Re: [cc65] 65816 (Was: Inserting Assembly Routines)

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From: MagerValp (MagerValp_at_cling.gu.se)
Date: 2002-11-28 16:24:46 

>>>>> "UvB" == Ullrich von Bassewitz <uz_at_musoftware.de> writes:

UvB> As long as the 816 code does not switch register sizes, it does
UvB> not need a special handler. And even if it does, a simple

UvB>         IRQ816: rep     #$30
UvB>                 jmp     IRQ

UvB> would be enough.

But more bytes are pushed on the stack in native mode and the hand-
ling of the BRK bit is different, so the kernal IRQ handler needs to
be completely rewritten. Also the new IRQ vectors ($FFE5..$FFEF)
collide with the kernal jump table. Having the DBR set to a bank
different than 0 breaks many kernal routines.

But heck, go for it ;)

-- 
    ___          .     .  .         .       . +  .         .      o   
  _|___|_   +   .  +     .     +         .  Per Olofsson, arkadspelare
    o-o    .      .     .   o         +          MagerValp_at_cling.gu.se
     -       +            +    .     http://www.cling.gu.se/~cl3polof/
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