Controlling process for a controlling apparatus having a CPU and special function units

A process for controlling a control unit including a CPU unit for conducting program sequence control and special function units for performing special function control in accordance with commands from said CPU unit, comprising the steps of:

• storing instruction information corresponding to said special function units into memory provided in said special function units and accessible from said CPU unit;
• creating a program having at least one instruction step which includes a function-symbol indicating a special function unit-corresponding instruction and a type-symbol denoting a special function type, said function-symbol and said type-symbol being independent of an address of said at least one instruction step;
• storing said program into a program memory;
• executing each instruction in said program, said executing step comprising:
• determining whether a current instruction from said program corresponds to one of said special function units, by checking for said function symbol and said type symbol, and checking whether said current instruction is valid on said one of said special function units, by reading said instruction information stored in said memory of said one of said special function units, and requesting said one of said special function units to execute said instruction step according to said instruction information when the instruction information matches the content of said instruction step;
• and
• executing said instruction according to said instruction information stored in said memory in said one of said special function units.