From 76177aa280494bb36d7a0bcbda1078d4db717020 Mon Sep 17 00:00:00 2001 From: Ali Labbene Date: Mon, 9 Dec 2019 11:25:19 +0100 Subject: Official ARM version: v4.5 --- Documentation/DSP/html/group__shift.html | 311 +++++++++++++++++++++++++++++++ 1 file changed, 311 insertions(+) create mode 100644 Documentation/DSP/html/group__shift.html (limited to 'Documentation/DSP/html/group__shift.html') diff --git a/Documentation/DSP/html/group__shift.html b/Documentation/DSP/html/group__shift.html new file mode 100644 index 0000000..7f4f2ad --- /dev/null +++ b/Documentation/DSP/html/group__shift.html @@ -0,0 +1,311 @@ + + + + + +Vector Shift +CMSIS-DSP: Vector Shift + + + + + + + + + + + + + + + +
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CMSIS-DSP +  Version 1.4.7 +
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CMSIS DSP Software Library
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+Functions
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Vector Shift
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Basic Math Functions
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+Functions

void arm_shift_q15 (q15_t *pSrc, int8_t shiftBits, q15_t *pDst, uint32_t blockSize)
 Shifts the elements of a Q15 vector a specified number of bits.
 
void arm_shift_q31 (q31_t *pSrc, int8_t shiftBits, q31_t *pDst, uint32_t blockSize)
 Shifts the elements of a Q31 vector a specified number of bits.
 
void arm_shift_q7 (q7_t *pSrc, int8_t shiftBits, q7_t *pDst, uint32_t blockSize)
 Shifts the elements of a Q7 vector a specified number of bits.
 
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Description

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Shifts the elements of a fixed-point vector by a specified number of bits. There are separate functions for Q7, Q15, and Q31 data types. The underlying algorithm used is:

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+    pDst[n] = pSrc[n] << shift,   0 <= n < blockSize.        
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If shift is positive then the elements of the vector are shifted to the left. If shift is negative then the elements of the vector are shifted to the right.

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The functions support in-place computation allowing the source and destination pointers to reference the same memory buffer.

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Function Documentation

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void arm_shift_q15 (q15_t * pSrc,
int8_t shiftBits,
q15_t * pDst,
uint32_t blockSize 
)
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Parameters
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[in]*pSrcpoints to the input vector
[in]shiftBitsnumber of bits to shift. A positive value shifts left; a negative value shifts right.
[out]*pDstpoints to the output vector
[in]blockSizenumber of samples in the vector
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Returns
none.
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Scaling and Overflow Behavior:

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The function uses saturating arithmetic. Results outside of the allowable Q15 range [0x8000 0x7FFF] will be saturated.
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References __SIMD32, and blockSize.

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Referenced by arm_dct4_q15().

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void arm_shift_q31 (q31_t * pSrc,
int8_t shiftBits,
q31_t * pDst,
uint32_t blockSize 
)
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Parameters
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[in]*pSrcpoints to the input vector
[in]shiftBitsnumber of bits to shift. A positive value shifts left; a negative value shifts right.
[out]*pDstpoints to the output vector
[in]blockSizenumber of samples in the vector
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Returns
none.
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Scaling and Overflow Behavior:

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The function uses saturating arithmetic. Results outside of the allowable Q31 range [0x80000000 0x7FFFFFFF] will be saturated.
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References blockSize, and clip_q63_to_q31().

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Referenced by arm_dct4_q31().

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void arm_shift_q7 (q7_t * pSrc,
int8_t shiftBits,
q7_t * pDst,
uint32_t blockSize 
)
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Parameters
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[in]*pSrcpoints to the input vector
[in]shiftBitsnumber of bits to shift. A positive value shifts left; a negative value shifts right.
[out]*pDstpoints to the output vector
[in]blockSizenumber of samples in the vector
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Returns
none.
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Conditions for optimum performance
Input and output buffers should be aligned by 32-bit
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Scaling and Overflow Behavior:

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The function uses saturating arithmetic. Results outside of the allowable Q7 range [0x8 0x7F] will be saturated.
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References __PACKq7, __SIMD32, and blockSize.

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+ + + + -- cgit