Re: resetting RM IVT BIOS vectors to their defaults

From	Rod Pemberton <NoHaveNotOne@zxdehrnyya.cam>
Newsgroups	alt.os.development, comp.os.msdos.programmer, alt.comp.bios
Subject	Re: resetting RM IVT BIOS vectors to their defaults
Date	2016-08-26 16:17 -0400
Organization	Aioe.org NNTP Server
Message-ID	<20160826161733.0dc1d275@_> (permalink)
References	<20160825185407.4aab5263@_>

Cross-posted to 3 groups.

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On Thu, 25 Aug 2016 18:54:07 -0400
Rod Pemberton <NoHaveNotOne@zxdehrnyya.cam> wrote:

> Original AT BIOS entry points.
> All modern BIOSes "should" use these values in their IVT:
> 
> 02h F000:E2C3
> 05h F000:FF54
> 08h F000:FEA5  IRQ0
> 09h F000:E987  IRQ1
> 0Eh F000:EF57  IRQ6
> 10h F000:F065 or F000:FF53
> .(FF53 is IRET routine for no video card found)
> 11h F000:F84D
> 12h F000:F841
> 13h F000:EC59 or F000:E3FE
> .(E3FE is harddisk, EC59 is floppy)
> .(floppy reassigned to Int 40h if hard disk is found)
> 14h F000:E739
> 15h F000:F859
> 16h F000:E82E
> 17h F000:EFD2
> 18h F000:6000
> 19h F000:E6F2
> 1Ah F000:FE6E
> 1Bh F000:FF53  (IRET routine)
> 1Ch F000:FF53  (IRET routine)
> 1Dh F000:F0A4
> 1Eh F000:EFC7
> 40h F000:EC59  (set to EC59 if hard disk is found)
> 42h            (may have original or hooked Int 10h)
> 6dh            (may have original or hooked Int 10h)
> 

0Ah F000:"D11"
0Bh F000:"D11"
0Ch F000:"D11"
0Dh F000:"D11"
0Fh F000:"D11"
72h F000:"D11"
73h F000:"D11"
74h F000:"D11"
76h F000:"D11"
77h F000:"D11"
1Fh F000:0000h

I have a copy of the original XT vectors someone posted, but I haven't
found a copy of the original AT vectors.  So, I don't know the default
AT values for 70h, 71h, 75h, and I also don't know what D11's offset
is.  D11 is the label used in the original AT BIOS source code for a
common routine.

I've recorded nine different values from many BIOS dumps online for D11,
but these BIOSes may have had their vectors hooked by DOS or an OS.  The
most common value seems to be F000:EF6F, but I don't know if that's the
original value.

However, knowing that the D11 interrupts all use the same initial value
might help you to reset them without using the default BIOS table at
FEF3.  Some of these seem to be set by the BIOS, option ROMs, or
hardware later.

Rod Pemberton

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Thread

resetting RM IVT BIOS vectors to their defaults Rod Pemberton <NoHaveNotOne@zxdehrnyya.cam> - 2016-08-25 18:54 -0400
  Re: resetting RM IVT BIOS vectors to their defaults "Alexei A. Frounze" <alexfrunews@gmail.com> - 2016-08-25 20:22 -0700
  Re: resetting RM IVT BIOS vectors to their defaults Rod Pemberton <NoHaveNotOne@zxdehrnyya.cam> - 2016-08-26 16:17 -0400
    Re: resetting RM IVT BIOS vectors to their defaults "Mike Gonta" <mikegonta@gmail.com> - 2016-08-26 18:10 -0400
  Re: resetting RM IVT BIOS vectors to their defaults James Harris <james.harris.1@gmail.com> - 2016-08-27 14:05 +0100
    Re: resetting RM IVT BIOS vectors to their defaults Rod Pemberton <NoHaveNotOne@zxdehrnyya.cam> - 2016-08-27 19:11 -0400
      Re: resetting RM IVT BIOS vectors to their defaults James Harris <james.harris.1@gmail.com> - 2016-08-28 11:09 +0100
        Re: resetting RM IVT BIOS vectors to their defaults "Alexei A. Frounze" <alexfrunews@gmail.com> - 2016-08-28 03:35 -0700
          Re: resetting RM IVT BIOS vectors to their defaults James Harris <james.harris.1@gmail.com> - 2016-08-28 14:03 +0100
        Re: resetting RM IVT BIOS vectors to their defaults "Mike Gonta" <mikegonta@gmail.com> - 2016-08-28 09:08 -0400
        Re: resetting RM IVT BIOS vectors to their defaults rridge@taurine.csclub.uwaterloo.ca (Ross Ridge) - 2016-08-28 19:30 -0400
          Re: resetting RM IVT BIOS vectors to their defaults James Harris <james.harris.1@gmail.com> - 2016-08-29 07:59 +0100
          Re: resetting RM IVT BIOS vectors to their defaults "Mike Gonta" <mikegonta@gmail.com> - 2016-08-29 06:29 -0400
            Re: resetting RM IVT BIOS vectors to their defaults rridge@taurine.csclub.uwaterloo.ca (Ross Ridge) - 2016-09-03 20:43 -0400
          Re: resetting RM IVT BIOS vectors to their defaults "wolfgang kern" <nowhere@never.at> - 2016-08-30 10:06 +0200
            Re: resetting RM IVT BIOS vectors to their defaults "Mike Gonta" <mikegonta@gmail.com> - 2016-08-30 06:37 -0400
              Re: resetting RM IVT BIOS vectors to their defaults "wolfgang kern" <nowhere@never.at> - 2016-08-31 12:25 +0200

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