Re: A86: TI-86 VAT

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Re: A86: TI-86 VAT


TGaArdvark@aol.com wrote:

> I would personally be horrified and demand my money
> back.  A better question might be, "Who is going to

:-)

> even notice?"  And even then, they probably will semi-
> understand... that the way it's indexed on the expander
> is slightly different.  I wouldn't worry about it.

Well, I only asked because the TI-92 handles the VAT
far better than the TI-8X calcs do. On the 92 the
size of a program is the size of its data plus 2 (the
size word). It doesn't count the meanial 10 or so bytes for
the VAT entry. That is also what the 92 EII driver does --
it doesn't count the first ~12 bytes that the variable info
is stored in as part of the program or part of NV EEPROM
memory. But for the TI-86 I suppose I will count the EII
"VAT" as part of program size. I personally think TI
could have done a much better job on VAT design... but who
am I to criticise, the EII doesn't even HAVE a real VAT. It
just stores file info right before each program and always on
the beginning of a page. At least TI's method doesn't waste
memory.

Speaking of which, would the average user be interested 
in knowing how much of the EII's space is 'wasted'? The 
EII has a block size of 264 bytes. So if you have a 265 
byte program because of the VAT it'll waste about 250 
bytes of that second EEPROM page. In most cases the 
wasted space compares very favorably to that of the 
Expander SF which had 4096 byte blocks... and, after all,
calculator programs are small enough. I think I may just
save time and not write the code to do that.

Has anybody writen 32 bit addition/subtraction routines?
I doubt I'll need 32b division or multiplication routines
(I can imagine how many cycles 32 bit division takes on
an 8 bit processor...) but I know there are routines for
* and / on ticalc.org. Is addition really simple, or has
nobody bothered to write them yet?

-- 
Bryan Rittmeyer
mailto:bryanr@flash.net
http://www.bridges.edu/horizon/
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