Am 27.04.20 um 21:12 schrieb Marco van de Voort:
Op 2020-04-27 om 18:28 schreef Florian Klaempfl:
I have no idea, but quickly read through some docs, and it seems the
GameBoy CPU doesn't have IX/IY registers, which seems to be very
useful to
implement some of the more complex references handling, according to
what
Nikolay wrote earlier.
Yes. IX and IY are the key for the FPC Z80 port. Without them it's
getting really difficult. And I suspect we need to work without a
normal stack but allocate local variables globally, so basically no
recursion will be possible.
Well, for 6502 working 16-bit ptr indirect via volatile zp memory
locations needs to be implemented anyway :-)
Does that CPU have no hardware stack at all, or only limited (128/256
bytes or so?)
It has a full stack but too little registers to use it efficiently for
local variables: it has 3 8 bit registers pair plus accumulator (so 7 8
bit registers), two of them can be used as pairs for indirect
addressing, so this makes life very hard, but maybe, when I think about
it, doable ;) 8085 assembler was the first assembler I learned, at a
certain time I knew the hex. codes for most instructions.
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