Industrial Technology Research Institute

Lung-Chung Chang

Chung-Ping Chung

Hsien-Wen Dai

Lee-Ren Ton

Min-Fu Kao

A method and apparatus for native method invocation and changing memory bank. A method return frame of a smart card stores the status of a native method invocation, and a memory bank flag points a program counter to a runtime environment (RE) memory bank or an operating system (OS) memory bank. First, upon a method invocation, the method return frame is pushed and set as a native method invocation when the method invocation is the native method invocation. Then, the memory bank flag points the program counter to the OS memory bank. Next, the method return frame is popped after the native method has been executed. Finally, the memory bank flag is changed to point the program counter to the RE memory bank if the method return frame is set as the native method invocation.

Method and apparatus for native method invocation and changing memory bank

The present invention provides a stack machine for executing a plurality of instructions one by one. The stack machine comprises an operation folder and an execution unit. The operation folder is used for checking if one or more instructions of a predetermined number of instructions following a specific instruction in a predetermined sequence can be folded with the specific instruction according to a POC folding rule. If they are foldable, these instructions will be combined to form a new instruction. The execution unit is used for executing instructions which cannot be folded by the operation folder or new instructions generated by the operation folder one by one. The instructions are folded to enhance operation efficiency of the stack machine.

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Jhubei, Taiwan

Lung-Chung Chang