From 9dd9b025d1cd86be8dfb085fc9b59ae13b246f41 Mon Sep 17 00:00:00 2001
From: Gav Wood <i@gavwood.com>
Date: Mon, 5 Jan 2015 11:35:56 +0000
Subject: [PATCH] BLOCKHASH

---
 libethcore/CommonEth.cpp           |  2 +-
 libevm/VM.h                        | 12 ++++--------
 libevmcore/Instruction.cpp         |  4 ++--
 libevmcore/Instruction.h           |  2 +-
 libserpent/opcodes.cpp             |  2 +-
 libsolidity/ExpressionCompiler.cpp |  6 +++---
 6 files changed, 12 insertions(+), 16 deletions(-)

diff --git a/libethcore/CommonEth.cpp b/libethcore/CommonEth.cpp
index 9801bc89f..c70bc353b 100644
--- a/libethcore/CommonEth.cpp
+++ b/libethcore/CommonEth.cpp
@@ -32,7 +32,7 @@ namespace dev
 namespace eth
 {
 
-const unsigned c_protocolVersion = 49;
+const unsigned c_protocolVersion = 51;
 const unsigned c_databaseVersion = 5;
 
 static const vector<pair<u256, string>> g_units =
diff --git a/libevm/VM.h b/libevm/VM.h
index 47efbfcba..6cdb53400 100644
--- a/libevm/VM.h
+++ b/libevm/VM.h
@@ -219,9 +219,8 @@ inline bytesConstRef VM::go(ExtVMFace& _ext, OnOpFunc const& _onOp, uint64_t _st
 			break;
 		}
 
-		case Instruction::PREVHASH:
-			if (c_protocolVersion > 49)
-				require(1);
+		case Instruction::BLOCKHASH:
+			require(1);
 		break;
 
 		case Instruction::PC:
@@ -563,11 +562,8 @@ inline bytesConstRef VM::go(ExtVMFace& _ext, OnOpFunc const& _onOp, uint64_t _st
 		case Instruction::GASPRICE:
 			m_stack.push_back(_ext.gasPrice);
 			break;
-		case Instruction::PREVHASH:
-			if (c_protocolVersion > 49)
-				m_stack.back() = (u256)_ext.prevhash(m_stack.back());
-			else
-				m_stack.push_back(_ext.previousBlock.hash);
+		case Instruction::BLOCKHASH:
+			m_stack.back() = (u256)_ext.prevhash(m_stack.back());
 			break;
 		case Instruction::COINBASE:
 			m_stack.push_back((u160)_ext.currentBlock.coinbaseAddress);
diff --git a/libevmcore/Instruction.cpp b/libevmcore/Instruction.cpp
index b4a4d9f3b..bba3d7745 100644
--- a/libevmcore/Instruction.cpp
+++ b/libevmcore/Instruction.cpp
@@ -67,7 +67,7 @@ const std::map<std::string, Instruction> dev::eth::c_instructions =
 	{ "GASPRICE", Instruction::GASPRICE },
 	{ "EXTCODESIZE", Instruction::EXTCODESIZE },
 	{ "EXTCODECOPY", Instruction::EXTCODECOPY },
-	{ "PREVHASH", Instruction::PREVHASH },
+	{ "BLOCKHASH", Instruction::BLOCKHASH },
 	{ "COINBASE", Instruction::COINBASE },
 	{ "TIMESTAMP", Instruction::TIMESTAMP },
 	{ "NUMBER", Instruction::NUMBER },
@@ -200,7 +200,7 @@ static const std::map<Instruction, InstructionInfo> c_instructionInfo =
 	{ Instruction::GASPRICE,	{ "GASPRICE",		0, 0, 1, false } },
 	{ Instruction::EXTCODESIZE,	{ "EXTCODESIZE",	0, 1, 1, false } },
 	{ Instruction::EXTCODECOPY,	{ "EXTCODECOPY",	0, 4, 0, true } },
-	{ Instruction::PREVHASH,	{ "PREVHASH",		0, 0, 1, false } },
+	{ Instruction::BLOCKHASH,	{ "BLOCKHASH",		0, 1, 1, false } },
 	{ Instruction::COINBASE,	{ "COINBASE",		0, 0, 1, false } },
 	{ Instruction::TIMESTAMP,	{ "TIMESTAMP",		0, 0, 1, false } },
 	{ Instruction::NUMBER,		{ "NUMBER",			0, 0, 1, false } },
diff --git a/libevmcore/Instruction.h b/libevmcore/Instruction.h
index 555dbf0ea..a28e8f8da 100644
--- a/libevmcore/Instruction.h
+++ b/libevmcore/Instruction.h
@@ -73,7 +73,7 @@ enum class Instruction: uint8_t
 	EXTCODESIZE,		///< get external code size (from another contract)
 	EXTCODECOPY,		///< copy external code (from another contract)
 
-	PREVHASH = 0x40,	///< get hash of most recent complete block
+	BLOCKHASH = 0x40,	///< get hash of most recent complete block
 	COINBASE,			///< get the block's coinbase address
 	TIMESTAMP,			///< get the block's timestamp
 	NUMBER,				///< get the block's number
diff --git a/libserpent/opcodes.cpp b/libserpent/opcodes.cpp
index b24144e46..2fc7d7530 100644
--- a/libserpent/opcodes.cpp
+++ b/libserpent/opcodes.cpp
@@ -44,7 +44,7 @@ Mapping mapping[] = {
     Mapping("GASPRICE", 0x3a, 0, 1),
     Mapping("EXTCODESIZE", 0x3b, 1, 1),
     Mapping("EXTCODECOPY", 0x3c, 4, 0),
-    Mapping("PREVHASH", 0x40, 0, 1),
+	Mapping("BLOCKHASH", 0x40, 1, 1),
     Mapping("COINBASE", 0x41, 0, 1),
     Mapping("TIMESTAMP", 0x42, 0, 1),
     Mapping("NUMBER", 0x43, 0, 1),
diff --git a/libsolidity/ExpressionCompiler.cpp b/libsolidity/ExpressionCompiler.cpp
index cf641935a..6bf14f559 100644
--- a/libsolidity/ExpressionCompiler.cpp
+++ b/libsolidity/ExpressionCompiler.cpp
@@ -344,9 +344,9 @@ void ExpressionCompiler::endVisit(MemberAccess const& _memberAccess)
 			m_context << eth::Instruction::COINBASE;
 		else if (member == "timestamp")
 			m_context << eth::Instruction::TIMESTAMP;
-		else if (member == "prevhash")
-			m_context << eth::Instruction::PREVHASH;
-		else if (member == "difficulty")
+/*		else if (member == "blockhash")
+			m_context << eth::Instruction::BLOCKHASH;
+*/		else if (member == "difficulty")
 			m_context << eth::Instruction::DIFFICULTY;
 		else if (member == "number")
 			m_context << eth::Instruction::NUMBER;