Re: A86: RAM paging

To: assembly-86@lists.ticalc.org
Subject: Re: A86: RAM paging
From: Chicane <chicane@reninet.com>
Date: Tue, 29 Sep 1998 07:05:42 -0700
Delivered-To: assembly-86-outgoing@towerguard.unix.edu.sollentuna.se
In-Reply-To: <3610DF58.BDE4607B@oregontrail.net>
Reply-To: assembly-86@lists.ticalc.org


At 06:23 AM 9/29/98 -0700, you wrote:
>
>How do I access stuff on different RAM pages?
You use Ports 5 and 6

>Do I have to change to that page, or can I call a three byte address?  
You can do some things with absolute addressing, but its a bit of a pain,
so i generally just use the ports.

>HOW do you change the RAM page?
You want RAM page 3 set?

Some_Code:
	ld	a,$03		;the page
	add	a,$40		;i dont remember why you have to add 40
	out	(6),a		;the actuall switch
	ret

If you have an absolute address in ahl, you can do a rom call:
call	_load_ram_ahl
or just to convert the address to asic:
call	_conv_ahl

Both of these calls can be found in ti86un.inc on Dux's site.

>And what tokens mean a program is written in BASIC?
If you know the name of a program, do this:

The_code:
	ld	hl,ProgName-1	;where ProgName it the name of the prog
	rst	20h		;name to op1
	rst	10h		;find address
	ld	a,b		;move it to ahl form bde
	ex	de,hl		
	call	_load_ram_ahl	;rom call to set page and point hl to 
	inc	hl		;3 bytes past the size
	inc	hl
	inc	hl
	ld	a,(hl)		;load the identifier into a
	cp	$28		;is it Regular ASM?
	jr	z,AsmProgram	;if so, jump here
	cp	$27		;is it a hex program
	jr	z,HexProgram	;jump here
	cp	$29		;protected basic?
	jr	z,ProtBasic
	jr	BasicProg	;if it isnt any of these, goto basicprog

I dont know what the token is for basic. All i know is that a program is
basic if its not any of the other types.

Hope this helps.
CHICANE
ICQ: #14727618
chicane on EFNET #ti
Homepage: Under Construction.

References:

A86: RAM paging

From: Cassady Roop <croop@oregontrail.net>