From c109dbecf3bf72b464f994e1870d93af34095e9c Mon Sep 17 00:00:00 2001
From: Daniel Larimer <dan@bitshares.org>
Date: Mon, 27 Jun 2016 16:22:14 -0400
Subject: [PATCH] improve performince of fc::uin128 divide

---
 src/asio.cpp               | 10 ++++++----
 src/network/tcp_socket.cpp |  2 +-
 src/uint128.cpp            | 26 ++++++++++++++++++++++++--
 3 files changed, 31 insertions(+), 7 deletions(-)

diff --git a/src/asio.cpp b/src/asio.cpp
index 0319eaa..4a512f1 100644
--- a/src/asio.cpp
+++ b/src/asio.cpp
@@ -140,10 +140,12 @@ namespace fc {
 
     /// If cleanup is true, do not use the return value; it is a null reference
     boost::asio::io_service& default_io_service(bool cleanup) {
-        static default_io_service_scope fc_asio_service;
-        if (cleanup)
-           fc_asio_service.cleanup();
-        return *fc_asio_service.io;
+        static default_io_service_scope fc_asio_service[4];
+        if (cleanup) {
+           for( int i = 0; i < 4; ++i )
+              fc_asio_service[i].cleanup();
+        }
+        return *fc_asio_service[0].io;
     }
 
     namespace tcp {
diff --git a/src/network/tcp_socket.cpp b/src/network/tcp_socket.cpp
index 499a0ed..7eee2ab 100644
--- a/src/network/tcp_socket.cpp
+++ b/src/network/tcp_socket.cpp
@@ -309,7 +309,7 @@ namespace fc {
     try
     {
       my->_accept.bind(boost::asio::ip::tcp::endpoint(boost::asio::ip::address_v4(), port));
-      my->_accept.listen();
+      my->_accept.listen(256);
     } 
     FC_RETHROW_EXCEPTIONS(warn, "error listening on socket");
   }
diff --git a/src/uint128.cpp b/src/uint128.cpp
index dae2aef..66128ce 100644
--- a/src/uint128.cpp
+++ b/src/uint128.cpp
@@ -1,15 +1,18 @@
 #include <fc/uint128.hpp>
 #include <fc/variant.hpp>
 #include <fc/crypto/bigint.hpp>
+#include <boost/multiprecision/cpp_int.hpp>
+
 #include <stdexcept>
 #include "byteswap.hpp"
 
 namespace fc 
 {
+    typedef boost::multiprecision::uint128_t  m128;
+
     template <typename T>
     static void divide(const T &numerator, const T &denominator, T &quotient, T &remainder) 
     {
-
       static const int bits = sizeof(T) * 8;//CHAR_BIT;
 
       if(denominator == 0) {
@@ -220,8 +223,27 @@ namespace fc
 
     uint128& uint128::operator/=(const uint128 &b) 
     {
+        auto self = (m128(hi) << 64) + m128(lo);
+        auto other = (m128(b.hi) << 64) + m128(b.lo);
+        self /= other;
+        hi = static_cast<uint64_t>(self >> 64);
+        lo = static_cast<uint64_t>((self << 64 ) >> 64);
+
+        /*
         uint128 remainder;
-        divide(*this, b, *this, remainder);
+        divide(*this, b, *this, remainder ); //, *this);
+        if( tmp.hi != hi || tmp.lo != lo ) {
+           std::cerr << tmp.hi << "  " << hi <<"\n";
+           std::cerr << tmp.lo << "  " << lo << "\n";
+           exit(1);
+        }
+        */
+       
+        /*
+        const auto&  b128 = std::reinterpret_cast<const m128&>(b);
+        auto&     this128 = std::reinterpret_cast<m128&>(*this);
+        this128 /= b128;
+        */
         return *this;
     }