Page 8: Using the 6502 Simulator

OSHONSOFT 6502 SIMULATOR

We have been using OshonSoft's products for a couple of years and very much like their simulators. Yes, they have their quirks but for the most part they get the job done. Additionally, we are not aware of a lot of other Sims available for the 6502 MPU.

Math_Menu_v1.0_SIM.asm

Math_Menu_v1.0_SIM.asm is the Math_Menu_v1.0.asm file that's been modified to make it easier to use with the Simulator. Like the Math boot file, it contains only what we need to demo the Math Menu.

When you have run the file through the simulator once and know that the menu display routines like those found in "Math00:" to "Math04:" are working properly, then you'll want to comment out the lines. Otherwise you'll find yourself waiting a while each time you make a change to the .asm file and restart the Sim.

So that's what we did: we made sure the display routines worked properly then commented them out with three semi-colons: ";;;". One semicolon means the line is not to be run  - period. Three semicolons means "let's save some time here".

Another technique is to include a jump statement; check out lines 161 and 192. Thanks to the "JMP" instruction everything between those two lines will be ignored by the Assembler.

Setting Up The SIM

Setting up the simulator does take a bit of work but it you need to know specifically what's running and when, it's worth it. We'll do that on the next page.

Simulator File