diff --git a/x86_64/pclmul/ghash-update.asm b/x86_64/pclmul/ghash-update.asm
index 7764ef4860542d20108baf34b71ecf9ea4c0ff03..917a142744f76be3d7cc5331867bbdc04b49df6c 100644
--- a/x86_64/pclmul/ghash-update.asm
+++ b/x86_64/pclmul/ghash-update.asm
@@ -141,7 +141,7 @@ PROLOGUE(_nettle_ghash_update)
 	jnz		.Loop
 
 .L1_block:
-	and		$1, BLOCKS
+	test		$1, BLOCKS
 	jz		.Ldone
 
 	movups		(DATA), M