Mercurial > sdl-ios-xcode
view src/video/riscos/SDL_riscosASM.S @ 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 | 1e8582152d44 |
children | 99210400e8b9 |
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; ; SDL - Simple DirectMedia Layer ; Copyright (C) 1997-2004 Sam Lantinga ; ; This library is free software; you can redistribute it and/or ; modify it under the terms of the GNU Library General Public ; License as published by the Free Software Foundation; either ; version 2 of the License, or (at your option) any later version. ; ; This library is distributed in the hope that it will be useful, ; but WITHOUT ANY WARRANTY; without even the implied warranty of ; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU ; Library General Public License for more details. ; ; You should have received a copy of the GNU Library General Public ; License along with this library; if not, write to the Free ; Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA ; ; Sam Lantinga ; slouken@libsdl.org ; ; Assembler routines for RISC OS display ; AREA |C$$CODE| EXPORT |RISCOS_Put32| ; Display 32bpp to 32bpp, 1:1 ; ; Code provided by Adrain Lees ; ; entry a1 -> destination ; a2 = dest width in pixels ; a3 = dest line length in bytes ; a4 = dest height in scanlines ; arg5 -> source ; arg6 = byte offset from end of source line to start of next Arg5 * 10*4 Arg6 * Arg5+4 RISCOS_Put32 ROUT STMFD sp!,{a2,v1-v6,sl,fp,lr} LDR ip,[sp,#Arg5] MOV lr,a1 B ucp64lp 00 ;tail strip of 1-15 pixels LDR v1,[ip],#4 01 SUBS a2,a2,#1 STR v1,[lr],#4 LDRHI v1,[ip],#4 BHI %01 B %02 ucp64end ADDS a2,a2,#16 BNE %00 02 SUBS a4,a4,#1 ;height-- LDRHI v1,[sp,#Arg6] LDRHI a2,[sp] ;reload width BLS %03 ;move to start of next scanline ADD lr,a1,a3 ADD a1,a1,a3 ADD ip,ip,v1 ucp64lp SUBS a2,a2,#16 BLO ucp64end PLD [ip,#64] LDR v1,[ip],#4 LDR v2,[ip],#4 LDR v3,[ip],#4 LDR v4,[ip],#4 LDR v5,[ip],#4 LDR v6,[ip],#4 LDR sl,[ip],#4 LDR fp,[ip],#4 STR v1,[lr],#4 STR v2,[lr],#4 STR v3,[lr],#4 STR v4,[lr],#4 STR v5,[lr],#4 STR v6,[lr],#4 STR sl,[lr],#4 STR fp,[lr],#4 PLD [ip,#64] LDR v1,[ip],#4 LDR v2,[ip],#4 LDR v3,[ip],#4 LDR v4,[ip],#4 LDR v5,[ip],#4 LDR v6,[ip],#4 LDR sl,[ip],#4 LDR fp,[ip],#4 STR v1,[lr],#4 STR v2,[lr],#4 STR v3,[lr],#4 STR v4,[lr],#4 STR v5,[lr],#4 STR v6,[lr],#4 STR sl,[lr],#4 STR fp,[lr],#4 B ucp64lp 03 LDMFD sp!,{a2,v1-v6,sl,fp,pc}