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openethereum/ethcore/src/evm/interpreter/mod.rs

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// Copyright 2015, 2016 Ethcore (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/>.
//! Rust VM implementation
#[macro_use]
mod informant;
mod gasometer;
mod stack;
mod memory;
mod shared_cache;
use self::gasometer::Gasometer;
use self::stack::{Stack, VecStack};
use self::memory::Memory;
pub use self::shared_cache::SharedCache;
use std::marker::PhantomData;
use common::*;
use types::executed::CallType;
use super::instructions::{self, Instruction, InstructionInfo};
use evm::{self, MessageCallResult, ContractCreateResult, GasLeft, CostType};
use bit_set::BitSet;
type CodePosition = usize;
type ProgramCounter = usize;
const ONE: U256 = U256([1, 0, 0, 0]);
const TWO: U256 = U256([2, 0, 0, 0]);
const TWO_POW_5: U256 = U256([0x20, 0, 0, 0]);
const TWO_POW_8: U256 = U256([0x100, 0, 0, 0]);
const TWO_POW_16: U256 = U256([0x10000, 0, 0, 0]);
const TWO_POW_24: U256 = U256([0x1000000, 0, 0, 0]);
const TWO_POW_64: U256 = U256([0, 0x1, 0, 0]); // 0x1 00000000 00000000
const TWO_POW_96: U256 = U256([0, 0x100000000, 0, 0]); //0x1 00000000 00000000 00000000
const TWO_POW_224: U256 = U256([0, 0, 0, 0x100000000]); //0x1 00000000 00000000 00000000 00000000 00000000 00000000 00000000
const TWO_POW_248: U256 = U256([0, 0, 0, 0x100000000000000]); //0x1 00000000 00000000 00000000 00000000 00000000 00000000 00000000 000000
/// Abstraction over raw vector of Bytes. Easier state management of PC.
struct CodeReader<'a> {
position: ProgramCounter,
code: &'a Bytes
}
#[cfg_attr(feature="dev", allow(len_without_is_empty))]
impl<'a> CodeReader<'a> {
/// Create new code reader - starting at position 0.
fn new(code: &'a Bytes) -> Self {
CodeReader {
position: 0,
code: code,
}
}
/// Get `no_of_bytes` from code and convert to U256. Move PC
fn read(&mut self, no_of_bytes: usize) -> U256 {
let pos = self.position;
self.position += no_of_bytes;
let max = cmp::min(pos + no_of_bytes, self.code.len());
U256::from(&self.code[pos..max])
}
fn len (&self) -> usize {
self.code.len()
}
}
enum InstructionResult<Gas> {
Ok,
UseAllGas,
GasLeft(Gas),
UnusedGas(Gas),
JumpToPosition(U256),
// gas left, init_orf, init_size
StopExecutionNeedsReturn(Gas, U256, U256),
StopExecution,
}
/// Intepreter EVM implementation
pub struct Interpreter<Cost: CostType> {
mem: Vec<u8>,
cache: Arc<SharedCache>,
_type: PhantomData<Cost>,
}
impl<Cost: CostType> evm::Evm for Interpreter<Cost> {
fn exec(&mut self, params: ActionParams, ext: &mut evm::Ext) -> evm::Result<GasLeft> {
self.mem.clear();
let mut informant = informant::EvmInformant::new(ext.depth());
let code = &params.code.as_ref().unwrap();
let valid_jump_destinations = self.cache.jump_destinations(&params.code_hash, code);
let mut gasometer = Gasometer::<Cost>::new(try!(Cost::from_u256(params.gas)));
let mut stack = VecStack::with_capacity(ext.schedule().stack_limit, U256::zero());
let mut reader = CodeReader::new(code);
let infos = &*instructions::INSTRUCTIONS;
while reader.position < code.len() {
let instruction = code[reader.position];
reader.position += 1;
let info = infos[instruction as usize];
try!(self.verify_instruction(ext, instruction, &info, &stack));
// Calculate gas cost
let (gas_cost, mem_gas, mem_size) = try!(gasometer.get_gas_cost_mem(ext, instruction, &info, &stack, self.mem.size()));
// TODO: make compile-time removable if too much of a performance hit.
