YA6S is Yet Another 6502 Simulator, impelemting a cycle-accurate WDC 65C02S microprocessor. It includes simulated RAM, ROM, and a 16550-compatible UART. It provides a set of interfaces that can be implemented to provide additional types of devices to the simulated system. All 65C02S instructions are supported, and YA6S succefully passes the widely-used functional tests provided by Klaus Dormann.
Motivation
YA6S is intended to be a prototyping platform for designing software for a physical 6502 based microcomputer. It has a pluggable device architecture and a configurable memory map, allowing for simple changes in hardware configuration to accommodate different hardware designs.
It is inspired by the SimH retrocomputing emulator, used to emulate vintage minicomputer systems such as the DEC PDP-11 and Data General Nova. SimH also provides a flexible configuration system for devices, and includes a montor interface that allows users to suspend the operation of the emulated machine, check registers and memory, and set breakpoints.