80368/80486 exceptions & interrupts: INT 10h

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#3559

From: Tim Barnett - programmer
Date: Tue, 10 Nov 1992 16:22

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Trivial question ...
I have Microsoft's 80386/80486 Programming Guide which says on page 119 ...
(my parentheses)

   Interrupt number      Class      Description
   --------------------------------------------------
      16 (decimal,=10h)  Fault      Coprocessor error

... but under MS-DOS I know that  INT 10h  traps to the EGA/VGA BIOS.  Eg:
    MOV al, 3
    MOV ah, 0
    INT 10h
... which sets the EGA into video mode 3, according to the Waite Group's
MS-DOS Developer's Guide.

I assume I am missing a level of indirection somewhere, but I thought MS-DOS
ran in Real-Mode, so I assume I do not have to worry about indirection through
the 80x86 IDT ?  Could anyone explain to me why the  INT 10h  instruction
doesn't just trap to the  Coprocessor-Error  code ?

(E-mail replies might be better, to save bandwidth)

Many thanks in advance for any help or clarification,
Tim

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From: spxtrb@thor.cf.ac.uk (Tim Barnett - programmer)
Newsgroups: comp.os.msdos.programmer
Subject: 80368/80486 exceptions & interrupts: INT 10h
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Date: 10 Nov 92 16:22:35 GMT
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