diff --git a/src/uint256.cpp b/src/uint256.cpp
index 444814515..515669dd8 100644
--- a/src/uint256.cpp
+++ b/src/uint256.cpp
@@ -1,69 +1,68 @@
 // Copyright (c) 2009-2010 Satoshi Nakamoto
 // Copyright (c) 2009-2016 The Bitcoin Core developers
 // Distributed under the MIT software license, see the accompanying
 // file COPYING or http://www.opensource.org/licenses/mit-license.php.
 
 #include <uint256.h>
 
 #include <util/strencodings.h>
 
 template <unsigned int BITS>
 base_blob<BITS>::base_blob(const std::vector<uint8_t> &vch) {
     assert(vch.size() == sizeof(data));
     memcpy(data, vch.data(), sizeof(data));
 }
 
 template <unsigned int BITS> std::string base_blob<BITS>::GetHex() const {
     return HexStr(std::reverse_iterator<const uint8_t *>(data + sizeof(data)),
                   std::reverse_iterator<const uint8_t *>(data));
 }
 
 template <unsigned int BITS> void base_blob<BITS>::SetHex(const char *psz) {
     memset(data, 0, sizeof(data));
 
     // skip leading spaces
     while (IsSpace(*psz)) {
         psz++;
     }
 
     // skip 0x
     if (psz[0] == '0' && ToLower(psz[1]) == 'x') {
         psz += 2;
     }
 
     // hex string to uint
-    const char *pbegin = psz;
-    while (::HexDigit(*psz) != -1) {
-        psz++;
+    size_t digits = 0;
+    while (::HexDigit(psz[digits]) != -1) {
+        digits++;
     }
 
-    psz--;
     uint8_t *p1 = (uint8_t *)data;
     uint8_t *pend = p1 + WIDTH;
-    while (psz >= pbegin && p1 < pend) {
-        *p1 = ::HexDigit(*psz--);
-        if (psz >= pbegin) {
-            *p1 |= uint8_t(::HexDigit(*psz--) << 4);
+    while (digits > 0 && p1 < pend) {
+        *p1 = ::HexDigit(psz[--digits]);
+        if (digits > 0) {
+            *p1 |= uint8_t(::HexDigit(psz[--digits])) << 4;
             p1++;
         }
     }
 }
 
 template <unsigned int BITS>
 void base_blob<BITS>::SetHex(const std::string &str) {
     SetHex(str.c_str());
 }
 
 // Explicit instantiations for base_blob<160>
 template base_blob<160>::base_blob(const std::vector<uint8_t> &);
 template std::string base_blob<160>::GetHex() const;
 template std::string base_blob<160>::ToString() const;
 template void base_blob<160>::SetHex(const char *);
 template void base_blob<160>::SetHex(const std::string &);
 
 // Explicit instantiations for base_blob<256>
 template base_blob<256>::base_blob(const std::vector<uint8_t> &);
 template std::string base_blob<256>::GetHex() const;
 template std::string base_blob<256>::ToString() const;
 template void base_blob<256>::SetHex(const char *);
 template void base_blob<256>::SetHex(const std::string &);