Decouple virtual machines (#6184)

* work in progress for splitting vms * evm working * Evm -> Vm * wasm converted * ethcore working * test fixes
2017-08-01 13:37:57 +03:00 · 2017-08-01 13:37:57 +03:00 · b7006034b1
commit b7006034b1
parent c4025622de
65 changed files with 534 additions and 400 deletions
--- a/Cargo.lock
+++ b/Cargo.lock
@ -1,6 +1,14 @@
 [root]
-name = "using_queue"
+name = "wasm"
 version = "0.1.0"
+dependencies = [
+ "byteorder 1.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "ethcore-util 1.8.0",
+ "log 0.3.7 (registry+https://github.com/rust-lang/crates.io-index)",
+ "parity-wasm 0.12.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "vm 0.1.0",
+ "wasm-utils 0.1.0 (git+https://github.com/paritytech/wasm-utils)",
+]

 [[package]]
 name = "advapi32-sys"
@ -504,6 +512,8 @@ dependencies = [
 "stats 0.1.0",
 "time 0.1.35 (registry+https://github.com/rust-lang/crates.io-index)",
 "transient-hashmap 0.4.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "vm 0.1.0",
+ "wasm 0.1.0",
 ]

 [[package]]
@ -625,6 +635,7 @@ dependencies = [
 "smallvec 0.4.0 (registry+https://github.com/rust-lang/crates.io-index)",
 "stats 0.1.0",
 "time 0.1.35 (registry+https://github.com/rust-lang/crates.io-index)",
+ "vm 0.1.0",
 ]

 [[package]]
@ -888,6 +899,7 @@ dependencies = [
 "parity-wasm 0.12.1 (registry+https://github.com/rust-lang/crates.io-index)",
 "rlp 0.2.0",
 "rustc-hex 1.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "vm 0.1.0",
 "wasm-utils 0.1.0 (git+https://github.com/paritytech/wasm-utils)",
 ]

@ -1933,7 +1945,6 @@ dependencies = [
 "ethkey 0.2.0",
 "ethstore 0.1.0",
 "ethsync 1.8.0",
- "evm 0.1.0",
 "fetch 0.1.0",
 "futures 0.1.11 (registry+https://github.com/rust-lang/crates.io-index)",
 "futures-cpupool 0.1.5 (registry+https://github.com/rust-lang/crates.io-index)",
@ -1962,6 +1973,7 @@ dependencies = [
 "time 0.1.35 (registry+https://github.com/rust-lang/crates.io-index)",
 "tokio-timer 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
 "transient-hashmap 0.4.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "vm 0.1.0",
 ]

 [[package]]
@ -3044,6 +3056,10 @@ dependencies = [
 "winapi-build 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
 ]

+[[package]]
+name = "using_queue"
+version = "0.1.0"
+
 [[package]]
 name = "utf8-ranges"
 version = "1.0.0"
@ -3072,6 +3088,20 @@ dependencies = [
 "time 0.1.35 (registry+https://github.com/rust-lang/crates.io-index)",
 ]

+[[package]]
+name = "vm"
+version = "0.1.0"
+dependencies = [
+ "byteorder 1.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "common-types 0.1.0",
+ "ethcore-util 1.8.0",
+ "ethjson 0.1.0",
+ "evmjit 1.8.0",
+ "lazy_static 0.2.8 (registry+https://github.com/rust-lang/crates.io-index)",
+ "log 0.3.7 (registry+https://github.com/rust-lang/crates.io-index)",
+ "rlp 0.2.0",
+]
+
 [[package]]
 name = "void"
 version = "1.0.2"
--- a/ethcore/Cargo.toml
+++ b/ethcore/Cargo.toml
@ -53,6 +53,8 @@ semver = "0.6"
 stats = { path = "../util/stats" }
 time = "0.1"
 transient-hashmap = "0.4"
+vm = { path = "vm" }
+wasm = { path = "wasm" }

 [dev-dependencies]
 native-contracts = { path = "native_contracts", features = ["test_contracts"] }
--- a/ethcore/evm/Cargo.toml
+++ b/ethcore/evm/Cargo.toml
@ -13,6 +13,7 @@ ethjson = { path = "../../json" }
 lazy_static = "0.2"
 log = "0.3"
 rlp = { path = "../../util/rlp" }
+vm = { path = "../vm" }
 parity-wasm = "0.12"
 wasm-utils = { git = "https://github.com/paritytech/wasm-utils" }

--- a/ethcore/evm/src/benches/mod.rs
+++ b/ethcore/evm/src/benches/mod.rs
@ -25,7 +25,7 @@ extern crate test;
 use self::test::{Bencher, black_box};

 use util::*;
-use evm::action_params::ActionParams;
+use vm::ActionParams;
 use evm::{self, Factory, VMType};
 use evm::tests::FakeExt;

--- a/ethcore/evm/src/evm.rs
+++ b/ethcore/evm/src/evm.rs
@ -17,142 +17,8 @@
 //! Evm interface.

 use std::{ops, cmp, fmt};
-use util::{U128, U256, U512, trie};
-use action_params::ActionParams;
-use {Ext};
-
-use super::wasm;
-
-/// Evm errors.
-#[derive(Debug, Clone, PartialEq)]
-pub enum Error {
-	/// `OutOfGas` is returned when transaction execution runs out of gas.
-	/// The state should be reverted to the state from before the
-	/// transaction execution. But it does not mean that transaction
-	/// was invalid. Balance still should be transfered and nonce
-	/// should be increased.
-	OutOfGas,
-	/// `BadJumpDestination` is returned when execution tried to move
-	/// to position that wasn't marked with JUMPDEST instruction
-	BadJumpDestination {
-		/// Position the code tried to jump to.
-		destination: usize
-	},
-	/// `BadInstructions` is returned when given instruction is not supported
-	BadInstruction {
-		/// Unrecognized opcode
-		instruction: u8,
-	},
-	/// `StackUnderflow` when there is not enough stack elements to execute instruction
-	StackUnderflow {
-		/// Invoked instruction
-		instruction: &'static str,
-		/// How many stack elements was requested by instruction
-		wanted: usize,
-		/// How many elements were on stack
-		on_stack: usize
-	},
-	/// When execution would exceed defined Stack Limit
-	OutOfStack {
-		/// Invoked instruction
-		instruction: &'static str,
-		/// How many stack elements instruction wanted to push
-		wanted: usize,
-		/// What was the stack limit
-		limit: usize
-	},
-	/// Built-in contract failed on given input
-	BuiltIn(&'static str),
-	/// When execution tries to modify the state in static context
-	MutableCallInStaticContext,
-	/// Likely to cause consensus issues.
-	Internal(String),
-	/// Wasm runtime error
-	Wasm(String),
-}
-
-impl From<Box<trie::TrieError>> for Error {
-	fn from(err: Box<trie::TrieError>) -> Self {
-		Error::Internal(format!("Internal error: {}", err))
-	}
-}
-
-impl From<wasm::RuntimeError> for Error {
-	fn from(err: wasm::RuntimeError) -> Self {
-		Error::Wasm(format!("Runtime error: {:?}", err))
-	}
-}
-
-impl fmt::Display for Error {
-	fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-		use self::Error::*;
-		match *self {
-			OutOfGas => write!(f, "Out of gas"),
-			BadJumpDestination { destination } => write!(f, "Bad jump destination {:x}", destination),
-			BadInstruction { instruction } => write!(f, "Bad instruction {:x}",  instruction),
-			StackUnderflow { instruction, wanted, on_stack } => write!(f, "Stack underflow {} {}/{}", instruction, wanted, on_stack),
-			OutOfStack { instruction, wanted, limit } => write!(f, "Out of stack {} {}/{}", instruction, wanted, limit),
-			BuiltIn(name) => write!(f, "Built-in failed: {}", name),
-			Internal(ref msg) => write!(f, "Internal error: {}", msg),
-			MutableCallInStaticContext => write!(f, "Mutable call in static context"),
-			Wasm(ref msg) => write!(f, "Internal error: {}", msg),
-		}
-	}
-}
-
-/// A specialized version of Result over EVM errors.
-pub type Result<T> = ::std::result::Result<T, Error>;
-
-/// Return data buffer. Holds memory from a previous call and a slice into that memory.
-#[derive(Debug)]
-pub struct ReturnData {
-	mem: Vec<u8>,
-	offset: usize,
-	size: usize,
-}
-
-impl ::std::ops::Deref for ReturnData {
-	type Target = [u8];
-	fn deref(&self) -> &[u8] {
-		&self.mem[self.offset..self.offset + self.size]
-	}
-}
-
-impl ReturnData {
-	/// Create empty `ReturnData`.
-	pub fn empty() -> Self {
-		ReturnData {
-			mem: Vec::new(),
-			offset: 0,
-			size: 0,
-		}
-	}
-	/// Create `ReturnData` from give buffer and slice.
-	pub fn new(mem: Vec<u8>, offset: usize, size: usize) -> Self {
-		ReturnData {
-			mem: mem,
-			offset: offset,
-			size: size,
-		}
-	}
-}
-
-/// Gas Left: either it is a known value, or it needs to be computed by processing
-/// a return instruction.
-#[derive(Debug)]
-pub enum GasLeft {
-	/// Known gas left
-	Known(U256),
-	/// Return or Revert instruction must be processed.
-	NeedsReturn {
-		/// Amount of gas left.
-		gas_left: U256,
-		/// Return data buffer.
-		data: ReturnData,
-		/// Apply or revert state changes on revert.
-		apply_state: bool
-	},
-}
+use util::{U128, U256, U512};
+use vm::{Ext, Result, ReturnData, GasLeft, Error};

 /// Finalization result. Gas Left: either it is a known value, or it needs to be computed by processing
 /// a return instruction.
@ -281,15 +147,6 @@ impl CostType for usize {
 	}
 }

-/// Evm interface
-pub trait Evm {
-	/// This function should be used to execute transaction.
-	///
-	/// It returns either an error, a known amount of gas left, or parameters to be used
-	/// to compute the final gas left.
-	fn exec(&mut self, params: ActionParams, ext: &mut Ext) -> Result<GasLeft>;
-}
-
 #[cfg(test)]
 mod tests {
 	use util::U256;
--- a/ethcore/evm/src/factory.rs
+++ b/ethcore/evm/src/factory.rs
@ -17,7 +17,7 @@
 //! Evm factory.
 //!
 use std::sync::Arc;
-use evm::Evm;
+use vm::Vm;
 use util::U256;
 use super::interpreter::SharedCache;
 use super::vmtype::VMType;
@ -33,7 +33,7 @@ impl Factory {
 	/// Create fresh instance of VM
 	/// Might choose implementation depending on supplied gas.
 	#[cfg(feature = "jit")]
-	pub fn create(&self, gas: U256) -> Box<Evm> {
+	pub fn create(&self, gas: U256) -> Box<Vm> {
 		match self.evm {
 			VMType::Jit => {
 				Box::new(super::jit::JitEvm::default())
@ -49,7 +49,7 @@ impl Factory {
 	/// Create fresh instance of VM
 	/// Might choose implementation depending on supplied gas.
 	#[cfg(not(feature = "jit"))]
-	pub fn create(&self, gas: U256) -> Box<Evm> {
+	pub fn create(&self, gas: U256) -> Box<Vm> {
 		match self.evm {
 			VMType::Interpreter => if Self::can_fit_in_usize(gas) {
 				Box::new(super::interpreter::Interpreter::<usize>::new(self.evm_cache.clone()))
--- a/ethcore/evm/src/interpreter/gasometer.rs
+++ b/ethcore/evm/src/interpreter/gasometer.rs
@ -17,15 +17,15 @@
 use util::*;
 use super::u256_to_address;

