mirror of
https://github.com/Relintai/sdl2_frt.git
synced 2024-12-20 22:16:49 +01:00
SDL_blit_N.c: Correct vec_perm() application on little-endian 64-bit PowerPC
The LE transformation for vec_perm has an implicit assumption that the permutation is being used to reorder vector elements (in this case 4-byte integer word elements), not to reorder bytes within those elements. Although this is legal behavior, it is not anticipated by the transformation performed by the compilers. This causes pygame-1.9.1 test failure on PPC64LE because blitted pixmaps are corrupted there due to how SDL uses vec_perm(). From RedHat / Fedora: https://bugzilla.redhat.com/show_bug.cgi?id=1392465 Original patch was provided by: Menanteau Guy <menantea@linux.vnet.ibm.com>
This commit is contained in:
parent
2d37d29183
commit
715e070d29
@ -165,6 +165,34 @@ calc_swizzle32(const SDL_PixelFormat * srcfmt, const SDL_PixelFormat * dstfmt)
|
||||
return (vswiz);
|
||||
}
|
||||
|
||||
#if defined(__powerpc__) && (SDL_BYTEORDER == SDL_LIL_ENDIAN)
|
||||
/* reorder bytes for PowerPC little endian */
|
||||
static vector unsigned char reorder_ppc64le_vec(vector unsigned char vpermute)
|
||||
{
|
||||
/* The result vector of calc_swizzle32 reorder bytes using vec_perm.
|
||||
The LE transformation for vec_perm has an implicit assumption
|
||||
that the permutation is being used to reorder vector elements,
|
||||
not to reorder bytes within those elements.
|
||||
Unfortunatly the result order is not the expected one for powerpc
|
||||
little endian when the two first vector parameters of vec_perm are
|
||||
not of type 'vector char'. This is because the numbering from the
|
||||
left for BE, and numbering from the right for LE, produces a
|
||||
different interpretation of what the odd and even lanes are.
|
||||
Refer to fedora bug 1392465
|
||||
*/
|
||||
|
||||
const vector unsigned char ppc64le_reorder = VECUINT8_LITERAL(
|
||||
0x01, 0x00, 0x03, 0x02,
|
||||
0x05, 0x04, 0x07, 0x06,
|
||||
0x09, 0x08, 0x0B, 0x0A,
|
||||
0x0D, 0x0C, 0x0F, 0x0E );
|
||||
|
||||
vector unsigned char vswiz_ppc64le;
|
||||
vswiz_ppc64le = vec_perm(vpermute, vpermute, ppc64le_reorder);
|
||||
return(vswiz_ppc64le);
|
||||
}
|
||||
#endif
|
||||
|
||||
static void Blit_RGB888_RGB565(SDL_BlitInfo * info);
|
||||
static void
|
||||
Blit_RGB888_RGB565Altivec(SDL_BlitInfo * info)
|
||||
@ -658,6 +686,10 @@ Blit32to32KeyAltivec(SDL_BlitInfo * info)
|
||||
/* vsel is set for items that match the key */
|
||||
vsel = (vector unsigned char) vec_and(vs, vrgbmask);
|
||||
vsel = (vector unsigned char) vec_cmpeq(vs, vckey);
|
||||
#if defined(__powerpc__) && (SDL_BYTEORDER == SDL_LIL_ENDIAN)
|
||||
/* reorder bytes for PowerPC little endian */
|
||||
vpermute = reorder_ppc64le_vec(vpermute);
|
||||
#endif
|
||||
/* permute the src vec to the dest format */
|
||||
vs = vec_perm(vs, valpha, vpermute);
|
||||
/* load the destination vec */
|
||||
@ -737,6 +769,10 @@ ConvertAltivec32to32_noprefetch(SDL_BlitInfo * info)
|
||||
src += 4;
|
||||
width -= 4;
|
||||
vbits = vec_perm(vbits, voverflow, valigner); /* src is ready. */
|
||||
#if defined(__powerpc__) && (SDL_BYTEORDER == SDL_LIL_ENDIAN)
|
||||
/* reorder bytes for PowerPC little endian */
|
||||
vpermute = reorder_ppc64le_vec(vpermute);
|
||||
#endif
|
||||
vbits = vec_perm(vbits, vzero, vpermute); /* swizzle it. */
|
||||
vec_st(vbits, 0, dst); /* store it back out. */
|
||||
dst += 4;
|
||||
@ -828,6 +864,10 @@ ConvertAltivec32to32_prefetch(SDL_BlitInfo * info)
|
||||
src += 4;
|
||||
width -= 4;
|
||||
vbits = vec_perm(vbits, voverflow, valigner); /* src is ready. */
|
||||
#if defined(__powerpc__) && (SDL_BYTEORDER == SDL_LIL_ENDIAN)
|
||||
/* reorder bytes for PowerPC little endian */
|
||||
vpermute = reorder_ppc64le_vec(vpermute);
|
||||
#endif
|
||||
vbits = vec_perm(vbits, vzero, vpermute); /* swizzle it. */
|
||||
vec_st(vbits, 0, dst); /* store it back out. */
|
||||
dst += 4;
|
||||
|
Loading…
Reference in New Issue
Block a user