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 convert to zoned from decimal floating point function; a first register field designating a first register, the first register comprising a first operand; a second register field and a displacement field, wherein contents of a second register designated by the second register field are combined with contents of the displacement field to form an address of a second operand; and a mask field, the mask field comprising one or more controls used during execution of the machine instruction; and executing the machine instruction, the executing comprising: converting at least a portion of the first operand in a decimal floating point format to a zoned format; and placing a result of the converting at a location designated by the address of the second operand.