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authorRonald S. Bultje <rsbultje@gmail.com>2015-10-23 11:11:53 -0400
committerRonald S. Bultje <rsbultje@gmail.com>2015-10-24 14:34:50 -0400
commit52f84d82bdf1851ecfcc412c1719e5f6f3396209 (patch)
tree63451deab3c0da41c136f6eb249f04c973ad1e79
parent683462911db5ba1b17c32c523cdefe921f5aaf17 (diff)
downloadffmpeg-52f84d82bdf1851ecfcc412c1719e5f6f3396209.tar.gz
videodsp: don't overread edges in vfix3 emu_edge.
Fixes trac ticket 3226. Also see Andreas' analysis in https://bugs.debian.org/801745, which was very helpful.
-rw-r--r--libavcodec/x86/videodsp.asm15
1 files changed, 11 insertions, 4 deletions
diff --git a/libavcodec/x86/videodsp.asm b/libavcodec/x86/videodsp.asm
index 25d43640ab..48f5ac0ce6 100644
--- a/libavcodec/x86/videodsp.asm
+++ b/libavcodec/x86/videodsp.asm
@@ -194,8 +194,12 @@ hvar_fn
%elif (%2-%%off) == 2
mov valw, [srcq+%2-2]
%elifidn %1, body
- mov vald, [srcq+%2-3]
-%else
+ mov valb, [srcq+%2-1]
+ sal vald, 16
+ mov valw, [srcq+%2-3]
+%elifidn %1, bottom
+ movd mm %+ %%mmx_idx, [srcq+%2-4]
+%else ; top
movd mm %+ %%mmx_idx, [srcq+%2-3]
%endif
%endif ; (%2-%%off) >= 1
@@ -251,12 +255,15 @@ hvar_fn
mov [dstq+%2-2], valw
%elifidn %1, body
mov [dstq+%2-3], valw
- shr vald, 16
+ sar vald, 16
mov [dstq+%2-1], valb
%else
movd vald, mm %+ %%mmx_idx
+%ifidn %1, bottom
+ sar vald, 8
+%endif
mov [dstq+%2-3], valw
- shr vald, 16
+ sar vald, 16
mov [dstq+%2-1], valb
%endif
%endif ; (%2-%%off) >= 1