Integer Built-In Functions

Click an item in the table below for details about that function.

abs |x|
abs_diff |x-y| without modulo overflow
add_sat x+y and saturate result
hadd (x+y) >> 1. The intermediate sum does not modulo overflow
rhadd (x+y+1) >> 1. The intermediate sum does not modulo overflow.
clamp min(max( x, minval), maxval)
clz Number of leading 0-bits in x
ctz Number of trailing 0-bits in x
mad_hi mul_hi(a,b)+c
mad24 (Fast integer function.) Multiply 24-bit integer then add the 32-bit result to 32-bit integer
mad_sat a*b+c and saturate the result
max The greater of x or y
min The lesser of x or y
mul_hi High half of the product of x and y
mul24 (Fast integer function.) Multiply 24-bit integer values a and b
rotate result[indx]=v[indx]<< i[indx]
sub_sat x - y and saturate the result
upsample result[i] = ((gentype)hi[i] << 8|16|32) | lo[i]
popcount Returns the number of non-zero bits in x.


Built-in integer functions take scalar or vector arguments. The vector versions of the integer functions operate component-wise. The description is per component.

We use the generic type name gentype to indicate that the function can take char, char{2|3|4|8|16}, uchar, uchar{2|3|4|8|16}, short, short{2|3|4|8|16}, ushort, ushort{2|3|4|8|16}, int, int{2|3|4|8|16}, uint, uint{2|3|4|8|16}, long, long{2|3|4|8|16}, ulong, or ulong{2|3|4|8|16} as the type for the arguments. We use the generic type name ugentype to refer to unsigned versions of gentype. For example, if gentype is char4, ugentype is uchar4.

We also use the generic type name sgentype to indicate that the function can take a scalar data type i.e. char, uchar, short, ushort, int, uint, long, or ulong as the type for the arguments. For built-in integer functions that take gentype and sgentype arguments, the gentype argument must be a vector or scalar version of the sgentype argument. For example, if sgentype is uchar, gentype must be uchar or uchar{2|3|4|8|16}. For vector versions, sgentype is implicitly widened to gentype as described in section 6.3.a of the OpenCL specification.

For any specific use of a function, the actual type has to be the same for all arguments and the return type unless otherwise specified.


OpenCL Specification

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