Compiler

A system for minimizing the code size of an object program executable on a computer, the object program having been translated from a source program using a compiler, the source program including a plurality of instructions, the compiler comprising:

• first instruction length calculating means for calculating a total length of the instructions where variables for the source program are allocated to a first type of register resources in accordance with a first instruction format;
• and
• second instruction length calculating means for calculating a total length of the instructions where the variables are allocated to a second type of register resources in accordance with a second instruction format, the length of one instruction defined by the second instruction format being different from that defined by the first instruction format,
• wherein the variables are allocated to respectively appropriate ones of the register resources based on the results of calculation derived by the first and second instruction length calculating means.