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fixes gas computation of evm arithemtic instructions #9379

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Merged
0xRVE merged 1 commit into from
Jul 30, 2025
Merged

fixes gas computation of evm arithemtic instructions #9379

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32 changes: 21 additions & 11 deletions substrate/frame/revive/src/vm/evm/instructions/arithmetic.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -37,21 +37,21 @@ pub fn add<'ext, E: Ext>(context: Context<'_, 'ext, E>) {

/// Implements the MUL instruction - multiplies two values from stack.
pub fn mul<'ext, E: Ext>(context: Context<'_, 'ext, E>) {
gas_legacy!(context.interpreter, revm_gas::LOW);
gas!(context.interpreter, RuntimeCosts::EVMGas(5));
popn_top!([op1], op2, context.interpreter);
*op2 = op1.wrapping_mul(*op2);
}

/// Implements the SUB instruction - subtracts two values from stack.
pub fn sub<'ext, E: Ext>(context: Context<'_, 'ext, E>) {
gas_legacy!(context.interpreter, revm_gas::VERYLOW);
gas!(context.interpreter, RuntimeCosts::EVMGas(3));
popn_top!([op1], op2, context.interpreter);
*op2 = op1.wrapping_sub(*op2);
}

/// Implements the DIV instruction - divides two values from stack.
pub fn div<'ext, E: Ext>(context: Context<'_, 'ext, E>) {
gas_legacy!(context.interpreter, revm_gas::LOW);
gas!(context.interpreter, RuntimeCosts::EVMGas(5));
popn_top!([op1], op2, context.interpreter);
if !op2.is_zero() {
*op2 = op1.wrapping_div(*op2);
Expand All @@ -62,7 +62,7 @@ pub fn div<'ext, E: Ext>(context: Context<'_, 'ext, E>) {
///
/// Performs signed division of two values from stack.
pub fn sdiv<'ext, E: Ext>(context: Context<'_, 'ext, E>) {
gas_legacy!(context.interpreter, revm_gas::LOW);
gas!(context.interpreter, RuntimeCosts::EVMGas(5));
popn_top!([op1], op2, context.interpreter);
*op2 = i256_div(op1, *op2);
}
Expand All @@ -71,7 +71,7 @@ pub fn sdiv<'ext, E: Ext>(context: Context<'_, 'ext, E>) {
///
/// Pops two values from stack and pushes the remainder of their division.
pub fn rem<'ext, E: Ext>(context: Context<'_, 'ext, E>) {
gas_legacy!(context.interpreter, revm_gas::LOW);
gas!(context.interpreter, RuntimeCosts::EVMGas(5));
popn_top!([op1], op2, context.interpreter);
if !op2.is_zero() {
*op2 = op1.wrapping_rem(*op2);
Expand All @@ -82,7 +82,7 @@ pub fn rem<'ext, E: Ext>(context: Context<'_, 'ext, E>) {
///
/// Performs signed modulo of two values from stack.
pub fn smod<'ext, E: Ext>(context: Context<'_, 'ext, E>) {
gas_legacy!(context.interpreter, revm_gas::LOW);
gas!(context.interpreter, RuntimeCosts::EVMGas(5));
popn_top!([op1], op2, context.interpreter);
*op2 = i256_mod(op1, *op2)
}
Expand All @@ -91,7 +91,7 @@ pub fn smod<'ext, E: Ext>(context: Context<'_, 'ext, E>) {
///
/// Pops three values from stack and pushes (a + b) % n.
pub fn addmod<'ext, E: Ext>(context: Context<'_, 'ext, E>) {
gas_legacy!(context.interpreter, revm_gas::MID);
gas!(context.interpreter, RuntimeCosts::EVMGas(8));
popn_top!([op1, op2], op3, context.interpreter);
*op3 = op1.add_mod(op2, *op3)
}
Expand All @@ -100,16 +100,26 @@ pub fn addmod<'ext, E: Ext>(context: Context<'_, 'ext, E>) {
///
/// Pops three values from stack and pushes (a * b) % n.
pub fn mulmod<'ext, E: Ext>(context: Context<'_, 'ext, E>) {
gas_legacy!(context.interpreter, revm_gas::MID);
gas!(context.interpreter, RuntimeCosts::EVMGas(8));
popn_top!([op1, op2], op3, context.interpreter);
*op3 = op1.mul_mod(op2, *op3)
}

/// Implements the EXP instruction - exponentiates two values from stack.
pub fn exp<'ext, E: Ext>(context: Context<'_, 'ext, E>) {
let spec_id = context.interpreter.runtime_flag.spec_id();
popn_top!([op1], op2, context.interpreter);
gas_or_fail!(context.interpreter, revm_gas::exp_cost(spec_id, *op2));

// Calculate gas cost for EXP: 10 (base) + 50 * byte_length_of_exponent
// For zero exponent, byte length is 1. For non-zero, calculate based on significant bits.
let exp_byte_len = if op2.is_zero() {
1u64
} else {
let significant_bits = 256 - op2.leading_zeros() as u64;
(significant_bits + 7) / 8 // Round up to nearest byte
};
let gas_cost = 10u64.saturating_add(50u64.saturating_mul(exp_byte_len));
gas!(context.interpreter, RuntimeCosts::EVMGas(gas_cost));

*op2 = op1.pow(*op2);
}

Expand Down Expand Up @@ -143,7 +153,7 @@ pub fn exp<'ext, E: Ext>(context: Context<'_, 'ext, E>) {
/// Similarly, if `b == 0` then the yellow paper says the output should start with all zeros,
/// then end with bits from `b`; this is equal to `y & mask` where `&` is bitwise `AND`.
pub fn signextend<'ext, E: Ext>(context: Context<'_, 'ext, E>) {
gas_legacy!(context.interpreter, revm_gas::LOW);
gas!(context.interpreter, RuntimeCosts::EVMGas(5));
popn_top!([ext], x, context.interpreter);
// For 31 we also don't need to do anything.
if ext < U256::from(31) {
Expand Down
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