-use {evm, ext};
+use {evm, vm};
 use instructions::{self, Instruction, InstructionInfo};
 use interpreter::stack::Stack;
-use schedule::Schedule;
+use vm::Schedule;

 macro_rules! overflowing {
 	($x: expr) => {{
 		let (v, overflow) = $x;
-		if overflow { return Err(evm::Error::OutOfGas); }
+		if overflow { return Err(vm::Error::OutOfGas); }
 		v
 	}}
 }
@ -59,16 +59,16 @@ impl<Gas: evm::CostType> Gasometer<Gas> {
 		}
 	}

-	pub fn verify_gas(&self, gas_cost: &Gas) -> evm::Result<()> {
+	pub fn verify_gas(&self, gas_cost: &Gas) -> vm::Result<()> {
 		match &self.current_gas < gas_cost {
-			true => Err(evm::Error::OutOfGas),
+			true => Err(vm::Error::OutOfGas),
 			false => Ok(())
 		}
 	}

 	/// How much gas is provided to a CALL/CREATE, given that we need to deduct `needed` for this operation
 	/// and that we `requested` some.
-	pub fn gas_provided(&self, schedule: &Schedule, needed: Gas, requested: Option<U256>) -> evm::Result<Gas> {
+	pub fn gas_provided(&self, schedule: &Schedule, needed: Gas, requested: Option<U256>) -> vm::Result<Gas> {
 		// Try converting requested gas to `Gas` (`U256/u64`)
 		// but in EIP150 even if we request more we should never fail from OOG
 		let requested = requested.map(Gas::from_u256);
@ -107,12 +107,12 @@ impl<Gas: evm::CostType> Gasometer<Gas> {
 	/// it will be the amount of gas that the current context provides to the child context.
 	pub fn requirements(
 		&mut self,
-		ext: &ext::Ext,
+		ext: &vm::Ext,
 		instruction: Instruction,
 		info: &InstructionInfo,
 		stack: &Stack<U256>,
 		current_mem_size: usize,
-	) -> evm::Result<InstructionRequirements<Gas>> {
+	) -> vm::Result<InstructionRequirements<Gas>> {
 		let schedule = ext.schedule();
 		let tier = instructions::get_tier_idx(info.tier);
 		let default_gas = Gas::from(schedule.tier_step_gas[tier]);
@ -291,7 +291,7 @@ impl<Gas: evm::CostType> Gasometer<Gas> {
 		})
 	}

-	fn mem_gas_cost(&self, schedule: &Schedule, current_mem_size: usize, mem_size: &Gas) -> evm::Result<(Gas, Gas, usize)> {
+	fn mem_gas_cost(&self, schedule: &Schedule, current_mem_size: usize, mem_size: &Gas) -> vm::Result<(Gas, Gas, usize)> {
 		let gas_for_mem = |mem_size: Gas| {
 			let s = mem_size >> 5;
 			// s * memory_gas + s * s / quad_coeff_div
@ -319,12 +319,12 @@ impl<Gas: evm::CostType> Gasometer<Gas> {


 #[inline]
-fn mem_needed_const<Gas: evm::CostType>(mem: &U256, add: usize) -> evm::Result<Gas> {
+fn mem_needed_const<Gas: evm::CostType>(mem: &U256, add: usize) -> vm::Result<Gas> {
 	Gas::from_u256(overflowing!(mem.overflowing_add(U256::from(add))))
 }

 #[inline]
-fn mem_needed<Gas: evm::CostType>(offset: &U256, size: &U256) -> evm::Result<Gas> {
+fn mem_needed<Gas: evm::CostType>(offset: &U256, size: &U256) -> vm::Result<Gas> {
 	if size.is_zero() {
 		return Ok(Gas::from(0));
 	}
--- a/ethcore/evm/src/interpreter/memory.rs
+++ b/ethcore/evm/src/interpreter/memory.rs
@ -15,7 +15,7 @@
 // along with Parity.  If not, see <http://www.gnu.org/licenses/>.

 use util::U256;
-use {ReturnData};
+use vm::ReturnData;

 const MAX_RETURN_WASTE_BYTES: usize = 16384;

--- a/ethcore/evm/src/interpreter/mod.rs
+++ b/ethcore/evm/src/interpreter/mod.rs
@ -23,17 +23,21 @@ mod stack;
 mod memory;
 mod shared_cache;

+use std::marker::PhantomData;
+
+use vm::{
+	self, ActionParams, ActionValue, CallType, MessageCallResult,
+	ContractCreateResult, CreateContractAddress, ReturnData, GasLeft
+};
+
+use evm::CostType;
+use instructions::{self, Instruction, InstructionInfo};
+
 use self::gasometer::Gasometer;
 use self::stack::{Stack, VecStack};
 use self::memory::Memory;
 pub use self::shared_cache::SharedCache;

-use std::marker::PhantomData;
-use action_params::{ActionParams, ActionValue};
-use call_type::CallType;
-use instructions::{self, Instruction, InstructionInfo};
-use evm::{self, GasLeft, CostType, ReturnData};
-use ext::{self, MessageCallResult, ContractCreateResult, CreateContractAddress};
 use bit_set::BitSet;

 use util::*;
@ -107,8 +111,8 @@ pub struct Interpreter<Cost: CostType> {
 	_type: PhantomData<Cost>,
 }

-impl<Cost: CostType> evm::Evm for Interpreter<Cost> {
-	fn exec(&mut self, params: ActionParams, ext: &mut ext::Ext) -> evm::Result<GasLeft> {
+impl<Cost: CostType> vm::Vm for Interpreter<Cost> {
+	fn exec(&mut self, params: ActionParams, ext: &mut vm::Ext) -> vm::Result<GasLeft> {
 		self.mem.clear();

 		let mut informant = informant::EvmInformant::new(ext.depth());
@ -205,7 +209,7 @@ impl<Cost: CostType> Interpreter<Cost> {
 		}
 	}

-	fn verify_instruction(&self, ext: &ext::Ext, instruction: Instruction, info: &InstructionInfo, stack: &Stack<U256>) -> evm::Result<()> {
+	fn verify_instruction(&self, ext: &vm::Ext, instruction: Instruction, info: &InstructionInfo, stack: &Stack<U256>) -> vm::Result<()> {
 		let schedule = ext.schedule();

 		if (instruction == instructions::DELEGATECALL && !schedule.have_delegate_call) ||
@ -214,25 +218,25 @@ impl<Cost: CostType> Interpreter<Cost> {
 			((instruction == instructions::RETURNDATACOPY || instruction == instructions::RETURNDATASIZE) && !schedule.have_return_data) ||
 			(instruction == instructions::REVERT && !schedule.have_revert) {

-			return Err(evm::Error::BadInstruction {
+			return Err(vm::Error::BadInstruction {
 				instruction: instruction
 			});
 		}

 		if info.tier == instructions::GasPriceTier::Invalid {
-			return Err(evm::Error::BadInstruction {
+			return Err(vm::Error::BadInstruction {
 				instruction: instruction
 			});
 		}

 		if !stack.has(info.args) {
-			Err(evm::Error::StackUnderflow {
+			Err(vm::Error::StackUnderflow {
 				instruction: info.name,
 				wanted: info.args,
 				on_stack: stack.size()
 			})
 		} else if stack.size() - info.args + info.ret > schedule.stack_limit {
-			Err(evm::Error::OutOfStack {
+			Err(vm::Error::OutOfStack {
 				instruction: info.name,
 				wanted: info.ret - info.args,
 				limit: schedule.stack_limit
@ -272,12 +276,12 @@ impl<Cost: CostType> Interpreter<Cost> {
 		&mut self,
 		gas: Cost,
 		params: &ActionParams,
-		ext: &mut ext::Ext,
+		ext: &mut vm::Ext,
 		instruction: Instruction,
 		code: &mut CodeReader,
 		stack: &mut Stack<U256>,
 		provided: Option<Cost>
-	) -> evm::Result<InstructionResult<Cost>> {
+	) -> vm::Result<InstructionResult<Cost>> {
 		match instruction {
 			instructions::JUMP => {
 				let jump = stack.pop_back();
@ -593,13 +597,13 @@ impl<Cost: CostType> Interpreter<Cost> {
 		}
 	}

-	fn verify_jump(&self, jump_u: U256, valid_jump_destinations: &BitSet) -> evm::Result<usize> {
+	fn verify_jump(&self, jump_u: U256, valid_jump_destinations: &BitSet) -> vm::Result<usize> {
 		let jump = jump_u.low_u64() as usize;

 		if valid_jump_destinations.contains(jump) && U256::from(jump) == jump_u {
 			Ok(jump)
 		} else {
-			Err(evm::Error::BadJumpDestination {
+			Err(vm::Error::BadJumpDestination {
 				destination: jump
 			})
 		}
@ -617,7 +621,7 @@ impl<Cost: CostType> Interpreter<Cost> {
 		}
 	}

-	fn exec_stack_instruction(&self, instruction: Instruction, stack: &mut Stack<U256>) -> evm::Result<()> {
+	fn exec_stack_instruction(&self, instruction: Instruction, stack: &mut Stack<U256>) -> vm::Result<()> {
 		match instruction {
 			instructions::DUP1...instructions::DUP16 => {
 				let position = instructions::get_dup_position(instruction);
@ -822,7 +826,7 @@ impl<Cost: CostType> Interpreter<Cost> {
 				}
 			},
 			_ => {
-				return Err(evm::Error::BadInstruction {
+				return Err(vm::Error::BadInstruction {
 					instruction: instruction
 				});
 			}
--- a/ethcore/evm/src/jit.rs
+++ b/ethcore/evm/src/jit.rs
@ -19,6 +19,7 @@ use util::*;
 use evmjit;
 use evm::{self, GasLeft};
 use evm::CallType;
+use vm::{self, Vm};

 /// Should be used to convert jit types to ethcore
 trait FromJit<T>: Sized {
@ -318,7 +319,7 @@ pub struct JitEvm {
 	context: Option<evmjit::ContextHandle>,
 }

-impl evm::Evm for JitEvm {
+impl vm::Vm for JitEvm {
 	fn exec(&mut self, params: ActionParams, ext: &mut evm::Ext) -> evm::Result<GasLeft> {
 		// Dirty hack. This is unsafe, but we interact with ffi, so it's justified.
 		let ext_adapter: ExtAdapter<'static> = unsafe { ::std::mem::transmute(ExtAdapter::new(ext, params.address.clone())) };
@ -370,8 +371,8 @@ impl evm::Evm for JitEvm {
 				ext.suicide(&Address::from_jit(&context.suicide_refund_address()));
 				Ok(GasLeft::Known(U256::from(context.gas_left())))
 			},
-			evmjit::ReturnCode::OutOfGas => Err(evm::Error::OutOfGas),
-			_err => Err(evm::Error::Internal)
+			evmjit::ReturnCode::OutOfGas => Err(vm::Error::OutOfGas),
+			_err => Err(vm::Error::Internal)
 		}
 	}
 }
--- a/ethcore/evm/src/lib.rs
+++ b/ethcore/evm/src/lib.rs
@ -24,11 +24,11 @@ extern crate ethjson;
 extern crate rlp;
 extern crate parity_wasm;
 extern crate wasm_utils;
+extern crate vm;

