Summary

This chapter presented the essential elements of bytecode interpreters. Knowing how to implement a bytecode interpreter frees you to generate flexible code, without having to worry about hardware instruction sets, registers, or addressing modes.

First, you learned that the definition of an instruction set includes the opcodes and rules for processing any operands in those instructions. You also learned how to implement generic stack machine semantics, as well as bytecode instructions that correspond to domain-specific language features. Then, you learned how to read and execute bytecode files, including interchangeably working with sequences of bytes and words in both Unicon and Java.

Given the existence of a bytecode interpreter, in the next chapter, we will discuss generating bytecode from intermediate code so that we can run programs that are compiled using our compiler!