diff --git a/src/p25519/arch_ref64/f_impl.h b/src/p25519/arch_ref64/f_impl.h
index 639826d..535abd4 100644
--- a/src/p25519/arch_ref64/f_impl.h
+++ b/src/p25519/arch_ref64/f_impl.h
@@ -19,17 +19,15 @@ extern "C" {
 /* -------------- Inline functions begin here -------------- */
 
 void gf_add_RAW (gf out, const gf a, const gf b) {
-    unsigned int i;
-    for (i=0; i<5; i++) {
+    for (unsigned int i=0; i<5; i++) {
         out->limb[i] = a->limb[i] + b->limb[i];
     }
     gf_weak_reduce(out);
 }
 
 void gf_sub_RAW (gf out, const gf a, const gf b) {
-    unsigned int i;
     uint64_t co1 = ((1ull<<51)-1)*2, co2 = co1-36;
-    for (i=0; i<5; i++) {
+    for (unsigned int i=0; i<5; i++) {
         out->limb[i] = a->limb[i] - b->limb[i] + ((i==0) ? co2 : co1);
     }
     gf_weak_reduce(out);
@@ -43,8 +41,7 @@ void gf_bias (gf a, int amt) {
 void gf_weak_reduce (gf a) {
     uint64_t mask = (1ull<<51) - 1;
     uint64_t tmp = a->limb[4] >> 51;
-    int i;
-    for (i=4; i>0; i--) {
+    for (unsigned int i=4; i>0; i--) {
         a->limb[i] = (a->limb[i] & mask) + (a->limb[i-1]>>51);
     }
     a->limb[0] = (a->limb[0] & mask) + tmp*19;
diff --git a/src/p25519/arch_x86_64/f_impl.h b/src/p25519/arch_x86_64/f_impl.h
index 1b89171..5f093c6 100644
--- a/src/p25519/arch_x86_64/f_impl.h
+++ b/src/p25519/arch_x86_64/f_impl.h
@@ -15,24 +15,20 @@
 /* -------------- Inline functions begin here -------------- */
 
 void gf_add_RAW (gf out, const gf a, const gf b) {
-    unsigned int i;
-    for (i=0; i<5; i++) {
+    for (unsigned int i=0; i<5; i++) {
         out->limb[i] = a->limb[i] + b->limb[i];
     }
 }
 
 void gf_sub_RAW (gf out, const gf a, const gf b) {
-    unsigned int i;
-    uint64_t co1 = ((1ull<<51)-1)*2, co2 = co1-36;
-    for (i=0; i<5; i++) {
-        out->limb[i] = a->limb[i] - b->limb[i] + ((i==0) ? co2 : co1);
+    for (unsigned int i=0; i<5; i++) {
+        out->limb[i] = a->limb[i] - b->limb[i];
     }
 }
 
 void gf_bias (gf a, int amt) {
     a->limb[0] += ((uint64_t)(amt)<<52) - 38*amt;
-    int i;
-    for (i=1; i<5; i++) {
+    for (unsigned int i=1; i<5; i++) {
         a->limb[i] += ((uint64_t)(amt)<<52)-2*amt;
     }
 }
@@ -40,8 +36,7 @@ void gf_bias (gf a, int amt) {
 void gf_weak_reduce (gf a) {
     uint64_t mask = (1ull<<51) - 1;
     uint64_t tmp = a->limb[4] >> 51;
-    int i;
-    for (i=4; i>0; i--) {
+    for (unsigned int i=4; i>0; i--) {
         a->limb[i] = (a->limb[i] & mask) + (a->limb[i-1]>>51);
     }
     a->limb[0] = (a->limb[0] & mask) + tmp*19;
diff --git a/src/p448/arch_32/f_impl.h b/src/p448/arch_32/f_impl.h
index d6abb12..1c4d182 100644
--- a/src/p448/arch_32/f_impl.h
+++ b/src/p448/arch_32/f_impl.h
@@ -20,8 +20,7 @@ extern "C" {
 /* -------------- Inline functions begin here -------------- */
 
