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Initial implementation of couple of more instructions

This commit is contained in:
Tomusdrw 2016-01-15 03:12:39 +01:00
parent 5d0c294635
commit c4e5271651
1 changed files with 97 additions and 9 deletions
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106
src/evm/interpreter.rs
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@ -734,9 +734,33 @@ impl Interpreter {
U256::zero()
});
},
// TODO instructions::SDIV => {},
// TODO instructions::SMOD => {},
// TODO instructions::EXP => {},
instructions::SDIV => {
let (a, sign_a) = get_and_reset_sign(stack.pop_back());
let (b, sign_b) = get_and_reset_sign(stack.pop_back());
stack.push(if !self.is_zero(&b) {
let (c, _overflow) = a.overflowing_div(b);
set_sign(c, sign_a ^ sign_b)
} else {
U256::zero()
});
},
instructions::SMOD => {
let (a, sign_a) = get_and_reset_sign(stack.pop_back());
let (b, sign_b) = get_and_reset_sign(stack.pop_back());
stack.push(if !self.is_zero(&b) {
let (c, _overflow) = a.overflowing_rem(b);
set_sign(c, sign_a ^ sign_b)
} else {
U256::zero()
});
},
instructions::EXP => {
let base = stack.pop_back();
let expon = stack.pop_back();
stack.push(u256_pow(base, expon));
},
instructions::NOT => {
let a = stack.pop_back();
stack.push(!a);
@ -746,13 +770,31 @@ impl Interpreter {
let b = stack.pop_back();
stack.push(self.bool_to_u256(a < b));
},
// TODO instructions::SLT => {},
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) == false;
let is_negative_lt = a > b && (neg_a & neg_b) == true;
let has_different_signs = neg_a == true && neg_b == false;
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));
},
// TODO instructions::SGT => {},
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) == false;
let is_negative_gt = a < b && (neg_a & neg_b) == true;
let has_different_signs = neg_a == false && neg_b == true;
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();
@ -777,10 +819,42 @@ impl Interpreter {
let b = stack.pop_back();
stack.push(a ^ b);
},
// TODO instructions::BYTE => {},
// TODO instructions::ADDMOD => {},
// TODO instructions::MULMOD => {},
// TODO instructions::SIGNEXTEND => {},
instructions::BYTE => {
let word = stack.pop_back();
let byte = if word < U256::from(32) {
word >> (8 * (31 - word.low_u64() as usize))
} else {
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) {
let (res, _overflow) = a.overflowing_add(b);
let (x, _overflow) = res.overflowing_rem(c);
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 (res, _overflow) = a.overflowing_mul(b);
let (x, _overflow) = res.overflowing_rem(c);
x
} else {
U256::zero()
});
},
instructions::SIGNEXTEND => {},
_ => {
return Err(evm::Error::BadInstruction {
instruction: instruction
@ -810,6 +884,20 @@ impl Interpreter {
}
fn u256_pow(value: U256, expon: U256) -> U256 {
// TODO implement me!
U256::zero()
}
fn get_and_reset_sign(value: U256) -> (U256, bool) {
let sign = value.bit(255);
(set_sign(value, false), sign)
}
fn set_sign(value: U256, sign: bool) -> U256 {
value | (U256::from(sign as usize) << 256)
}
fn add_u256_usize(value: &U256, num: usize) -> U256 {
value.clone() + U256::from(num)
}