 #[macro_use]
 extern crate lazy_static;

-#[macro_use]
 extern crate log;

 #[cfg(feature = "jit")]
@ -37,14 +37,8 @@ extern crate evmjit;
 #[cfg(test)]
 extern crate rustc_hex;

-pub mod action_params;
-pub mod call_type;
-pub mod env_info;
-pub mod ext;
 pub mod evm;
 pub mod interpreter;
-pub mod schedule;
-pub mod wasm;

 #[macro_use]
 pub mod factory;
@ -59,12 +53,12 @@ mod tests;
 #[cfg(all(feature="benches", test))]
 mod benches;

-pub use self::action_params::ActionParams;
-pub use self::call_type::CallType;
-pub use self::env_info::EnvInfo;
-pub use self::evm::{Evm, Error, Finalize, FinalizationResult, GasLeft, Result, CostType, ReturnData};
-pub use self::ext::{Ext, ContractCreateResult, MessageCallResult, CreateContractAddress};
+pub use vm::{
+    Schedule, CleanDustMode, EnvInfo, CallType, ActionParams, Ext,
+    ContractCreateResult, MessageCallResult, CreateContractAddress,
+    GasLeft, ReturnData
+};
+pub use self::evm::{Finalize, FinalizationResult, CostType};
 pub use self::instructions::{InstructionInfo, INSTRUCTIONS, push_bytes};
 pub use self::vmtype::VMType;
 pub use self::factory::Factory;
-pub use self::schedule::{Schedule, CleanDustMode};
--- a/ethcore/evm/src/tests.rs
+++ b/ethcore/evm/src/tests.rs
@ -17,12 +17,12 @@
 use std::fmt::Debug;
 use rustc_hex::FromHex;
 use util::*;
-use action_params::{ActionParams, ActionValue};
-use env_info::EnvInfo;
-use call_type::CallType;
-use schedule::Schedule;
-use evm::{self, GasLeft, ReturnData};
-use ext::{Ext, ContractCreateResult, MessageCallResult, CreateContractAddress};
+use evm::{self, GasLeft};
+use vm::{
+	self, CallType, Schedule, EnvInfo, ActionParams, ActionValue,
+	ReturnData, Ext, ContractCreateResult, MessageCallResult,
+	CreateContractAddress,
+};
 use factory::Factory;
 use vmtype::VMType;

@ -66,7 +66,7 @@ pub struct FakeExt {
 }

 // similar to the normal `finalize` function, but ignoring NeedsReturn.
-fn test_finalize(res: Result<GasLeft, evm::Error>) -> Result<U256, evm::Error> {
+fn test_finalize(res: Result<GasLeft, vm::Error>) -> Result<U256, vm::Error> {
 	match res {
 		Ok(GasLeft::Known(gas)) => Ok(gas),
 		Ok(GasLeft::NeedsReturn{..}) => unimplemented!(), // since ret is unimplemented.
@ -80,35 +80,29 @@ impl FakeExt {
 	}
 }

-impl Default for Schedule {
-	fn default() -> Self {
-		Schedule::new_frontier()
-	}
-}
-
 impl Ext for FakeExt {
-	fn storage_at(&self, key: &H256) -> evm::Result<H256> {
+	fn storage_at(&self, key: &H256) -> vm::Result<H256> {
 		Ok(self.store.get(key).unwrap_or(&H256::new()).clone())
 	}

-	fn set_storage(&mut self, key: H256, value: H256) -> evm::Result<()> {
+	fn set_storage(&mut self, key: H256, value: H256) -> vm::Result<()> {
 		self.store.insert(key, value);
 		Ok(())
 	}

-	fn exists(&self, address: &Address) -> evm::Result<bool> {
+	fn exists(&self, address: &Address) -> vm::Result<bool> {
 		Ok(self.balances.contains_key(address))
 	}

-	fn exists_and_not_null(&self, address: &Address) -> evm::Result<bool> {
+	fn exists_and_not_null(&self, address: &Address) -> vm::Result<bool> {
 		Ok(self.balances.get(address).map_or(false, |b| !b.is_zero()))
 	}

-	fn origin_balance(&self) -> evm::Result<U256> {
+	fn origin_balance(&self) -> vm::Result<U256> {
 		unimplemented!()
 	}

-	fn balance(&self, address: &Address) -> evm::Result<U256> {
+	fn balance(&self, address: &Address) -> vm::Result<U256> {
 		Ok(self.balances[address])
 	}

@ -152,15 +146,15 @@ impl Ext for FakeExt {
 		MessageCallResult::Success(*gas, ReturnData::empty())
 	}

-	fn extcode(&self, address: &Address) -> evm::Result<Arc<Bytes>> {
+	fn extcode(&self, address: &Address) -> vm::Result<Arc<Bytes>> {
 		Ok(self.codes.get(address).unwrap_or(&Arc::new(Bytes::new())).clone())
 	}

-	fn extcodesize(&self, address: &Address) -> evm::Result<usize> {
+	fn extcodesize(&self, address: &Address) -> vm::Result<usize> {
 		Ok(self.codes.get(address).map_or(0, |c| c.len()))
 	}

-	fn log(&mut self, topics: Vec<H256>, data: &[u8]) -> evm::Result<()> {
+	fn log(&mut self, topics: Vec<H256>, data: &[u8]) -> vm::Result<()> {
 		self.logs.push(FakeLogEntry {
 			topics: topics,
 			data: data.to_vec()
@ -168,11 +162,11 @@ impl Ext for FakeExt {
 		Ok(())
 	}

-	fn ret(self, _gas: &U256, _data: &ReturnData) -> evm::Result<U256> {
+	fn ret(self, _gas: &U256, _data: &ReturnData) -> vm::Result<U256> {
 		unimplemented!();
 	}

-	fn suicide(&mut self, refund_address: &Address) -> evm::Result<()> {
+	fn suicide(&mut self, refund_address: &Address) -> vm::Result<()> {
 		self.suicides.insert(refund_address.clone());
 		Ok(())
 	}
@ -211,7 +205,7 @@ fn test_stack_underflow() {
 	};

 	match err {
-		evm::Error::StackUnderflow {wanted, on_stack, ..} => {
+		vm::Error::StackUnderflow {wanted, on_stack, ..} => {
 			assert_eq!(wanted, 2);
 			assert_eq!(on_stack, 0);
 		}
@ -849,7 +843,7 @@ fn test_badinstruction_int() {
 	};

 	match err {
-		evm::Error::BadInstruction { instruction: 0xaf } => (),
+		vm::Error::BadInstruction { instruction: 0xaf } => (),
 		_ => assert!(false, "Expected bad instruction")
 	}
 }
--- a/ethcore/light/Cargo.toml
+++ b/ethcore/light/Cargo.toml
@ -19,6 +19,7 @@ ethcore-io = { path = "../../util/io" }
 ethcore-ipc = { path = "../../ipc/rpc", optional = true }
 ethcore-devtools = { path = "../../devtools" }
 evm = { path = "../evm" }
+vm = { path = "../vm" }
 rlp = { path = "../../util/rlp" }
 time = "0.1"
 smallvec = "0.4"
--- a/ethcore/light/src/lib.rs
+++ b/ethcore/light/src/lib.rs
@ -80,6 +80,7 @@ extern crate serde;
 extern crate smallvec;
 extern crate stats;
 extern crate time;
+extern crate vm;

 #[cfg(feature = "ipc")]
 extern crate ethcore_ipc as ipc;
--- a/ethcore/light/src/on_demand/request.rs
+++ b/ethcore/light/src/on_demand/request.rs
@ -24,7 +24,7 @@ use ethcore::engines::Engine;
 use ethcore::receipt::Receipt;
 use ethcore::state::{self, ProvedExecution};
 use ethcore::transaction::SignedTransaction;
-use evm::env_info::EnvInfo;
+use vm::EnvInfo;

 use request::{self as net_request, IncompleteRequest, CompleteRequest, Output, OutputKind, Field};

--- a/ethcore/src/block.rs
+++ b/ethcore/src/block.rs
@ -25,7 +25,7 @@ use util::{Bytes, Address, Hashable, U256, H256, ordered_trie_root, SHA3_NULL_RL
 use util::error::{Mismatch, OutOfBounds};

 use basic_types::{LogBloom, Seal};
-use evm::env_info::{EnvInfo, LastHashes};
+use vm::{EnvInfo, LastHashes};
 use engines::Engine;
 use error::{Error, BlockError, TransactionError};
 use factory::Factories;
@ -667,7 +667,7 @@ mod tests {
 	use tests::helpers::*;
 	use super::*;
 	use engines::Engine;
-	use evm::env_info::LastHashes;
+	use vm::LastHashes;
 	use error::Error;
 	use header::Header;
 	use factory::Factories;
--- a/ethcore/src/builtin.rs
+++ b/ethcore/src/builtin.rs
@ -36,9 +36,9 @@ impl From<&'static str> for Error {
 	}
 }

-impl Into<::evm::Error> for Error {
-	fn into(self) -> ::evm::Error {
-		::evm::Error::BuiltIn(self.0)
+impl Into<::vm::Error> for Error {
+	fn into(self) -> ::vm::Error {
+		::vm::Error::BuiltIn(self.0)
 	}
 }

--- a/ethcore/src/client/client.rs
+++ b/ethcore/src/client/client.rs
@ -42,9 +42,8 @@ use client::{
 };
 use encoded;
 use engines::{Engine, EpochTransition};
-use evm::env_info::EnvInfo;
-use evm::env_info::LastHashes;
 use error::{ImportError, ExecutionError, CallError, BlockError, ImportResult, Error as EthcoreError};
+use vm::{EnvInfo, LastHashes};
 use evm::{Factory as EvmFactory, Schedule};
 use executive::{Executive, Executed, TransactOptions, contract_address};
 use factory::Factories;
--- a/ethcore/src/client/evm_test_client.rs
+++ b/ethcore/src/client/evm_test_client.rs
@ -23,7 +23,7 @@ use util::kvdb::{self, KeyValueDB};
 use {state, state_db, client, executive, trace, db, spec};
 use factory::Factories;
 use evm::{self, VMType};
-use evm::action_params::ActionParams;
+use vm::{self, ActionParams};