 void gf_add_RAW (gf out, const gf a, const gf b) {
-    unsigned int i;
-    for (i=0; i<sizeof(*out)/sizeof(uint32xn_t); i++) {
+    for (unsigned int i=0; i<sizeof(*out)/sizeof(uint32xn_t); i++) {
         ((uint32xn_t*)out)[i] = ((const uint32xn_t*)a)[i] + ((const uint32xn_t*)b)[i];
     }
     /*
@@ -33,8 +32,7 @@ void gf_add_RAW (gf out, const gf a, const gf b) {
 }
 
 void gf_sub_RAW (gf out, const gf a, const gf b) {
-    unsigned int i;
-    for (i=0; i<sizeof(*out)/sizeof(uint32xn_t); i++) {
+    for (unsigned int i=0; i<sizeof(*out)/sizeof(uint32xn_t); i++) {
         ((uint32xn_t*)out)[i] = ((const uint32xn_t*)a)[i] - ((const uint32xn_t*)b)[i];
     }
     /*
@@ -58,9 +56,8 @@ void gf_bias (gf a, int amt) {
 void gf_weak_reduce (gf a) {
     uint64_t mask = (1ull<<28) - 1;
     uint64_t tmp = a->limb[15] >> 28;
-    int i;
     a->limb[8] += tmp;
-    for (i=15; i>0; i--) {
+    for (unsigned int i=15; i>0; i--) {
         a->limb[i] = (a->limb[i] & mask) + (a->limb[i-1]>>28);
     }
     a->limb[0] = (a->limb[0] & mask) + tmp;
diff --git a/src/p448/arch_arm_32/f_impl.h b/src/p448/arch_arm_32/f_impl.h
index d6abb12..37d8d94 100644
--- a/src/p448/arch_arm_32/f_impl.h
+++ b/src/p448/arch_arm_32/f_impl.h
@@ -20,26 +20,22 @@ extern "C" {
 /* -------------- Inline functions begin here -------------- */
 
 void gf_add_RAW (gf out, const gf a, const gf b) {
-    unsigned int i;
-    for (i=0; i<sizeof(*out)/sizeof(uint32xn_t); i++) {
+    for (unsigned int i=0; i<sizeof(*out)/sizeof(uint32xn_t); i++) {
         ((uint32xn_t*)out)[i] = ((const uint32xn_t*)a)[i] + ((const uint32xn_t*)b)[i];
     }
     /*
-    unsigned int i;
-    for (i=0; i<sizeof(*out)/sizeof(out->limb[0]); i++) {
+    for (unsigned int i=0; i<sizeof(*out)/sizeof(out->limb[0]); i++) {
         out->limb[i] = a->limb[i] + b->limb[i];
     }
     */
 }
 
 void gf_sub_RAW (gf out, const gf a, const gf b) {
-    unsigned int i;
-    for (i=0; i<sizeof(*out)/sizeof(uint32xn_t); i++) {
+    for (unsigned int i=0; i<sizeof(*out)/sizeof(uint32xn_t); i++) {
         ((uint32xn_t*)out)[i] = ((const uint32xn_t*)a)[i] - ((const uint32xn_t*)b)[i];
     }
     /*
-    unsigned int i;
-    for (i=0; i<sizeof(*out)/sizeof(out->limb[0]); i++) {
+    for (unsigned int i=0; i<sizeof(*out)/sizeof(out->limb[0]); i++) {
         out->limb[i] = a->limb[i] - b->limb[i];
     }
     */
@@ -58,9 +54,8 @@ void gf_bias (gf a, int amt) {
 void gf_weak_reduce (gf a) {
     uint64_t mask = (1ull<<28) - 1;
     uint64_t tmp = a->limb[15] >> 28;
-    int i;
     a->limb[8] += tmp;
-    for (i=15; i>0; i--) {
+    for (unsigned int i=15; i>0; i--) {
         a->limb[i] = (a->limb[i] & mask) + (a->limb[i-1]>>28);
     }
     a->limb[0] = (a->limb[0] & mask) + tmp;
diff --git a/src/p448/arch_neon_experimental/f_impl.h b/src/p448/arch_neon_experimental/f_impl.h
index 2ed616b..ca99cbb 100644
--- a/src/p448/arch_neon_experimental/f_impl.h
+++ b/src/p448/arch_neon_experimental/f_impl.h
@@ -26,15 +26,13 @@ extern "C" {
 /* -------------- Inline functions begin here -------------- */
 
