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 Element Rotate And Insert Under Mask operation; a first register field to be used to designate a first register, the first register comprising a first operand; a second register field to be used to designate a second register, the second register comprising a second operand; a third register field to be used to designate a third register, the third register comprising a third operand; and executing the machine instruction, the executing comprising: rotating one or more elements of the second operand in a selected direction by a specified amount to rotate; checking the third operand for one or more data units having a particular value; and based on the third operand having the one or more data units with the particular value, replacing one or more values of corresponding data units in the first operand with one or more values of corresponding data units in the second operand that has been rotated.