eip-7883 implementation

src/Nethermind/Nethermind.Core/Specs/IReleaseSpec.cs

@@ -334,6 +334,11 @@ public interface IReleaseSpec : IEip1559Spec, IReceiptSpec
         /// </summary>
         bool IsEip7623Enabled { get; }
 
+        /// <summary>
+        ///  Increase ModExp Gas Cost
+        /// </summary>
+        bool IsEip7883Enabled { get; }
+
         /// <summary>
         /// Should transactions be validated against chainId.
         /// </summary>

src/Nethermind/Nethermind.Core/Specs/ReleaseSpecDecorator.cs

@@ -86,6 +86,7 @@ public class ReleaseSpecDecorator(IReleaseSpec spec) : IReleaseSpec
     public virtual bool IsOpGraniteEnabled => spec.IsOpGraniteEnabled;
     public virtual bool IsOpHoloceneEnabled => spec.IsOpHoloceneEnabled;
     public virtual bool IsEip7623Enabled => spec.IsEip7623Enabled;
+    public bool IsEip7883Enabled => spec.IsEip7883Enabled;
     public virtual ulong WithdrawalTimestamp => spec.WithdrawalTimestamp;
     public virtual ulong Eip4844TransitionTimestamp => spec.Eip4844TransitionTimestamp;
     public virtual bool IsEip158IgnoredAccount(Address address) => spec.IsEip158IgnoredAccount(address);

src/Nethermind/Nethermind.Evm.Test/Eip7883Tests.cs

@@ -0,0 +1,96 @@
+// SPDX-FileCopyrightText: 2025 Demerzel Solutions Limited
+// SPDX-License-Identifier: LGPL-3.0-only
+
+using System;
+using System.Collections.Generic;
+using FluentAssertions;
+using Nethermind.Core.Specs;
+using Nethermind.Evm.Precompiles;
+using Nethermind.Int256;
+using Nethermind.Specs;
+using NUnit.Framework;
+
+namespace Nethermind.Evm.Test;
+
+public class Eip7883Tests
+{
+    [Test]
+    public void DataGasCost([ValueSource(nameof(Eip7883TestCases))] Eip7883TestCase test)
+    {
+        var inputData = PrepareInput(test.BaseLength, test.ExpLength, test.ModulusLength);
+
+        long gas = ModExpPrecompile.Instance.DataGasCost(inputData, test.Spec);
+        gas.Should().Be(test.Result);
+    }
+
+    public class Eip7883TestCase
+    {
+        public IReleaseSpec Spec { get; set; }
+        public UInt256 BaseLength { get; set; }
+        public UInt256 ExpLength { get; set; }
+        public UInt256 ModulusLength { get; set; }
+        public long Result { get; set; }
+    }
+
+    private static readonly IReleaseSpec SpecEipEnabled = new ReleaseSpec
+    {
+        IsEip7883Enabled = true,
+        IsEip2565Enabled = true,
+    };
+
+    private static readonly IReleaseSpec SpecEipDisabled = new ReleaseSpec
+    {
+        IsEip7883Enabled = false,
+        IsEip2565Enabled = true,
+    };
+
+    private static IEnumerable<Eip7883TestCase> Eip7883TestCases()
+    {
+        // eip enabled test cases
+        yield return new Eip7883TestCase
+        { Spec = SpecEipEnabled, BaseLength = 32, ExpLength = 32, ModulusLength = 32, Result = 500L };
+        yield return new Eip7883TestCase
+        { Spec = SpecEipEnabled, BaseLength = 32, ExpLength = 32, ModulusLength = 10000, Result = 1041666L };
+        yield return new Eip7883TestCase
+        { Spec = SpecEipEnabled, BaseLength = 32, ExpLength = 10000, ModulusLength = 32, Result = 850602L };
+        yield return new Eip7883TestCase
+        { Spec = SpecEipEnabled, BaseLength = 10000, ExpLength = 32, ModulusLength = 32, Result = 1041666L };
+        yield return new Eip7883TestCase
+        { Spec = SpecEipEnabled, BaseLength = 32, ExpLength = 10000, ModulusLength = 10000, Result = 166133333333L };
+        yield return new Eip7883TestCase
+        { Spec = SpecEipEnabled, BaseLength = 10000, ExpLength = 10000, ModulusLength = 32, Result = 166133333333L };
+        yield return new Eip7883TestCase
+        { Spec = SpecEipEnabled, BaseLength = 10000, ExpLength = 32, ModulusLength = 10000, Result = 1041666L };
+        yield return new Eip7883TestCase
+        { Spec = SpecEipEnabled, BaseLength = 10000, ExpLength = 10000, ModulusLength = 10000, Result = 166133333333L };
+
+        // eip disabled test cases
+        yield return new Eip7883TestCase
+        { Spec = SpecEipDisabled, BaseLength = 32, ExpLength = 32, ModulusLength = 32, Result = 200L };
+        yield return new Eip7883TestCase
+        { Spec = SpecEipDisabled, BaseLength = 32, ExpLength = 32, ModulusLength = 10000, Result = 520833L };
+        yield return new Eip7883TestCase
+        { Spec = SpecEipDisabled, BaseLength = 32, ExpLength = 10000, ModulusLength = 32, Result = 425301L };
+        yield return new Eip7883TestCase
+        { Spec = SpecEipDisabled, BaseLength = 10000, ExpLength = 32, ModulusLength = 32, Result = 520833L };
+        yield return new Eip7883TestCase
+        { Spec = SpecEipDisabled, BaseLength = 32, ExpLength = 10000, ModulusLength = 10000, Result = 41533333333L };
+        yield return new Eip7883TestCase
+        { Spec = SpecEipDisabled, BaseLength = 10000, ExpLength = 10000, ModulusLength = 32, Result = 41533333333L };
+        yield return new Eip7883TestCase
+        { Spec = SpecEipDisabled, BaseLength = 10000, ExpLength = 32, ModulusLength = 10000, Result = 520833L };
+        yield return new Eip7883TestCase
+        { Spec = SpecEipDisabled, BaseLength = 10000, ExpLength = 10000, ModulusLength = 10000, Result = 41533333333L };
+    }
+
+    private static ReadOnlyMemory<byte> PrepareInput(UInt256 baseLength, UInt256 expLength, UInt256 modulusLength)
+    {
+        var inputBytes = new byte[96];
+
+        Array.Copy(baseLength.ToBigEndian(), 0, inputBytes, 0, 32);
+        Array.Copy(expLength.ToBigEndian(), 0, inputBytes, 32, 32);
+        Array.Copy(modulusLength.ToBigEndian(), 0, inputBytes, 64, 32);
+
+        return new ReadOnlyMemory<byte>(inputBytes);
+    }
+}

