diff --git a/src/memcpy.s b/src/memcpy.s
index 0b4fccb..4d501f0 100644
--- a/src/memcpy.s
+++ b/src/memcpy.s
@@ -117,7 +117,7 @@ add	r1, r2
 sub	r0, #1
 sub	r1, #1
 // r12 = num residual bytes
-and	r12, r2, #3
+and	r12, r2, #2
 .Lrbyte_copy:
 	subs	r12, #1
 	ldrcsb	r3, [r1], #-1
@@ -125,6 +125,7 @@ and	r12, r2, #3
 	bhi	.Lrbyte_copy
 // r12 = num residual words
 lsr	r12, r2, #2
+and	r12, #3
 // Move to the beginning of the current word
 sub	r0, #3
 sub	r1, #3