C/C++ and Fortran

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Usage of the vector function vec_popcnt

By Archive User posted Tue October 28, 2014 02:06 AM

  

Originally posted by: TracyR


IBM XL C/C++ for AIX, V13.1 supports a vector population count procedure vec_popcnt. This built-in function computes the population count (number of set bits) in each element of their input. This function is valid only when the -qarch option is set to target POWER8™ processors.

The syntax of this function is:

d=vec_popcnt(a)

where d represents the types of the returned value and a in parentheses represents the type of the function argument. For details about d and a, see the following table.

d a
vector unsigned char vector signed char
vector unsigned char vector unsigned char
vector unsigned short vector signed short
vector unsigned short vector unsigned short
vector unsigned int vector signed int
vector unsigned int vector unsigned int
vector unsigned long long vector signed long long
vector unsigned long long vector unsigned long long

Result value

Each element of the result is set to the number of set bits in the corresponding element of the input.

 

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