Handle negative continuation offsets (WIN64 with debug).

diff --git a/src/lj_frame.h b/src/lj_frame.h
index d9db581b5138da62e5803eec958f4eb4fb6b824c..0d7b177bcd7adb15e0d6a6c85b9ee1f5b5ea235d 100644 (file)
--- a/src/lj_frame.h
+++ b/src/lj_frame.h
@@ -37,7 +37,8 @@ enum {
 #define frame_contpc(f)                (frame_pc((f)-1))
 #if LJ_64
 #define frame_contf(f) \
-  ((ASMFunction)(void *)((intptr_t)lj_vm_asm_begin+(((f)-1)->u64 & 0xffffffff)))
+  ((ASMFunction)(void *)((intptr_t)lj_vm_asm_begin + \
+                        (intptr_t)(int32_t)((f)-1)->u32.lo))
 #else
 #define frame_contf(f)         ((ASMFunction)gcrefp(((f)-1)->gcr, void))
 #endif