1 /* ----------------------------------------------------------------------
2 * Copyright (C) 2010 ARM Limited. All rights reserved.
7 * Project: CMSIS DSP Library
10 * Description: Q31 vector absolute value.
12 * Target Processor: Cortex-M4/Cortex-M3/Cortex-M0
14 * Version 1.0.10 2011/7/15
15 * Big Endian support added and Merged M0 and M3/M4 Source code.
17 * Version 1.0.3 2010/11/29
18 * Re-organized the CMSIS folders and updated documentation.
20 * Version 1.0.2 2010/11/11
21 * Documentation updated.
23 * Version 1.0.1 2010/10/05
24 * Production release and review comments incorporated.
26 * Version 1.0.0 2010/09/20
27 * Production release and review comments incorporated.
29 * Version 0.0.7 2010/06/10
30 * Misra-C changes done
31 * -------------------------------------------------------------------- */
40 * @addtogroup BasicAbs
46 * @brief Q31 vector absolute value.
47 * @param[in] *pSrc points to the input buffer
48 * @param[out] *pDst points to the output buffer
49 * @param[in] blockSize number of samples in each vector
52 * <b>Scaling and Overflow Behavior:</b>
54 * The function uses saturating arithmetic.
55 * The Q31 value -1 (0x80000000) will be saturated to the maximum allowable positive value 0x7FFFFFFF.
63 uint32_t blkCnt; /* loop counter */
64 q31_t in; /* Input value */
68 /* Run the below code for Cortex-M4 and Cortex-M3 */
71 blkCnt = blockSize >> 2u;
73 /* First part of the processing with loop unrolling. Compute 4 outputs at a time.
74 ** a second loop below computes the remaining 1 to 3 samples. */
78 /* Calculate absolute of input (if -1 then saturated to 0x7fffffff) and then store the results in the destination buffer. */
80 *pDst++ = (in > 0) ? in : ((in == 0x80000000) ? 0x7fffffff : -in);
82 *pDst++ = (in > 0) ? in : ((in == 0x80000000) ? 0x7fffffff : -in);
84 *pDst++ = (in > 0) ? in : ((in == 0x80000000) ? 0x7fffffff : -in);
86 *pDst++ = (in > 0) ? in : ((in == 0x80000000) ? 0x7fffffff : -in);
88 /* Decrement the loop counter */
92 /* If the blockSize is not a multiple of 4, compute any remaining output samples here.
93 ** No loop unrolling is used. */
94 blkCnt = blockSize % 0x4u;
98 /* Run the below code for Cortex-M0 */
100 /* Initialize blkCnt with number of samples */
103 #endif /* #ifndef ARM_MATH_CM0 */
108 /* Calculate absolute value of the input (if -1 then saturated to 0x7fffffff) and then store the results in the destination buffer. */
110 *pDst++ = (in > 0) ? in : ((in == 0x80000000) ? 0x7fffffff : -in);
112 /* Decrement the loop counter */
119 * @} end of BasicAbs group