shithub: dav1d

Info  •  Files  •  Log  •  Branches

Prevent right-shift by 32

Fixes #93.

--- a/src/decode.c

+++ b/src/decode.c

@@ -298,9 +298,9 @@

     } else for (unsigned off = 0, xmask = masks[0]; np < 8 && xmask;) { // top

         const int tz = ctz(xmask);

         off += tz;

+        xmask >>= tz;

         add_sample(off, 0, 1, -1, &r[off - b4_stride]);

-        xmask >>= tz + 1;

-        off += 1;

+        xmask &= ~1;

     }

     if (np < 8 && masks[1] == 1) {

         const int off = t->by & (bs(&r[-1])[1] - 1);

@@ -308,9 +308,9 @@

     } else for (unsigned off = 0, ymask = masks[1]; np < 8 && ymask;) { // left

         const int tz = ctz(ymask);

         off += tz;

+        ymask >>= tz;

         add_sample(0, off, -1, 1, &r[off * b4_stride - 1]);

-        ymask >>= tz + 1;

-        off += 1;

+        ymask &= ~1;

     }

     if (np < 8 && masks[1] >> 32) // top/left

         add_sample(0, 0, -1, -1, &r[-(1 + b4_stride)]);