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 wrote: > From: Michael Snyder > Subject: Re: final i386.floating.record.patch > To: "paawan oza" > Cc: "Hui Zhu" , "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. > >