[A83] Re: ASM program space alocation

To: assembly-83@lists.ticalc.org
Subject: [A83] Re: ASM program space alocation
From: tlutz@stevens-tech.edu
Date: Sat, 23 Mar 2002 21:02:38 -0500 (EST)
In-Reply-To: <F1127AW9dXoXzp5bLvw00005c7c@hotmail.com>
References: <F1127AW9dXoXzp5bLvw00005c7c@hotmail.com>
Reply-To: assembly-83@lists.ticalc.org
User-Agent: IMP/PHP IMAP webmail program 2.2.8-cvs


Yeah, on the 83+ programs are used to userMem, which equals 9D95h... Because 
asm programs are "org" at 9D95h (at least normal, no shell ones) they must be 
copied to this location. I am assuming that the free memory on the calculator 
must at least equal the size of the assembly program to run, and since the 
assembly program is copied to 9D95h, you probably could use this for some 
temporary storage. Of course you would have to run your assembly program from 
somewhere else...

To go a little off topic, I found a neat little trick for those of you who wish 
to run multiple assembly program from within one assembly program...see, 
normally you can't do ChkFindSym and call DE after increasing it a few times, 
but you can copy the entire program to 9D95h manually, assuming that the main 
program is much larger than the program to be called, and you are doing this 
from the end of the program. After copying, call 9D95h...then find the original 
program in RAM and copy it back! I know that sounded a little 
confusing...here's a small example...there may be a bug or two...this is just 
to give an idea.

org 9D95h
StartOfProg:
   Lots and lots of code...
   ...
   ... ;the size of this section (RunAnotherProg-StartOfProg) must be greater
   ... than the size of PROG2
   ...
RunAnotherProg:
   ld hl,ProgDef
   rst rMOV9TOOP1
   B_CALL ChkFindSym
   ret c ;return if not found
   ld a,(de)
   ld c,a
   inc de
   ld a,(de)
   ld b,a
   inc de
   inc de
   inc de
   dec bc
   dec bc ;there is a two byte token at the beginning of asm progs...i think
   push bc ;save so we can restore faster
   ;we need to skip it
   ld hl,9D95h
   ex hl,de
   ldir
   call 9D95h ;execute the other program
   ld hl,OriginalProg
   rst rMOV9TOOP1
   B_CALL ChkFindSym
   inc de
   inc de
   inc de
   inc de
   pop bc
   ld hl,9D95h
   ex hl,de
   ldir ;running program restored...
   ld (yourMother),me ;continue the rest of your program



ProgDef: db ProtProgObj,"PROG2",0
OriginalProg: db ProtProgObj,"ORIG",0









Quoting Jimmy Pardey <j_pardey@hotmail.com>:

> 
> Greetings and Salutations,
> 
>     When a program is executed on the calculator, the calculator moves
> it to 
> a location (6346h or something) in ram. what space is allocated for this
> 
> purpose? As far as I can see, the extra space would not be used, as that
> 
> woud lead to the neccesity of major VAT shuffling, so it coud be used by
> 
> programs for tempory data storage. Is that possible?
> 
> Jimmy Pardey
> 
> _________________________________________________________________
> Join the world’s largest e-mail service with MSN Hotmail. 
> http://www.hotmail.com
> 
>

Follow-Ups:

[A83] Re: ASM program space alocation

From: Patai Gergely <patai.ti@freemail.hu>

References:

[A83] ASM program space alocation

From: "Jimmy Pardey" <j_pardey@hotmail.com>