Re: [GIT PULL] x86 breakpoint regression fix

From: Frederic Weisbecker
Date: Wed Jun 30 2010 - 15:04:09 EST

On Wed, Jun 30, 2010 at 03:40:51PM +0100, Maciej W. Rozycki wrote:
> On Wed, 30 Jun 2010, Frederic Weisbecker wrote:
> > - icebp/int01 trap. This instruction (0xf1) is undocumented and
> > generates an int 1 exception. Unlike single step through TF
> > flag, it doesn't set the single step origin of the exception
> > in dr6.
> Not quite completely undocumented, but a bit obscure indeed. GDB calls
> this instruction ICEBP and some Intel sources -- INT1. It's been around
> for a while (at least since 80286) and is mostly used by in-circuit
> emulators (hence the name GDB uses).

Right, in fact it was quite easy to find any documentation about it, it's
just officially undocumented.

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