1. A method of executing a machine instruction in a central processing unit, the method comprising: obtaining, by a processor, a machine instruction for execution, the machine instruction being defined for computer execution according to a computer architecture, the machine instruction comprising: at least one opcode field to provide an opcode, the opcode identifying a Vector Floating Point Test Data Class Immediate operation; a first register field to be used to designate a first register, the first register comprising a first operand; and a second register field to be used to designate a second register, the second register comprising a second operand; and a mask field; and executing the machine instruction, the executing comprising: determining properties of a chosen element of the second operand, wherein the mask field indicates whether one or more elements of the second operand are to be included in the determining; selecting from an input to the machine instruction a selected data unit representing the properties of the chosen element, the input including one or more data units to represent one or more properties; checking whether the selected data unit is set to a particular value; and based on the checking, setting an element in the first operand that corresponds to the chosen element of the second operand, the setting based on whether the selected data unit is set to the particular value.