Re: REM <SHIFT+L> and $E10C

From: Frank Kontros (
Date: 1998-09-22 21:22:17

Hi Steve,

>> Right. BTW, most of DOS speeders (SPEEDOS, PROLOGIC DOS, JIFFY DOS?) fixes that bug.
>> I also fixed it in my KERNAL patch (if someone would need, the source available).
>> Although Action Replay does not (!). Can anyone confirm other freezers (eg. FINAL 3,
>> Magic Formel, Super Snapshot) by trying list the '1 REM CTRL+L' line.
>It seems to me that the simplest fix would be to stick something other
>than a zero in the keyword table.

Hmmm. I can't agree with you. In early days of C64 there was three ROM's
inside of commie. BASIC, CHARROM and KERNAL. If you would like install a
speeder for instance you should replace only the KERNAL and no others,
so programmers patched some routines (like $E10C) or redirected the LIST
vector ($306/$307). The lattest is not so elagant because software can
disable it by resetting to default value. As now there still remains
many c64's with three ROM's, so obvious what I did in my patch.

>> >The one thing I'm not sure of is why the check for carry set is made
>> >in $E10C -- I'll try to look it up when I get home.
>> Because the BSOUT ($FFD2) checks the STOP flag which returns C=1 if pressed. Then in
>> $E107 'BREAK' message displayed if STOP pressed.
>I don't think so (calling STOP).
>In fact, I have gone through the FFD2 code about 10 times now, and I don't
>even see why carry is getting set at all.  It looks to me like it just
>shoots on through to $E6A8 as normal, which clears carry before RTSing.
>So I've suddenly lost confidence in my earlier explanation.

Look at $F1EA-$F207 locations (tape output routines). What you think about
instrucion under $F1ED :-?

>Anyone care to show me which part of $FFD2 sets the carry flag when
>printing to the screen?

I doesn't mentioned that screen output sets the carry.


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