Re: A86: check keyboard

To: assembly-86@lists.ticalc.org
Subject: Re: A86: check keyboard
From: rabidcow@juno.com (Joshua J Seagoe)
Date: Tue, 1 Dec 1998 16:32:45 -0800
Delivered-To: assembly-86-outgoing@towerguard.unix.edu.sollentuna.se
Reply-To: assembly-86@lists.ticalc.org

if port 5 is $0d, then the address is from page d.  the page switcher
takes things like this on page 0:
 call $28cb	;it's $28cb in rom 1.2
 .dw $7236	;address to call
 .db $01	;page to call
it saves the current page, reads the address and page from the return
address provided by THAT call (which is destroyed on the stack) and, when
the call returns, it restores the current page and returns to whatever
called the page 0 call.  i hope no one tries to understand that...

-josh

On Tue, 1 Dec 1998 15:56:43 EST ComAsYuAre@aol.com writes:
>
>In a message dated 12/1/98 15:49:17 Eastern Standard Time, 
>pmilheron@ti.com
>writes:
>
>> If they were not calls then no bank info is pushed
>>  onto the stack, and when the routine called exectutes a
>>  return, page 0Dh would not be paged in when control returns
>>  to the ASM program.
>>  
>>  Later,
>>  Pat
>>  
>
>
>how does the z80 know that an address is from page d?  is that info 
>somehow
>pushed onto the stack as well as the address?
>

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