 /// EVM test Error.
 #[derive(Debug)]
@ -31,7 +31,7 @@ pub enum EvmTestError {
 	/// Trie integrity error.
 	Trie(util::TrieError),
 	/// EVM error.
-	Evm(evm::Error),
+	Evm(vm::Error),
 	/// Initialization error.
 	Initialization(::error::Error),
 	/// Low-level database error.
--- a/ethcore/src/client/mod.rs
+++ b/ethcore/src/client/mod.rs
@ -40,7 +40,7 @@ pub use types::pruning_info::PruningInfo;
 pub use types::call_analytics::CallAnalytics;

 pub use executive::{Executed, Executive, TransactOptions};
-pub use evm::env_info::{LastHashes, EnvInfo};
+pub use vm::{LastHashes, EnvInfo};

 pub use error::{BlockImportError, TransactionImportError, TransactionImportResult};
 pub use verification::VerifierType;
--- a/ethcore/src/client/test_client.rs
+++ b/ethcore/src/client/test_client.rs
@ -36,7 +36,8 @@ use log_entry::LocalizedLogEntry;
 use receipt::{Receipt, LocalizedReceipt};
 use blockchain::extras::BlockReceipts;
 use error::{ImportResult, Error as EthcoreError};
-use evm::{Factory as EvmFactory, VMType, Schedule};
+use evm::{Factory as EvmFactory, VMType};
+use vm::Schedule;
 use miner::{Miner, MinerService, TransactionImportResult};
 use spec::Spec;
 use types::basic_account::BasicAccount;
--- a/ethcore/src/client/traits.rs
+++ b/ethcore/src/client/traits.rs
@ -19,7 +19,7 @@ use std::collections::BTreeMap;
 use block::{OpenBlock, SealedBlock, ClosedBlock};
 use blockchain::TreeRoute;
 use encoded;
-use evm::env_info::LastHashes;
+use vm::LastHashes;
 use error::{ImportResult, CallError, Error as EthcoreError};
 use error::{TransactionImportResult, BlockImportError};
 use evm::{Factory as EvmFactory, Schedule};
--- a/ethcore/src/engines/authority_round/mod.rs
+++ b/ethcore/src/engines/authority_round/mod.rs
@ -514,7 +514,7 @@ impl Engine for AuthorityRound {
 	fn on_new_block(
 		&self,
 		block: &mut ExecutedBlock,
-		last_hashes: Arc<::evm::env_info::LastHashes>,
+		last_hashes: Arc<::vm::LastHashes>,
 		epoch_begin: bool,
 	) -> Result<(), Error> {
 		let parent_hash = block.fields().header.parent_hash().clone();
--- a/ethcore/src/engines/mod.rs
+++ b/ethcore/src/engines/mod.rs
@ -43,15 +43,13 @@ use account_provider::AccountProvider;
 use block::ExecutedBlock;
 use builtin::Builtin;
 use client::Client;
-use evm::env_info::{EnvInfo, LastHashes};
+use vm::{EnvInfo, LastHashes, Schedule, CreateContractAddress};
 use error::Error;
-use evm::Schedule;
 use header::{Header, BlockNumber};
 use receipt::Receipt;
 use snapshot::SnapshotComponents;
 use spec::CommonParams;
 use transaction::{UnverifiedTransaction, SignedTransaction};
-use evm::CreateContractAddress;

 use ethkey::Signature;
 use util::*;
@ -394,12 +392,10 @@ pub trait Engine : Sync + Send {
 /// Common engine utilities
 pub mod common {
 	use block::ExecutedBlock;
-	use evm::env_info::{EnvInfo, LastHashes};
 	use error::Error;
 	use transaction::SYSTEM_ADDRESS;
 	use executive::Executive;
-	use evm::CallType;
-	use evm::action_params::{ActionParams, ActionValue};
+	use vm::{CallType, ActionParams, ActionValue, EnvInfo, LastHashes};
 	use trace::{NoopTracer, NoopVMTracer};
 	use state::Substate;

--- a/ethcore/src/engines/validator_set/safe_contract.rs
+++ b/ethcore/src/engines/validator_set/safe_contract.rs
@ -299,7 +299,7 @@ impl ValidatorSet for ValidatorSafeContract {
 			let (old_header, state_items) = decode_first_proof(&rlp)?;
 			let old_hash = old_header.hash();

-			let env_info = ::evm::env_info::EnvInfo {
+			let env_info = ::vm::EnvInfo {
 				number: old_header.number(),
 				author: *old_header.author(),
 				difficulty: *old_header.difficulty(),
--- a/ethcore/src/ethereum/ethash.rs
+++ b/ethcore/src/ethereum/ethash.rs
@ -19,7 +19,7 @@ use ethash::{quick_get_difficulty, slow_get_seedhash, EthashManager};
 use util::*;
 use block::*;
 use builtin::Builtin;
-use evm::env_info::EnvInfo;
+use vm::EnvInfo;
 use error::{BlockError, Error, TransactionError};
 use header::{Header, BlockNumber};
 use state::CleanupMode;
@ -29,7 +29,7 @@ use engines::{self, Engine};
 use evm::Schedule;
 use ethjson;
 use rlp::{self, UntrustedRlp};
-use evm::env_info::LastHashes;
+use vm::LastHashes;

 /// Parity tries to round block.gas_limit to multiple of this constant
 pub const PARITY_GAS_LIMIT_DETERMINANT: U256 = U256([37, 0, 0, 0]);
--- a/ethcore/src/executed.rs
+++ b/ethcore/src/executed.rs
@ -17,7 +17,7 @@
 //! Transaction execution format module.

 use util::{Bytes, U256, Address, U512, trie};
-use evm;
+use vm;
 use trace::{VMTrace, FlatTrace};
 use log_entry::LogEntry;
 use state_diff::StateDiff;
@ -28,7 +28,7 @@ use std::fmt;
 #[derive(Debug, PartialEq, Clone)]
 pub struct Executed {
 	/// True if the outer call/create resulted in an exceptional exit.
-	pub exception: Option<evm::Error>,
+	pub exception: Option<vm::Error>,

 	/// Gas paid up front for execution of transaction.
 	pub gas: U256,
--- a/ethcore/src/executive.rs
+++ b/ethcore/src/executive.rs
@ -16,13 +16,13 @@

 //! Transaction Execution environment.
 use util::*;
-use evm::action_params::{ActionParams, ActionValue};
 use state::{Backend as StateBackend, State, Substate, CleanupMode};
 use engines::Engine;
-use evm::CallType;
-use evm::env_info::EnvInfo;
+use vm::EnvInfo;
 use error::ExecutionError;
-use evm::{self, wasm, Factory, Ext, Finalize, CreateContractAddress, FinalizationResult, ReturnData, CleanDustMode};
+use evm::{CallType, Factory, Finalize, FinalizationResult};
+use vm::{self, Ext, CreateContractAddress, ReturnData, CleanDustMode, ActionParams, ActionValue};
+use wasm;
 use externalities::*;
 use trace::{FlatTrace, Tracer, NoopTracer, ExecutiveTracer, VMTrace, VMTracer, ExecutiveVMTracer, NoopVMTracer};
 use transaction::{Action, SignedTransaction};
@ -75,7 +75,7 @@ pub struct TransactOptions {
 }

 pub fn executor<E>(engine: &E, vm_factory: &Factory, params: &ActionParams)
-	-> Box<evm::Evm> where E: Engine + ?Sized
+	-> Box<vm::Vm> where E: Engine + ?Sized
 {
 	if engine.supports_wasm() && params.code.as_ref().map_or(false, |code| code.len() > 4 && &code[0..4] == WASM_MAGIC_NUMBER) {
 		Box::new(
@ -269,7 +269,7 @@ impl<'a, B: 'a + StateBackend, E: Engine + ?Sized> Executive<'a, B, E> {
 		output_policy: OutputPolicy,
 		tracer: &mut T,
 		vm_tracer: &mut V
-	) -> evm::Result<FinalizationResult> where T: Tracer, V: VMTracer {
+	) -> vm::Result<FinalizationResult> where T: Tracer, V: VMTracer {

 		let depth_threshold = ::io::LOCAL_STACK_SIZE.with(|sz| sz.get() / STACK_SIZE_PER_DEPTH);
 		let static_call = params.call_type == CallType::StaticCall;
@ -299,7 +299,7 @@ impl<'a, B: 'a + StateBackend, E: Engine + ?Sized> Executive<'a, B, E> {
 	/// Calls contract function with given contract params.
 	/// NOTE. It does not finalize the transaction (doesn't do refunds, nor suicides).
 	/// Modifies the substate and the output.
-	/// Returns either gas_left or `evm::Error`.
+	/// Returns either gas_left or `vm::Error`.
 	pub fn call<T, V>(
 		&mut self,
 		params: ActionParams,
@ -307,14 +307,14 @@ impl<'a, B: 'a + StateBackend, E: Engine + ?Sized> Executive<'a, B, E> {
 		mut output: BytesRef,
 		tracer: &mut T,
 		vm_tracer: &mut V
-	) -> evm::Result<(U256, ReturnData)> where T: Tracer, V: VMTracer {
+	) -> vm::Result<(U256, ReturnData)> where T: Tracer, V: VMTracer {

 		trace!("Executive::call(params={:?}) self.env_info={:?}", params, self.info);
 		if (params.call_type == CallType::StaticCall ||
 				((params.call_type == CallType::Call || params.call_type == CallType::DelegateCall) &&
 				 self.static_flag))
 			&& params.value.value() > 0.into() {
-			return Err(evm::Error::MutableCallInStaticContext);
+			return Err(vm::Error::MutableCallInStaticContext);
 		}

 		// backup used in case of running out of gas
@ -344,7 +344,7 @@ impl<'a, B: 'a + StateBackend, E: Engine + ?Sized> Executive<'a, B, E> {
 			if cost <= params.gas {
 				if let Err(e) = builtin.execute(data, &mut output) {
 					self.state.revert_to_checkpoint();
-					let evm_err: evm::evm::Error = e.into();
+					let evm_err: vm::Error = e.into();
 					tracer.trace_failed_call(trace_info, vec![], evm_err.clone().into());
 					Err(evm_err)
 				} else {
@ -371,9 +371,9 @@ impl<'a, B: 'a + StateBackend, E: Engine + ?Sized> Executive<'a, B, E> {
 				// just drain the whole gas
 				self.state.revert_to_checkpoint();

-				tracer.trace_failed_call(trace_info, vec![], evm::Error::OutOfGas.into());
+				tracer.trace_failed_call(trace_info, vec![], vm::Error::OutOfGas.into());

-				Err(evm::Error::OutOfGas)
+				Err(vm::Error::OutOfGas)
 			}
 		} else {
 			let trace_info = tracer.prepare_trace_call(&params);
@ -432,17 +432,17 @@ impl<'a, B: 'a + StateBackend, E: Engine + ?Sized> Executive<'a, B, E> {
 		substate: &mut Substate,
 		tracer: &mut T,
 		vm_tracer: &mut V,
-	) -> evm::Result<(U256, ReturnData)> where T: Tracer, V: VMTracer {
+	) -> vm::Result<(U256, ReturnData)> where T: Tracer, V: VMTracer {

 		let scheme = self.engine.create_address_scheme(self.info.number);
 		if scheme != CreateContractAddress::FromSenderAndNonce && self.state.exists_and_has_code(&params.address)? {
-			return Err(evm::Error::OutOfGas);
+			return Err(vm::Error::OutOfGas);
 		}

 		if params.call_type == CallType::StaticCall || self.static_flag {
 			let trace_info = tracer.prepare_trace_create(&params);
-			tracer.trace_failed_create(trace_info, vec![], evm::Error::MutableCallInStaticContext.into());
-			return Err(evm::Error::MutableCallInStaticContext);
+			tracer.trace_failed_create(trace_info, vec![], vm::Error::MutableCallInStaticContext.into());
+			return Err(vm::Error::MutableCallInStaticContext);
 		}