 void gf_add_RAW (gf out, const gf a, const gf b) {
-    unsigned int i;
-    for (i=0; i<sizeof(*out)/sizeof(uint32xn_t); i++) {
+    for (unsigned int i=0; i<sizeof(*out)/sizeof(uint32xn_t); i++) {
         ((uint32xn_t*)out)[i] = ((const uint32xn_t*)a)[i] + ((const uint32xn_t*)b)[i];
     }
 }
 
 void gf_sub_RAW (gf out, const gf a, const gf b) {
-    unsigned int i;
-    for (i=0; i<sizeof(*out)/sizeof(uint32xn_t); i++) {
+    for (unsigned int i=0; i<sizeof(*out)/sizeof(uint32xn_t); i++) {
         ((uint32xn_t*)out)[i] = ((const uint32xn_t*)a)[i] - ((const uint32xn_t*)b)[i];
     }
     /*
@@ -60,8 +58,7 @@ void gf_weak_reduce (gf a) {
     uint32x2_t *aa = (uint32x2_t*) a, vmask = {(1ull<<28)-1, (1ull<<28)-1}, vm2 = {0,-1},
        tmp = vshr_n_u32(aa[7],28);
        
-    int i;
-    for (i=7; i>=1; i--) {
+    for (unsigned int i=7; i>=1; i--) {
         aa[i] = vsra_n_u32(aa[i] & vmask, aa[i-1], 28);
     }
     aa[0] = (aa[0] & vmask) + vrev64_u32(tmp) + (tmp&vm2);
diff --git a/src/p448/arch_ref64/f_impl.h b/src/p448/arch_ref64/f_impl.h
index 0f9af8b..228df96 100644
--- a/src/p448/arch_ref64/f_impl.h
+++ b/src/p448/arch_ref64/f_impl.h
@@ -19,17 +19,15 @@ extern "C" {
 /* -------------- Inline functions begin here -------------- */
 
 void gf_add_RAW (gf  out, const gf  a, const gf  b) {
-    unsigned int i;
-    for (i=0; i<8; i++) {
+    for (unsigned int i=0; i<8; i++) {
         out->limb[i] = a->limb[i] + b->limb[i];
     }
     gf_weak_reduce(out);
 }
 
 void gf_sub_RAW (gf  out, const gf  a, const gf  b) {
-    unsigned int i;
     uint64_t co1 = ((1ull<<56)-1)*2, co2 = co1-2;
-    for (i=0; i<8; i++) {
+    for (unsigned int i=0; i<8; i++) {
         out->limb[i] = a->limb[i] - b->limb[i] + ((i==4) ? co2 : co1);
     }
     gf_weak_reduce(out);
@@ -43,9 +41,8 @@ void gf_bias (gf  a, int amt) {
 void gf_weak_reduce (gf  a) {
     uint64_t mask = (1ull<<56) - 1;
     uint64_t tmp = a->limb[7] >> 56;
-    int i;
     a->limb[4] += tmp;
-    for (i=7; i>0; i--) {
+    for (unsigned int i=7; i>0; i--) {
         a->limb[i] = (a->limb[i] & mask) + (a->limb[i-1]>>56);
     }
     a->limb[0] = (a->limb[0] & mask) + tmp;
diff --git a/src/p448/arch_x86_64/f_impl.h b/src/p448/arch_x86_64/f_impl.h
index 8f1b40c..12f8118 100644
--- a/src/p448/arch_x86_64/f_impl.h
+++ b/src/p448/arch_x86_64/f_impl.h
@@ -18,8 +18,7 @@ extern "C" {
 /* -------------- Inline functions begin here -------------- */
 
