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.
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, and may
indicate the data type double{2|4|8|16} if
the cl_khr_fp64 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); |
Copyright © 2007-2010 The Khronos Group Inc.
Permission is hereby granted, free of charge, to any person obtaining a
copy of this software and/or associated documentation files (the
"Materials"), to deal in the Materials without restriction, including
without limitation the rights to use, copy, modify, merge, publish,
distribute, sublicense, and/or sell copies of the Materials, and to
permit persons to whom the Materials are furnished to do so, subject to
the condition that this copyright notice and permission notice shall be included
in all copies or substantial portions of the Materials.