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From: carolyn@cbmvax.UUCP (Carolyn Scheppner CATS)
Newsgroups: comp.sys.amiga
Subject: Re: A2000 questions
Message-ID: <2515@cbmvax.UUCP>
Date: Thu, 15-Oct-87 20:05:08 EDT
Article-I.D.: cbmvax.2515
Posted: Thu Oct 15 20:05:08 1987
Date-Received: Sat, 17-Oct-87 11:22:53 EDT
References: <176@tahoma.ARPA> <2467@cbmvax.UUCP> <22314UH2@PSUVM> <317@a.UUCP>
Reply-To: carolyn@cbmvax.UUCP (Carolyn Scheppner CATS)
Organization: Commodore Technology, West Chester, PA
Lines: 110

In article <317@a.UUCP> adb@a.UUCP (Allen D Barnett) writes:
>
>Having had my A2000 (B2000, really, even though the box was labeled in
>German), I would appreciate some help with a particular problem.
>I have a code that neglects to clear register D0 before it does a
>_LVOOpenLibrary.  The garbage in D0 is larger than 33 so the library
>fails to open;  so, since we are trying to open dos.library, there is
>no way to report this failure other than through Alert.  However,
>when the Guru is summoned, with a recoverable alert, the entire screen turns
>blue and the power LED begins to blink benignly.  After waiting a while,
>I administer the nerve pinch and lo, the requstor appears.  I press the
>right mouse button and the machine resets itself.  When this code ran on
>my 1000, it properly displayed the alert and proceeded to clean up and exit
>properly when you pressed the mouse button.  No more.  What is the source of 
>this problem?  Any speculation is welcome.
>(oh, one other thing, I meant to say that I pressed the left mouse button
>in response to the alert; my mind wanders.)

1. Try pressing the LEFT mouse button.  I think the right mousebutton
   throws (or can throw) you into RomWack.  If you did not have a 9600
   baud terminal connected, all would would see is a freezing of the
   guru'd system.

2. Here's a patch for fixing executables afflicted with the trash-in-d0
   OpenDOS problem.  It patches in a piece of d0 init code and re-routes
   things through it.

/*
 * LPatch.c - C. Scheppner  03/87
 *
 *    Corrects the startup code of some 1.0/1.1 programs such as
 *    Atom so that they don't abort during startup with the Alert
 *    00038007. (can't open dos library).  The problem is caused
 *    by d0 (version) being uninitialized prior to the OpenLibrary.
 *
 *   LINKAGE INFO:
 *     Compile with -v flag on LC2
 *     Link with AStartup.obj ... LIBRARY Amiga.lib, LC.lib
 */

#include <exec/types.h>
#include <libraries/dos.h>
#include <libraries/dosextens.h>

/* Patch Offsets, Old Values, New Values */

ULONG  offset[] = {0x196,0x197, 0x213, 0x23E,0x23F,0x240,0x241,0x242,0x243};
UBYTE  oldval[] = {0x01, 0x4E,  0xD2,  0x24, 0x3C, 0x00, 0x00, 0x03, 0xED};
UBYTE  newval[] = {0x00, 0xA8,  0x2C,  0x70, 0x00, 0x60, 0x00, 0x00, 0xA2};

LONG file;

main(argc, argv)
int argc;
char **argv;
   {
   LONG            rLen, wLen;
   char            *filename;
   UBYTE  buf[4];
   int k;

   if (argc==0) cleanexit("");
   if ((argc==1)||(argc>2)||(*argv[1]=='?'))
      cleanexit("Usage: LPatch filename");

   filename = argv[1];

   if(!(file = Open(filename, MODE_OLDFILE)))
      cleanexit("File not found");

   for(k=0;k<9;k++)
      {
      Seek(file,offset[k],OFFSET_BEGINING);
      if((rLen = Read(file,buf,1)) < 1)  cleanexit("Read error");
      if(buf[0] != oldval[k])  cleanexit("File not correct for patch");
      }

   for(k=0;k<9;k++)
      {
      Seek(file,offset[k],OFFSET_BEGINING);
      if((wLen = Write(file,&newval[k],1)) < 1)  cleanexit("Write error");
      }

   cleanup();
   }


cleanexit(s)
   char  *s;
   {
   if (*s)
      {
      printf("%s \n",s);
      }
   cleanup();
   exit();
   }

cleanup()
   {
   if(file)  Close(file);
   }

/* end */
-- 
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Carolyn Scheppner -- CATS   >>Commodore Amiga Technical Support<<
                     UUCP  ...{allegra,ihnp4,rutgers}!cbmvax!carolyn 
                     PHONE 215-431-9180
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