From: Nigel Stephens <algor!nigel>
Date: Wed, 8 Jul 92 13:33:48 BST
To: na70103 AT mips DOT cc DOT mie-u DOT ac DOT jp (Makoto Kobayashi)
Cc: djgpp AT sun DOT soe DOT clarkson DOT edu
Subject: go32 on Cx486


Strictly speaking the granularity bit should not be set for the TSS
segments, since they are not a multiple of 4 Kb long.  Also all of the
calls to fillgdt which use sizeof(...), should probably use
sizeof(...)-1, since the field in the segment descriptor is a limit,
not a size.

Having said that, setting the granularity bit will cause the limit
field to be set to zero, which the CPU then harmlessly treats as a
limit of 0xfff; the Intel i486 Programmer's Reference Manual does not
forbid this.  I would guess that this is a bug in the Cyrix microcode,
which is failing to handle this condition correctly when checking that
the TSS limit is >= 0x67 bytes on a task switch.  

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Nigel Stephens
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