Micro64 is an cycle exact Commodore C64 emulator. It is still in development but you can try this beta version. Micro64 has beside a normal VIC II emulation also a half-cycle exact experimental emulation, but this emulation is a bit slow at the moment. You must also take a look at the program micro64ide.exe. This program shows you the how a program runs inside the C64 and you can watch the memory.