[A83] Re: rst 20h crap

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[A83] Re: rst 20h crap


But, what about the EDB0C90000???
I came to this by doing:

ld hl,20h
ld de,data+4
ld bc,8
ldir
ret

data: .db 0,0,0,0,0,0,0,0,0,0,0,0

After executing this program, I just checked the bytes
after data:, and did some disassembling.

   SUCKER


>At 0020h there's a jp to _HLToOP1 (to the real routine, not the equate)
>Btw, this routine copies 9 bytes, not 8 as you said.
>
> >From: "The one and only SUCKER ..." <sucker_pvn@hotmail.com>
> >Reply-To: assembly-83@lists.ticalc.org
> >To: assembly-83@lists.ticalc.org
> >Subject: [A83] rst 20h crap
> >Date: Tue, 21 Aug 2001 20:41:07 +0000
> >
> >
> >I found out something weird. rst 20h (TI-83-) is the
> >same as op1=(hl). So far so good. And rst 20h is the
> >same as call 20h. The next rst is rst 28h, so there
> >are eight bytes with possible code which is executed
> >with rst 20h. At 20h there is: EDB0C90000... , which
> >is ldir/ret. If you follow so far, rst 20h should then
> >be the same as ldir and the same as op1=(hl).
> >But this is not!
> >
> >for ldir, bc is how many bytes, hl is from where to
> >copy to the addres in bc, so bc would have to be eight
> >(like eight bytes with possible code in rst 20h) and
> >de would point to op1 so that whenever you execute
> >ldir, everything would be set to that to copy the
> >following bytes at (hl) to op1.
> >
> >But no!!
> >
> >What the hell this is about????
> >If I think this way everything should match (like replacing stuff)
> >But have I made an error??
> >
> >Here a prmg that uses rst 20h:
> >
> >	ld hl,name
> >	rst 20h
> >	call _chkfindsym
> >	ret nc
> >	jp _getkey
> >;when the prgm AWELCOME exists, and is not protected
> >;Done is displayed, otherwise it waits for a key input.
> >
> >name: .db 5,"AWELCOME",0
> >
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> >
>
>
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