Re: A86: VAT size

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Re: A86: VAT size


On Sat, 22 Jan 2000 19:18:30 -0800 Cassady Roop <croop@oregontrail.net>
writes:
>Some questions about calc resets...
>
>1.  Since stat vars are present at first power-up and can't 
>(normally)
>be deleted, can I trust that their positions in the VAT will not
>change?  Will they always be at the beginning, is what I'm asking I
>guess...

the following vars are created in order on a reset:
xStat, yStat, fStat, Ans, #, !
(i think that's all of 'em)

>2.  What other than a wipe of the VAT, does a mem reset do? (if
>anything?)

call _initMem: (this call disables interrupts)
 $014000 -> _P_TEMPMEM
 $014000 -> _FREE_MEM (deallocate actual memory)
 $014000 -> _newdataptr (no idea)
 $0000 -> _FPBASE
 $0000 -> _FPS
 $3fff -> _OPBASE
 $3fff -> _OPS

 $02bfff -> _P_PTEMP
 $02bfff -> _PTEMP_END
 set 0,(_FORMULA_BITMAP)
 $ce2c -> _LASTENTRYPTR (clear 2nd-ENTER)
 $00 -> _numlastentries (clear 2nd-ENTER)
 call _initlistvar (creates stat vars among other things)
 0.0000000000000 -> Ans
 call _flushallmenus
 $00 -> iy+$23
 $00 -> iy+$24
 $00 -> $d2ed + $0334 bytes (cleat alt interrupt space)
 $5a -> _alt_int_chksum
 $5a -> _alt_slink_chksum
 $5a -> _alt_on_chksum
 $5a -> _alt_off_chksum
 $fa70 -> _alt_asm_exec_btm
 $fa70 -> _altram_end
 $00 -> $d6d8 + $0070 bytes (clear asaps)
 call _init_math_menu (further reset asaps)

call _cmdInit:
 create 0 byte prog '#'
 $0000 -> _cmdCursor
 create 0 byte prog '!'
 load home screen context (?)
 call sqrthome (obviously not on reset)
 open '!' for editing (and some stuff)

clear the screen, print a message, misc fairly normal things

i'm pretty sure you can't return to the home screen without # and ! being
created.

>3.  If I were to change the _p_ptemp and _ptemp_end pointers to their
>default first power-up values, would the calc think the memory had 
>been
>wiped?  This is why I need an answer to number 1;  'cause I would 
>like
>the calc to think it has been mem wiped, but I want to make sure the
>default vars are there.

it would no longer see any variables on the calc.  the amount of
available memory wouldn't change (or at least, it wouldn't change
everywhere), and in fact, things might end up behaving very strangely

-josh


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