@ethereumjs/evm
Version:
JavaScript Ethereum Virtual Machine (EVM) implementation
165 lines • 6.12 kB
JavaScript
;
Object.defineProperty(exports, "__esModule", { value: true });
exports.expMod = expMod;
exports.precompile05 = precompile05;
const util_1 = require("@ethereumjs/util");
const evm_ts_1 = require("../evm.js");
const index_ts_1 = require("./index.js");
const util_ts_1 = require("./util.js");
const BIGINT_4 = BigInt(4);
const BIGINT_16 = BigInt(16);
const BIGINT_200 = BigInt(200);
const BIGINT_480 = BigInt(480);
const BIGINT_1024 = BigInt(1024);
const BIGINT_3072 = BigInt(3072);
const BIGINT_199680 = BigInt(199680);
const maxInt = BigInt(Number.MAX_SAFE_INTEGER);
const maxSize = BigInt(2147483647); // @ethereumjs/util setLengthRight limitation
function multiplicationComplexity(x) {
let fac1;
let fac2;
if (x <= util_1.BIGINT_64) {
return x ** util_1.BIGINT_2;
}
else if (x <= BIGINT_1024) {
// return Math.floor(Math.pow(x, 2) / 4) + 96 * x - 3072
fac1 = x ** util_1.BIGINT_2 / BIGINT_4;
fac2 = x * util_1.BIGINT_96;
return fac1 + fac2 - BIGINT_3072;
}
else {
// return Math.floor(Math.pow(x, 2) / 16) + 480 * x - 199680
fac1 = x ** util_1.BIGINT_2 / BIGINT_16;
fac2 = x * BIGINT_480;
return fac1 + fac2 - BIGINT_199680;
}
}
function multiplicationComplexityEIP2565(x) {
const words = (x + util_1.BIGINT_7) / util_1.BIGINT_8;
return words * words;
}
function getAdjustedExponentLength(data) {
let expBytesStart;
try {
const baseLen = (0, util_1.bytesToBigInt)(data.subarray(0, 32));
expBytesStart = 96 + Number(baseLen); // 96 for base length, then exponent length, and modulus length, then baseLen for the base data, then exponent bytes start
}
catch {
expBytesStart = Number.MAX_SAFE_INTEGER - 32;
}
const expLen = (0, util_1.bytesToBigInt)(data.subarray(32, 64));
let firstExpBytes = data.subarray(expBytesStart, expBytesStart + 32); // first word of the exponent data
firstExpBytes = (0, util_1.setLengthRight)(firstExpBytes, 32); // reading past the data reads virtual zeros
let firstExpBigInt = (0, util_1.bytesToBigInt)(firstExpBytes);
let max32expLen = 0;
if (expLen < util_1.BIGINT_32) {
max32expLen = 32 - Number(expLen);
}
firstExpBigInt = firstExpBigInt >> (util_1.BIGINT_8 * BigInt(Math.max(max32expLen, 0)));
let bitLen = -1;
while (firstExpBigInt > util_1.BIGINT_0) {
bitLen = bitLen + 1;
firstExpBigInt = firstExpBigInt >> util_1.BIGINT_1;
}
let expLenMinus32OrZero = expLen - util_1.BIGINT_32;
if (expLenMinus32OrZero < util_1.BIGINT_0) {
expLenMinus32OrZero = util_1.BIGINT_0;
}
const eightTimesExpLenMinus32OrZero = expLenMinus32OrZero * util_1.BIGINT_8;
let adjustedExpLen = eightTimesExpLenMinus32OrZero;
if (bitLen > 0) {
adjustedExpLen += BigInt(bitLen);
}
return adjustedExpLen;
}
function expMod(a, power, modulo) {
if (power === util_1.BIGINT_0) {
return util_1.BIGINT_1 % modulo;
}
let res = util_1.BIGINT_1;
while (power > util_1.BIGINT_0) {
if (power & util_1.BIGINT_1)
res = (res * a) % modulo;
a = (a * a) % modulo;
power >>= util_1.BIGINT_1;
}
return res;
}
function precompile05(opts) {
const pName = (0, index_ts_1.getPrecompileName)('05');
const data = opts.data.length < 96 ? (0, util_1.setLengthRight)(opts.data, 96) : opts.data;
let adjustedELen = getAdjustedExponentLength(data);
if (adjustedELen < util_1.BIGINT_1) {
adjustedELen = util_1.BIGINT_1;
}
const bLen = (0, util_1.bytesToBigInt)(data.subarray(0, 32));
const eLen = (0, util_1.bytesToBigInt)(data.subarray(32, 64));
const mLen = (0, util_1.bytesToBigInt)(data.subarray(64, 96));
let maxLen = bLen;
if (maxLen < mLen) {
maxLen = mLen;
}
const Gquaddivisor = opts.common.param('modexpGquaddivisorGas');
let gasUsed;
const bStart = util_1.BIGINT_96;
const bEnd = bStart + bLen;
const eStart = bEnd;
const eEnd = eStart + eLen;
const mStart = eEnd;
const mEnd = mStart + mLen;
if (!opts.common.isActivatedEIP(2565)) {
gasUsed = (adjustedELen * multiplicationComplexity(maxLen)) / Gquaddivisor;
}
else {
gasUsed = (adjustedELen * multiplicationComplexityEIP2565(maxLen)) / Gquaddivisor;
if (gasUsed < BIGINT_200) {
gasUsed = BIGINT_200;
}
}
if (!(0, util_ts_1.gasLimitCheck)(opts, gasUsed, pName)) {
return (0, evm_ts_1.OOGResult)(opts.gasLimit);
}
if (bLen === util_1.BIGINT_0 && mLen === util_1.BIGINT_0) {
return {
executionGasUsed: gasUsed,
returnValue: new Uint8Array(),
};
}
if (bLen > maxSize || eLen > maxSize || mLen > maxSize) {
if (opts._debug !== undefined) {
opts._debug(`${pName} failed: OOG`);
}
return (0, evm_ts_1.OOGResult)(opts.gasLimit);
}
if (mEnd > maxInt) {
if (opts._debug !== undefined) {
opts._debug(`${pName} failed: OOG`);
}
return (0, evm_ts_1.OOGResult)(opts.gasLimit);
}
const B = (0, util_1.bytesToBigInt)((0, util_1.setLengthRight)(data.subarray(Number(bStart), Number(bEnd)), Number(bLen)));
const E = (0, util_1.bytesToBigInt)((0, util_1.setLengthRight)(data.subarray(Number(eStart), Number(eEnd)), Number(eLen)));
const M = (0, util_1.bytesToBigInt)((0, util_1.setLengthRight)(data.subarray(Number(mStart), Number(mEnd)), Number(mLen)));
let R;
if (M === util_1.BIGINT_0) {
R = new Uint8Array();
}
else {
R = expMod(B, E, M);
if (R === util_1.BIGINT_0) {
R = new Uint8Array();
}
else {
R = (0, util_1.bigIntToBytes)(R);
}
}
const res = (0, util_1.setLengthLeft)(R, Number(mLen));
if (opts._debug !== undefined) {
opts._debug(`${pName} return value=${(0, util_1.bytesToHex)(res)}`);
}
return {
executionGasUsed: gasUsed,
returnValue: res,
};
}
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