handy.h: Create nBIT_MASK(n) macro

This encapsulates a common paradigm, making sure that it is done
correctly for the platform's size.

1 files changed, 1 insertions, 1 deletions

diff --git a/pp_pack.c b/pp_pack.c
index 8ac5316e85..53d63f9d9e 100644
--- a/pp_pack.c
+++ b/pp_pack.c
@@ -1808,7 +1808,7 @@ S_unpack_rec(pTHX_ tempsym_t* symptr, const char *s, const char *strbeg, const c
 	    }
 	    else {
 		if (checksum < bits_in_uv) {
-		    UV mask = ((UV)1 << checksum) - 1;
+		    UV mask = nBIT_MASK(checksum);
 		    cuv &= mask;
 		}
 		sv = newSVuv(cuv);