 void gf_add_RAW (gf  out, const gf  a, const gf  b) {
-    unsigned int i;
-    for (i=0; i<sizeof(*out)/sizeof(uint64xn_t); i++) {
+    for (unsigned int i=0; i<sizeof(*out)/sizeof(uint64xn_t); i++) {
         ((uint64xn_t*)out)[i] = ((const uint64xn_t*)a)[i] + ((const uint64xn_t*)b)[i];
     }
     /*
@@ -31,8 +30,7 @@ void gf_add_RAW (gf  out, const gf  a, const gf  b) {
 }
 
 void gf_sub_RAW (gf  out, const gf  a, const gf  b) {
-    unsigned int i;
-    for (i=0; i<sizeof(*out)/sizeof(uint64xn_t); i++) {
+    for (unsigned int i=0; i<sizeof(*out)/sizeof(uint64xn_t); i++) {
         ((uint64xn_t*)out)[i] = ((const uint64xn_t*)a)[i] - ((const uint64xn_t*)b)[i];
     }
     /*
@@ -59,8 +57,7 @@ void gf_bias (gf  a, int amt) {
     aa[2] += hi;
     aa[3] += lo;
 #else
-    unsigned int i;
-    for (i=0; i<sizeof(*a)/sizeof(uint64_t); i++) {
+    for (unsigned int i=0; i<sizeof(*a)/sizeof(uint64_t); i++) {
         a->limb[i] += (i==4) ? co2 : co1;
     }
 #endif
@@ -70,9 +67,8 @@ void gf_weak_reduce (gf  a) {
     /* PERF: use pshufb/palignr if anyone cares about speed of this */
     uint64_t mask = (1ull<<56) - 1;
     uint64_t tmp = a->limb[7] >> 56;
-    int i;
     a->limb[4] += tmp;
-    for (i=7; i>0; i--) {
+    for (unsigned int i=7; i>0; i--) {
         a->limb[i] = (a->limb[i] & mask) + (a->limb[i-1]>>56);
     }
     a->limb[0] = (a->limb[0] & mask) + tmp;
diff --git a/src/p480/arch_x86_64/f_impl.h b/src/p480/arch_x86_64/f_impl.h
index 7c1867c..ef94c3b 100644
--- a/src/p480/arch_x86_64/f_impl.h
+++ b/src/p480/arch_x86_64/f_impl.h
@@ -18,8 +18,7 @@ extern "C" {
 /* -------------- Inline functions begin here -------------- */
 
 void gf_add_RAW (gf  *out, const gf  *a, const gf  *b) {
-    unsigned int i;
-    for (i=0; i<sizeof(*out)/sizeof(uint64xn_t); i++) {
+    for (unsigned int i=0; i<sizeof(*out)/sizeof(uint64xn_t); i++) {
         ((uint64xn_t*)out)[i] = ((const uint64xn_t*)a)[i] + ((const uint64xn_t*)b)[i];
     }
     /*
@@ -31,8 +30,7 @@ void gf_add_RAW (gf  *out, const gf  *a, const gf  *b) {
 }
 
 void gf_sub_RAW (gf  *out, const gf  *a, const gf  *b) {
-    unsigned int i;
-    for (i=0; i<sizeof(*out)/sizeof(uint64xn_t); i++) {
+    for (unsigned int i=0; i<sizeof(*out)/sizeof(uint64xn_t); i++) {
         ((uint64xn_t*)out)[i] = ((const uint64xn_t*)a)[i] - ((const uint64xn_t*)b)[i];
     }
     /*
@@ -44,8 +42,7 @@ void gf_sub_RAW (gf  *out, const gf  *a, const gf  *b) {
 }
 
