diff options
Diffstat (limited to 'Drivers/CMSIS/DSP/Source/BasicMathFunctions/arm_shift_q15.c')
| -rw-r--r-- | Drivers/CMSIS/DSP/Source/BasicMathFunctions/arm_shift_q15.c | 201 |
1 files changed, 201 insertions, 0 deletions
diff --git a/Drivers/CMSIS/DSP/Source/BasicMathFunctions/arm_shift_q15.c b/Drivers/CMSIS/DSP/Source/BasicMathFunctions/arm_shift_q15.c new file mode 100644 index 0000000..360be97 --- /dev/null +++ b/Drivers/CMSIS/DSP/Source/BasicMathFunctions/arm_shift_q15.c @@ -0,0 +1,201 @@ +/* ----------------------------------------------------------------------
+ * Project: CMSIS DSP Library
+ * Title: arm_shift_q15.c
+ * Description: Shifts the elements of a Q15 vector by a specified number of bits
+ *
+ * $Date: 18. March 2019
+ * $Revision: V1.6.0
+ *
+ * Target Processor: Cortex-M cores
+ * -------------------------------------------------------------------- */
+/*
+ * Copyright (C) 2010-2019 ARM Limited or its affiliates. All rights reserved.
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * Licensed under the Apache License, Version 2.0 (the License); you may
+ * not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an AS IS BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "arm_math.h"
+
+/**
+ @ingroup groupMath
+ */
+
+/**
+ @addtogroup BasicShift
+ @{
+ */
+
+/**
+ @brief Shifts the elements of a Q15 vector a specified number of bits
+ @param[in] pSrc points to the input vector
+ @param[in] shiftBits number of bits to shift. A positive value shifts left; a negative value shifts right.
+ @param[out] pDst points to the output vector
+ @param[in] blockSize number of samples in each vector
+ @return none
+
+ @par Scaling and Overflow Behavior
+ The function uses saturating arithmetic.
+ Results outside of the allowable Q15 range [0x8000 0x7FFF] are saturated.
+ */
+
+void arm_shift_q15(
+ const q15_t * pSrc,
+ int8_t shiftBits,
+ q15_t * pDst,
+ uint32_t blockSize)
+{
+ uint32_t blkCnt; /* Loop counter */
+ uint8_t sign = (shiftBits & 0x80); /* Sign of shiftBits */
+
+#if defined (ARM_MATH_LOOPUNROLL)
+
+#if defined (ARM_MATH_DSP)
+ q15_t in1, in2; /* Temporary input variables */
+#endif
+
+ /* Loop unrolling: Compute 4 outputs at a time */
+ blkCnt = blockSize >> 2U;
+
+ /* If the shift value is positive then do right shift else left shift */
+ if (sign == 0U)
+ {
+ while (blkCnt > 0U)
+ {
+ /* C = A << shiftBits */
+
+#if defined (ARM_MATH_DSP)
+ /* read 2 samples from source */
+ in1 = *pSrc++;
+ in2 = *pSrc++;
+
+ /* Shift the inputs and then store the results in the destination buffer. */
+#ifndef ARM_MATH_BIG_ENDIAN
+ write_q15x2_ia (&pDst, __PKHBT(__SSAT((in1 << shiftBits), 16),
+ __SSAT((in2 << shiftBits), 16), 16));
+#else
+ write_q15x2_ia (&pDst, __PKHBT(__SSAT((in2 << shiftBits), 16),
+ __SSAT((in1 << shiftBits), 16), 16));
+#endif /* #ifndef ARM_MATH_BIG_ENDIAN */
+
+ /* read 2 samples from source */
+ in1 = *pSrc++;
+ in2 = *pSrc++;
+
+#ifndef ARM_MATH_BIG_ENDIAN
+ write_q15x2_ia (&pDst, __PKHBT(__SSAT((in1 << shiftBits), 16),
+ __SSAT((in2 << shiftBits), 16), 16));
+#else
+ write_q15x2_ia (&pDst, __PKHBT(__SSAT((in2 << shiftBits), 16),
+ __SSAT((in1 << shiftBits), 16), 16));
+#endif /* #ifndef ARM_MATH_BIG_ENDIAN */
+
+#else
+ *pDst++ = __SSAT(((q31_t) *pSrc++ << shiftBits), 16);
+ *pDst++ = __SSAT(((q31_t) *pSrc++ << shiftBits), 16);
+ *pDst++ = __SSAT(((q31_t) *pSrc++ << shiftBits), 16);
+ *pDst++ = __SSAT(((q31_t) *pSrc++ << shiftBits), 16);
+#endif
+
+ /* Decrement loop counter */
+ blkCnt--;
+ }
+ }
+ else
+ {
+ while (blkCnt > 0U)
+ {
+ /* C = A >> shiftBits */
+
+#if defined (ARM_MATH_DSP)
+ /* read 2 samples from source */
+ in1 = *pSrc++;
+ in2 = *pSrc++;
+
+ /* Shift the inputs and then store the results in the destination buffer. */
+#ifndef ARM_MATH_BIG_ENDIAN
+ write_q15x2_ia (&pDst, __PKHBT((in1 >> -shiftBits),
+ (in2 >> -shiftBits), 16));
+#else
+ write_q15x2_ia (&pDst, __PKHBT((in2 >> -shiftBits),
+ (in1 >> -shiftBits), 16));
+#endif /* #ifndef ARM_MATH_BIG_ENDIAN */
+
+ /* read 2 samples from source */
+ in1 = *pSrc++;
+ in2 = *pSrc++;
+
+#ifndef ARM_MATH_BIG_ENDIAN
+ write_q15x2_ia (&pDst, __PKHBT((in1 >> -shiftBits),
+ (in2 >> -shiftBits), 16));
+#else
+ write_q15x2_ia (&pDst, __PKHBT((in2 >> -shiftBits),
+ (in1 >> -shiftBits), 16));
+#endif /* #ifndef ARM_MATH_BIG_ENDIAN */
+
+#else
+ *pDst++ = (*pSrc++ >> -shiftBits);
+ *pDst++ = (*pSrc++ >> -shiftBits);
+ *pDst++ = (*pSrc++ >> -shiftBits);
+ *pDst++ = (*pSrc++ >> -shiftBits);
+#endif
+
+ /* Decrement loop counter */
+ blkCnt--;
+ }
+ }
+
+ /* Loop unrolling: Compute remaining outputs */
+ blkCnt = blockSize % 0x4U;
+
+#else
+
+ /* Initialize blkCnt with number of samples */
+ blkCnt = blockSize;
+
+#endif /* #if defined (ARM_MATH_LOOPUNROLL) */
+
+ /* If the shift value is positive then do right shift else left shift */
+ if (sign == 0U)
+ {
+ while (blkCnt > 0U)
+ {
+ /* C = A << shiftBits */
+
+ /* Shift input and store result in destination buffer. */
+ *pDst++ = __SSAT(((q31_t) *pSrc++ << shiftBits), 16);
+
+ /* Decrement loop counter */
+ blkCnt--;
+ }
+ }
+ else
+ {
+ while (blkCnt > 0U)
+ {
+ /* C = A >> shiftBits */
+
+ /* Shift input and store result in destination buffer. */
+ *pDst++ = (*pSrc++ >> -shiftBits);
+
+ /* Decrement loop counter */
+ blkCnt--;
+ }
+ }
+
+}
+
+/**
+ @} end of BasicShift group
+ */
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