Apparatus and method for prefetching data based on information contained in a compiler generated program map

摘要

An apparatus and method for pre-loading a cache memory based on information contained in a compiler generated program map are disclosed. The program map is generated by the compiler at the time source code is compiled into object code. For each application program, the user would have this program map stored with the object file. At the beginning of the program execution cycle, the operating system will determine whether or not a program map exists for the application. If a program map exists, the operating system will load the program map into an area of RAM designated as the program map random access memory (RAM). The program map will be used to pre-load the cache with the appropriate data and instructions for the central processing unit (CPU) to process. The program mapping would be the address location of each jump/branch target that the CPU might encounter during the execution cycle. Each of these locations represent a starting point for a new code sequence. At the start of the map will be an identifier field to mark the start of the map. The next field in the program map will provide the entry point of the starting address of the application program. If a particular application program does not have a program map, the program and cache operation will remain unchanged. This feature provides backwards compatibility with existing application programs.