Mercurial > sdl-ios-xcode
view src/hermes/HeadMMX.h @ 1544:ab1e4c41ab71
Fixed bug #33
Mike Frysinger wrote:
> with libsdl-1.2.9, some games (like bomberclone) started
> segfaulting in Gentoo
[...snip...]
> the last change in the last hunk:
[...snip...]
> if i change the statement to read:
> (table[which].blit_features & GetBlitFeatures()) == GetBlitFeatures()
> bomberclone no longer segfaults on my box
Alex Volkov wrote:
> The test "(table[which].blit_features & GetBlitFeatures()) ==
> table[which].blit_features)" is correct, and the previous
> "(table[which].cpu_mmx == SDL_HasMMX())" was actually broken.
I think there is potentially a slightly different cause of the above problem.
During the introduction of the Altivec code, the blit_table struct field
'alpha' got changed from a straightforward enum to a bitmask, which makes
perfect sense by itself. However, now the table driven blitter selection code
in SDL_CalculateBlitN() can choose the wrong blitters when searching for a
NO_ALPHA blitter because of the following code:
int a_need = 0;
...
(a_need & table[which].alpha) == a_need &&
When searching through the normal_blit_2[] table, a SET_ALPHA blitter (like
Blit_RGB565_ARGB8888) can now be selected instead of a NO_ALPHA one, causing
alpha channel bits to appear in a non-alpha destination surface. I suppose this
could theoretically be an indirect cause of the segfault mentioned above.
I *think* this can be fixed by changing to
int a_need = NO_ALPHA;
author | Sam Lantinga <slouken@libsdl.org> |
---|---|
date | Wed, 15 Mar 2006 15:47:49 +0000 |
parents | d910939febfa |
children | 782fd950bd46 c121d94672cb 39b9405d3cb6 |
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/* Header definitions for the MMX routines for the HERMES library Copyright (c) 1998 Christian Nentwich (c.nentwich@cs.ucl.ac.uk) This source code is licensed under the GNU LGPL Please refer to the file COPYING.LIB contained in the distribution for licensing conditions */ #include "SDL_config.h" #ifndef __HERMES_HEAD_MMX__ #define __HERMES_HEAD_MMX__ /* If you cannot stand ifdefs, then please do not look into this file, it's going to end your life :) */ #ifdef X86_ASSEMBLER #ifdef __cplusplus extern "C" { #endif void STACKCALL ConvertMMX(HermesConverterInterface *); void STACKCALL ClearMMX_32(HermesClearInterface *); void STACKCALL ClearMMX_24(HermesClearInterface *); void STACKCALL ClearMMX_16(HermesClearInterface *); void STACKCALL ClearMMX_8(HermesClearInterface *); void ConvertMMXpII32_24RGB888(); void ConvertMMXpII32_16RGB565(); void ConvertMMXpII32_16BGR565(); void ConvertMMXpII32_16RGB555(); void ConvertMMXpII32_16BGR565(); void ConvertMMXpII32_16BGR555(); void ConvertMMXp32_16RGB555(); #ifdef __cplusplus } #endif /* Fix the underscore business with ELF compilers */ #if defined(__ELF__) && defined(__GNUC__) #ifdef __cplusplus extern "C" { #endif extern void _ConvertMMX(HermesConverterInterface *); extern void _ConvertMMXpII32_24RGB888(); extern void _ConvertMMXpII32_16RGB565(); extern void _ConvertMMXpII32_16BGR565(); extern void _ConvertMMXpII32_16RGB555(); extern void _ConvertMMXpII32_16BGR555(); #define ConvertMMX _ConvertMMX #define ConvertMMXpII32_24RGB888 _ConvertMMXpII32_24RGB888 #define ConvertMMXpII32_16RGB565 _ConvertMMXpII32_16RGB565 #define ConvertMMXpII32_16BGR565 _ConvertMMXpII32_16BGR565 #define ConvertMMXpII32_16RGB555 _ConvertMMXpII32_16RGB555 #define ConvertMMXpII32_16BGR555 _ConvertMMXpII32_16BGR555 #ifdef __cplusplus } #endif #endif /* ELF and GNUC */ /* Make it work with Watcom */ #ifdef __WATCOMC__ #pragma warning 601 9 #pragma aux ConvertMMX "_*" modify [EAX EBX ECX EDX ESI EDI] #pragma aux ClearMMX_32 "_*" modify [EAX EBX ECX EDX ESI EDI] #pragma aux ClearMMX_24 "_*" modify [EAX EBX ECX EDX ESI EDI] #pragma aux ClearMMX_16 "_*" modify [EAX EBX ECX EDX ESI EDI] #pragma aux ClearMMX_8 "_*" modify [EAX EBX ECX EDX ESI EDI] #pragma aux ConvertMMXpII32_24RGB888 "_*" #pragma aux ConvertMMXpII32_16RGB565 "_*" #pragma aux ConvertMMXpII32_16BGR565 "_*" #pragma aux ConvertMMXpII32_16RGB555 "_*" #pragma aux ConvertMMXpII32_16BGR555 "_*" #pragma aux ConvertMMXp32_16RGB555 "_*" #endif /* WATCOM */ #endif /* X86_ASSEMBLER */ #endif