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Re: [Qemu-devel] [Qemu-ppc] How to add my implementation of the fmadds i
From: |
David Gibson |
Subject: |
Re: [Qemu-devel] [Qemu-ppc] How to add my implementation of the fmadds instruction to QEMU |
Date: |
Fri, 30 Sep 2016 10:39:57 +1000 |
User-agent: |
Mutt/1.7.0 (2016-08-17) |
On Thu, Sep 29, 2016 at 12:55:23PM -0400, Programmingkid wrote:
>
> On Sep 29, 2016, at 11:41 AM, Peter Maydell wrote:
>
> > On 28 September 2016 at 21:17, David Gibson <address@hidden> wrote:
> >> I think there is a way you could get both speed and accuracy, but it's
> >> a huge project:
> >>
> >> You'd need to add full float awareness to TCG - so floating point TCG
> >> values and floating point operations as tcp micro-ops, defined
> >> according to IEEE semantics. Then you'd need to rewrite the TCG
> >> frontends in terms of those new ops, at least for target CPUs close
> >> enough to IEEE semantics for that to work. And you'd need to rewrite
> >> the TCG backends to implement those fp ops in terms of host cpu fp
> >> instructions .. at least when the host has fp behaviour close enough
> >> to IEEE to make that work, with a fallback to soft float when that's
> >> not the case.
> >
> > Also even if you have float support in both frontend and backend
> > you still need to fall back to fully-emulated for the runtime
> > corner cases (like where tininess before/after rounding makes a
> > difference or where you need to care about minutiae of the
> > floating point exception flags, etc). It's not impossible
> > but it is a very large amount of technically complicated work.
>
>
> This project sounds like it should have its own web page. Maybe even
> its own Google Summer of Code entry. I created a mindmap of
> this project. The picture is attached to this email. This is
> just a start. Please let me know what should be added or changed.
TBH, I think this is rather bigger than a GSoC project.
--
David Gibson | I'll have my music baroque, and my code
david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ _other_
| _way_ _around_!
http://www.ozlabs.org/~dgibson
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- Re: [Qemu-devel] How to add my implementation of the fmadds instruction to QEMU, (continued)
- Re: [Qemu-devel] How to add my implementation of the fmadds instruction to QEMU, G 3, 2016/09/27
- Re: [Qemu-devel] How to add my implementation of the fmadds instruction to QEMU, Peter Maydell, 2016/09/27
- Re: [Qemu-devel] [Qemu-ppc] How to add my implementation of the fmadds instruction to QEMU, David Gibson, 2016/09/29
- Re: [Qemu-devel] [Qemu-ppc] How to add my implementation of the fmadds instruction to QEMU, Programmingkid, 2016/09/29
- Re: [Qemu-devel] [Qemu-ppc] How to add my implementation of the fmadds instruction to QEMU, Alex Bennée, 2016/09/29
- Re: [Qemu-devel] [Qemu-ppc] How to add my implementation of the fmadds instruction to QEMU, Programmingkid, 2016/09/29
- Re: [Qemu-devel] [Qemu-ppc] How to add my implementation of the fmadds instruction to QEMU, Alex Bennée, 2016/09/29
- Re: [Qemu-devel] [Qemu-ppc] How to add my implementation of the fmadds instruction to QEMU, Programmingkid, 2016/09/29
- Re: [Qemu-devel] [Qemu-ppc] How to add my implementation of the fmadds instruction to QEMU, Peter Maydell, 2016/09/29
- Re: [Qemu-devel] [Qemu-ppc] How to add my implementation of the fmadds instruction to QEMU, Programmingkid, 2016/09/29
- Re: [Qemu-devel] [Qemu-ppc] How to add my implementation of the fmadds instruction to QEMU,
David Gibson <=
- Re: [Qemu-devel] [Qemu-ppc] How to add my implementation of the fmadds instruction to QEMU, Programmingkid, 2016/09/29