let trace_executed = ext.trace_prepare_execute(reader.position - 1, instruction, &gas_cost.as_u256());
try!(gasometer.verify_gas(&gas_cost));
self.mem.expand(mem_size);
gasometer.current_mem_gas = mem_gas;
gasometer.current_gas = gasometer.current_gas - gas_cost;
evm_debug!({ informant.before_instruction(reader.position, instruction, &info, &gasometer.current_gas, &stack) });
let (mem_written, store_written) = match trace_executed {
true => (Self::mem_written(instruction, &stack), Self::store_written(instruction, &stack)),
false => (None, None),
};
// Execute instruction
let result = try!(self.exec_instruction(
gasometer.current_gas, &params, ext, instruction, &mut reader, &mut stack
));
evm_debug!({ informant.after_instruction(instruction) });
if trace_executed {
ext.trace_executed(gasometer.current_gas.as_u256(), stack.peek_top(info.ret), mem_written.map(|(o, s)| (o, &(self.mem[o..(o + s)]))), store_written);
}
// Advance
match result {
InstructionResult::Ok => {},
InstructionResult::UnusedGas(gas) => {
gasometer.current_gas = gasometer.current_gas + gas;
},
InstructionResult::UseAllGas => {
gasometer.current_gas = Cost::from(0);
},
InstructionResult::GasLeft(gas_left) => {
gasometer.current_gas = gas_left;
},
InstructionResult::JumpToPosition(position) => {
let pos = try!(self.verify_jump(position, &valid_jump_destinations));
reader.position = pos;
},
InstructionResult::StopExecutionNeedsReturn(gas, off, size) => {
informant.done();
return Ok(GasLeft::NeedsReturn(gas.as_u256(), self.mem.read_slice(off, size)));
},
InstructionResult::StopExecution => break,
}
}
informant.done();
Ok(GasLeft::Known(gasometer.current_gas.as_u256()))
}
}
impl<Cost: CostType> Interpreter<Cost> {
/// Create a new `Interpreter` instance with shared cache.
pub fn new(cache: Arc<SharedCache>) -> Interpreter<Cost> {
Interpreter {
mem: Vec::new(),
cache: cache,
_type: PhantomData::default(),
}
}
fn verify_instruction(&self, ext: &evm::Ext, instruction: Instruction, info: &InstructionInfo, stack: &Stack<U256>) -> evm::Result<()> {
let schedule = ext.schedule();
if !schedule.have_delegate_call && instruction == instructions::DELEGATECALL {
return Err(evm::Error::BadInstruction {
instruction: instruction
});
}
if info.tier == instructions::GasPriceTier::Invalid {
return Err(evm::Error::BadInstruction {
instruction: instruction
});
}
if !stack.has(info.args) {
Err(evm::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 {
instruction: info.name,
wanted: info.ret - info.args,
limit: schedule.stack_limit
})
} else {
Ok(())
}
}
fn mem_written(
instruction: Instruction,
stack: &Stack<U256>
) -> Option<(usize, usize)> {
match instruction {
instructions::MSTORE | instructions::MLOAD => Some((stack.peek(0).low_u64() as usize, 32)),
instructions::MSTORE8 => Some((stack.peek(0).low_u64() as usize, 1)),
instructions::CALLDATACOPY | instructions::CODECOPY => Some((stack.peek(0).low_u64() as usize, stack.peek(2).low_u64() as usize)),
instructions::EXTCODECOPY => Some((stack.peek(1).low_u64() as usize, stack.peek(3).low_u64() as usize)),
instructions::CALL | instructions::CALLCODE => Some((stack.peek(5).low_u64() as usize, stack.peek(6).low_u64() as usize)),
instructions::DELEGATECALL => Some((stack.peek(4).low_u64() as usize, stack.peek(5).low_u64() as usize)),
_ => None,
}
}
fn store_written(
instruction: Instruction,
stack: &Stack<U256>
) -> Option<(U256, U256)> {
match instruction {
instructions::SSTORE => Some((stack.peek(0).clone(), stack.peek(1).clone())),
_ => None,
}
}
#[cfg_attr(feature="dev", allow(too_many_arguments))]
fn exec_instruction(
&mut self,
gas: Cost,
params: &ActionParams,
ext: &mut evm::Ext,
instruction: Instruction,
code: &mut CodeReader,
stack: &mut Stack<U256>
) -> evm::Result<InstructionResult<Cost>> {
match instruction {
instructions::JUMP => {
let jump = stack.pop_back();
return Ok(InstructionResult::JumpToPosition(
jump
));
},
instructions::JUMPI => {
let jump = stack.pop_back();
let condition = stack.pop_back();
if !self.is_zero(&condition) {
return Ok(InstructionResult::JumpToPosition(
jump
));
}
},
instructions::JUMPDEST => {
// ignore
},
instructions::CREATE => {
let endowment = stack.pop_back();
let init_off = stack.pop_back();
let init_size = stack.pop_back();
let contract_code = self.mem.read_slice(init_off, init_size);
let can_create = ext.balance(&params.address) >= endowment && ext.depth() < ext.schedule().max_depth;
if !can_create {
stack.push(U256::zero());
return Ok(InstructionResult::Ok);
}
let create_result = ext.create(&gas.as_u256(), &endowment, contract_code);
return match create_result {
ContractCreateResult::Created(address, gas_left) => {
stack.push(address_to_u256(address));
Ok(InstructionResult::GasLeft(Cost::from_u256(gas_left).expect("Gas left cannot be greater.")))
