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vp8: ppc: fix invalid reads in altivec epel mc 

The 4-tap filters should only access one row/column before the
reference block.

Signed-off-by: Mans Rullgard <mans@mansr.com>
This commit is contained in:
Mans Rullgard 2011-02-21 15:47:27 +00:00
parent 381efba0ec
commit e0e46cae37
1 changed files with 14 additions and 7 deletions
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21
libavcodec/ppc/vp8dsp_altivec.c
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@ -56,8 +56,8 @@ static const vec_s8 h_subpel_filters_outer[3] =
vec_s8 filter_outerl = vec_sld(filter_outerh, filter_outerh, 2)
#define FILTER_H(dstv, off) \
a = vec_ld((off)-2, src); \
b = vec_ld((off)-2+15, src); \
a = vec_ld((off)-is6tap-1, src); \
b = vec_ld((off)-is6tap-1+15, src); \
\
pixh = vec_perm(a, b, permh##off); \
pixl = vec_perm(a, b, perml##off); \
@ -86,13 +86,15 @@ void put_vp8_epel_h_altivec_core(uint8_t *dst, int dst_stride,
vec_s16 f16h, f16l;
vec_s32 filth, filtl;
vec_u8 perm_inner = { 1,2,3,4, 2,3,4,5, 3,4,5,6, 4,5,6,7 };
vec_u8 perm_inner6 = { 1,2,3,4, 2,3,4,5, 3,4,5,6, 4,5,6,7 };
vec_u8 perm_inner4 = { 0,1,2,3, 1,2,3,4, 2,3,4,5, 3,4,5,6 };
vec_u8 perm_inner = is6tap ? perm_inner6 : perm_inner4;
vec_u8 perm_outer = { 4,9, 0,5, 5,10, 1,6, 6,11, 2,7, 7,12, 3,8 };
vec_s32 c64 = vec_sl(vec_splat_s32(1), vec_splat_u32(6));
vec_u16 c7 = vec_splat_u16(7);
align_vec0 = vec_lvsl( -2, src);
align_vec8 = vec_lvsl(8-2, src);
align_vec0 = vec_lvsl( -is6tap-1, src);
align_vec8 = vec_lvsl(8-is6tap-1, src);
permh0 = vec_perm(align_vec0, align_vec0, perm_inner);
permh8 = vec_perm(align_vec8, align_vec8, perm_inner);
@ -239,8 +241,13 @@ void put_vp8_epel ## WIDTH ## _v ## TAPS ## _altivec(uint8_t *dst, int dst_strid
static void put_vp8_epel ## WIDTH ## _h ## HTAPS ## v ## VTAPS ## _altivec(uint8_t *dst, int stride, uint8_t *src, int s, int h, int mx, int my) \
{ \
DECLARE_ALIGNED(16, uint8_t, tmp)[(2*WIDTH+5)*16]; \
put_vp8_epel ## WIDTH ## _h ## HTAPS ## _altivec(tmp, 16, src-2*stride, stride, h+5, mx, my); \
put_vp8_epel ## WIDTH ## _v ## VTAPS ## _altivec(dst, stride, tmp+2*16, 16, h, mx, my); \
if (VTAPS == 6) { \
put_vp8_epel ## WIDTH ## _h ## HTAPS ## _altivec(tmp, 16, src-2*stride, stride, h+5, mx, my); \
put_vp8_epel ## WIDTH ## _v ## VTAPS ## _altivec(dst, stride, tmp+2*16, 16, h, mx, my); \
} else { \
put_vp8_epel ## WIDTH ## _h ## HTAPS ## _altivec(tmp, 16, src-stride, stride, h+4, mx, my); \
put_vp8_epel ## WIDTH ## _v ## VTAPS ## _altivec(dst, stride, tmp+16, 16, h, mx, my); \
} \
}
EPEL_FUNCS(16,6)