POWER8 built-in function vec

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POWER8 built-in function vec_bperm

By Archive User posted Wed November 26, 2014 04:33 AM

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Originally posted by: TracyR

For vector processing, IBM XL C/C++ for Linux V13.1 supports a new POWER8 built-in function vec_bperm. The vec_bperm can gather up to 16-bit values from a quadword in the specified order and it operates on vectors as 128-bit unsigned integers. The vec_bperm function is valid only when the -qarch option is set to target POWER8™ processors.

Syntax

The function has the following syntax, where d represents the function returned value; a and b represent the arguments.

d=vec_bperm(a, b)

Result and argument types

The following table describes the types of the returned value and the function arguments.

d	a	b
vector unsigned char	vector unsigned char	vector unsigned char

Result value

The following table describes the function result. For each i (0 <= i < 16), let index denote the byte value of the i^thelement of the argument b.

Value of index	Function result
*index* >= 128	bit 48+i of the result is set to 0.
*index* < 128	bit 48+i of the result is set to the value of the index^thbit of the input a.

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C/C++ and Fortran