 void gf_copy (gf  *out, const gf  *a) {
-    unsigned int i;
-    for (i=0; i<sizeof(*out)/sizeof(big_register_t); i++) {
+    for (unsigned int i=0; i<sizeof(*out)/sizeof(big_register_t); i++) {
         ((big_register_t *)out)[i] = ((const big_register_t *)a)[i];
     }
 }
@@ -68,8 +65,7 @@ void gf_bias (
     aa[2] += hi;
     aa[3] += lo;
 #else
-    unsigned int i;
-    for (i=0; i<sizeof(*a)/sizeof(uint64_t); i++) {
+    for (unsigned int i=0; i<sizeof(*a)/sizeof(uint64_t); i++) {
         a->limb[i] += (i==4) ? co2 : co1;
     }
 #endif
@@ -79,9 +75,8 @@ void gf_weak_reduce (gf  *a) {
     /* PERF: use pshufb/palignr if anyone cares about speed of this */
     uint64_t mask = (1ull<<60) - 1;
     uint64_t tmp = a->limb[7] >> 60;
-    int i;
     a->limb[4] += tmp;
-    for (i=7; i>0; i--) {
+    for (unsigned int i=7; i>0; i--) {
         a->limb[i] = (a->limb[i] & mask) + (a->limb[i-1]>>60);
     }
     a->limb[0] = (a->limb[0] & mask) + tmp;
diff --git a/src/p521/arch_ref64/f_impl.h b/src/p521/arch_ref64/f_impl.h
index ddb784f..679b6fa 100644
--- a/src/p521/arch_ref64/f_impl.h
+++ b/src/p521/arch_ref64/f_impl.h
@@ -17,17 +17,15 @@ extern "C" {
 /* -------------- Inline functions begin here -------------- */
 
 void gf_add_RAW (gf  *out, const gf  *a, const gf  *b) {
-    unsigned int i;
-    for (i=0; i<9; i++) {
+    for (unsigned int i=0; i<9; i++) {
         out->limb[i] = a->limb[i] + b->limb[i];
     }
     gf_weak_reduce(out);
 }
 
 void gf_sub_RAW (gf  *out, const gf  *a, const gf  *b) {
-    unsigned int i;
     uint64_t co1 = ((1ull<<58)-1)*4, co2 = ((1ull<<57)-1)*4;
-    for (i=0; i<9; i++) {
+    for (unsigned int i=0; i<9; i++) {
         out->limb[i] = a->limb[i] - b->limb[i] + ((i==8) ? co2 : co1);
     }
     gf_weak_reduce(out);
@@ -41,8 +39,7 @@ void gf_bias (gf *a, int amt) {
 void gf_weak_reduce (gf  *a) {
     uint64_t mask = (1ull<<58) - 1;
     uint64_t tmp = a->limb[8] >> 57;
-    int i;
-    for (i=8; i>0; i--) {
+    for (unsigned int i=8; i>0; i--) {
         a->limb[i] = (a->limb[i] & ((i==8) ? mask>>1 : mask)) + (a->limb[i-1]>>58);
     }
     a->limb[0] = (a->limb[0] & mask) + tmp;
diff --git a/src/p521/arch_x86_64_r12/f_impl.h b/src/p521/arch_x86_64_r12/f_impl.h
index 6dce421..c5883aa 100644
--- a/src/p521/arch_x86_64_r12/f_impl.h
+++ b/src/p521/arch_x86_64_r12/f_impl.h
@@ -32,15 +32,13 @@ static inline uint64x3_t timesW (uint64x3_t u) {
 }
 
 void gf_add_RAW (gf  *out, const gf  *a, const gf  *b) {
-    unsigned int i;
-    for (i=0; i<sizeof(*out)/sizeof(uint64xn_t); i++) {
+    for (unsigned int i=0; i<sizeof(*out)/sizeof(uint64xn_t); i++) {
         ((uint64xn_t*)out)[i] = ((const uint64xn_t*)a)[i] + ((const uint64xn_t*)b)[i];
     }
 }
 
 void gf_sub_RAW (gf  *out, const gf  *a, const gf  *b) {
-    unsigned int i;
-    for (i=0; i<sizeof(*out)/sizeof(uint64xn_t); i++) {
+    for (unsigned int i=0; i<sizeof(*out)/sizeof(uint64xn_t); i++) {
         ((uint64xn_t*)out)[i] = ((const uint64xn_t*)a)[i] - ((const uint64xn_t*)b)[i];
     }
 }