Re: final i386.floating.record.patch

Hui Zhu
2009-08-07T15:42:20Z

Thanks for your work.

I try with fp program, looks ok now.

And for format of the patch:
There is a lot of spaces tail in the tail of the codes.
For example:
"+ return -1; "
"/* Opcode is an extension of modR/M byte. */ "

Hui

On Fri, Aug 7, 2009 at 15:17, paawan oza<paawan1982@yahoo.com> wrote:
> 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.
>>
>>
>
>
>