Skip to content

building altivec support on ppc64e results in color corruption in end products #3428

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Jump to bottom
Closed
SDLBugzilla opened this issue Feb 11, 2021 · 0 comments · Fixed by #7684
Closed

building altivec support on ppc64e results in color corruption in end products #3428

SDLBugzilla opened this issue Feb 11, 2021 · 0 comments · Fixed by #7684
Labels
waiting Waiting on user response

Comments

@SDLBugzilla
Copy link
Collaborator

This bug report was migrated from our old Bugzilla tracker.

Reported in version: 2.0.10
Reported for operating system, platform: Linux, PowerPC

Comments on the original bug report:

On 2019-10-20 12:36:38 +0000, wrote:

Observed running Wesnoth on Gentoo ppc64le, if libsdl2 is built with altivec enabled there is color corruption in the game. Simply rebuilding without the altivec support the problem goes away.

It appears there is an endianness assumption in the altivec code.

On 2019-10-20 14:10:36 +0000, Ozkan Sezer wrote:

How does 2.0.11 (current hg) behave? A fix was merged
for altivec with ppc64le about a month or so ago:
https://hg.libsdl.org/SDL/rev/9aa7aea27dec

On 2019-10-23 08:51:53 +0000, wrote:

I built 2.0.10 with the patch linked applied, and the patch on it's own doesn't seem to fix the issue.

I will investigate building from hg.

On 2019-12-01 23:59:13 +0000, wrote:

I have built libsdl2 from hg and it is still exhibiting the color corruption if built with altivec support enabled.

On 2019-12-02 00:17:34 +0000, Ozkan Sezer wrote:

(In reply to robert from comment # 3)

I have built libsdl2 from hg and it is still exhibiting the color
corruption if built with altivec support enabled.

Do you have a patch?

On 2019-12-02 00:41:34 +0000, wrote:

I haven't actually looked at the source code at this point. I am building from mercurial using a live ebuild in Gentoo.

On 2019-12-04 06:13:58 +0000, Sam Lantinga wrote:

We don't have a test environment to reproduce this. Can you investigate the code and provide a tested patch that fixes the issue for you?

Thanks!

On 2019-12-04 18:53:20 +0000, Ryan C. Gordon wrote:

(In reply to Sam Lantinga from comment # 6)

We don't have a test environment to reproduce this. Can you investigate the
code and provide a tested patch that fixes the issue for you?

Out of curiosity, where does one get a machine that supports this? Can it just be installed on an old G5 Mac and the OS will flip the CPU into littleendian mode at startup?

--ryan.

On 2019-12-04 22:53:30 +0000, wrote:

I have a Talos 2 from Raptor Computing Systems which uses POWER9 CPUs, and is bi-endian so can be run as either ppc64 or ppc64le. I opted to run ppc64le as it has less issues with endianness assumptions. Their website is https://www.raptorcs.com/ .

AIUI the PowerPC 970 CPU used in the Apple G5 systems was big endian only, as were most if not all IBM chips before the POWER7.
@SDLBugzilla SDLBugzilla added bug waiting Waiting on user response labels Feb 11, 2021
@slouken slouken removed the bug label May 11, 2022
JeremyRand pushed a commit to JeremyRand/SDL that referenced this issue May 6, 2023
SDL_blit_N.c: Move ppc64le swizzle outside of loop
2b6f423 
An in-place swizzle mutation was erroneously inside of a loop, which
caused each consecutive 4-pixel vector to alternate between correct and
incorrect endianness.

The bug was introduced in 715e070.

Thanks to RobbieAB for reporting the bug.

Fixes libsdl-org#3428
@JeremyRand JeremyRand mentioned this issue May 6, 2023
Merged
JeremyRand pushed a commit to JeremyRand/SDL that referenced this issue May 6, 2023
SDL_blit_N.c: Move ppc64le swizzle outside of loop
d021233 
An in-place swizzle mutation was erroneously inside of a loop, which
caused each consecutive 4-pixel vector to alternate between correct and
incorrect endianness.

The bug was introduced in 715e070.

Thanks to RobbieAB for reporting the bug.