 		// backup used in case of running out of gas
@ -496,7 +496,7 @@ impl<'a, B: 'a + StateBackend, E: Engine + ?Sized> Executive<'a, B, E> {
 		&mut self,
 		t: &SignedTransaction,
 		mut substate: Substate,
-		result: evm::Result<(U256, ReturnData)>,
+		result: vm::Result<(U256, ReturnData)>,
 		output: Bytes,
 		trace: Vec<FlatTrace>,
 		vm_trace: Option<VMTrace>
@ -538,7 +538,7 @@ impl<'a, B: 'a + StateBackend, E: Engine + ?Sized> Executive<'a, B, E> {
 		self.state.kill_garbage(&substate.touched, schedule.kill_empty, &min_balance, schedule.kill_dust == CleanDustMode::WithCodeAndStorage)?;

 		match result {
-			Err(evm::Error::Internal(msg)) => Err(ExecutionError::Internal(msg)),
+			Err(vm::Error::Internal(msg)) => Err(ExecutionError::Internal(msg)),
 			Err(exception) => {
 				Ok(Executed {
 					exception: Some(exception),
@ -572,20 +572,20 @@ impl<'a, B: 'a + StateBackend, E: Engine + ?Sized> Executive<'a, B, E> {
 		}
 	}

-	fn enact_result(&mut self, result: &evm::Result<FinalizationResult>, substate: &mut Substate, un_substate: Substate) {
+	fn enact_result(&mut self, result: &vm::Result<FinalizationResult>, substate: &mut Substate, un_substate: Substate) {
 		match *result {
-			Err(evm::Error::OutOfGas)
-				| Err(evm::Error::BadJumpDestination {..})
-				| Err(evm::Error::BadInstruction {.. })
-				| Err(evm::Error::StackUnderflow {..})
-				| Err(evm::Error::BuiltIn {..})
-				| Err(evm::Error::Wasm {..})
-				| Err(evm::Error::OutOfStack {..})
-				| Err(evm::Error::MutableCallInStaticContext)
+			Err(vm::Error::OutOfGas)
+				| Err(vm::Error::BadJumpDestination {..})
+				| Err(vm::Error::BadInstruction {.. })
+				| Err(vm::Error::StackUnderflow {..})
+				| Err(vm::Error::BuiltIn {..})
+				| Err(vm::Error::Wasm {..})
+				| Err(vm::Error::OutOfStack {..})
+				| Err(vm::Error::MutableCallInStaticContext)
 				| Ok(FinalizationResult { apply_state: false, .. }) => {
 					self.state.revert_to_checkpoint();
 			},
-			Ok(_) | Err(evm::Error::Internal(_)) => {
+			Ok(_) | Err(vm::Error::Internal(_)) => {
 				self.state.discard_checkpoint();
 				substate.accrue(un_substate);
 			}
@ -602,9 +602,8 @@ mod tests {
 	use super::*;
 	use util::{H256, U256, U512, Address, FromStr};
 	use util::bytes::BytesRef;
-	use evm::action_params::{ActionParams, ActionValue};
-	use evm::env_info::EnvInfo;
-	use evm::{Factory, VMType, CreateContractAddress};
+	use vm::{ActionParams, ActionValue, CallType, EnvInfo, CreateContractAddress};
+	use evm::{Factory, VMType};
 	use error::ExecutionError;
 	use state::{Substate, CleanupMode};
 	use tests::helpers::*;
@ -613,8 +612,6 @@ mod tests {
 	use trace::{VMTrace, VMOperation, VMExecutedOperation, MemoryDiff, StorageDiff, VMTracer, NoopVMTracer, ExecutiveVMTracer};
 	use transaction::{Action, Transaction};

-	use evm::CallType;
-
 	#[test]
 	fn test_contract_address() {
 		let address = Address::from_str("0f572e5295c57f15886f9b263e2f6d2d6c7b5ec6").unwrap();
--- a/ethcore/src/externalities.rs
+++ b/ethcore/src/externalities.rs
@ -16,13 +16,14 @@

 //! Transaction Execution environment.
 use util::*;
-use evm::action_params::{ActionParams, ActionValue};
 use state::{Backend as StateBackend, State, Substate, CleanupMode};
 use engines::Engine;
-use evm::env_info::EnvInfo;
 use executive::*;
-use evm::{self, Schedule, Ext, ContractCreateResult, MessageCallResult, CreateContractAddress, ReturnData};
-use evm::CallType;
+use vm::{
+	self, ActionParams, ActionValue, EnvInfo, CallType, Schedule,
+	Ext, ContractCreateResult, MessageCallResult, CreateContractAddress,
+	ReturnData
+};
 use transaction::UNSIGNED_SENDER;
 use trace::{Tracer, VMTracer};

@ -109,31 +110,31 @@ impl<'a, T: 'a, V: 'a, B: 'a, E: 'a> Externalities<'a, T, V, B, E>
 impl<'a, T: 'a, V: 'a, B: 'a, E: 'a> Ext for Externalities<'a, T, V, B, E>
 	where T: Tracer, V: VMTracer, B: StateBackend, E: Engine + ?Sized
 {
-	fn storage_at(&self, key: &H256) -> evm::Result<H256> {
+	fn storage_at(&self, key: &H256) -> vm::Result<H256> {
 		self.state.storage_at(&self.origin_info.address, key).map_err(Into::into)
 	}

-	fn set_storage(&mut self, key: H256, value: H256) -> evm::Result<()> {
+	fn set_storage(&mut self, key: H256, value: H256) -> vm::Result<()> {
 		if self.static_flag {
-			Err(evm::Error::MutableCallInStaticContext)
+			Err(vm::Error::MutableCallInStaticContext)
 		} else {
 			self.state.set_storage(&self.origin_info.address, key, value).map_err(Into::into)
 		}
 	}

-	fn exists(&self, address: &Address) -> evm::Result<bool> {
+	fn exists(&self, address: &Address) -> vm::Result<bool> {
 		self.state.exists(address).map_err(Into::into)
 	}

-	fn exists_and_not_null(&self, address: &Address) -> evm::Result<bool> {
+	fn exists_and_not_null(&self, address: &Address) -> vm::Result<bool> {
 		self.state.exists_and_not_null(address).map_err(Into::into)
 	}

-	fn origin_balance(&self) -> evm::Result<U256> {
+	fn origin_balance(&self) -> vm::Result<U256> {
 		self.balance(&self.origin_info.address).map_err(Into::into)
 	}

-	fn balance(&self, address: &Address) -> evm::Result<U256> {
+	fn balance(&self, address: &Address) -> vm::Result<U256> {
 		self.state.balance(address).map_err(Into::into)
 	}

@ -274,16 +275,16 @@ impl<'a, T: 'a, V: 'a, B: 'a, E: 'a> Ext for Externalities<'a, T, V, B, E>
 		}
 	}

-	fn extcode(&self, address: &Address) -> evm::Result<Arc<Bytes>> {
+	fn extcode(&self, address: &Address) -> vm::Result<Arc<Bytes>> {
 		Ok(self.state.code(address)?.unwrap_or_else(|| Arc::new(vec![])))
 	}

-	fn extcodesize(&self, address: &Address) -> evm::Result<usize> {
+	fn extcodesize(&self, address: &Address) -> vm::Result<usize> {
 		Ok(self.state.code_size(address)?.unwrap_or(0))
 	}

 	#[cfg_attr(feature="dev", allow(match_ref_pats))]
-	fn ret(mut self, gas: &U256, data: &ReturnData) -> evm::Result<U256>
+	fn ret(mut self, gas: &U256, data: &ReturnData) -> vm::Result<U256>
 		where Self: Sized {
 		let handle_copy = |to: &mut Option<&mut Bytes>| {
 			to.as_mut().map(|b| **b = data.to_vec());
@ -307,7 +308,7 @@ impl<'a, T: 'a, V: 'a, B: 'a, E: 'a> Ext for Externalities<'a, T, V, B, E>
 				let return_cost = U256::from(data.len()) * U256::from(self.schedule.create_data_gas);
 				if return_cost > *gas || data.len() > self.schedule.create_data_limit {
 					return match self.schedule.exceptional_failed_code_deposit {
-						true => Err(evm::Error::OutOfGas),
+						true => Err(vm::Error::OutOfGas),
 						false => Ok(*gas)
 					}
 				}
@ -320,11 +321,11 @@ impl<'a, T: 'a, V: 'a, B: 'a, E: 'a> Ext for Externalities<'a, T, V, B, E>
 		}
 	}

-	fn log(&mut self, topics: Vec<H256>, data: &[u8]) -> evm::Result<()> {
+	fn log(&mut self, topics: Vec<H256>, data: &[u8]) -> vm::Result<()> {
 		use log_entry::LogEntry;

 		if self.static_flag {
-			return Err(evm::Error::MutableCallInStaticContext);
+			return Err(vm::Error::MutableCallInStaticContext);
 		}

 		let address = self.origin_info.address.clone();
@ -337,9 +338,9 @@ impl<'a, T: 'a, V: 'a, B: 'a, E: 'a> Ext for Externalities<'a, T, V, B, E>
 		Ok(())
 	}

-	fn suicide(&mut self, refund_address: &Address) -> evm::Result<()> {
+	fn suicide(&mut self, refund_address: &Address) -> vm::Result<()> {
 		if self.static_flag {
-			return Err(evm::Error::MutableCallInStaticContext);
+			return Err(vm::Error::MutableCallInStaticContext);
 		}

 		let address = self.origin_info.address.clone();
@ -396,13 +397,11 @@ impl<'a, T: 'a, V: 'a, B: 'a, E: 'a> Ext for Externalities<'a, T, V, B, E>
 mod tests {
 	use util::*;
 	use engines::Engine;
-	use evm::env_info::EnvInfo;
-	use evm::Ext;
+	use evm::{EnvInfo, Ext, CallType};
 	use state::{State, Substate};
 	use tests::helpers::*;
 	use super::*;
 	use trace::{NoopTracer, NoopVMTracer};
-	use evm::CallType;

 	fn get_test_origin() -> OriginInfo {
 		OriginInfo {
--- a/ethcore/src/json_tests/executive.rs
+++ b/ethcore/src/json_tests/executive.rs
@ -15,15 +15,16 @@
 // along with Parity.  If not, see <http://www.gnu.org/licenses/>.

 use super::test_common::*;
-use evm::action_params::ActionParams;
 use state::{Backend as StateBackend, State, Substate};
 use executive::*;
 use engines::Engine;
-use evm::env_info::EnvInfo;
-use evm;
-use evm::{Schedule, Ext, Finalize, VMType, ContractCreateResult, MessageCallResult, CreateContractAddress, ReturnData};
+use evm::{VMType, Finalize};
+use vm::{
+	self, ActionParams, CallType, Schedule, Ext,
+	ContractCreateResult, EnvInfo, MessageCallResult,
+	CreateContractAddress, ReturnData,
+};
 use externalities::*;
-use evm::CallType;
 use tests::helpers::*;
 use ethjson;
 use trace::{Tracer, NoopTracer};
@ -88,27 +89,27 @@ impl<'a, T: 'a, V: 'a, B: 'a, E: 'a> TestExt<'a, T, V, B, E>
 impl<'a, T: 'a, V: 'a, B: 'a, E: 'a> Ext for TestExt<'a, T, V, B, E>
 	where T: Tracer, V: VMTracer, B: StateBackend, E: Engine + ?Sized
 {
-	fn storage_at(&self, key: &H256) -> evm::Result<H256> {
+	fn storage_at(&self, key: &H256) -> vm::Result<H256> {
 		self.ext.storage_at(key)
 	}

-	fn set_storage(&mut self, key: H256, value: H256) -> evm::Result<()> {
+	fn set_storage(&mut self, key: H256, value: H256) -> vm::Result<()> {
 		self.ext.set_storage(key, value)
 	}

