Summary

A stack_machine evaluates programs using a stack. Data follows last_in_first_out order. Instructions use push to place values and pop to remove them. Most operations read the top_of_stack, combine values, then push results. There are few or no general registers. Control moves via an instruction_pointer. Programs are sequences of simple opcodes. Arithmetic, comparison, and call_frames use the same operand_stack. This model is common in bytecode virtual_machine designs. Remember: stack effects determine how many values each opcode consumes and produces.