src/Nethermind/Nethermind.Evm/Precompiles/ModExpPrecompile.cs

@@ -59,15 +59,15 @@ public long DataGasCost(ReadOnlyMemory<byte> inputData, IReleaseSpec releaseSpec
                 UInt256 expLength = new(extendedInput.Slice(32, 32), true);
                 UInt256 modulusLength = new(extendedInput.Slice(64, 32), true);
 
-                UInt256 complexity = MultComplexity(baseLength, modulusLength);
+                UInt256 complexity = MultComplexity(baseLength, modulusLength, releaseSpec.IsEip7883Enabled);
 
                 UInt256 expLengthUpTo32 = UInt256.Min(32, expLength);
                 UInt256 startIndex = 96 + baseLength; //+ expLength - expLengthUpTo32; // Geth takes head here, why?
                 UInt256 exp = new(inputData.Span.SliceWithZeroPaddingEmptyOnError((int)startIndex, (int)expLengthUpTo32), true);
-                UInt256 iterationCount = CalculateIterationCount(expLength, exp);
+                UInt256 iterationCount = CalculateIterationCount(expLength, exp, releaseSpec.IsEip7883Enabled);
                 bool overflow = UInt256.MultiplyOverflow(complexity, iterationCount, out UInt256 result);
                 result /= 3;
-                return result > long.MaxValue || overflow ? long.MaxValue : Math.Max(200L, (long)result);
+                return result > long.MaxValue || overflow ? long.MaxValue : Math.Max(releaseSpec.IsEip7883Enabled ? 500L : 200L, (long)result);
             }
             catch (OverflowException)
             {
@@ -173,12 +173,12 @@ public static (byte[], bool) OldRun(byte[] inputData)
         /// return words**2
         /// </summary>
         /// <returns></returns>
-        private static UInt256 MultComplexity(in UInt256 baseLength, in UInt256 modulusLength)
+        private static UInt256 MultComplexity(in UInt256 baseLength, in UInt256 modulusLength, bool isEip7883Enabled)
         {
             UInt256 maxLength = UInt256.Max(baseLength, modulusLength);
             UInt256.Mod(maxLength, 8, out UInt256 mod8);
             UInt256 words = (maxLength / 8) + ((mod8.IsZero) ? UInt256.Zero : UInt256.One);
-            return words * words;
+            return maxLength > 32 && isEip7883Enabled ? 2 * words * words : words * words;
         }
 
         /// <summary>
@@ -191,8 +191,9 @@ private static UInt256 MultComplexity(in UInt256 baseLength, in UInt256 modulusL
         /// </summary>
         /// <param name="exponentLength"></param>
         /// <param name="exponent"></param>
+        /// <param name="isEip7883Enabled"></param>
         /// <returns></returns>
-        private static UInt256 CalculateIterationCount(UInt256 exponentLength, UInt256 exponent)
+        private static UInt256 CalculateIterationCount(UInt256 exponentLength, UInt256 exponent, bool isEip7883Enabled)
         {
             try
             {
@@ -209,7 +210,8 @@ private static UInt256 CalculateIterationCount(UInt256 exponentLength, UInt256 e
                         bitLength--;
                     }
 