},
ContractCreateResult::Failed => {
stack.push(U256::zero());
// TODO [todr] Should we just StopExecution here?
Ok(InstructionResult::UseAllGas)
}
};
},
instructions::CALL | instructions::CALLCODE | instructions::DELEGATECALL => {
assert!(ext.schedule().call_value_transfer_gas > ext.schedule().call_stipend, "overflow possible");
let call_gas = Cost::from_u256(stack.pop_back()).expect("Gas is already validated.");
let code_address = stack.pop_back();
let code_address = u256_to_address(&code_address);
let value = if instruction == instructions::DELEGATECALL {
None
} else {
Some(stack.pop_back())
};
let in_off = stack.pop_back();
let in_size = stack.pop_back();
let out_off = stack.pop_back();
let out_size = stack.pop_back();
// Add stipend (only CALL|CALLCODE when value > 0)
let call_gas = call_gas + value.map_or_else(|| Cost::from(0), |val| match val.is_zero() {
false => Cost::from(ext.schedule().call_stipend),
true => Cost::from(0)
});
// Get sender & receive addresses, check if we have balance
let (sender_address, receive_address, has_balance, call_type) = match instruction {
instructions::CALL => {
let has_balance = ext.balance(&params.address) >= value.unwrap();
(&params.address, &code_address, has_balance, CallType::Call)
},
instructions::CALLCODE => {
let has_balance = ext.balance(&params.address) >= value.unwrap();
(&params.address, &params.address, has_balance, CallType::CallCode)
},
instructions::DELEGATECALL => (&params.sender, &params.address, true, CallType::DelegateCall),
_ => panic!(format!("Unexpected instruction {} in CALL branch.", instruction))
};
let can_call = has_balance && ext.depth() < ext.schedule().max_depth;
if !can_call {
stack.push(U256::zero());
return Ok(InstructionResult::UnusedGas(call_gas));
}
let call_result = {
// we need to write and read from memory in the same time
// and we don't want to copy
let input = unsafe { ::std::mem::transmute(self.mem.read_slice(in_off, in_size)) };
let output = self.mem.writeable_slice(out_off, out_size);
ext.call(&call_gas.as_u256(), sender_address, receive_address, value, input, &code_address, output, call_type)
};
return match call_result {
MessageCallResult::Success(gas_left) => {
stack.push(U256::one());
Ok(InstructionResult::UnusedGas(Cost::from_u256(gas_left).expect("Gas left cannot be greater then current one")))
},
MessageCallResult::Failed => {
stack.push(U256::zero());
Ok(InstructionResult::Ok)
}
};
},
instructions::RETURN => {
let init_off = stack.pop_back();
let init_size = stack.pop_back();
return Ok(InstructionResult::StopExecutionNeedsReturn(gas, init_off, init_size))
},
instructions::STOP => {
return Ok(InstructionResult::StopExecution);
},
instructions::SUICIDE => {
let address = stack.pop_back();
ext.suicide(&u256_to_address(&address));
return Ok(InstructionResult::StopExecution);
},
instructions::LOG0...instructions::LOG4 => {
let no_of_topics = instructions::get_log_topics(instruction);
let offset = stack.pop_back();
let size = stack.pop_back();
let topics = stack.pop_n(no_of_topics)
.iter()
.map(H256::from)
.collect();
ext.log(topics, self.mem.read_slice(offset, size));
},
instructions::PUSH1...instructions::PUSH32 => {
let bytes = instructions::get_push_bytes(instruction);
let val = code.read(bytes);
stack.push(val);
},
instructions::MLOAD => {
let word = self.mem.read(stack.pop_back());
stack.push(U256::from(word));
},
