Microprocessor having apparatus for dynamically controlling a kind of operation to be performed by instructions to be executed

A method of controlling a process for indicating a kind of operation to be performed in a microprocessor including instruction memory means for storing in sequential order macro-instructions within a fixable program to be performed, instruction executing means for performing an operation specified by operation code information of a macro-instruction output from said instruction memory means, memory means for storing data transferred from data storage means in which changeable data is stored, and control means for controlling operation of said instruction memory means, said instruction executing means and said memory means, comprising the steps of:

• (a) transferring, by said control means, data which specifies a kind of operation to be performed by the instruction executing means, from the data storage means to the memory means upon execution of a first macro-instruction, said data being transferred from said data storage means to said memory means to modify a kind of operation to be performed by a second macro-instruction to be performed after said first macro-instruction;
• (b) specifying, by said control means, a kind of operation to be performed by the instruction executing means in response to the data stored in the memory means;
• and
• (c) causing, by said control means, the instruction executing means to dynamically perform the kind of operation specified by the data stored in the memory means instead of the kind of operation to be performed by the second macro-instruction when operation code information of the second macro-instruction specifies that the operation to be performed by said instruction executing means is the kind of operation specified by the data stored in the memory means.

A microprocessor for use with data storage means in which changeable data is stored, comprising:

• instruction memory means for storing in sequential order macro-instructions within a fixable program to be performed;
• control means, coupled to said instruction memory means, for performing a control in accordance with a macro-instruction output from said instruction memory means;
• information holding means, coupled to said control means, for storing data transferred from said data storage means, said data being transferred from said data storage means to said information holding means in response to a first macro-instruction to modify a kind of operation to be performed by a second macro-instruction to be performed after the first macro-instruction;
• and
• instruction executing means, coupled to said control means and to said information holding means, for dynamically performing the kind of operation specified by the data stored in the information holding means instead of the kind of operation to be performed by the second macro-instruction in response to control by said control means when the second macro-instruction has operation code information which specifies that the operation to be performed by said instruction executing means is the kind of operation specified by the data stored in the information holding means.