Re: [GIT PULL] x86 breakpoint regression fix

From: Maciej W. Rozycki
Date: Wed Jun 30 2010 - 10:40:58 EST


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).

Maciej
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