instructions::MSTORE => {
let offset = stack.pop_back();
let word = stack.pop_back();
Memory::write(&mut self.mem, offset, word);
},
instructions::MSTORE8 => {
let offset = stack.pop_back();
let byte = stack.pop_back();
self.mem.write_byte(offset, byte);
},
instructions::MSIZE => {
stack.push(U256::from(self.mem.size()));
},
instructions::SHA3 => {
let offset = stack.pop_back();
let size = stack.pop_back();
let sha3 = self.mem.read_slice(offset, size).sha3();
stack.push(U256::from(&*sha3));
},
instructions::SLOAD => {
let key = H256::from(&stack.pop_back());
let word = U256::from(&*ext.storage_at(&key));
stack.push(word);
},
instructions::SSTORE => {
let address = H256::from(&stack.pop_back());
let val = stack.pop_back();
let current_val = U256::from(&*ext.storage_at(&address));
// Increase refund for clear
if !self.is_zero(&current_val) && self.is_zero(&val) {
ext.inc_sstore_clears();
}
ext.set_storage(address, H256::from(&val));
},
instructions::PC => {
stack.push(U256::from(code.position - 1));
},
instructions::GAS => {
stack.push(gas.as_u256());
},
instructions::ADDRESS => {
stack.push(address_to_u256(params.address.clone()));
},
instructions::ORIGIN => {
stack.push(address_to_u256(params.origin.clone()));
},
instructions::BALANCE => {
let address = u256_to_address(&stack.pop_back());
let balance = ext.balance(&address);
stack.push(balance);
},
instructions::CALLER => {
stack.push(address_to_u256(params.sender.clone()));
},
instructions::CALLVALUE => {
stack.push(match params.value {
ActionValue::Transfer(val) | ActionValue::Apparent(val) => val
});
},
instructions::CALLDATALOAD => {
let big_id = stack.pop_back();
let id = big_id.low_u64() as usize;
let max = id.wrapping_add(32);
if let Some(data) = params.data.as_ref() {
let bound = cmp::min(data.len(), max);
if id < bound && big_id < U256::from(data.len()) {
let mut v = [0u8; 32];
v[0..bound-id].clone_from_slice(&data[id..bound]);
stack.push(U256::from(&v[..]))
} else {
stack.push(U256::zero())
}
} else {
stack.push(U256::zero())
}
},
instructions::CALLDATASIZE => {
stack.push(U256::from(params.data.clone().map_or(0, |l| l.len())));
},
instructions::CODESIZE => {
stack.push(U256::from(code.len()));
},
instructions::EXTCODESIZE => {
let address = u256_to_address(&stack.pop_back());
let len = ext.extcodesize(&address);
stack.push(U256::from(len));
},
instructions::CALLDATACOPY => {
self.copy_data_to_memory(stack, params.data.as_ref().map_or_else(|| &[] as &[u8], |d| &*d as &[u8]));
},
instructions::CODECOPY => {
self.copy_data_to_memory(stack, params.code.as_ref().map_or_else(|| &[] as &[u8], |c| &**c as &[u8]));
},
instructions::EXTCODECOPY => {
let address = u256_to_address(&stack.pop_back());
let code = ext.extcode(&address);
self.copy_data_to_memory(stack, &code);
},
instructions::GASPRICE => {
stack.push(params.gas_price.clone());
},
instructions::BLOCKHASH => {
let block_number = stack.pop_back();
let block_hash = ext.blockhash(&block_number);
stack.push(U256::from(&*block_hash));
},
instructions::COINBASE => {
stack.push(address_to_u256(ext.env_info().author.clone()));
},
instructions::TIMESTAMP => {
stack.push(U256::from(ext.env_info().timestamp));
},
instructions::NUMBER => {
stack.push(U256::from(ext.env_info().number));
},
instructions::DIFFICULTY => {
stack.push(ext.env_info().difficulty.clone());
},
instructions::GASLIMIT => {
