[FFmpeg-devel] [PATCH v2 03/15] swscale/x86/swscale: Fix undefined left shifts of negative numbers

Andreas Rheinhardt andreas.rheinhardt at gmail.com
Sat Sep 28 05:25:58 EEST 2019


This affected many FATE-tests: The number of failing tests went down
from 663 to 344. (Both numbers exclude tests that failed because of
unaligned accesses in code that is inside #if HAVE_FAST_UNALIGNED.)

Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt at gmail.com>
---
 libswscale/x86/swscale.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/libswscale/x86/swscale.c b/libswscale/x86/swscale.c
index 7dc2d70574..0eed4f18d5 100644
--- a/libswscale/x86/swscale.c
+++ b/libswscale/x86/swscale.c
@@ -160,7 +160,7 @@ void ff_updateMMXDitherTables(SwsContext *c, int dstY, int lumBufIndex, int chrB
                 *(const void**)&lumMmxFilter[s*i+APCK_PTR2/4  ]= lumSrcPtr[i+(vLumFilterSize>1)];
                 lumMmxFilter[s*i+APCK_COEF/4  ]=
                 lumMmxFilter[s*i+APCK_COEF/4+1]= vLumFilter[dstY*vLumFilterSize + i    ]
-                + (vLumFilterSize>1 ? vLumFilter[dstY*vLumFilterSize + i + 1]<<16 : 0);
+                    + (vLumFilterSize>1 ? vLumFilter[dstY*vLumFilterSize + i + 1] * (1 << 16) : 0);
                 if (CONFIG_SWSCALE_ALPHA && hasAlpha) {
                     *(const void**)&alpMmxFilter[s*i              ]= alpSrcPtr[i  ];
                     *(const void**)&alpMmxFilter[s*i+APCK_PTR2/4  ]= alpSrcPtr[i+(vLumFilterSize>1)];
@@ -173,7 +173,7 @@ void ff_updateMMXDitherTables(SwsContext *c, int dstY, int lumBufIndex, int chrB
                 *(const void**)&chrMmxFilter[s*i+APCK_PTR2/4  ]= chrUSrcPtr[i+(vChrFilterSize>1)];
                 chrMmxFilter[s*i+APCK_COEF/4  ]=
                 chrMmxFilter[s*i+APCK_COEF/4+1]= vChrFilter[chrDstY*vChrFilterSize + i    ]
-                + (vChrFilterSize>1 ? vChrFilter[chrDstY*vChrFilterSize + i + 1]<<16 : 0);
+                    + (vChrFilterSize>1 ? vChrFilter[chrDstY*vChrFilterSize + i + 1] * (1 << 16) : 0);
             }
         } else {
             for (i=0; i<vLumFilterSize; i++) {
-- 
2.20.1



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