Abstract: A condition code producing system for an arithmetic unit which is controlled by a micro program and operate on binary floating point data produces a condition code having a plurality of bits and describing an attribute of the binary floating point data. The condition code producing system comprises: a storing device for storing each bit of the condition code; a device for producing a plurality of detection signals from values of predetermined bits of the binary floating point data. This data is transferred to a bus within the arithmetic unit by a micro instruction which involves a data transfer, where the micro instruction is one of a plurality of micro instructions constituting the micro program. The micro instruction comprises a condition control field constituted by a plurality of bits having values depending on at least precision and data portions of the binary floating point data which is transferred.