shuffle, shuffle2
shuffle, shuffle2
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3
shuffle Constructs a permutation of elements from one (or two) input vectors.

##

gentypen `shuffle` gentypem x ugentypen mask gentypen `shuffle2` gentypem x gentypem y ugentypen mask

## Description

The `shuffle` and `shuffle2` built-in functions construct a permutation of elements from one or two input vectors respectively that are of the same type, returning a vector with the same element type as the input and length that is the same as the shuffle mask. The size of each element in the `mask` must match the size of each element in the result. For `shuffle`, only the ilogb(2m-1) least significant bits of each `mask` element are considered. For `shuffle2`, only the ilogb(2m-1)+1 least significant bits of each `mask` element are considered. Other bits in the `mask` shall be ignored.

The elements of the input vectors are numbered from left to right across one or both of the vectors. For this purpose, the number of elements in a vector is given by vec_step(gentypem). The shuffle `mask` operand specifies, for each element of the result vector, which element of the one or two input vectors the result element gets.

We use the generic type name gentypen (or gentypem) to indicate the built-in data types char{2|4|8|16}, uchar{2|4|8|16}, short{2|4|8|16}, ushort{2|4|8|16}, int{2|4|8|16}, uint{2|4|8|16}, long{2|4|8|16}, ulong{2|4|8|16}, or float{2|4|8|16} as the type for the arguments unless otherwise stated. We use the generic name ugentypen to indicate the built-in unsigned integer data types. If the double is supported, then gentypen (or gentypem) also indicate the built-in data types double{2|4|8|16}.

The generic type name gentypen (or gentypem) may indicate the data type half{2|4|8|16} if the cl_khr_fp16 extension is supported.

## Example

uint4 mask = (uint4)(3, 2, 1, 0); float4 a; float4 r = shuffle(a, mask); // r.s0123 = a.wzyx uint8 mask = (uint8)(0, 1, 2, 3, 4, 5, 6, 7); float4 a, b; float8 r = shuffle2(a, b, mask); // r.s0123 = a.xyzw // r.s4567 = b.xyzw uint4 mask; float8 a; float4 b; b = shuffle(a, mask);

Examples that are not valid are:

uint8 mask; short16 a; short8 b; b = shuffle(a, mask);

## Specification

OpenCL Specification

## Also see

Miscellaneous Vector Functions

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