[question] Assembly and C?

[Fabrizio-Caruso]

First of all sorry to use an issue for a question.

I would like to have a routine getk that just polls the MC-10 keyboard without waiting.

In BASIC I could just read values at 17023 and 2 to poll the keyboard. But if I use CC68 and I try to "peek" at location 17023 I do not get the ASCII code of the last key pressed. Nor does the value at 2 gets updated if any key is pressed. So I guess something is different. Maybe those values are updated by some interrupt that your crt disables.

So I suppose I need to resort to some little Assembly. I am not an Assembly coder and my best guess would be a .s file with this content:

.export _getk
.setcpu 6803

.code

_getk:
    pshx
    ldx $FFDC
    jsr ,x
    pulx
    tab
    clra
    rts

If I try to compile it, cc68 complains with multiple errors of this type: test/mc10_getk.s: 1: Q: unexpected character.

With CC65 I can compiler and link a mix for .c and .s. How do I do it with CC68?

[EtchedPixels]

Looks correct and works for me in fact I think it's the same code as is in target-mc10.

Are you sure you don't have any unicode order markers at the start or the wrong kind of newlines (it's not found of \r\n only the proper Unix \n).

[EtchedPixels]

Pushed support for legacy DOS \r\n newlines

[Fabrizio-Caruso]

@EtchedPixels Thanks a lot! It does work, indeed! Unfortunately it seems not to auto-repeat, i.e., if I keep a key pressed, it will just detect it once. I need to figure out how to have it auto-repeat.

P.S.: I stole your code for cgetc and I tried to adapt it for my purpose. I hope it is OK for you.

[EtchedPixels]

Sure.. I suspect for pure game use you may need to scan the matrix yourself.

The basic ones btw are updated by the BASIC interpreter as it runs - there is no interrupt. For some reason the 6847 vsync isn't wired through the interrupt on the 6803, instead the 6803 irq line is just pulled high.

[Fabrizio-Caruso]

@EtchedPixels Indeed I will have to write a scanning routine. My Assembly skills are poor. I will start with a simple C version that "pokes" at location 2 and "peeks" at 49151. It should be fast enough for my purpose. Indeed Cross-Lib is mostly meant for games and auto-repeat is necessary.

[Fabrizio-Caruso]

@EtchedPixels if the BASIC routine puts the ASCII value of the pressed key into 17023, couldn't I you use this routine as long as no code is stored there. How can I know where in memory your compiler stores the code? I could not find a .cfg file as in CC65.

[EtchedPixels]

I don't believe there is any way to just call the relevant code in the BASIC ROM - not officially anyway.

The compiler packs everything from address 17500 onwards, so just above the BASIC workspace if no BASIC program is present