--- /dev/null
+/* ----------------------------------------------------------------------
+* Copyright (C) 2010-2013 ARM Limited. All rights reserved.
+*
+* $Date: 17. January 2013
+* $Revision: V1.4.1
+*
+* Project: CMSIS DSP Library
+* Title: arm_scale_q31.c
+*
+* Description: Multiplies a Q31 vector by a scalar.
+*
+* Target Processor: Cortex-M4/Cortex-M3/Cortex-M0
+*
+* Redistribution and use in source and binary forms, with or without
+* modification, are permitted provided that the following conditions
+* are met:
+* - Redistributions of source code must retain the above copyright
+* notice, this list of conditions and the following disclaimer.
+* - Redistributions in binary form must reproduce the above copyright
+* notice, this list of conditions and the following disclaimer in
+* the documentation and/or other materials provided with the
+* distribution.
+* - Neither the name of ARM LIMITED nor the names of its contributors
+* may be used to endorse or promote products derived from this
+* software without specific prior written permission.
+*
+* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
+* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+* POSSIBILITY OF SUCH DAMAGE.
+* -------------------------------------------------------------------- */
+
+#include "arm_math.h"
+
+/**
+ * @ingroup groupMath
+ */
+
+/**
+ * @addtogroup scale
+ * @{
+ */
+
+/**
+ * @brief Multiplies a Q31 vector by a scalar.
+ * @param[in] *pSrc points to the input vector
+ * @param[in] scaleFract fractional portion of the scale value
+ * @param[in] shift number of bits to shift the result by
+ * @param[out] *pDst points to the output vector
+ * @param[in] blockSize number of samples in the vector
+ * @return none.
+ *
+ * <b>Scaling and Overflow Behavior:</b>
+ * \par
+ * The input data <code>*pSrc</code> and <code>scaleFract</code> are in 1.31 format.
+ * These are multiplied to yield a 2.62 intermediate result and this is shifted with saturation to 1.31 format.
+ */
+
+void arm_scale_q31(
+ q31_t * pSrc,
+ q31_t scaleFract,
+ int8_t shift,
+ q31_t * pDst,
+ uint32_t blockSize)
+{
+ int8_t kShift = shift + 1; /* Shift to apply after scaling */
+ int8_t sign = (kShift & 0x80);
+ uint32_t blkCnt; /* loop counter */
+ q31_t in, out;
+
+#ifndef ARM_MATH_CM0_FAMILY
+
+/* Run the below code for Cortex-M4 and Cortex-M3 */
+
+ q31_t in1, in2, in3, in4; /* temporary input variables */
+ q31_t out1, out2, out3, out4; /* temporary output variabels */
+
+
+ /*loop Unrolling */
+ blkCnt = blockSize >> 2u;
+
+ if(sign == 0u)
+ {
+ /* First part of the processing with loop unrolling. Compute 4 outputs at a time.
+ ** a second loop below computes the remaining 1 to 3 samples. */
+ while(blkCnt > 0u)
+ {
+ /* read four inputs from source */
+ in1 = *pSrc;
+ in2 = *(pSrc + 1);
+ in3 = *(pSrc + 2);
+ in4 = *(pSrc + 3);
+
+ /* multiply input with scaler value */
+ in1 = ((q63_t) in1 * scaleFract) >> 32;
+ in2 = ((q63_t) in2 * scaleFract) >> 32;
+ in3 = ((q63_t) in3 * scaleFract) >> 32;
+ in4 = ((q63_t) in4 * scaleFract) >> 32;
+
+ /* apply shifting */
+ out1 = in1 << kShift;
+ out2 = in2 << kShift;
+
+ /* saturate the results. */
+ if(in1 != (out1 >> kShift))
+ out1 = 0x7FFFFFFF ^ (in1 >> 31);
+
+ if(in2 != (out2 >> kShift))
+ out2 = 0x7FFFFFFF ^ (in2 >> 31);
+
+ out3 = in3 << kShift;
+ out4 = in4 << kShift;
+
+ *pDst = out1;
+ *(pDst + 1) = out2;
+
+ if(in3 != (out3 >> kShift))
+ out3 = 0x7FFFFFFF ^ (in3 >> 31);
+
+ if(in4 != (out4 >> kShift))
+ out4 = 0x7FFFFFFF ^ (in4 >> 31);
+
+ /* Store result destination */
+ *(pDst + 2) = out3;
+ *(pDst + 3) = out4;
+
+ /* Update pointers to process next sampels */
+ pSrc += 4u;
+ pDst += 4u;
+
+ /* Decrement the loop counter */
+ blkCnt--;
+ }
+
+ }
+ else
+ {
+ /* First part of the processing with loop unrolling. Compute 4 outputs at a time.
+ ** a second loop below computes the remaining 1 to 3 samples. */
+ while(blkCnt > 0u)
+ {
+ /* read four inputs from source */
+ in1 = *pSrc;
+ in2 = *(pSrc + 1);
+ in3 = *(pSrc + 2);
+ in4 = *(pSrc + 3);
+
+ /* multiply input with scaler value */
+ in1 = ((q63_t) in1 * scaleFract) >> 32;
+ in2 = ((q63_t) in2 * scaleFract) >> 32;
+ in3 = ((q63_t) in3 * scaleFract) >> 32;
+ in4 = ((q63_t) in4 * scaleFract) >> 32;
+
+ /* apply shifting */
+ out1 = in1 >> -kShift;
+ out2 = in2 >> -kShift;
+
+ out3 = in3 >> -kShift;
+ out4 = in4 >> -kShift;
+
+ /* Store result destination */
+ *pDst = out1;
+ *(pDst + 1) = out2;
+
+ *(pDst + 2) = out3;
+ *(pDst + 3) = out4;
+
+ /* Update pointers to process next sampels */
+ pSrc += 4u;
+ pDst += 4u;
+
+ /* Decrement the loop counter */
+ blkCnt--;
+ }
+ }
+ /* If the blockSize is not a multiple of 4, compute any remaining output samples here.
+ ** No loop unrolling is used. */
+ blkCnt = blockSize % 0x4u;
+
+#else
+
+ /* Run the below code for Cortex-M0 */
+
+ /* Initialize blkCnt with number of samples */
+ blkCnt = blockSize;
+
+#endif /* #ifndef ARM_MATH_CM0_FAMILY */
+
+ if(sign == 0)
+ {
+ while(blkCnt > 0u)
+ {
+ /* C = A * scale */
+ /* Scale the input and then store the result in the destination buffer. */
+ in = *pSrc++;
+ in = ((q63_t) in * scaleFract) >> 32;
+
+ out = in << kShift;
+
+ if(in != (out >> kShift))
+ out = 0x7FFFFFFF ^ (in >> 31);
+
+ *pDst++ = out;
+
+ /* Decrement the loop counter */
+ blkCnt--;
+ }
+ }
+ else
+ {
+ while(blkCnt > 0u)
+ {
+ /* C = A * scale */
+ /* Scale the input and then store the result in the destination buffer. */
+ in = *pSrc++;
+ in = ((q63_t) in * scaleFract) >> 32;
+
+ out = in >> -kShift;
+
+ *pDst++ = out;
+
+ /* Decrement the loop counter */
+ blkCnt--;
+ }
+
+ }
+}
+
+/**
+ * @} end of scale group
+ */
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