stack.push(ext.env_info().gas_limit.clone());
},
_ => {
try!(self.exec_stack_instruction(instruction, stack));
}
};
Ok(InstructionResult::Ok)
}
fn copy_data_to_memory(&mut self, stack: &mut Stack<U256>, source: &[u8]) {
let dest_offset = stack.pop_back();
let source_offset = stack.pop_back();
let size = stack.pop_back();
let source_size = U256::from(source.len());
let output_end = match source_offset > source_size || size > source_size || source_offset + size > source_size {
true => {
let zero_slice = if source_offset > source_size {
self.mem.writeable_slice(dest_offset, size)
} else {
self.mem.writeable_slice(dest_offset + source_size - source_offset, source_offset + size - source_size)
};
for i in zero_slice.iter_mut() {
*i = 0;
}
source.len()
},
false => (size.low_u64() + source_offset.low_u64()) as usize
};
if source_offset < source_size {
let output_begin = source_offset.low_u64() as usize;
self.mem.write_slice(dest_offset, &source[output_begin..output_end]);
}
}
fn verify_jump(&self, jump_u: U256, valid_jump_destinations: &BitSet) -> evm::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 {
destination: jump
})
}
}
fn is_zero(&self, val: &U256) -> bool {
val.is_zero()
}
fn bool_to_u256(&self, val: bool) -> U256 {
if val {
U256::one()
} else {
U256::zero()
}
}
fn exec_stack_instruction(&self, instruction: Instruction, stack: &mut Stack<U256>) -> evm::Result<()> {
match instruction {
instructions::DUP1...instructions::DUP16 => {
let position = instructions::get_dup_position(instruction);
let val = stack.peek(position).clone();
stack.push(val);
},
instructions::SWAP1...instructions::SWAP16 => {
let position = instructions::get_swap_position(instruction);
stack.swap_with_top(position)
},
instructions::POP => {
stack.pop_back();
},
instructions::ADD => {
let a = stack.pop_back();
let b = stack.pop_back();
stack.push(a.overflowing_add(b).0);
},
instructions::MUL => {
let a = stack.pop_back();
let b = stack.pop_back();
stack.push(a.overflowing_mul(b).0);
},
instructions::SUB => {
let a = stack.pop_back();
let b = stack.pop_back();
stack.push(a.overflowing_sub(b).0);
},
instructions::DIV => {
let a = stack.pop_back();
let b = stack.pop_back();
stack.push(if !self.is_zero(&b) {
match b {
ONE => a,
TWO => a >> 1,
TWO_POW_5 => a >> 5,
TWO_POW_8 => a >> 8,
TWO_POW_16 => a >> 16,
TWO_POW_24 => a >> 24,
TWO_POW_64 => a >> 64,
TWO_POW_96 => a >> 96,
TWO_POW_224 => a >> 224,
TWO_POW_248 => a >> 248,
_ => a.overflowing_div(b).0,
}
} else {
U256::zero()
});
},
instructions::MOD => {
let a = stack.pop_back();
let b = stack.pop_back();
stack.push(if !self.is_zero(&b) {
a.overflowing_rem(b).0
} else {
U256::zero()
});
},
instructions::SDIV => {
let (a, sign_a) = get_and_reset_sign(stack.pop_back());
let (b, sign_b) = get_and_reset_sign(stack.pop_back());
// -2^255
let min = (U256::one() << 255) - U256::one();
stack.push(if self.is_zero(&b) {
U256::zero()
} else if a == min && b == !U256::zero() {
min
} else {
let c = a.overflowing_div(b).0;
set_sign(c, sign_a ^ sign_b)
});
},
instructions::SMOD => {
let ua = stack.pop_back();
let ub = stack.pop_back();
let (a, sign_a) = get_and_reset_sign(ua);
let b = get_and_reset_sign(ub).0;
stack.push(if !self.is_zero(&b) {
let c = a.overflowing_rem(b).0;
set_sign(c, sign_a)
} else {
U256::zero()
});
},
instructions::EXP => {
let base = stack.pop_back();
let expon = stack.pop_back();