-	fn exists(&self, address: &Address) -> evm::Result<bool> {
+	fn exists(&self, address: &Address) -> vm::Result<bool> {
 		self.ext.exists(address)
 	}

-	fn exists_and_not_null(&self, address: &Address) -> evm::Result<bool> {
+	fn exists_and_not_null(&self, address: &Address) -> vm::Result<bool> {
 		self.ext.exists_and_not_null(address)
 	}

-	fn balance(&self, address: &Address) -> evm::Result<U256> {
+	fn balance(&self, address: &Address) -> vm::Result<U256> {
 		self.ext.balance(address)
 	}

-	fn origin_balance(&self) -> evm::Result<U256> {
+	fn origin_balance(&self) -> vm::Result<U256> {
 		self.ext.origin_balance()
 	}

@ -146,23 +147,23 @@ impl<'a, T: 'a, V: 'a, B: 'a, E: 'a> Ext for TestExt<'a, T, V, B, E>
 		MessageCallResult::Success(*gas, ReturnData::empty())
 	}

-	fn extcode(&self, address: &Address) -> evm::Result<Arc<Bytes>>  {
+	fn extcode(&self, address: &Address) -> vm::Result<Arc<Bytes>>  {
 		self.ext.extcode(address)
 	}

-	fn extcodesize(&self, address: &Address) -> evm::Result<usize> {
+	fn extcodesize(&self, address: &Address) -> vm::Result<usize> {
 		self.ext.extcodesize(address)
 	}

-	fn log(&mut self, topics: Vec<H256>, data: &[u8]) -> evm::Result<()> {
+	fn log(&mut self, topics: Vec<H256>, data: &[u8]) -> vm::Result<()> {
 		self.ext.log(topics, data)
 	}

-	fn ret(self, gas: &U256, data: &ReturnData) -> Result<U256, evm::Error> {
+	fn ret(self, gas: &U256, data: &ReturnData) -> Result<U256, vm::Error> {
 		self.ext.ret(gas, data)
 	}

-	fn suicide(&mut self, refund_address: &Address) -> evm::Result<()> {
+	fn suicide(&mut self, refund_address: &Address) -> vm::Result<()> {
 		self.ext.suicide(refund_address)
 	}

--- a/ethcore/src/json_tests/state.rs
+++ b/ethcore/src/json_tests/state.rs
@ -22,7 +22,7 @@ use spec::Spec;
 use ethjson;
 use ethjson::state::test::ForkSpec;
 use transaction::SignedTransaction;
-use evm::env_info::EnvInfo;
+use vm::EnvInfo;

 lazy_static! {
 	pub static ref FRONTIER: Spec = ethereum::new_frontier_test();
--- a/ethcore/src/lib.rs
+++ b/ethcore/src/lib.rs
@ -106,6 +106,8 @@ extern crate semver;
 extern crate stats;
 extern crate time;
 extern crate transient_hashmap;
+extern crate vm;
+extern crate wasm;

 #[macro_use]
 extern crate log;
--- a/ethcore/src/spec/spec.rs
+++ b/ethcore/src/spec/spec.rs
@ -20,10 +20,9 @@ use rustc_hex::FromHex;
 use super::genesis::Genesis;
 use super::seal::Generic as GenericSeal;

-use evm::action_params::{ActionValue, ActionParams};
 use builtin::Builtin;
 use engines::{Engine, NullEngine, InstantSeal, BasicAuthority, AuthorityRound, Tendermint, DEFAULT_BLOCKHASH_CONTRACT};
-use evm::env_info::EnvInfo;
+use vm::{EnvInfo, CallType, ActionValue, ActionParams};
 use error::Error;
 use ethereum;
 use ethjson;
@ -36,7 +35,6 @@ use state_db::StateDB;
 use state::{Backend, State, Substate};
 use state::backend::Basic as BasicBackend;
 use trace::{NoopTracer, NoopVMTracer};
-use evm::CallType;
 use util::*;

 /// Parameters common to ethereum-like blockchains.
@ -102,14 +100,14 @@ pub struct CommonParams {

 impl CommonParams {
 	/// Schedule for an EVM in the post-EIP-150-era of the Ethereum main net.
-	pub fn schedule(&self, block_number: u64) -> ::evm::Schedule {
-		let mut schedule = ::evm::Schedule::new_post_eip150(usize::max_value(), true, true, true);
+	pub fn schedule(&self, block_number: u64) -> ::vm::Schedule {
+		let mut schedule = ::vm::Schedule::new_post_eip150(usize::max_value(), true, true, true);
 		self.update_schedule(block_number, &mut schedule);
 		schedule
 	}

 	/// Apply common spec config parameters to the schedule.
- 	pub fn update_schedule(&self, block_number: u64, schedule: &mut ::evm::Schedule) {
+ 	pub fn update_schedule(&self, block_number: u64, schedule: &mut ::vm::Schedule) {
 		schedule.have_create2 = block_number >= self.eip86_transition;
 		schedule.have_revert = block_number >= self.eip140_transition;
 		schedule.have_static_call = block_number >= self.eip214_transition;
@ -119,8 +117,8 @@ impl CommonParams {
 		}
 		if block_number >= self.dust_protection_transition {
 			schedule.kill_dust = match self.remove_dust_contracts {
-				true => ::evm::CleanDustMode::WithCodeAndStorage,
-				false => ::evm::CleanDustMode::BasicOnly,
+				true => ::vm::CleanDustMode::WithCodeAndStorage,
+				false => ::vm::CleanDustMode::BasicOnly,
 			};
 		}
 	}
--- a/ethcore/src/state/mod.rs
+++ b/ethcore/src/state/mod.rs
@ -24,7 +24,7 @@ use std::collections::hash_map::Entry;

 use receipt::Receipt;
 use engines::Engine;
-use evm::env_info::EnvInfo;
+use vm::EnvInfo;
 use error::Error;
 use executive::{Executive, TransactOptions};
 use factory::Factories;
@ -982,7 +982,7 @@ mod tests {
 	use ethkey::Secret;
 	use util::{U256, H256, Address, Hashable};
 	use tests::helpers::*;
-	use evm::env_info::EnvInfo;
+	use vm::EnvInfo;
 	use spec::*;
 	use transaction::*;
 	use ethcore_logger::init_log;
--- a/ethcore/src/tests/evm.rs
+++ b/ethcore/src/tests/evm.rs
@ -1,9 +1,7 @@
 //! Tests of EVM integration with transaction execution.

-use evm::action_params::{ActionParams, ActionValue};
-use evm::env_info::EnvInfo;
+use vm::{EnvInfo, ActionParams, ActionValue, CallType};
 use evm::{Factory, VMType};
-use evm::call_type::CallType;
 use executive::Executive;
 use state::Substate;
 use tests::helpers::*;
--- a/ethcore/src/trace/executive_tracer.rs
+++ b/ethcore/src/trace/executive_tracer.rs
@ -17,7 +17,7 @@
 //! Simple executive tracer.

 use util::{Bytes, Address, U256};
-use evm::action_params::ActionParams;
+use vm::ActionParams;
 use trace::trace::{Call, Create, Action, Res, CreateResult, CallResult, VMTrace, VMOperation, VMExecutedOperation, MemoryDiff, StorageDiff, Suicide};
 use trace::{Tracer, VMTracer, FlatTrace, TraceError};

--- a/ethcore/src/trace/mod.rs
+++ b/ethcore/src/trace/mod.rs
@ -39,7 +39,7 @@ pub use self::types::filter::{Filter, AddressesFilter};

 use util::{Bytes, Address, U256, H256, DBTransaction};
 use self::trace::{Call, Create};
-use evm::action_params::ActionParams;
+use vm::ActionParams;
 use header::BlockNumber;

 /// This trait is used by executive to build traces.
--- a/ethcore/src/trace/noop_tracer.rs
+++ b/ethcore/src/trace/noop_tracer.rs
@ -17,7 +17,7 @@
 //! Nonoperative tracer.

 use util::{Bytes, Address, U256};
-use evm::action_params::ActionParams;
+use vm::ActionParams;
 use trace::{Tracer, VMTracer, FlatTrace, TraceError};
 use trace::trace::{Call, Create, VMTrace};

--- a/ethcore/src/trace/types/error.rs
+++ b/ethcore/src/trace/types/error.rs
@ -18,7 +18,7 @@

 use std::fmt;
 use rlp::{Encodable, RlpStream, Decodable, DecoderError, UntrustedRlp};
-use evm::Error as EvmError;
+use vm::Error as VmError;

 /// Trace evm errors.
 #[derive(Debug, PartialEq, Clone)]
@ -45,24 +45,24 @@ pub enum Error {
 	Wasm,
 }

-impl<'a> From<&'a EvmError> for Error {
-	fn from(e: &'a EvmError) -> Self {
+impl<'a> From<&'a VmError> for Error {
+	fn from(e: &'a VmError) -> Self {
 		match *e {
-			EvmError::OutOfGas => Error::OutOfGas,
-			EvmError::BadJumpDestination { .. } => Error::BadJumpDestination,
-			EvmError::BadInstruction { .. } => Error::BadInstruction,
-			EvmError::StackUnderflow { .. } => Error::StackUnderflow,
-			EvmError::OutOfStack { .. } => Error::OutOfStack,
-			EvmError::BuiltIn { .. } => Error::BuiltIn,
-			EvmError::Wasm { .. } => Error::Wasm,
-			EvmError::Internal(_) => Error::Internal,
-			EvmError::MutableCallInStaticContext => Error::MutableCallInStaticContext,
+			VmError::OutOfGas => Error::OutOfGas,
+			VmError::BadJumpDestination { .. } => Error::BadJumpDestination,
+			VmError::BadInstruction { .. } => Error::BadInstruction,
+			VmError::StackUnderflow { .. } => Error::StackUnderflow,
+			VmError::OutOfStack { .. } => Error::OutOfStack,
+			VmError::BuiltIn { .. } => Error::BuiltIn,
+			VmError::Wasm { .. } => Error::Wasm,
+			VmError::Internal(_) => Error::Internal,
+			VmError::MutableCallInStaticContext => Error::MutableCallInStaticContext,
 		}
 	}
 }

-impl From<EvmError> for Error {
-	fn from(e: EvmError) -> Self {
+impl From<VmError> for Error {
+	fn from(e: VmError) -> Self {
 		Error::from(&e)
 	}
 }
--- a/ethcore/src/trace/types/trace.rs
+++ b/ethcore/src/trace/types/trace.rs
@ -21,7 +21,7 @@ use util::sha3::Hashable;
 use util::bloom::Bloomable;
 use rlp::*;

-use evm::action_params::ActionParams;
+use vm::ActionParams;
 use basic_types::LogBloom;
 use evm::CallType;
 use super::error::Error;
--- a/ethcore/vm/Cargo.toml
+++ b/ethcore/vm/Cargo.toml
@ -0,0 +1,14 @@
+[package]
+name = "vm"
+version = "0.1.0"
+authors = ["Parity Technologies <admin@parity.io>"]
+
+[dependencies]
+byteorder = "1.0"
+ethcore-util = { path = "../../util" }
+log = "0.3"
+common-types = { path = "../types" }
+evmjit = { path = "../../evmjit", optional = true }
+ethjson = { path = "../../json" }
+lazy_static = "0.2"
+rlp = { path = "../../util/rlp" }
--- a/ethcore/evm/src/action_params.rs
+++ b/ethcore/evm/src/action_params.rs
@ -20,7 +20,7 @@ use util::hash::{H256};
 use util::sha3::{Hashable, SHA3_EMPTY};
 use ethjson;

