diff --git a/src/sm3_xmss.c b/src/sm3_xmss.c
index ea9b63a0..0dc2ce0c 100644
--- a/src/sm3_xmss.c
+++ b/src/sm3_xmss.c
@@ -381,7 +381,7 @@ void sm3_xmss_derive_root(const uint8_t xmss_secret[32], int height,
 	hash256_prf_init(&prf_seed_ctx, seed);
 
 	// generate all the wots pk[]
-	for (i = 0; i < (1<<height); i++) {
+	for (i = 0; i < (uint32_t)(1<<height); i++) {
 		//HASH256_CTX prf_ctx = prf_keygen_ctx;
 		hash256_bytes_t wots_sk[67];
 		hash256_bytes_t wots_pk[67];
diff --git a/src/sm9_z256.c b/src/sm9_z256.c
index c048eab9..6e56278b 100644
--- a/src/sm9_z256.c
+++ b/src/sm9_z256.c
@@ -2001,7 +2001,7 @@ void sm9_z256_point_mul(SM9_Z256_POINT *R, const sm9_z256_t k, const SM9_Z256_PO
 	uint64_t window_size = 5;
 	SM9_Z256_POINT T[16];
 	int R_infinity = 1;
-	int n = (int)(256 + window_size - 1)/window_size;
+	int n = (int)((256 + window_size - 1)/window_size);
 	int i;
 
 	// T[i] = (i + 1) * P
diff --git a/tools/sdftest.c b/tools/sdftest.c
index 66b9a13d..1ce64e76 100644
--- a/tools/sdftest.c
+++ b/tools/sdftest.c
@@ -399,7 +399,6 @@ static int test_SDF_ExternalVerify_ECC(void)
 		0x3e, 0xb4, 0xb6, 0x66, 0x20, 0x52, 0x0c, 0xf4,
 		},
 	};
-	unsigned char saved_byte;
 	int ret;
 
 	ret = SDF_OpenDevice(&hDeviceHandle);