Patent ID: 6279079
Filing Date: 2001-08-21
Classification: G06F

Abstract:
A program execution system comprising:first storage means provided with permanent addresses located in a memory space and characterized by a relatively fast access;second storage means for storing a program, provided with permanent addresses located in the memory space and characterized by a comparatively slower access;control means for decoding the program and outputting a decoded result to an instruction execution means; whereinsaid control means further comprises:hit determination means for determining, when a function code in the program is called, whether a duplicate of the function code, originally residing in said second storage means, is located in said first storage means;memory allocation means for allocating a free block for storing the duplicate of the function code;memory release means for releasing a block created in said first storage means so as to create the free block;code duplicating means for creating a duplicate of the function code in said free block created by said memory release means in said first storage means;release determination means for determining whether the duplicate of the function code created in said first storage means can be removed from said first storage means; andrelease resolution means for determining which of the function codes determined to be ready for removal should be removed from said first storage means; and whereinsaid control means effects control such that, when the function code is called, the duplicate of the function code is read from said first storage means and executed;in the absence of the duplicate of the function code, the duplicate of the function code is created in said first storage means so that the instruction execution means executes the function code; andthe free block capable of storing the duplicate of the called function code is made available after the function code ready for removal is removed from said first storage means.