Re: [Qemu-ppc] [Qemu-devel] [PATCH 00/34] tcg, target/ppc vector improvements

[Mark Cave-Ayland]

On 18/12/2018 06:38, Richard Henderson wrote:

> This implements some of the things that I talked about with Mark
> this morning / yesterday.  In particular:
> 
> (0) Implement expanders for nand, nor, eqv logical operations.
> 
> (1) Implement saturating arithmetic for the tcg backend.
> 
>     While I had expanders for these, they always went to helpers.
>     It's easy enough to expand byte and half-word operations for x86.
>     Beyond that, 32 and 64-bit operations can be expanded with integers.
> 
> (2) Implement minmax arithmetic for the tcg backend.
> 
>     While I had integral minmax operations, I had not yet added
>     any vector expanders for this.  (The integral stuff came in
>     for atomic minmax.)
> 
> (3) Trivial conversions to minmax for target/arm.
> 
> (4) Patches 11-18 are identical to Mark's.
> 
> (5) Patches 19-25 implement splat and logicals for VMX and VSX.
> 
>     VSX is no more difficult than VMX for these.  It does seem to be
>     just about everything that we can do for VSX at the momement.
> 
> (6) Patches 26-33 implement saturating arithmetic for VMX.
> 
> (7) Patch 34 implements minmax arithmetic for VMX.
> 
> I've tested the new operations via aarch64 guest, as that's the set
> of risu test cases I've got handy.  The rest is untested so far.

I've taken my previous PPC patchsets below:

[PATCH v5 0/9] target/ppc: prepare for conversion to TCG vector operations
https://lists.gnu.org/archive/html/qemu-devel/2019-01/msg00063.html

[PATCH v2 0/8] target/ppc: remove various endian hacks from int_helper.c
https://lists.gnu.org/archive/html/qemu-devel/2018-12/msg06149.html

and then rebased this patchset on top of them (including a squash of the vsplt 
fix
posted earlier today at
https://lists.gnu.org/archive/html/qemu-devel/2019-01/msg00287.html) and pushed 
the
result to https://github.com/mcayland/qemu/tree/ppc-altivec-v5.5-rth.

Fixing the vsplt instruction now gives a readable display in my MacOS tests, 
but I'm
still seeing "shadows" such as https://www.ilande.co.uk/tmp/qemu/badapple4.png 
which
I've bisected down to:


commit 71f229eb331e979971a0a79e5a2fcdfb9380bd06
Author: Richard Henderson <address@hidden>
Date:   Mon Dec 17 22:39:10 2018 -0800

    target/ppc: convert vadd*s and vsub*s to vector operations

    Signed-off-by: Richard Henderson <address@hidden>


So looks like there's something still not quite right with the saturation 
flag/vector
saturation implementation.


ATB,

Mark.