[A83] Re: call vs. bcall()

To: assembly-83@lists.ticalc.org
Subject: [A83] Re: call vs. bcall()
From: Gavin Olson <gtolson@comcast.net>
Date: Mon, 23 Dec 2002 19:59:10 -0500
In-reply-to: <F92uN3g4wCpgiaux3qd000190f9@hotmail.com>
Reply-To: assembly-83@lists.ticalc.org

At 10:18 PM 12/23/2002 +0000, you wrote:

>>First of all...
>>
>>Bjump is 2 bytes larger than bcall.
>>bjump = call $0050 \ .dw xxxx
>>
>>also, bjump resets the stack pointer, and does other stuff like that.  It 
>>puts the calc into a state where it can safely return from an app.
>
>That sounds nice... But is my logic of "the last instruction of the actual 
>call is always 'ret', so if I jump (even bjump) to it is exactly the same, 
>it doesn't matter where the actual 'ret' is executed" ? I know that it's 
>alright with a regular Ti-83, but what about the layout of the 83+'s 
>system that prevents this kinda usage?
>
>Or doesn't anybody care or just don't know what it really does... ?

A bjump is not a jump.  It is a part of the process of quitting an 
app.  You can use the jp to quit thing for anything on an 83-, or to exit 
after running a user routine on 83x.  Further, the end of the os routines 
on the 83+ most likely contain some kind of b_ret, to get back to your 
program after the pages have been messed with.

References:

[A83] Re: call vs. bcall()

From: "Pieter Van Nuffel [aka SUCKER]" <sucker_pvn@hotmail.com>