🚀 go-pugleaf

RetroBBS NetNews Server

Inspired by RockSolid Light RIP Retro Guy

Article View: net.micro.mac
Article #6982

Application Heap Jockeying

#6982
From: Jim Cathey
Date: Wed, 27 Aug 1986 16:38
41 lines
2246 bytes
Help!  I am trying to write an application program for my 512E Mac to
permanently move the application heap from where it is normally to an
extra 1MB of non-contiguous ram that I usually use as a non-volatile
RAMdisk.  I would prefer to leave the system heap where it is (perhaps
bumping the size to encompass the range normally used by the
application heap).  Right now, all I get is a system bomb (no specified
number as it doesn't get that far) when I try.  Is there any way to do
this?  Must I settle for a "Mega-launch" application that chains
another desired program with a temporary application heap up there?
Mind you, I don't know if this is possible either, but the Switcher
does something like this.  Anyway, using MacsBug is no help since
Tracing through this code gives different results than running it.
When MemTop is moved the next PC shown is the SysErr routine.  Manually
putting it back into my program causes it to run normally with an exit
to Finder, but with all interrupts trashed (no mouse, disk runs
forever).  Should I be looking at an INIT resource to do this instead?
I would prefer an application.  

The current (off the cuff but you get the idea) sequence I am using is:
NewZone of the 1MB area
(which affects TheZone too)
MemTop
ApplLimit
ApplZone
HeapEnd
Stack Pointer,
CurStack
StkLowPt (0 to turn off sniffer)
ExitToShell

What's going on here?  Any information would be gratefully appreciated.
-- 

+----------------+
! II      CCCCCC !  Jim Cathey
! II  SSSSCC     !  ISC Systems Corp.
! II      CC     !  Spokane, WA
! IISSSS  CC     !  UUCP: ihnp4!tektronix!reed!iscuva!jimc
! II      CCCCCC !  (509)927-5757
+----------------+
			"With excitement like this, who is needing enemas?"
Technical Details
Message-ID: <250@iscuva.UUCP>
Path: arc1-ca.pugleaf.net!utzoo!mnetor!seismo!nbires!hao!hplabs!tektronix!reed!iscuva!jimc

Show Full Headers
Complete Article Headers
Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP
Path: arc1-ca.pugleaf.net!utzoo!mnetor!seismo!nbires!hao!hplabs!tektronix!reed!iscuva!jimc
From: jimc@iscuva.UUCP (Jim Cathey)
Newsgroups: net.micro.mac
Subject: Application Heap Jockeying
Message-ID: <250@iscuva.UUCP>
Date: Wed, 27-Aug-86 12:38:02 EDT
Article-I.D.: iscuva.250
Posted: Wed Aug 27 12:38:02 1986
Date-Received: Fri, 29-Aug-86 01:16:44 EDT
Distribution: net
Organization: ISC Systems Corporation, Spokane, Wa.
Lines: 41