diff --git a/src/curve25519/curve25519-donna.c b/src/curve25519/curve25519-donna.c
index f2c2ac58..8047db35 100644
--- a/src/curve25519/curve25519-donna.c
+++ b/src/curve25519/curve25519-donna.c
@@ -273,16 +273,6 @@ div_by_2_25(const limb v)
   return (v + roundoff) >> 25;
 }
 
-/* return v / (2^25), using only shifts and adds.
- *
- * On entry: v can take any value. */
-static inline s32
-div_s32_by_2_25(const s32 v)
-{
-   const s32 roundoff = ((uint32_t)(v >> 31)) >> 7;
-   return (v + roundoff) >> 25;
-}
-
 /* Reduce all coefficients of the short form input so that |x| < 2^26.
  *
  * On entry: |output[i]| < 280*2^54 */
@@ -487,7 +477,7 @@ fcontract(u8 *output, limb *input_limbs) {
 
   /* |input_limbs[i]| < 2^26, so it's valid to convert to an s32. */
   for (i = 0; i < 10; i++) {
-    input[i] = input_limbs[i];
+    input[i] = (s32) input_limbs[i];
   }
 
   for (j = 0; j < 2; ++j) {
diff --git a/src/curve25519/ed25519/additions/zeroize.h b/src/curve25519/ed25519/additions/zeroize.h
index 0db68bb4..95e974ae 100644
--- a/src/curve25519/ed25519/additions/zeroize.h
+++ b/src/curve25519/ed25519/additions/zeroize.h
@@ -7,6 +7,6 @@
 
 void zeroize(unsigned char* b, size_t len);
 
-void zeroize_stack();
+void zeroize_stack(void);
 
 #endif
diff --git a/src/curve25519/ed25519/fe_frombytes.c b/src/curve25519/ed25519/fe_frombytes.c
index 5c179174..87e24942 100644
--- a/src/curve25519/ed25519/fe_frombytes.c
+++ b/src/curve25519/ed25519/fe_frombytes.c
@@ -60,14 +60,14 @@ void fe_frombytes(fe h,const unsigned char *s)
   carry6 = (h6 + (crypto_int64) (1<<25)) >> 26; h7 += carry6; h6 -= carry6 << 26;
   carry8 = (h8 + (crypto_int64) (1<<25)) >> 26; h9 += carry8; h8 -= carry8 << 26;
 
-  h[0] = h0;
-  h[1] = h1;
-  h[2] = h2;
-  h[3] = h3;
-  h[4] = h4;
-  h[5] = h5;
-  h[6] = h6;
-  h[7] = h7;
-  h[8] = h8;
-  h[9] = h9;
+  h[0] = (crypto_int32) h0;
+  h[1] = (crypto_int32) h1;
+  h[2] = (crypto_int32) h2;
+  h[3] = (crypto_int32) h3;
+  h[4] = (crypto_int32) h4;
+  h[5] = (crypto_int32) h5;
+  h[6] = (crypto_int32) h6;
+  h[7] = (crypto_int32) h7;
+  h[8] = (crypto_int32) h8;
+  h[9] = (crypto_int32) h9;
 }
diff --git a/src/curve25519/ed25519/fe_mul.c b/src/curve25519/ed25519/fe_mul.c
index 26ca8b36..d68e2101 100644
--- a/src/curve25519/ed25519/fe_mul.c
+++ b/src/curve25519/ed25519/fe_mul.c
@@ -240,14 +240,14 @@ void fe_mul(fe h,const fe f,const fe g)
   /* |h0| <= 2^25; from now on fits into int32 unchanged */
   /* |h1| <= 1.01*2^24 */
 
-  h[0] = h0;
-  h[1] = h1;
-  h[2] = h2;
-  h[3] = h3;
-  h[4] = h4;
-  h[5] = h5;
-  h[6] = h6;
-  h[7] = h7;
-  h[8] = h8;
-  h[9] = h9;
+  h[0] = (crypto_int32) h0;
+  h[1] = (crypto_int32) h1;
+  h[2] = (crypto_int32) h2;
+  h[3] = (crypto_int32) h3;
+  h[4] = (crypto_int32) h4;
+  h[5] = (crypto_int32) h5;
+  h[6] = (crypto_int32) h6;
+  h[7] = (crypto_int32) h7;
+  h[8] = (crypto_int32) h8;
+  h[9] = (crypto_int32) h9;
 }
diff --git a/src/curve25519/ed25519/fe_sq.c b/src/curve25519/ed25519/fe_sq.c
index 8dd11984..54a39496 100644
--- a/src/curve25519/ed25519/fe_sq.c
+++ b/src/curve25519/ed25519/fe_sq.c
@@ -136,14 +136,14 @@ void fe_sq(fe h,const fe f)
 
   carry0 = (h0 + (crypto_int64) (1<<25)) >> 26; h1 += carry0; h0 -= carry0 << 26;
 
-  h[0] = h0;
-  h[1] = h1;
-  h[2] = h2;
-  h[3] = h3;
-  h[4] = h4;
-  h[5] = h5;
-  h[6] = h6;
-  h[7] = h7;
-  h[8] = h8;
-  h[9] = h9;
+  h[0] = (crypto_int32) h0;
+  h[1] = (crypto_int32) h1;
+  h[2] = (crypto_int32) h2;
+  h[3] = (crypto_int32) h3;
+  h[4] = (crypto_int32) h4;
+  h[5] = (crypto_int32) h5;
+  h[6] = (crypto_int32) h6;
+  h[7] = (crypto_int32) h7;
+  h[8] = (crypto_int32) h8;
+  h[9] = (crypto_int32) h9;
 }
diff --git a/src/curve25519/ed25519/fe_sq2.c b/src/curve25519/ed25519/fe_sq2.c
index 026ed3aa..01b149f5 100644
--- a/src/curve25519/ed25519/fe_sq2.c
+++ b/src/curve25519/ed25519/fe_sq2.c
@@ -147,14 +147,14 @@ void fe_sq2(fe h,const fe f)
 
   carry0 = (h0 + (crypto_int64) (1<<25)) >> 26; h1 += carry0; h0 -= carry0 << 26;
 
-  h[0] = h0;
-  h[1] = h1;
-  h[2] = h2;
-  h[3] = h3;
-  h[4] = h4;
-  h[5] = h5;
-  h[6] = h6;
-  h[7] = h7;
-  h[8] = h8;
-  h[9] = h9;
+  h[0] = (crypto_int32) h0;
+  h[1] = (crypto_int32) h1;
+  h[2] = (crypto_int32) h2;
+  h[3] = (crypto_int32) h3;
+  h[4] = (crypto_int32) h4;
+  h[5] = (crypto_int32) h5;
+  h[6] = (crypto_int32) h6;
+  h[7] = (crypto_int32) h7;
+  h[8] = (crypto_int32) h8;
+  h[9] = (crypto_int32) h9;
 }
diff --git a/src/curve25519/ed25519/nacl_sha512/hash.c b/src/curve25519/ed25519/nacl_sha512/hash.c
index 8934cc18..c4d20166 100644
--- a/src/curve25519/ed25519/nacl_sha512/hash.c
+++ b/src/curve25519/ed25519/nacl_sha512/hash.c
@@ -26,7 +26,7 @@ int crypto_hash_sha512(unsigned char *out,const unsigned char *in,unsigned long
 {
   unsigned char h[64];
   unsigned char padded[256];
-  int i;
+  unsigned long long i;
   unsigned long long bytes = inlen;
 
   for (i = 0;i < 64;++i) h[i] = iv[i];