let res = base.overflowing_pow(expon).0;
stack.push(res);
},
instructions::NOT => {
let a = stack.pop_back();
stack.push(!a);
},
instructions::LT => {
let a = stack.pop_back();
let b = stack.pop_back();
stack.push(self.bool_to_u256(a < b));
},
instructions::SLT => {
let (a, neg_a) = get_and_reset_sign(stack.pop_back());
let (b, neg_b) = get_and_reset_sign(stack.pop_back());
let is_positive_lt = a < b && !(neg_a | neg_b);
let is_negative_lt = a > b && (neg_a & neg_b);
let has_different_signs = neg_a && !neg_b;
stack.push(self.bool_to_u256(is_positive_lt | is_negative_lt | has_different_signs));
},
instructions::GT => {
let a = stack.pop_back();
let b = stack.pop_back();
stack.push(self.bool_to_u256(a > b));
},
instructions::SGT => {
let (a, neg_a) = get_and_reset_sign(stack.pop_back());
let (b, neg_b) = get_and_reset_sign(stack.pop_back());
let is_positive_gt = a > b && !(neg_a | neg_b);
let is_negative_gt = a < b && (neg_a & neg_b);
let has_different_signs = !neg_a && neg_b;
stack.push(self.bool_to_u256(is_positive_gt | is_negative_gt | has_different_signs));
},
instructions::EQ => {
let a = stack.pop_back();
let b = stack.pop_back();
stack.push(self.bool_to_u256(a == b));
},
instructions::ISZERO => {
let a = stack.pop_back();
stack.push(self.bool_to_u256(self.is_zero(&a)));
},
instructions::AND => {
let a = stack.pop_back();
let b = stack.pop_back();
stack.push(a & b);
},
instructions::OR => {
let a = stack.pop_back();
let b = stack.pop_back();
stack.push(a | b);
},
instructions::XOR => {
let a = stack.pop_back();
let b = stack.pop_back();
stack.push(a ^ b);
},
instructions::BYTE => {
let word = stack.pop_back();
let val = stack.pop_back();
let byte = match word < U256::from(32) {
true => (val >> (8 * (31 - word.low_u64() as usize))) & U256::from(0xff),
false => U256::zero()
};
stack.push(byte);
},
instructions::ADDMOD => {
let a = stack.pop_back();
let b = stack.pop_back();
let c = stack.pop_back();
stack.push(if !self.is_zero(&c) {
// upcast to 512
let a5 = U512::from(a);
let res = a5.overflowing_add(U512::from(b)).0;
let x = res.overflowing_rem(U512::from(c)).0;
U256::from(x)
} else {
U256::zero()
});
},
instructions::MULMOD => {
let a = stack.pop_back();
let b = stack.pop_back();
let c = stack.pop_back();
stack.push(if !self.is_zero(&c) {
let a5 = U512::from(a);
let res = a5.overflowing_mul(U512::from(b)).0;
let x = res.overflowing_rem(U512::from(c)).0;
U256::from(x)
} else {
U256::zero()
});
},
instructions::SIGNEXTEND => {
let bit = stack.pop_back();
if bit < U256::from(32) {
let number = stack.pop_back();
let bit_position = (bit.low_u64() * 8 + 7) as usize;
let bit = number.bit(bit_position);
let mask = (U256::one() << bit_position) - U256::one();
stack.push(if bit {
number | !mask
} else {
number & mask
});
}
},
_ => {
return Err(evm::Error::BadInstruction {
instruction: instruction
});
}
}
Ok(())
}
}
fn get_and_reset_sign(value: U256) -> (U256, bool) {
let U256(arr) = value;
let sign = arr[3].leading_zeros() == 0;
(set_sign(value, sign), sign)
}
fn set_sign(value: U256, sign: bool) -> U256 {
if sign {
(!U256::zero() ^ value).overflowing_add(U256::one()).0
} else {
value
}
}
#[inline]
fn u256_to_address(value: &U256) -> Address {
Address::from(H256::from(value))
}
#[inline]
fn address_to_u256(value: Address) -> U256 {
U256::from(&*H256::from(value))
}
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