   uint32_t blockSize)
00077 {
00078   q7_t *pIn = pSrc;                              /* Src pointer */
00079   uint32_t blkCnt;                               /* loop counter */
00080 
00081 #ifndef ARM_MATH_CM0_FAMILY
00082   q31_t in;
00083   q31_t in1, in2;
00084   q31_t out1, out2;
00085 
00086   /* Run the below code for Cortex-M4 and Cortex-M3 */
00087 
00088   /*loop Unrolling */
00089   blkCnt = blockSize >> 2u;
00090 
00091   /* First part of the processing with loop unrolling.  Compute 4 outputs at a time.    
00092    ** a second loop below computes the remaining 1 to 3 samples. */
00093   while(blkCnt > 0u)
00094   {
00095     /* C = (q15_t) A << 8 */
00096     /* convert from q7 to q15 and then store the results in the destination buffer */
00097     in = *__SIMD32(pIn)++;
00098 
00099     /* rotatate in by 8 and extend two q7_t values to q15_t values */
00100     in1 = __SXTB16(__ROR(in, 8));
00101 
00102     /* extend remainig two q7_t values to q15_t values */
00103     in2 = __SXTB16(in);
00104 
00105     in1 = in1 << 8u;
00106     in2 = in2 << 8u;
00107 
00108     in1 = in1 & 0xFF00FF00;
00109     in2 = in2 & 0xFF00FF00;
00110 
00111 #ifndef ARM_MATH_BIG_ENDIAN
00112 
00113     out2 = __PKHTB(in1, in2, 16);
00114     out1 = __PKHBT(in2, in1, 16);
00115 
00116 #else
00117 
00118     out1 = __PKHTB(in1, in2, 16);
00119     out2 = __PKHBT(in2, in1, 16);
00120 
00121 #endif
00122 
00123     *__SIMD32(pDst)++ = out1;
00124     *__SIMD32(pDst)++ = out2;
00125 
00126     /* Decrement the loop counter */
00127     blkCnt--;
00128   }
00129 
00130   /* If the blockSize is not a multiple of 4, compute any remaining output samples here.    
00131    ** No loop unrolling is used. */
00132   blkCnt = blockSize % 0x4u;
00133 
00134 #else
00135 
00136   /* Run the below code for Cortex-M0 */
00137 
00138   /* Loop over blockSize number of values */
00139   blkCnt = blockSize;
00140 
00141 #endif /* #ifndef ARM_MATH_CM0_FAMILY */
00142 
00143   while(blkCnt > 0u)
00144   {
00145     /* C = (q15_t) A << 8 */
00146     /* convert from q7 to q15 and then store the results in the destination buffer */
00147     *pDst++ = (q15_t) * pIn++ << 8;
00148 
00149     /* Decrement the loop counter */
00150     blkCnt--;
00151   }
00152 
00153 }
00154 
00155 /**    
00156  * @} end of q7_to_x group    
00157  */