Re: [cc65] Playing a PSID file

On Sat, Nov 5, 2011 at 3:27 AM, Marc 'BlackJack' Rintsch <marc@rintsch.de>wrote:

> Hi Payton,
>
> > I've done some initial googling and haven't found anything, so I want
> > to pose a general question "What's the best way to play a PSID file
> > from cc65" and to expand on what I believe the steps to be and the
> > issues that I need to understand.
> >
> > 1) Assume I have a PSID that has loads at $1000 through $1900.  It
> > inits at $1000 and plays at $1003.
> > 2) I need to load that PSID into memory.  I'm assuming I can simply
> > put the bytes of the data into an ASM file and it will get linked
> > into the program at $1000.  However, I do need to understand if
> > there will need to be any custom memory mappings for this and
> > exactly what syntax to use in the ASM file to accomplish setting the
> > bytes at a specific memory location.
>
> Including the data can be done with the ``.incbin`` command in the
> assembler file.  Use the offset argument to skip the PSID header.
>
> Placing the data at a specific memory location requires a little more
> than just assembler syntax.  What ends up where is decided by the linker
> and the linker configuration you have to write.  The memory from $1000
> upwards is part of the memory where cc65 and the runtime can put code,
> data, and stack, so you have to write a memory configuration to protect
> the space for your music and define a segment to place it there.
>
> So the assembler file might look like this:
>
>  .export _music_init, _music_play
>  .segment MUSIC_SEGMENT
>      _music_init = *
>      _music_play = _music_init + 3
>      .incbin "music.sid", $7c  ; $7c = offset of data in PSIDv2 format
>
> Here is the header file to use it from C:
>
>  #ifndef MUSIC_H
>  #define MUSIC_H
>
>  #include <stdint.h>
>
>  void __fastcall__ music_init(uint8_t song_number);
>  void music_play(void);
>
>  #endif
>
>
> Ciao,
>        Marc 'BlackJack' Rintsch
> --
> “Programmers should be paid by the amount of code
>  that they avoid writing.”  -- Michael P. Soulier
>

Marc,

Thank you so much for this info.  It's exactly what I was needing for this
part.  I'll play around with a memory map and see if I can figure out the
part with the linker.

-- 
Payton Byrd
<http://www.paytonbyrd.com>
<http://it.toolbox.com/blogs/paytonbyrd>

----------------------------------------------------------------------
To unsubscribe from the list send mail to majordomo@musoftware.de with
the string "unsubscribe cc65" in the body(!) of the mail.