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;

.TH "SDL_SemValue" "3" "Tue 11 Sep 2001, 23:00" "SDL" "SDL API Reference" +
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.SH "NAME"+
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SDL_SemValue\- Return the current value of a semaphore\&.+
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.SH "SYNOPSIS"+
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.PP+
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\fB#include "SDL\&.h"+
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#include "SDL/SDL_thread\&.h"+
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.sp+
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\fBUint32 \fBSDL_SemValue\fP\fR(\fBSDL_sem *sem\fR);+
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.SH "DESCRIPTION"+
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.PP+
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\fBSDL_SemValue()\fP returns the current semaphore value from the semaphore pointed to by \fBsem\fR\&.+
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.SH "RETURN VALUE"+
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.PP+
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Returns current value of the semaphore\&.+
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.SH "EXAMPLES"+
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.PP+
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.PP+
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.nf+
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\f(CW  sem_value = SDL_SemValue(my_sem);\fR+
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.fi+
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.PP+
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.SH "SEE ALSO"+
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.PP+
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\fI\fBSDL_CreateSemaphore\fP\fR, \fI\fBSDL_DestroySemaphore\fP\fR, \fI\fBSDL_SemWait\fP\fR, \fI\fBSDL_SemTryWait\fP\fR, \fI\fBSDL_SemWaitTimeout\fP\fR, \fI\fBSDL_SemPost\fP\fR+
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...\" created by instant / docbook-to-man, Tue 11 Sep 2001, 23:00+
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