-use {CallType};
+use call_type::CallType;

 use std::sync::Arc;

--- a/ethcore/evm/src/call_type.rs
+++ b/ethcore/evm/src/call_type.rs
--- a/ethcore/evm/src/env_info.rs
+++ b/ethcore/evm/src/env_info.rs
--- a/ethcore/vm/src/error.rs
+++ b/ethcore/vm/src/error.rs
@ -0,0 +1,100 @@
+// Copyright 2015-2017 Parity Technologies (UK) Ltd.
+// This file is part of Parity.
+
+// Parity is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+
+// Parity is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with Parity.  If not, see <http://www.gnu.org/licenses/>.
+
+//! VM errors module
+
+use util::trie;
+use std::fmt;
+
+/// VM errors.
+#[derive(Debug, Clone, PartialEq)]
+pub enum Error {
+	/// `OutOfGas` is returned when transaction execution runs out of gas.
+	/// The state should be reverted to the state from before the
+	/// transaction execution. But it does not mean that transaction
+	/// was invalid. Balance still should be transfered and nonce
+	/// should be increased.
+	OutOfGas,
+	/// `BadJumpDestination` is returned when execution tried to move
+	/// to position that wasn't marked with JUMPDEST instruction
+	BadJumpDestination {
+		/// Position the code tried to jump to.
+		destination: usize
+	},
+	/// `BadInstructions` is returned when given instruction is not supported
+	BadInstruction {
+		/// Unrecognized opcode
+		instruction: u8,
+	},
+	/// `StackUnderflow` when there is not enough stack elements to execute instruction
+	StackUnderflow {
+		/// Invoked instruction
+		instruction: &'static str,
+		/// How many stack elements was requested by instruction
+		wanted: usize,
+		/// How many elements were on stack
+		on_stack: usize
+	},
+	/// When execution would exceed defined Stack Limit
+	OutOfStack {
+		/// Invoked instruction
+		instruction: &'static str,
+		/// How many stack elements instruction wanted to push
+		wanted: usize,
+		/// What was the stack limit
+		limit: usize
+	},
+	/// Built-in contract failed on given input
+	BuiltIn(&'static str),
+	/// When execution tries to modify the state in static context
+	MutableCallInStaticContext,
+	/// Likely to cause consensus issues.
+	Internal(String),
+	/// Wasm runtime error
+	Wasm(String),
+}
+
+
+impl From<Box<trie::TrieError>> for Error {
+	fn from(err: Box<trie::TrieError>) -> Self {
+		Error::Internal(format!("Internal error: {}", err))
+	}
+}
+
+// impl From<wasm::RuntimeError> for Error {
+// 	fn from(err: wasm::RuntimeError) -> Self {
+// 		Error::Wasm(format!("Runtime error: {:?}", err))
+// 	}
+// }
+
+impl fmt::Display for Error {
+	fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+		use self::Error::*;
+		match *self {
+			OutOfGas => write!(f, "Out of gas"),
+			BadJumpDestination { destination } => write!(f, "Bad jump destination {:x}", destination),
+			BadInstruction { instruction } => write!(f, "Bad instruction {:x}",  instruction),
+			StackUnderflow { instruction, wanted, on_stack } => write!(f, "Stack underflow {} {}/{}", instruction, wanted, on_stack),
+			OutOfStack { instruction, wanted, limit } => write!(f, "Out of stack {} {}/{}", instruction, wanted, limit),
+			BuiltIn(name) => write!(f, "Built-in failed: {}", name),
+			Internal(ref msg) => write!(f, "Internal error: {}", msg),
+			MutableCallInStaticContext => write!(f, "Mutable call in static context"),
+			Wasm(ref msg) => write!(f, "Internal error: {}", msg),
+		}
+	}
+}
+
+pub type Result<T> = ::std::result::Result<T, Error>;
--- a/ethcore/evm/src/ext.rs
+++ b/ethcore/evm/src/ext.rs
@ -20,7 +20,8 @@ use util::*;
 use call_type::CallType;
 use env_info::EnvInfo;
 use schedule::Schedule;
-use evm::{self, ReturnData};
+use return_data::ReturnData;
+use error::Result;

 /// Result of externalities create function.
 pub enum ContractCreateResult {
@ -56,22 +57,22 @@ pub enum CreateContractAddress {
 /// Externalities interface for EVMs
 pub trait Ext {
 	/// Returns a value for given key.
-	fn storage_at(&self, key: &H256) -> evm::Result<H256>;
+	fn storage_at(&self, key: &H256) -> Result<H256>;

 	/// Stores a value for given key.
-	fn set_storage(&mut self, key: H256, value: H256) -> evm::Result<()>;
+	fn set_storage(&mut self, key: H256, value: H256) -> Result<()>;

 	/// Determine whether an account exists.
-	fn exists(&self, address: &Address) -> evm::Result<bool>;
+	fn exists(&self, address: &Address) -> Result<bool>;

 	/// Determine whether an account exists and is not null (zero balance/nonce, no code).
-	fn exists_and_not_null(&self, address: &Address) -> evm::Result<bool>;
+	fn exists_and_not_null(&self, address: &Address) -> Result<bool>;

 	/// Balance of the origin account.
-	fn origin_balance(&self) -> evm::Result<U256>;
+	fn origin_balance(&self) -> Result<U256>;

 	/// Returns address balance.
-	fn balance(&self, address: &Address) -> evm::Result<U256>;
+	fn balance(&self, address: &Address) -> Result<U256>;

 	/// Returns the hash of one of the 256 most recent complete blocks.
 	fn blockhash(&mut self, number: &U256) -> H256;
@ -99,21 +100,21 @@ pub trait Ext {
 	) -> MessageCallResult;

 	/// Returns code at given address
-	fn extcode(&self, address: &Address) -> evm::Result<Arc<Bytes>>;
+	fn extcode(&self, address: &Address) -> Result<Arc<Bytes>>;

 	/// Returns code size at given address
-	fn extcodesize(&self, address: &Address) -> evm::Result<usize>;
+	fn extcodesize(&self, address: &Address) -> Result<usize>;

 	/// Creates log entry with given topics and data
-	fn log(&mut self, topics: Vec<H256>, data: &[u8]) -> evm::Result<()>;
+	fn log(&mut self, topics: Vec<H256>, data: &[u8]) -> Result<()>;

 	/// Should be called when transaction calls `RETURN` opcode.
 	/// Returns gas_left if cost of returning the data is not too high.
-	fn ret(self, gas: &U256, data: &ReturnData) -> evm::Result<U256>;
+	fn ret(self, gas: &U256, data: &ReturnData) -> Result<U256>;

 	/// Should be called when contract commits suicide.
 	/// Address to which funds should be refunded.
-	fn suicide(&mut self, refund_address: &Address) -> evm::Result<()> ;
+	fn suicide(&mut self, refund_address: &Address) -> Result<()> ;

 	/// Returns schedule.
 	fn schedule(&self) -> &Schedule;
--- a/ethcore/vm/src/lib.rs
+++ b/ethcore/vm/src/lib.rs
@ -0,0 +1,46 @@
+// Copyright 2015-2017 Parity Technologies (UK) Ltd.
+// This file is part of Parity.
+
+// Parity is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+
+// Parity is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with Parity.  If not, see <http://www.gnu.org/licenses/>.
+
+//! Virtual machines support library
+
+extern crate ethcore_util as util;
+extern crate common_types as types;
+extern crate ethjson;
+extern crate rlp;
+
+mod action_params;
+mod call_type;
+mod env_info;
+mod schedule;
+mod ext;
+mod return_data;
+mod error;
+
+pub use action_params::{ActionParams, ActionValue};
+pub use call_type::CallType;
+pub use env_info::{EnvInfo, LastHashes};
+pub use schedule::{Schedule, CleanDustMode};
+pub use ext::{Ext, MessageCallResult, ContractCreateResult, CreateContractAddress};
+pub use return_data::{ReturnData, GasLeft};
+pub use error::{Error, Result};
+
+/// Virtual Machine interface
+pub trait Vm {
+	/// This function should be used to execute transaction.
+	/// It returns either an error, a known amount of gas left, or parameters to be used
+	/// to compute the final gas left.
+	fn exec(&mut self, params: ActionParams, ext: &mut Ext) -> Result<GasLeft>;
+}
--- a/ethcore/vm/src/return_data.rs
+++ b/ethcore/vm/src/return_data.rs
@ -0,0 +1,68 @@
+
+// Parity is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+
+// Parity is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with Parity.  If not, see <http://www.gnu.org/licenses/>.
+
+//! Return data structures
+
+use util::U256;
+
+/// Return data buffer. Holds memory from a previous call and a slice into that memory.
+#[derive(Debug)]
+pub struct ReturnData {
+	mem: Vec<u8>,
+	offset: usize,
+	size: usize,
+}
+
+impl ::std::ops::Deref for ReturnData {
+	type Target = [u8];
+	fn deref(&self) -> &[u8] {
+		&self.mem[self.offset..self.offset + self.size]
+	}
+}
+
+impl ReturnData {
+	/// Create empty `ReturnData`.
+	pub fn empty() -> Self {
+		ReturnData {
+			mem: Vec::new(),
+			offset: 0,
+			size: 0,
+		}
+	}
+	/// Create `ReturnData` from give buffer and slice.
+	pub fn new(mem: Vec<u8>, offset: usize, size: usize) -> Self {
+		ReturnData {
+			mem: mem,
+			offset: offset,
+			size: size,
+		}
+	}
+}
+
+/// Gas Left: either it is a known value, or it needs to be computed by processing
+/// a return instruction.
+#[derive(Debug)]
+pub enum GasLeft {
+	/// Known gas left
+	Known(U256),
+	/// Return or Revert instruction must be processed.
+	NeedsReturn {
+		/// Amount of gas left.
+		gas_left: U256,
+		/// Return data buffer.
+		data: ReturnData,
+		/// Apply or revert state changes on revert.
+		apply_state: bool
+	},
+}
--- a/ethcore/evm/src/schedule.rs
+++ b/ethcore/evm/src/schedule.rs
@ -250,6 +250,12 @@ impl Schedule {
 	}
 }

+impl Default for Schedule {
+	fn default() -> Self {
+		Schedule::new_frontier()
+	}
+}
+
 #[test]
 #[cfg(test)]
 fn schedule_evm_assumptions() {
@ -260,3 +266,4 @@ fn schedule_evm_assumptions() {
 	assert_eq!(s1.quad_coeff_div, 512);
 	assert_eq!(s2.quad_coeff_div, 512);
 }
+
--- a/ethcore/wasm/Cargo.toml
+++ b/ethcore/wasm/Cargo.toml
@ -0,0 +1,12 @@
+[package]
+name = "wasm"
+version = "0.1.0"
+authors = ["Parity Technologies <admin@parity.io>"]
+
+[dependencies]
+byteorder = "1.0"
+ethcore-util = { path = "../../util" }
+log = "0.3"
+parity-wasm = "0.12"
+wasm-utils = { git = "https://github.com/paritytech/wasm-utils" }
+vm = { path = "../vm" }
--- a/ethcore/evm/src/wasm/call_args.rs
+++ b/ethcore/evm/src/wasm/call_args.rs
--- a/ethcore/evm/src/wasm/env.rs
+++ b/ethcore/evm/src/wasm/env.rs
--- a/ethcore/evm/src/wasm/mod.rs
+++ b/ethcore/evm/src/wasm/mod.rs
@ -16,6 +16,13 @@

