Re: [Qemu-devel] [PATCH] target-tilegx: Finish decoding the first TB block.

[Chris Metcalf]

On 2/21/2015 7:25 PM, Chen Gang S wrote:
> On 2/22/15 00:33, Richard Henderson wrote:
> > >On 02/21/2015 07:31 AM, Chen Gang S wrote:
> > > >>
> > > >>  - We can still use the original pipes order: "y0, y2, y1" and "x0, x1".
> > >
> > >I guess, sure, though I don't think that'll help as much as you imagine.
> > >
> OK, thanks. For me, your idea is OK, it is more simpler (although with
> more tcg temporary variables).

Richard pretty much said all I wanted to say, but I just wanted to reinforce
that the semantics of the multiple pipes is always "all together". So if you 
have
{ move r1, r2; move r2, r1 } then that swaps r1 and r2.  Or if you have
{ ld r1, sp; jrp r1 } then you are restoring r1 but jumping to wherever its
previous value said you needed to go.  Etc.

Similarly, if any pipeline takes an exception (a TLB fault from a memory op,
a GPV fault from an illegal mfspr, etc) then no pipeline completes its action.

--
Chris Metcalf, EZChip Semiconductor
http://www.ezchip.com