-                    bool overflow = UInt256.MultiplyOverflow((exponentLength - 32), 8, out UInt256 multiplicationResult);
+                    var multiplier = (UInt256)(isEip7883Enabled ? 16 : 8);
+                    bool overflow = UInt256.MultiplyOverflow(exponentLength - 32, multiplier, out UInt256 multiplicationResult);
                     overflow |= UInt256.AddOverflow(multiplicationResult, (UInt256)bitLength, out iterationCount);
                     if (overflow)
                     {

src/Nethermind/Nethermind.Specs.Test/OverridableReleaseSpec.cs

@@ -123,6 +123,8 @@ public UInt256 BlockReward
 
         public bool IsEip7623Enabled => _spec.IsEip7623Enabled;
 
+        public bool IsEip7883Enabled => _spec.IsEip7883Enabled;
+
         public bool IsEip3607Enabled { get; set; }
 
         public bool IsEip158IgnoredAccount(Address address) => _spec.IsEip158IgnoredAccount(address);

src/Nethermind/Nethermind.Specs/ChainSpecStyle/ChainParameters.cs

@@ -133,6 +133,7 @@ public class ChainParameters
     public ulong? OpGraniteTransitionTimestamp { get; set; }
     public ulong? OpHoloceneTransitionTimestamp { get; set; }
     public ulong? Eip7623TransitionTimestamp { get; set; }
+    public ulong? Eip7883TransitionTimestamp { get; set; }
 
     public Dictionary<string, ChainSpecBlobCountJson> BlobSchedule { get; set; } = [];
 

src/Nethermind/Nethermind.Specs/ChainSpecStyle/ChainSpecBasedSpecProvider.cs

@@ -233,6 +233,7 @@ protected virtual ReleaseSpec CreateReleaseSpec(ChainSpec chainSpec, long releas
             releaseSpec.IsEip7251Enabled = (chainSpec.Parameters.Eip7251TransitionTimestamp ?? ulong.MaxValue) <= releaseStartTimestamp;
             releaseSpec.Eip7251ContractAddress = chainSpec.Parameters.Eip7251ContractAddress;
             releaseSpec.IsEip7623Enabled = (chainSpec.Parameters.Eip7623TransitionTimestamp ?? ulong.MaxValue) <= releaseStartTimestamp;
+            releaseSpec.IsEip7883Enabled = (chainSpec.Parameters.Eip7883TransitionTimestamp ?? ulong.MaxValue) <= releaseStartTimestamp;
 
             bool eip1559FeeCollector = releaseSpec.IsEip1559Enabled && (chainSpec.Parameters.Eip1559FeeCollectorTransition ?? long.MaxValue) <= releaseStartBlock;
             bool eip4844FeeCollector = releaseSpec.IsEip4844Enabled && (chainSpec.Parameters.Eip4844FeeCollectorTransitionTimestamp ?? long.MaxValue) <= releaseStartTimestamp;

src/Nethermind/Nethermind.Specs/ChainSpecStyle/ChainSpecLoader.cs

@@ -165,6 +165,7 @@ bool GetForInnerPathExistence(KeyValuePair<string, JsonElement> o) =>
                 () => chainSpecJson.Params.ChainId == BlockchainIds.Mainnet ? Eip6110Constants.MainnetDepositContractAddress : null),
             Eip7002TransitionTimestamp = chainSpecJson.Params.Eip7002TransitionTimestamp,
             Eip7623TransitionTimestamp = chainSpecJson.Params.Eip7623TransitionTimestamp,
+            Eip7883TransitionTimestamp = chainSpecJson.Params.Eip7883TransitionTimestamp,
             Eip7002ContractAddress = chainSpecJson.Params.Eip7002ContractAddress ?? Eip7002Constants.WithdrawalRequestPredeployAddress,
             Eip7251TransitionTimestamp = chainSpecJson.Params.Eip7251TransitionTimestamp,
             Eip7251ContractAddress = chainSpecJson.Params.Eip7251ContractAddress ?? Eip7251Constants.ConsolidationRequestPredeployAddress,

src/Nethermind/Nethermind.Specs/ChainSpecStyle/Json/ChainSpecParamsJson.cs

@@ -157,6 +157,7 @@ internal class ChainSpecParamsJson
     public Address Eip7251ContractAddress { get; set; }
     public ulong? Rip7212TransitionTimestamp { get; set; }
     public ulong? Eip7702TransitionTimestamp { get; set; }
+    public ulong? Eip7883TransitionTimestamp { get; set; }
     public ulong? OpGraniteTransitionTimestamp { get; set; }
     public ulong? OpHoloceneTransitionTimestamp { get; set; }
     public Dictionary<string, ChainSpecBlobCountJson> BlobSchedule { get; set; } = [];

src/Nethermind/Nethermind.Specs/ReleaseSpec.cs

@@ -86,6 +86,7 @@ public bool IsEip1559Enabled
         public bool IsOpGraniteEnabled { get; set; }
         public bool IsOpHoloceneEnabled { get; set; }
         public bool IsEip7623Enabled { get; set; }
+        public bool IsEip7883Enabled { get; set; }
         public bool IsEip5656Enabled { get; set; }
         public bool IsEip6780Enabled { get; set; }
         public bool IsEip4788Enabled { get; set; }