Re: A85: FIND_PIXEL
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Re: A85: FIND_PIXEL
JUSTIN BOSCH wrote:
>
> OK, this is my LAST question about FIND_PIXEL. After using it, or any
> other rom call that uses mem page 4, do you need to set it to whatever
> it was before? Thanks.
Nope. I should explain how the TI's Rom works. The ROM is 128k, but 16 bit
addressing would only allow 64k to be accessed! So the 64k is divided into
32k RAM, 16k ROM, and 16K paged ROM. The ROM is divided into 8 pages: page 0
holds the important functions (all ROM_CALLS except FIND_PIXEL). So the first
16k of ROM is page 0, and it is always present! by changing to page 4 you
change the 2nd 16K of ROM. Of course, since FIND_PIXEL is the only ROM_CALL
NOT on page 0, you do not need to change it back, until you exit the shell.
But the shell does it automatically! So you really don't have to do anything.
TI-ROM experts, correct me if I am wrong.
BTW, why doesn't the shell automatically set page 4? this could be useful. I
think this should be in Usgard 1.0.
--
Terry Peng
email- tpeng@geocities.com
web- http://www.geocities.com/SiliconValley/Bay/5104/index.html
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