From a37d62f602f084089a8da4b0b172c06e2ce53b9b Mon Sep 17 00:00:00 2001
From: Gav Wood <i@gavwood.com>
Date: Wed, 3 Sep 2014 22:26:37 +0200
Subject: [PATCH] EXTCODECOPY/SIZE.

---
 libethereum/ExtVM.h        |  3 +++
 libevm/ExtVMFace.h         |  3 +++
 libevm/VM.h                | 20 ++++++++++++++++++++
 libevmface/Instruction.cpp |  4 ++++
 libevmface/Instruction.h   |  2 ++
 5 files changed, 32 insertions(+)

diff --git a/libethereum/ExtVM.h b/libethereum/ExtVM.h
index 48099b8fc..f3d8bee50 100644
--- a/libethereum/ExtVM.h
+++ b/libethereum/ExtVM.h
@@ -49,6 +49,9 @@ public:
 	/// Write a value in storage.
 	void setStore(u256 _n, u256 _v) { m_s.setStorage(myAddress, _n, _v); if (m_ms) m_ms->altered.push_back(_n); }
 
+	/// Read address's code.
+	bytes const& codeAt(Address _a) { return m_s.code(_a); }
+
 	/// Create a new contract.
 	h160 create(u256 _endowment, u256* _gas, bytesConstRef _code, OnOpFunc const& _onOp = OnOpFunc())
 	{
diff --git a/libevm/ExtVMFace.h b/libevm/ExtVMFace.h
index 54bb86ae7..2c32c74f4 100644
--- a/libevm/ExtVMFace.h
+++ b/libevm/ExtVMFace.h
@@ -66,6 +66,9 @@ public:
 	/// Read address's balance.
 	u256 balance(Address) { return 0; }
 
+	/// Read address's code.
+	bytes const& codeAt(Address) { return NullBytes; }
+
 	/// Subtract amount from account's balance.
 	void subBalance(u256) {}
 
diff --git a/libevm/VM.h b/libevm/VM.h
index b3cdc9be1..76b68a11c 100644
--- a/libevm/VM.h
+++ b/libevm/VM.h
@@ -401,6 +401,26 @@ template <class Ext> eth::bytesConstRef eth::VM::go(Ext& _ext, OnOpFunc const& _
 			memset(m_temp.data() + mf + el, 0, l - el);
 			break;
 		}
+		case Instruction::EXTCODESIZE:
+			require(1);
+			m_stack.back() = _ext.codeAt(asAddress(m_stack.back())).size();
+			break;
+		case Instruction::EXTCODECOPY:
+		{
+			require(4);
+			Address a = asAddress(m_stack.back());
+			m_stack.pop_back();
+			unsigned mf = (unsigned)m_stack.back();
+			m_stack.pop_back();
+			unsigned cf = (unsigned)m_stack.back();
+			m_stack.pop_back();
+			unsigned l = (unsigned)m_stack.back();
+			m_stack.pop_back();
+			unsigned el = cf + l > _ext.codeAt(a).size() ? _ext.codeAt(a).size() < cf ? 0 : _ext.codeAt(a).size() - cf : l;
+			memcpy(m_temp.data() + mf, _ext.codeAt(a).data() + cf, el);
+			memset(m_temp.data() + mf + el, 0, l - el);
+			break;
+		}
 		case Instruction::GASPRICE:
 			m_stack.push_back(_ext.gasPrice);
 			break;
diff --git a/libevmface/Instruction.cpp b/libevmface/Instruction.cpp
index 734dc7792..7d6fdd366 100644
--- a/libevmface/Instruction.cpp
+++ b/libevmface/Instruction.cpp
@@ -61,6 +61,8 @@ const std::map<std::string, Instruction> eth::c_instructions =
 	{ "CODESIZE", Instruction::CODESIZE },
 	{ "CODECOPY", Instruction::CODECOPY },
 	{ "GASPRICE", Instruction::GASPRICE },
+	{ "EXTCODESIZE", Instruction::EXTCODESIZE },
+	{ "EXTCODECOPY", Instruction::EXTCODECOPY },
 	{ "PREVHASH", Instruction::PREVHASH },
 	{ "COINBASE", Instruction::COINBASE },
 	{ "TIMESTAMP", Instruction::TIMESTAMP },
@@ -186,6 +188,8 @@ static const std::map<Instruction, InstructionInfo> c_instructionInfo =
 	{ Instruction::CODESIZE,	{ "CODESIZE",		0, 0, 1 } },
 	{ Instruction::CODECOPY,	{ "CODECOPY",		0, 3, 0 } },
 	{ Instruction::GASPRICE,	{ "GASPRICE",		0, 0, 1 } },
+	{ Instruction::EXTCODESIZE,	{ "EXTCODESIZE",	0, 1, 1 } },
+	{ Instruction::EXTCODECOPY,	{ "EXTCODECOPY",	0, 4, 0 } },
 	{ Instruction::PREVHASH,	{ "PREVHASH",		0, 0, 1 } },
 	{ Instruction::COINBASE,	{ "COINBASE",		0, 0, 1 } },
 	{ Instruction::TIMESTAMP,	{ "TIMESTAMP",		0, 0, 1 } },
diff --git a/libevmface/Instruction.h b/libevmface/Instruction.h
index ca65d4bbe..1af42bada 100644
--- a/libevmface/Instruction.h
+++ b/libevmface/Instruction.h
@@ -72,6 +72,8 @@ enum class Instruction: uint8_t
 	CODESIZE,
 	CODECOPY,
 	GASPRICE,
+	EXTCODESIZE,
+	EXTCODECOPY,
 
 	PREVHASH = 0x40,
 	COINBASE,