Here you will find a 6502 simulator which resembles the early 6502 single board computers such as the KIM-1, but implemented in software and providing additional features made possible by the Windows operating system.
The simulator files, including a Windows help system and demonstration programs, can be downloaded here. This program is well-suited to training novices in assembler language programming and in 'resurrecting' 6502 software from the past. The simulator supports the complete 6502 instruction set and both binary and decimal operating modes.
The simulator and the software tools use a special file format with a file extender of 'h6x'. This format is intended to provide a simple representation of 6502 code in an ASCII environment for easy editing. For example,
0200 A9 23
0202 8D 01 80
is a fragment from a file named 'test.h6x'. Each line begins with an address in hex format and one or more bytes of hex data separated by spaces. The example above is the 6502 code for loading the accumulator with 23 (hex) and storing that value in memory location 8001 (hex). A break instruction completes the fragment.