Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!wuarchive!usc!cs.utexas.edu!sun-barr!decwrl!shelby!portia!bir7
From: bir7@portia.Stanford.EDU (Ross Biro)
Newsgroups: comp.sys.ibm.pc.programmer
Subject: Re: How to do a warm-boot from ASM
Keywords: boot, ASM, TASM, MASM
Message-ID: <9334@portia.Stanford.EDU>
Date: 20 Feb 90 05:49:12 GMT
References: <2028@milton.acs.washington.edu> <P#$#92_@rpi.edu> <25E0BD4E.35EB@deimos.cis.ksu.edu>
Sender: Ross Biro <bir7@portia.stanford.edu>
Reply-To: bir7@portia.Stanford.EDU (Ross Biro)
Distribution: na
Organization: Stanford University
Lines: 18

In article <25E0BD4E.35EB@deimos.cis.ksu.edu> bdn@phobos.cis.ksu.edu (Bryan D. Nehl) writes:
>In article <P#$#92_@rpi.edu> mcintyre@turing.cs.rpi.edu (David McIntyre) writes:
>
>>Yes, just do an Interrupt 25 (which is 19h).  That will do it nicely.
>
>I am trying do the same thing from assembler but when I call
>int 19h it acts like its going to reboot, seems like it's rebooting
>and then just hangs.

The problem is that int 19h just reexecutes the boot loader.  It does not
reset all the interrupt vectors etc, so when dos is trashed by the new
copy that is loading; the system hangs.  The only way I know of to do a
reliable warm boot is to talk to the keyboard and tell it to reset the
system, something like out 64h,0f1h when the keyboard input buffer
is empty should do it.  But I have to agree with the earlier posting;
resetting the computer is probably a very bad idea.

	Ross Biro bir7@portia.stanford.edu