Re: final i386.floating.record.patch

[paawan oza <paawan1982 at yahoo dot com>]

Hi Hui & Michael,
Now we revert status registers also.
please find the patch attached.
I am sorry, if I am not pasting the patch in email-body due to tabs&spaces problem faced by Michael last time.
Regards,
Oza.

--- On Wed, 8/5/09, Michael Snyder <msnyder@vmware.com> wrote:

> From: Michael Snyder <msnyder@vmware.com>
> Subject: Re: final i386.floating.record.patch
> To: "paawan oza" <paawan1982@yahoo.com>
> Cc: "Hui Zhu" <teawater@gmail.com>, "gdb-patches@sourceware.org" <gdb-patches@sourceware.org>
> Date: Wednesday, August 5, 2009, 7:03 AM
> paawan oza wrote:
> > Hi Hui,
> > 
> > please find my analysis as follows.
> > 
> > following are the registers which you may find it
> different.
> > 
> > fstat
> > ftag
> > fiseg
> > fioff
> > foseg
> > fooff
> > fop
> > 
> > In my opinion, we do not need to record all these
> registers. because these registers are purly depends on
> instruction's execution status in FPU unit.
> > 
> > 
> > for e.g.
> > fop register stores te last opcode executed by x87 FPU
> unit.
> > fstat register may contain c0, c1, c2, c3 flag
> status...
> > 
> > why we dont need to record, because even if we reply
> the recod...
> > Anyway these register are going to be change by FPU HW
> unit based on any fp insn's nature and its execution. (next
> insn which FPU is going to execute)
> > 
> > so it doesnt make much sense to store it, because even
> if we restore it, FPU unit doesnt use them directly, but FPU
> HW sets them after executing current fp insn. so anyway they
> are going to reset as soon as FPU executes next insn.
> > 
> > but still if you feel that we must record those
> registers because user might want to observe those
> registers, then I can do that.
> > 
> > please let me know you opinion about it.
> 
> It may be that saving the registers is not purely
> necessary, but
> we are not just a simulator -- we are a debugger.? The
> user might
> be confused if he steps backward and sees that the register
> did not
> change.
> 
> So I think we should preserve it and revert it.
> 
>

Attachment: i386.record.float.aug-07.patch
Description: Binary data