Re: [RFC] [PATCH 1/7] User Space Breakpoint Assistance Layer (UBP)

From: Jim Keniston
Date: Mon Jan 18 2010 - 14:21:46 EST

On Mon, 2010-01-18 at 10:58 -0500, Masami Hiramatsu wrote:
> Jim Keniston wrote:
> > Not really. For #3 (boosting), you need to know everything for #2,
> > plus be able to compute the length of each instruction -- which we can
> > now do for x86. To emulate an instruction (#4), you need to replicate
> > what it does, side-effects and all. The x86 instruction set seems to
> > be adding new floating-point instructions all the time, and I bet even
> > Masami doesn't know what they all do, but so far, they all seem to
> > adhere to the instruction-length rules encoded in Masami's instruction
> > decoder.
> Actually, current x86 decoder doesn't support FP(x87) instructions.(even
> it already supported AVX) But I think it's not so hard to add it.

At one point I verified that it worked for all the x87 instructions in
I'm pretty sure I tested mmx instructions as well. But I guess this was
before you rearranged the opcode tables.

Yeah, it wouldn't be hard to add back in, at least for purposes of
computing instruction lengths.


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