diff --git a/wolfcrypt/src/sp_int.c b/wolfcrypt/src/sp_int.c
index 422614e3d..18d1615a6 100644
--- a/wolfcrypt/src/sp_int.c
+++ b/wolfcrypt/src/sp_int.c
@@ -179,6 +179,7 @@ int sp_read_unsigned_bin(sp_int* a, const byte* in, word32 inSz)
 
     for (j++; j < a->size; j++)
         a->dp[j] = 0;
+    sp_clamp(a);
 
     return MP_OKAY;
 }
@@ -234,6 +235,7 @@ int sp_read_radix(sp_int* a, const char* in, int radix)
         for (k++; k < a->size; k++)
             a->dp[k] = 0;
     }
+    sp_clamp(a);
 
     return err;
 }
@@ -402,13 +404,13 @@ int sp_copy(sp_int* a, sp_int* r)
 /* creates "a" then copies b into it */
 int sp_init_copy (sp_int * a, sp_int * b)
 {
-  int     res;
-  if ((res = sp_init(a)) == MP_OKAY) {
-      if((res = sp_copy (b, a)) != MP_OKAY) {
+  int err;
+  if ((err = sp_init(a)) == MP_OKAY) {
+      if((err = sp_copy (b, a)) != MP_OKAY) {
           sp_clear(a);
       }
   }
-  return res;
+  return err;
 }
 #endif
 
@@ -420,8 +422,14 @@ int sp_init_copy (sp_int * a, sp_int * b)
  */
 int sp_set(sp_int* a, sp_int_digit d)
 {
-    a->dp[0] = d;
-    a->used = 1;
+    if (d == 0) {
+      a->dp[0] = d;
+      a->used = 0;
+    }
+    else {
+      a->dp[0] = d;
+      a->used = 1;
+    }
     return MP_OKAY;
 }
 
@@ -479,6 +487,7 @@ int sp_sub_d(sp_int* a, sp_int_digit d, sp_int* r)
     }
     for (++i; i < a->used; i++)
         r->dp[i] = a->dp[i];
+    sp_clamp(r);
 
     return MP_OKAY;
 }
@@ -635,6 +644,8 @@ static void _sp_mul_d(sp_int* a, sp_int_digit n, sp_int* r, int o)
 static int sp_div(sp_int* a, sp_int* d, sp_int* r, sp_int* rem)
 {
     int err = MP_OKAY;
+    int ret;
+    int done = 0;
     int i;
     int s;
     sp_int_word w = 0;
@@ -655,8 +666,38 @@ static int sp_div(sp_int* a, sp_int* d, sp_int* r, sp_int* rem)
     if (sp_iszero(d))
         err = MP_VAL;
 
+    ret = sp_cmp(a, d);
+    if (ret == MP_LT) {
+        if (rem != NULL) {
+            sp_copy(a, rem);
+        }
+        if (r != NULL) {
+            sp_set(r, 0);
+        }
+        done = 1;
+    }
+    else if (ret == MP_EQ) {
+        if (rem != NULL) {
+            sp_set(rem, 0);
+        }
+        if (r != NULL) {
+            sp_set(r, 1);
+        }
+        done = 1;
+    }
+    else if (sp_count_bits(a) == sp_count_bits(d)) {
+        /* a is greater than d but same bit length */
+        if (rem != NULL) {
+            sp_sub(a, d, rem);
+        }
+        if (r != NULL) {
+            sp_set(r, 1);
+        }
+        done = 1;
+    }
+
 #ifdef WOLFSSL_SMALL_STACK
-    if (err == MP_OKAY) {
+    if (!done && err == MP_OKAY) {
         sa = (sp_int*)XMALLOC(sizeof(sp_int) * 4, NULL, DYNAMIC_TYPE_BIGINT);
         if (sa == NULL)
             err = MP_MEM;
@@ -668,7 +709,7 @@ static int sp_div(sp_int* a, sp_int* d, sp_int* r, sp_int* rem)
     }
 #endif
 
-    if (err == MP_OKAY) {
+    if (!done && err == MP_OKAY) {
         sp_init(sa);
         sp_init(sd);
         sp_init(tr);
@@ -685,26 +726,30 @@ static int sp_div(sp_int* a, sp_int* d, sp_int* r, sp_int* rem)
         }
 
         tr->used = sa->used - d->used;
-        if ((sa->dp[sa->used-1] >> (SP_WORD_SIZE - 1)) == 1) {
-            _sp_mul_d(d, 1, trial, sa->used - d->used);
-            if (sp_cmp(sa, trial) != MP_LT) {
-                tr->used++;
-                sp_sub(sa, trial, sa);
-                tr->dp[sa->used - d->used] = 1;
-            }
-        }
-
+        sp_clear(tr);
+        tr->used = sa->used - d->used;
         dt = d->dp[d->used-1];
         for (i = sa->used - 1; i >= d->used; i--) {
             w = ((sp_int_word)sa->dp[i] << SP_WORD_SIZE) | sa->dp[i-1];
-            t = (sp_int_digit)(w / dt);
-            _sp_mul_d(d, t, trial, i - d->used);
-            while (sp_cmp(trial, sa) == MP_GT) {
-                t--;
-                _sp_mul_d(d, t, trial, i - d->used);
+            w /= dt;
+            if (w > (sp_int_digit)-1) {
+                t = (sp_int_digit)-1;
+            }
+            else {
+                t = (sp_int_digit)w;
+            }
+            if (t > 0) {
+                _sp_mul_d(d, t, trial, i - d->used);
+                while (sp_cmp(trial, sa) == MP_GT) {
+                    t--;
+                    _sp_mul_d(d, t, trial, i - d->used);
+                }
+                sp_sub(sa, trial, sa);
+                tr->dp[i - d->used] += t;
+                if (w > (sp_int_digit)-1) {
+                    i++;
+                }
             }
-            sp_sub(sa, trial, sa);
-            tr->dp[i - d->used] = t;
         }
 
         sp_clamp(tr);
@@ -800,6 +845,7 @@ int sp_lshd(sp_int* a, int s)
     XMEMMOVE(a->dp + s, a->dp, a->used * sizeof(sp_int_digit));
     a->used += s;
     XMEMSET(a->dp, 0, s * sizeof(sp_int_digit));
+    sp_clamp(a);
 
     return MP_OKAY;
 }
@@ -1268,8 +1314,9 @@ int sp_invmod(sp_int* a, sp_int* m, sp_int* r)
     sp_int u[1], v[1], t[1], b[1], c[1];
 #endif
 
-    if (sp_iszero(a) || sp_iszero(m))
+    if (sp_iszero(a) || sp_iszero(m)) {
         err = MP_VAL;
+    }
     else if (sp_iseven(m)) {
         /* a^-1 mod m = m + (1 - m*(m^-1 % a)) / a
          *            = m - (m*(m^-1 % a) - 1) / a
@@ -1882,7 +1929,7 @@ int sp_prime_is_prime_ex(sp_int* a, int t, int* result, WC_RNG* rng)
 }
 
 #ifndef NO_DH
-int sp_exch (sp_int* a, sp_int* b)
+int sp_exch(sp_int* a, sp_int* b)
 {
     int err = MP_OKAY;
 #ifndef WOLFSSL_SMALL_STACK