Re: A86: TI-86 VAT
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Re: A86: TI-86 VAT
> How can the use of _get_word_ahl allow you to find the variable data size of
> the VAT? I didnt know the VAT contained
> information that contained the size of a variable
The VAT contains the abs address to the variable, and the first word of
most variables is the size of the data following. This is not what the
ROM displays though. What the ROM displays is this word + 2 (for the
size word itself) + 6 (overhead of the VAT) + length of VAR name (rest
of VAT entry). I wrote a routine to calculate this but if anyone knows
the ROM call I'd love to use it instead.
> >I call the routine _get_var_size. It's at $477f.
> >Input: a=type, bhl=var data ptr
> >Output: de=size (in bytes), ahl=var data ptr.
I'm not quite sure how this call works. Is bhl a ptr to the
beginning of the var's VAT entry, or does bhl contain the
address in that VAT entry that points to the start of the
variable data?
Also... does _get_word_ahl swap the RAM page back or will
I be forced to do that myself?
--
Bryan Rittmeyer
mailto:bryanr@flash.net
http://www.bridges.edu/horizon/
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