While I am waiting for Apple 1 PCB to show up so I can begin my build, I decided to read the manual. In the manual is a test program written in 6502 machine lanuage.
So I decided to disassemble that code and turn it into readable 6502 assembly language. So for those of you who are interested in what the test program does or is looking to learn 6502 assembly language, here something to get you started.
AA9 00 LDA #$0 Load A (Accumulator) register with 0
AA TAX Transfer what is in the A register to the X Register. The contents of the A register are unaffected
20 EF FF JSR $FFEF This is the output character routine in the Apple 1 monitor. Let the monitor do the work for you
E8 INX Increment the X register
8A TXA Transfer the contents of the X register and put it in A register
4C 02 00 JMP $0002 Jump to the TAX instruction to get the Next Character and after we get to the last character the program starts over
All the instructions and numbers are in hexidecimal.
I hope this will peak your interest and you will want to learn 6502 assembly language.
If you have any questons, please ask.