A83: Re: LDIR timing / saferam1
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A83: Re: LDIR timing / saferam1
The correct timing for LDIR is 21*BC+16. Keep
in mind that in terms of the actual time it takes to go through the complete
command, it may be longer if interrupts are enabled. Interrupts can occur
i the middle of an LDIR command.
Saferam1 (aka savesscreen) is a 768 byte area that
you can use for whatever you want. If it's crashing due to you loading
there, it means you're probably loading past the boundaries of the memory
block. TIOS does not care what sort of data you leave there. Also
keep in mind that the address is not the same on the 83 and 83 Plus, so if
you're trying to do something on the 83 Plus, don't load directly to 8265h, load
to the SavesScreen equate.
Hope this helps,
-Dan Englender
----- Original Message -----
Sent: Tuesday, August 22, 2000 11:37
AM
Subject: A83: LDIR timing /
saferam1
My problems with the AND sprite routine have been solved.
I've now got a fully functional AND XOR routine that is very fast. I still
want to know what the correct timing is for LDIR (1+21*[bc] ?). Also, when I
write 768 bytes of data to the saferam1 location (8265h), my program scews up
sometimes when I quit it. This only happens when I write/read a lot of times
to this location. Should the APD(?) ram at that position be rewritten by 0's,
or is the 'safe ram' not as safe as stated?
Thanks in advance,
Frank Schoep
References: