Instruction-set architecture simulation techniques using just in time compilation

A method comprising:

• receiving, by an interface from a program simulator, a request for compiled data of a given instruction;
• accessing, by said interface, a protection table, stored in memory, that indicates whether locations in a cache table are individually protected or unprotected from being overwritten for each of a plurality of instructions in said cache table;
• accessing, by said interface, said cache table of compiled data, stored in said memory;
• compiling, by an instruction compiler, said given instruction and storing compiled data relating to said given instruction at a given location in said cache table, if compiled data is not stored at said given location in said cache table;
• verifying, by said interface, that said compiled data at said given location in said cache table is related to said given instruction, and not a different instruction that was previously executed at a same instruction address as the given instruction, if compiled data is stored at said given location in said cache table;
• compiling, by said instruction compiler, said given instruction to produce said compiled data relating to said given instruction, if said compiled data at said given location in said cache table is not related to said given instruction;
• storing, by said interface, said compiled data relating to said given instruction or a reference thereto at said given location in said cache table, if said protection table indicates that compiled data of said different instruction at said given location is not protected from being overwritten;
• and
• returning, by said interface to said program simulator, said compiled data relating to said given instruction or said reference thereto.

A non-transitory computer readable medium having stored therein instructions which when executed on a processor implement a simulator comprising:

• determining if compiled data for a given instruction is stored in a data structure of compiled instructions, wherein compiled instructions are individually selectively protected from being overwritten;
• decoding said given instruction, determining said compiled data for said decoded given instruction, and storing said compiled data in said data structure, if said compiled data is not in said data structure;
• determining if said given instruction has changed from a previous execution of an instruction having compiled data in said data structure;
• decoding said given instruction and determining said compiled data for said decoded given instruction, if said given instruction has changed from said previous execution of said instruction having compiled data in said data structure, determining if said compiled data in said data structure from a previous execution is protected, storing said compiled data for said decoded given instruction in said data structure if said compiled data in said data structure from a pervious execution is not protected, and not storing said compiled data for said decoded given instruction in said data structure if said compiled data in said data structure from a previous execution is protected;
• and
• returning said compiled data.