Changeset 99106 in vbox for trunk

Timestamp:

Mar 22, 2023 8:50:27 AM (22 months ago)

Author:

vboxsync

Message:

include/iprt/asm.h: Fix ASMBitTest on arm64. Despite being buggy due to offBitmap being miscalculated on the misaligned case it won't work with passed memory regions not aligned on a 32-bit boundary because it will always load a 32-bit of data, possibly exceeding the end of the buffer. This fixes the tstRTGetOptArgv testcase on darwin.arm64.

File:

• trunk/include/iprt/asm.h (modified) (1 diff)

trunk/include/iprt/asm.h

@@ -6819 +6819 @@
 
 # else
-    int32_t offBitmap = iBit / 32;
-    AssertStmt(!((uintptr_t)pvBitmap & 3), offBitmap += (uintptr_t)pvBitmap & 3; iBit += ((uintptr_t)pvBitmap & 3) * 8);
-    rc.u32 = RT_LE2H_U32(ASMAtomicUoReadU32(&((uint32_t volatile *)pvBitmap)[offBitmap])) >> (iBit & 31);
+    int32_t offBitmap = iBit >> 3;
+    rc.u32 = ASMAtomicUoReadU8(&((uint8_t volatile *)pvBitmap)[offBitmap]) >> (iBit & 7);
     rc.u32 &= 1;
 # endif