 //! Wasm Interpreter

+extern crate vm;
+extern crate ethcore_util as util;
+#[macro_use] extern crate log;
+extern crate byteorder;
+extern crate parity_wasm;
+extern crate wasm_utils;
+
 mod runtime;
 mod ptr;
 mod call_args;
@ -30,10 +37,8 @@ const DEFAULT_STACK_SPACE: u32 = 5 * 1024 * 1024;

 use parity_wasm::{interpreter, elements};
 use parity_wasm::interpreter::ModuleInstanceInterface;
-use wasm_utils;

-use evm::{self, GasLeft, ReturnData};
-use action_params::ActionParams;
+use vm::{GasLeft, ReturnData, ActionParams};
 use self::runtime::Runtime;

 pub use self::runtime::Error as RuntimeError;
@ -56,9 +61,9 @@ impl WasmInterpreter {
 	}
 }

-impl evm::Evm for WasmInterpreter {
+impl vm::Vm for WasmInterpreter {

-	fn exec(&mut self, params: ActionParams, ext: &mut ::ext::Ext) -> evm::Result<GasLeft> {
+	fn exec(&mut self, params: ActionParams, ext: &mut vm::Ext) -> vm::Result<GasLeft> {
 		use parity_wasm::elements::Deserialize;

 		let code = params.code.expect("exec is only called on contract with code; qed");
@ -74,7 +79,7 @@ impl evm::Evm for WasmInterpreter {
 			.expect("Linear memory to exist in wasm runtime");

 		if params.gas > ::std::u64::MAX.into() {
-			return Err(evm::Error::Wasm("Wasm interpreter cannot run contracts with gas >= 2^64".to_owned()));
+			return Err(vm::Error::Wasm("Wasm interpreter cannot run contracts with gas >= 2^64".to_owned()));
 		}

 		let mut runtime = Runtime::with_params(
@ -90,7 +95,7 @@ impl evm::Evm for WasmInterpreter {
 			elements::Module::deserialize(
 				&mut cursor
 			).map_err(|err| {
-				evm::Error::Wasm(format!("Error deserializing contract code ({:?})", err))
+				vm::Error::Wasm(format!("Error deserializing contract code ({:?})", err))
 			})?
 		);

@ -111,7 +116,7 @@ impl evm::Evm for WasmInterpreter {
 					interpreter::env_native_module(env_instance, native_bindings(&mut runtime))
 						.map_err(|err| {
 							// todo: prefer explicit panic here also?
-							evm::Error::Wasm(format!("Error instantiating native bindings: {:?}", err))
+							vm::Error::Wasm(format!("Error instantiating native bindings: {:?}", err))
 						})?
 				)
 			).add_argument(interpreter::RuntimeValue::I32(d_ptr.as_raw() as i32));
@ -119,13 +124,13 @@ impl evm::Evm for WasmInterpreter {
 			let module_instance = self.program.add_module("contract", contract_module, Some(&execution_params.externals))
 				.map_err(|err| {
 					trace!(target: "wasm", "Error adding contract module: {:?}", err);
-					evm::Error::from(RuntimeError::Interpreter(err))
+					vm::Error::from(RuntimeError::Interpreter(err))
 				})?;

 			module_instance.execute_export("_call", execution_params)
 				.map_err(|err| {
 					trace!(target: "wasm", "Error executing contract: {:?}", err);
-					evm::Error::from(RuntimeError::Interpreter(err))
+					vm::Error::from(RuntimeError::Interpreter(err))
 				})?;
 		}

@ -157,3 +162,9 @@ fn native_bindings<'a>(runtime: &'a mut Runtime) -> interpreter::UserFunctions<'
 		functions: ::std::borrow::Cow::from(env::SIGNATURES),
 	}
 }
+
+impl From<runtime::Error> for vm::Error {
+	fn from(err: runtime::Error) -> vm::Error {
+		vm::Error::Wasm(format!("WASM runtime-error: {:?}", err))
+	}
+}
--- a/ethcore/evm/src/wasm/ptr.rs
+++ b/ethcore/evm/src/wasm/ptr.rs
--- a/ethcore/evm/src/wasm/result.rs
+++ b/ethcore/evm/src/wasm/result.rs
--- a/ethcore/evm/src/wasm/runtime.rs
+++ b/ethcore/evm/src/wasm/runtime.rs
@ -20,8 +20,7 @@ use std::sync::Arc;

 use byteorder::{LittleEndian, ByteOrder};

-use ext;
-
+use vm;
 use parity_wasm::interpreter;
 use util::{Address, H256, U256};

@ -62,14 +61,14 @@ pub struct Runtime<'a> {
 	gas_counter: u64,
 	gas_limit: u64,
 	dynamic_top: u32,
-	ext: &'a mut ext::Ext,
+	ext: &'a mut vm::Ext,
 	memory: Arc<interpreter::MemoryInstance>,
 }

 impl<'a> Runtime<'a> {
 	/// New runtime for wasm contract with specified params
 	pub fn with_params<'b>(
-		ext: &'b mut ext::Ext,
+		ext: &'b mut vm::Ext,
 		memory: Arc<interpreter::MemoryInstance>,
 		stack_space: u32,
 		gas_limit: u64,
@ -153,14 +152,14 @@ impl<'a> Runtime<'a> {
 			.map_err(|_| interpreter::Error::Trap("Gas state error".to_owned()))?
 			.into();

-		match self.ext.create(&gas_left, &endowment, &code, ext::CreateContractAddress::FromSenderAndCodeHash) {
-			ext::ContractCreateResult::Created(address, gas_left) => {
+		match self.ext.create(&gas_left, &endowment, &code, vm::CreateContractAddress::FromSenderAndCodeHash) {
+			vm::ContractCreateResult::Created(address, gas_left) => {
 				self.memory.set(result_ptr, &*address)?;
 				self.gas_counter = self.gas_limit - gas_left.low_u64();
 				trace!(target: "wasm", "runtime: create contract success (@{:?})", address);
 				Ok(Some(0i32.into()))
 			},
-			ext::ContractCreateResult::Failed => {
+			vm::ContractCreateResult::Failed => {
 				trace!(target: "wasm", "runtime: create contract fail");
 				Ok(Some((-1i32).into()))
 			}
--- a/ethcore/evm/src/wasm/tests.rs
+++ b/ethcore/evm/src/wasm/tests.rs
@ -28,7 +28,7 @@ macro_rules! load_sample {
 	}
 }

-fn test_finalize(res: Result<GasLeft, evm::Error>) -> Result<U256, evm::Error> {
+fn test_finalize(res: Result<GasLeft, vm::Error>) -> Result<U256, vm::Error> {
 	match res {
 		Ok(GasLeft::Known(gas)) => Ok(gas),
 		Ok(GasLeft::NeedsReturn{..}) => unimplemented!(), // since ret is unimplemented.
--- a/evmbin/benches/mod.rs
+++ b/evmbin/benches/mod.rs
@ -31,7 +31,7 @@ extern crate rustc_hex;
 use self::test::{Bencher, black_box};

 use evm::run_vm;
-use ethcore::evm::action_params::ActionParams;
+use ethcore::vm::ActionParams;
 use ethcore_util::U256;
 use rustc_hex::FromHex;

--- a/evmbin/src/main.rs
+++ b/evmbin/src/main.rs
@ -34,7 +34,7 @@ use docopt::Docopt;
 use rustc_hex::FromHex;
 use util::{U256, Bytes, Address};
 use ethcore::spec;
-use evm::action_params::ActionParams;
+use vm::ActionParams;

 mod vm;
 mod display;
--- a/evmbin/src/vm.rs
+++ b/evmbin/src/vm.rs
@ -20,7 +20,7 @@ use std::time::{Instant, Duration};
 use util::U256;
 use ethcore::{trace, spec};
 use ethcore::client::{EvmTestClient, EvmTestError};
-use evm::action_params::ActionParams;
+use vm::ActionParams;

 /// VM execution informant
 pub trait Informant: trace::VMTracer {
--- a/rpc/Cargo.toml
+++ b/rpc/Cargo.toml
@ -46,7 +46,7 @@ ethjson = { path = "../json" }
 ethcore-devtools = { path = "../devtools" }
 ethcore-light = { path = "../ethcore/light" }
 ethcore-logger = { path = "../logger" }
-evm = { path = "../ethcore/evm" }
+vm = { path = "../ethcore/vm" }
 parity-updater = { path = "../updater" }
 parity-reactor = { path = "../util/reactor" }
 rlp = { path = "../util/rlp" }
--- a/rpc/src/lib.rs
+++ b/rpc/src/lib.rs
@ -52,7 +52,7 @@ extern crate ethkey;
 extern crate ethstore;
 extern crate ethsync;
 extern crate ethcore_logger;
-extern crate evm;
+extern crate vm;
 extern crate fetch;
 extern crate parity_reactor;
 extern crate parity_updater as updater;
--- a/rpc/src/v1/helpers/light_fetch.rs
+++ b/rpc/src/v1/helpers/light_fetch.rs
@ -327,7 +327,7 @@ struct ExecuteParams {
 	from: Address,
 	tx: EthTransaction,
 	hdr: encoded::Header,
-	env_info: ::evm::env_info::EnvInfo,
+	env_info: ::vm::EnvInfo,
 	engine: Arc<::ethcore::engines::Engine>,
 	on_demand: Arc<OnDemand>,
 	sync: Arc<LightSync>,
--- a/rpc/src/v1/tests/mocked/traces.rs
+++ b/rpc/src/v1/tests/mocked/traces.rs
@ -21,7 +21,7 @@ use ethcore::trace::trace::{Action, Res, Call};
 use ethcore::trace::LocalizedTrace;
 use ethcore::client::TestBlockChainClient;

-use evm::CallType;
+use vm::CallType;

 use jsonrpc_core::IoHandler;
 use v1::tests::helpers::{TestMinerService};
--- a/rpc/src/v1/types/trace.rs
+++ b/rpc/src/v1/types/trace.rs
@ -22,7 +22,7 @@ use ethcore::trace as et;
 use ethcore::state_diff;
 use ethcore::account_diff;
 use ethcore::client::Executed;
-use evm;
+use vm;
 use v1::types::{Bytes, H160, H256, U256};

 #[derive(Debug, Serialize)]
@ -256,14 +256,14 @@ pub enum CallType {
 	StaticCall,
 }

-impl From<evm::CallType> for CallType {
-	fn from(c: evm::CallType) -> Self {
+impl From<vm::CallType> for CallType {
+	fn from(c: vm::CallType) -> Self {
 		match c {
-			evm::CallType::None => CallType::None,
-			evm::CallType::Call => CallType::Call,
-			evm::CallType::CallCode => CallType::CallCode,
-			evm::CallType::DelegateCall => CallType::DelegateCall,
-			evm::CallType::StaticCall => CallType::StaticCall,
+			vm::CallType::None => CallType::None,
+			vm::CallType::Call => CallType::Call,
+			vm::CallType::CallCode => CallType::CallCode,
+			vm::CallType::DelegateCall => CallType::DelegateCall,
+			vm::CallType::StaticCall => CallType::StaticCall,
 		}
 	}
 }