Fixes libsdl-org#3428
JeremyRand pushed a commit to JeremyRand/SDL that referenced this issue May 6, 2023
SDL_blit_N.c: Move ppc64le swizzle outside of loop
50c41ad 
An in-place swizzle mutation was erroneously inside of a loop, which
caused each consecutive 4-pixel vector to alternate between correct and
incorrect endianness.

The bug was introduced in 715e070.

Thanks to RobbieAB for reporting the bug.

Fixes libsdl-org#3428
icculus pushed a commit that referenced this issue May 6, 2023
@icculus
SDL_blit_N.c: Move ppc64le swizzle outside of loop
9142292 
An in-place swizzle mutation was erroneously inside of a loop, which
caused each consecutive 4-pixel vector to alternate between correct and
incorrect endianness.

The bug was introduced in 715e070.

Thanks to RobbieAB for reporting the bug.

Fixes #3428
slouken pushed a commit that referenced this issue May 6, 2023
@slouken
SDL_blit_N.c: Move ppc64le swizzle outside of loop
5e74365 
An in-place swizzle mutation was erroneously inside of a loop, which
caused each consecutive 4-pixel vector to alternate between correct and
incorrect endianness.

The bug was introduced in 715e070.

Thanks to RobbieAB for reporting the bug.

Fixes #3428

(cherry picked from commit 9142292)
sezero pushed a commit to libsdl-org/SDL-1.2 that referenced this issue May 6, 2023
@sezero
SDL_blit_N.c: Move ppc64le swizzle outside of loop
788e1b9 
An in-place swizzle mutation was erroneously inside of a loop, which
caused each consecutive 4-pixel vector to alternate between correct and
incorrect endianness.

The bug was introduced in libsdl-org/SDL@715e070
(77a2237).

Thanks to RobbieAB for reporting the bug.

Fixes libsdl-org/SDL#3428

(cherry picked from commit libsdl-org/SDL@9142292)
icculus pushed a commit to icculus/SDL that referenced this issue May 12, 2023
@icculus
SDL_blit_N.c: Move ppc64le swizzle outside of loop
00c6af5 
An in-place swizzle mutation was erroneously inside of a loop, which
caused each consecutive 4-pixel vector to alternate between correct and
incorrect endianness.

The bug was introduced in 715e070.

Thanks to RobbieAB for reporting the bug.

Fixes libsdl-org#3428
sezero pushed a commit to sezero/SDL that referenced this issue May 17, 2023
@sezero
SDL_blit_N.c: Move ppc64le swizzle outside of loop
b1c1754 
An in-place swizzle mutation was erroneously inside of a loop, which
caused each consecutive 4-pixel vector to alternate between correct and
incorrect endianness.

The bug was introduced in 715e070.

Thanks to RobbieAB for reporting the bug.

Fixes libsdl-org#3428

(cherry picked from commit 9142292)
lexi-the-cute pushed a commit to lexi-the-cute/SDL that referenced this issue May 22, 2023
@lexi-the-cute
SDL_blit_N.c: Move ppc64le swizzle outside of loop
7242ab9 
An in-place swizzle mutation was erroneously inside of a loop, which
caused each consecutive 4-pixel vector to alternate between correct and
incorrect endianness.

The bug was introduced in 715e070.

Thanks to RobbieAB for reporting the bug.

Fixes libsdl-org#3428

(cherry picked from commit 9142292)
mikrosk pushed a commit to mikrosk/SDL-1.2 that referenced this issue Dec 21, 2023
@sezero
SDL_blit_N.c: Move ppc64le swizzle outside of loop
a649c7c 
An in-place swizzle mutation was erroneously inside of a loop, which
caused each consecutive 4-pixel vector to alternate between correct and
incorrect endianness.

The bug was introduced in libsdl-org/SDL@715e070
(libsdl-org@77a2237).

Thanks to RobbieAB for reporting the bug.

Fixes libsdl-org/SDL#3428

(cherry picked from commit libsdl-org/SDL@9142292)
Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment
Assignees
No one assigned
Labels
waiting Waiting on user response
Projects
None yet
Milestone
No milestone
Development

Successfully merging a pull request may close this issue.

SDL_blit_N.c: Move ppc64le swizzle outside of loop JeremyRand/SDL
2 participants
@slouken @SDLBugzilla