1. A microcomputer comprising: a first processor; a second processor; a program memory for storing a program, said program including instructions of a first type to be executed by said first processor and instructions of a second type to be executed by said second processor; and a system bus interconnecting said first processor, said second processor and said program memory; said first processor including: means for executing said first type of instructions; means, responsive to said second type of instructions, for producing a token which contains sequence control information representative of a calculation task to be executed by said second processor and data to be processed by said second processor; and means for transferring said token to said second processor via said system bus; said second processor including: input means, coupled to said system bus, for temporarily storing said token; a first memory; a second memory; means, coupled between said input means and said first memory, for writing the data in said token into said first memory; means, coupled between said input means and said second memory, for writing the sequence control information in said token into said second memory; storage means for storing a plurality of calculation programs each designated by the sequence control information representative of the calculation task to be executed by said second processor; means for reading the sequence control information from said second memory; means, coupled to said first and second memories and to said sequence control information reading means, for feeding back the read sequence control information to said second memory to restore the read sequence control information therein if said first memory does not contain all data required for executing the calculation program designated by the read sequence control information; means, coupled to said first memory and to said sequence control information reading means, for designating one of said calculation programs in response to the read sequence control information if said first memory does contain all data required for executing the calculation program designated by the read sequence control information; means for reading data to be processed from said first memory; an execution unit for executing the designated calculation program by use of the data read from said first memory and obtaining an execution result; and output mean for transferring the execution result from said execution unit to said system bus.