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Date: Wed, 22 Oct 2008 17:19:00 -0000
From: teawater <teawater@gmail.com>
To: "Dave Korn" <dave.korn@artimi.com>
Subject: Re: [discuss] semantics, "replay debugging" vs. "reverse debugging"
Cc: "Daniel Jacobowitz" <drow@false.org>, "Jakob Engblom" <jakob@virtutech.com>,  	"Michael Snyder" <msnyder@vmware.com>, gdb@sourceware.org
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So I just say "some insn". Not all.

On Thu, Oct 23, 2008 at 01:09, Dave Korn <dave.korn@artimi.com> wrote:
> teawater wrote on 22 October 2008 17:43:
>
>> Sorry I am wrong.
>> In ARM, Just adds set cpsr reg. So:
>> add r0,r0,#10
>> Can reverse without record too.
>
>  Your examples are too limited to be of practical use; almost every
> instruction executed destroys information.
>
>  It's easy to reverse "add r0,r0,#10" by subtracting 10 from r0.  But how do
> you reverse "add r0,r1,#10", or anything else where the source and dest
> register are different?  The original value of r0 is gone without trace, and
> r1 was not changed by the instruction!
>
>
>    cheers,
>      DaveK
> --
> Can't think of a witty .sigline today....
>
>