WebSVN – dashGPS – Blame – /branches/dashGPS-bmp/Drivers/CMSIS/DSP/Source/MatrixFunctions/arm_mat_scale_q15.c

Rev	Author	Line No.	Line
2	mjames	1	/* ----------------------------------------------------------------------
		2	* Project: CMSIS DSP Library
		3	* Title: arm_mat_scale_q15.c
		4	* Description: Multiplies a Q15 matrix by a scalar
		5	*
		6	* $Date: 27. January 2017
		7	* $Revision: V.1.5.1
		8	*
		9	* Target Processor: Cortex-M cores
		10	* -------------------------------------------------------------------- */
		11	/*
		12	* Copyright (C) 2010-2017 ARM Limited or its affiliates. All rights reserved.
		13	*
		14	* SPDX-License-Identifier: Apache-2.0
		15	*
		16	* Licensed under the Apache License, Version 2.0 (the License); you may
		17	* not use this file except in compliance with the License.
		18	* You may obtain a copy of the License at
		19	*
		20	* www.apache.org/licenses/LICENSE-2.0
		21	*
		22	* Unless required by applicable law or agreed to in writing, software
		23	* distributed under the License is distributed on an AS IS BASIS, WITHOUT
		24	* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
		25	* See the License for the specific language governing permissions and
		26	* limitations under the License.
		27	*/
		28
		29	#include "arm_math.h"
		30
		31	/**
		32	* @ingroup groupMatrix
		33	*/
		34
		35	/**
		36	* @addtogroup MatrixScale
		37	* @{
		38	*/
		39
		40	/**
		41	* @brief Q15 matrix scaling.
		42	* @param[in] *pSrc points to input matrix
		43	* @param[in] scaleFract fractional portion of the scale factor
		44	* @param[in] shift number of bits to shift the result by
		45	* @param[out] *pDst points to output matrix structure
		46	* @return The function returns either
		47	* <code>ARM_MATH_SIZE_MISMATCH</code> or <code>ARM_MATH_SUCCESS</code> based on the outcome of size checking.
		48	*
		49	* @details
		50	* <b>Scaling and Overflow Behavior:</b>
		51	* \par
		52	* The input data <code>*pSrc</code> and <code>scaleFract</code> are in 1.15 format.
		53	* These are multiplied to yield a 2.30 intermediate result and this is shifted with saturation to 1.15 format.
		54	*/
		55
		56	arm_status arm_mat_scale_q15(
		57	const arm_matrix_instance_q15 * pSrc,
		58	q15_t scaleFract,
		59	int32_t shift,
		60	arm_matrix_instance_q15 * pDst)
		61	{
		62	q15_t pIn = pSrc->pData; / input data matrix pointer */
		63	q15_t pOut = pDst->pData; / output data matrix pointer */
		64	uint32_t numSamples; /* total number of elements in the matrix */
		65	int32_t totShift = 15 - shift; /* total shift to apply after scaling */
		66	uint32_t blkCnt; /* loop counters */
		67	arm_status status; /* status of matrix scaling */
		68
		69	#if defined (ARM_MATH_DSP)
		70
		71	q15_t in1, in2, in3, in4;
		72	q31_t out1, out2, out3, out4;
		73	q31_t inA1, inA2;
		74
		75	#endif // #if defined (ARM_MATH_DSP)
		76
		77	#ifdef ARM_MATH_MATRIX_CHECK
		78	/* Check for matrix mismatch */
		79	if ((pSrc->numRows != pDst->numRows) \|\| (pSrc->numCols != pDst->numCols))
		80	{
		81	/* Set status as ARM_MATH_SIZE_MISMATCH */
		82	status = ARM_MATH_SIZE_MISMATCH;
		83	}
		84	else
		85	#endif // #ifdef ARM_MATH_MATRIX_CHECK
		86	{
		87	/* Total number of samples in the input matrix */
		88	numSamples = (uint32_t) pSrc->numRows * pSrc->numCols;
		89
		90	#if defined (ARM_MATH_DSP)
		91
		92	/* Run the below code for Cortex-M4 and Cortex-M3 */
		93	/* Loop Unrolling */
		94	blkCnt = numSamples >> 2;
		95
		96	/* First part of the processing with loop unrolling. Compute 4 outputs at a time.
		97	** a second loop below computes the remaining 1 to 3 samples. */
		98	while (blkCnt > 0U)
		99	{
		100	/* C(m,n) = A(m,n) * k */
		101	/* Scale, saturate and then store the results in the destination buffer. */
		102	/* Reading 2 inputs from memory */
		103	inA1 = _SIMD32_OFFSET(pIn);
		104	inA2 = _SIMD32_OFFSET(pIn + 2);
		105
		106	/* C = A * scale */
		107	/* Scale the inputs and then store the 2 results in the destination buffer
		108	* in single cycle by packing the outputs */
		109	out1 = (q31_t) ((q15_t) (inA1 >> 16) * scaleFract);
		110	out2 = (q31_t) ((q15_t) inA1 * scaleFract);
		111	out3 = (q31_t) ((q15_t) (inA2 >> 16) * scaleFract);
		112	out4 = (q31_t) ((q15_t) inA2 * scaleFract);
		113
		114	out1 = out1 >> totShift;
		115	inA1 = _SIMD32_OFFSET(pIn + 4);
		116	out2 = out2 >> totShift;
		117	inA2 = _SIMD32_OFFSET(pIn + 6);
		118	out3 = out3 >> totShift;
		119	out4 = out4 >> totShift;
		120
		121	in1 = (q15_t) (__SSAT(out1, 16));
		122	in2 = (q15_t) (__SSAT(out2, 16));
		123	in3 = (q15_t) (__SSAT(out3, 16));
		124	in4 = (q15_t) (__SSAT(out4, 16));
		125
		126	_SIMD32_OFFSET(pOut) = __PKHBT(in2, in1, 16);
		127	_SIMD32_OFFSET(pOut + 2) = __PKHBT(in4, in3, 16);
		128
		129	/* update pointers to process next sampels */
		130	pIn += 4U;
		131	pOut += 4U;
		132
		133
		134	/* Decrement the numSamples loop counter */
		135	blkCnt--;
		136	}
		137
		138	/* If the numSamples is not a multiple of 4, compute any remaining output samples here.
		139	** No loop unrolling is used. */
		140	blkCnt = numSamples % 0x4U;
		141
		142	#else
		143
		144	/* Run the below code for Cortex-M0 */
		145
		146	/* Initialize blkCnt with number of samples */
		147	blkCnt = numSamples;
		148
		149	#endif /* #if defined (ARM_MATH_DSP) */
		150
		151	while (blkCnt > 0U)
		152	{
		153	/* C(m,n) = A(m,n) * k */
		154	/* Scale, saturate and then store the results in the destination buffer. */
		155	*pOut++ =
		156	(q15_t) (__SSAT(((q31_t) (pIn++) scaleFract) >> totShift, 16));
		157
		158	/* Decrement the numSamples loop counter */
		159	blkCnt--;
		160	}
		161	/* Set status as ARM_MATH_SUCCESS */
		162	status = ARM_MATH_SUCCESS;
		163	}
		164
		165	/* Return to application */
		166	return (status);
		167	}
		168
		169	/**
		170	* @} end of MatrixScale group
		171	*/

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