Re: A83:STILL NEED HELP!
[Prev][Next][Index][Thread]
Re: A83:STILL NEED HELP!
> dWait: in a,(10h) ; 11 T
> rla ; 4 T
> jr c,dWait ; 12/7
> ret ; 10 T
>
> call dWait ; 17T
>
> So the port is read after 17+11 T states. Since it takes at least 30
before
> it is finished the port will be read again after:
> 17+11+4+12+11 = 55 T. So you will return from the subroutine after
> 55T+4+7+10= 76T states. This is more than twice the amount needed, and
thus
> very inefficient.
Ah, first, the idea of calling this routine is insane. Subroutines are a
crime if one needs speed. So just use a macro, okay? Takes already 27
T-states less. Further, the wait-time of fastCopy in the zGFXL library of
SOS is 53 T-states, and since 53+53 is 106 the 76 T-states is way not twice
the amount needed.
But indeed, the ready-signal will always be detected at least 22 T-states
later... And in case of fastCopy, all kinds of stuff is being done in the
meanwhile. Ofcourse with this routine that's not possible. Although if you
call it right before an out instead of after it will loop only once (hence
taking only 22 extra T-states).
Well, and now the conclusion: just use the fastCopy routine of SOS / ION
since it will surely work on all TI-83 and 83+s (since it is thoroughly
tested) and it is FAST. When you do not need the real speed but for some
reason do want to use your own displayroutines (because you use a nice
effect or so) use the 'official' wait. Not as a subroutine ofcourse, but as
a macro. And if you need speed for a fast effect or so, then at least make
sure you wait 53 T-states on a TI-83. I don't know about the TI-83+,
somebody has to look up the minimal wait in fastCopy in ION's sources.
~Grauw
--
>>>>>>>>>>>>>>>>>>>>>>>>><<<<<<<<<<<<<<<<<<<<<<<<<
email me: laurensh@geocities.com or ICQ: 10196372
visit the Datax homepage at http://datax.cjb.net/
MSX fair Bussum / MSX Marathon homepage: http://msxfair.cjb.net/
>>>>>>>>>>>>>>>>>>>>>>>>><<<<<<<<<<<<<<<<<<<<<<<<<
References: