diff --git a/crypto/bn/bn_lcl.h b/crypto/bn/bn_lcl.h
index f9bebc05a7d03ed68b69faeda6371c1aaad05cd7..9ce0bc910bcb2bcc5f122ac2f182896af0ef299e 100644
--- a/crypto/bn/bn_lcl.h
+++ b/crypto/bn/bn_lcl.h
@@ -246,7 +246,7 @@ extern int bn_limit_num_mont;   /* (1<<bn_limit_bits_mont) */
 BIGNUM *bn_expand2(BIGNUM *b, int bits);
 
 #ifdef X86_ASM
-void bn_add_words(BN_ULONG *r,BN_ULONG *a,int num);
+void bn_add_words(BN_ULONG *r,BN_ULONG *a,BN_ULONG *b,int num);
 #endif
 
 #ifdef  __cplusplus