Sylvain
I did various benches. with clang 6.0.0 on linux, and ndk-r16b on android (NDK_TOOLCHAIN_VERSION=clang).
- still see a x10 speed factor.
- with duff_loops, it does not use vectorisation (but doesn't seem to be a problem).
on linux my patch is already at full speed on -O2, whereas the duff_loops need -O3 (200 ms at -03, and 300ms at -02).
I realized that on Android, I had a slight variation which fits best.
both on linux with -O2 and -O3, and on android with 02/03 and armeabi-v7a/arm64.
Here's the patch.
suffix to the temp Pixel local in the DUFFS_LOOP.
SDL_blit.h (ASSEMBLE_RGB): add _ prefix to temp Pixel locals to avoid
any possible shadowings.
The warnings were like the following:
In file included from src/video/SDL_blit_N.c:26:0:
src/video/SDL_blit_N.c: In function 'BlitNtoNKeyCopyAlpha':
src/video/SDL_blit_N.c:2421:24: warning: declaration of 'Pixel' shadows a previous local [-Wshadow]
Uint32 Pixel = ((*src32 & rgbmask) == ckey) ? *dst32 : *src32;
^
src/video/SDL_blit.h:475:21: note: in definition of macro 'DUFFS_LOOP8'
case 0: do { pixel_copy_increment; /* fallthrough */ \
^
src/video/SDL_blit_N.c:2419:13: note: in expansion of macro 'DUFFS_LOOP'
DUFFS_LOOP(
^
src/video/SDL_blit_N.c:2399:12: warning: shadowed declaration is here [-Wshadow]
Uint32 Pixel;
^
Sylvain
Patch a few warnings when using:
-Wmissing-prototypes -Wdocumentation -Wdocumentation-unknown-command
They are automatically enabled with -Wall
/home/fedora/SDL2-2.0.5/src/video/SDL_blit_N.c: In function 'calc_swizzle32':
/home/fedora/SDL2-2.0.5/src/video/SDL_blit_N.c:127:5: error: ISO C90 forbids mixed declarations and code [-Werror=declaration-after-statement]
const vector unsigned char plus = VECUINT8_LITERAL(0x00, 0x00, 0x00, 0x00,
^
The internal function SDL_EGL_LoadLibrary() did not delete and remove a mostly
uninitialized data structure if loading the library first failed. A later try to
use EGL then skipped initialization and assumed it was previously successful
because the data structure now already existed. This led to at least one crash
in the internal function SDL_EGL_ChooseConfig() because a NULL pointer was
dereferenced to make a call to eglBindAPI().
