Date: Fri, 5 Feb 1999 08:35:18 -0500
Message-Id: <199902051335.IAA14844@envy.delorie.com>
From: DJ Delorie <dj AT delorie DOT com>
To: djgpp AT delorie DOT com
In-reply-to: <3.0.6.32.19990205013626.00872510@pop.netaddress.com> (message
	from Paul Derbyshire on Fri, 05 Feb 1999 01:36:26 -0500)
Subject: Re: Ralf Brown's Interrupt List has a booboo
References:  <3 DOT 0 DOT 6 DOT 32 DOT 19990205013626 DOT 00872510 AT pop DOT netaddress DOT com>
Reply-To: djgpp AT delorie DOT com


> This seems screwed up to me. I mean everyone knows int 10h is for
> setting VIDEO.

Ha!  Intel reserved interrupts 0-31 for CPU use, but IBM screwed up
and used 16-31 for BIOS interrupts.  When the 80286 was released, it
*also* used interrupt 16 (0x10) for the FPU interrupt.  Many hacks
later, Linux *still* has to scan to find out how the FPU interrupts
the CPU.

> 10 INT 10 C - CPU-generated (80286+) - COPROCESSOR ERROR

A plain old unadorned hardware INT 0x10 *is* a coprocessor error.

>  00 01 02 03 04 05 06 07 08 09 0A 0B 0C 0D 0E 0F
>  10 11 12 13 14 15       18 19 1A 1B 1C 1D 1E 1F
>                                                 
>  30                      38 39                  
>  40 41 42 43 44 45 46 47 48 49 4A 4B 4C 4D 4E 4F
>  50 51 52 53    55                            5F

The rest of these are subsections for software interrupts also using
INT 0x10, all of which require a value in AH.