BLuRry wrote:
> On Jan 14, 9:04 pm, lyricalnanoha
>  wrote:
>> I'm gonna do a rerelease of Apple Crunch.  I've recompressed a bunch of
>> the games, recracked a couple, reripped a few more.
>>
>> Though, I really don't like the menus I'm capable of doing in the current
>> system. :(  And since I keep the files as BASIC-type (it makes them easier
>> to handle), I can't use Beautiful Boot without hacking them.
>>
>> Here's my questions:
>>
>> 1. Does anyone know how I might go about doing something like Beautiful
>> Boot - a menu with a fastloader that runs in HGR mode - but with the
>> ability to run BASIC programs as well as binary?  My current approach is
>> to use RDOS 3.3.
> 
> Executing a basic program as a binary is pretty easy... (once you know
> about the onerr flag anyway)
> ; Clear onErr flag
> LDA #$00
> STA $d8
> ; Store start of basic program (e.g. $801)
> LDA #$01
> STA $67
> LDA #$08
> STA $68
> ; Store end of basic program (start + filesize -- e.g. $6000)
> LDA #$00
> STA $AF
> LDA #$60
> STA $B0
> ;Set LOMEM (optional?)
> LDA #$00
> STA $69
> LDA #$80
> STA $69
?? must be $6A.
> ;Set HIMEM (optional?)
> LDA #$ff
> STA $69
STA $73
> LDA #$af
> STA $69
STA $74

Should also set $6F.70 to HIMEM value so strings go in the
right place.

> ;Start the basic program
> JMP $d566
> 
> So you could shove this loader somewhere low in memory like $300 or
> you could pre-pend it to the beginning of the basic file.  This is
> exactly what I use for AGS to execute basic programs and it seems to
> work pretty well.  I set LOMEM to START+SIZE+1 and HIMEM to DOS -1
> (and if you don't care about DOS, then just DFFF).   I have a feeling
> that what you're doing probably doesn't matter too much if LOMEM or
> HIMEM are set -- but I could be mistaken.

HIMEM should be set to the next page boundary *after* the last RAM
address usable by Applesoft.  So on a "bare" machine, it is $C000,
and similarly for any OS, buffers, addons present.  In several places
it is assumed that it is a page-aligned address.

LOMEM (end of program) should be set to program start + size (not +1).

-michael

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