EVM Compatibility

eSpace 实现了一个以太坊虚拟机 (EVM)。 以下是 eSpace 和以太坊之间的一些区别：

Transaction Type

Currently eSpace only support 155 type transaction. 1559 type transaction is not support.

EVM Opcodes

• The BLOCKHASH opcode can only take NUMBER-1 as input. (Unlike Ethereum, which takes any integer in NUMBER-256 to NUMBER-1 as input). This is the only break opcode.

Block Time

NUMBER opcode将返回树图epoch number。 因此，在 eSpace 合约中使用的 block.number 不会以稳定和可预测的速率增长，因此它可能不适合用于测量时间。

Block generate rate is 1.25s per block (mainnet), is same as Core Space Epoch time.

Contract Size

Contract max code size is 49152 double as Ethereum

Transaction Fees

• SSTORE 操作码和 SUICIDE opcode中不会退还gas。
• 占用存储的操作有不同的gas消耗。
  1. 当将存储条目从零更改为非零时，SSTORE 花费 40000 gas（而以太坊中为 20000 gas）。
  2. 部署新合约时，每个字节花费 400 gas（而以太坊中为 200 gas）。
  3. 通过 CALL 或 SUICIDE 创建新账户时，该操作消耗 50000 gas（而以太坊中为 25000 gas）。
• 最多 1/4 的交易 gasLimit 可以被退还（如果未使用）

Transaction Gas limit

Only the block whose block height is a multiple of 5 can pack Ethereum type transaction. The total gas limit of these transaction cannot exceed half of the block gas limit (1500w).

EVM Precompiles

All standard precompiles are supported.

Address	ID	Name	Spec	Status
0x01	ECRecover	ECDSA public key recovery	Yellow Paper	✅
0x02	SHA256	SHA-2 256-bit hash function	Yellow Paper	✅
0x03	RIPEMD160	RIPEMD 160-bit hash function	Yellow Paper	✅
0x04	Identity	Identity function	Yellow Paper	✅
0x05	ModExp	Big integer modular exponentiation	EIP-198	✅
0x06	BN128Add	Elliptic curve addition	EIP-196	✅
0x07	BN128Mul	Elliptic curve scalar multiplication	EIP-196	✅
0x08	BN128Pair	Elliptic curve pairing check	EIP-197	✅
0x09	Blake2F	BLAKE2b F compression function	EIP-152	✅

Phantom transactions

A cross-space transaction is a transaction in the Conflux core space that, at some point during its execution, calls one of the state-changing (i.e., not view) methods of the CrossSpaceCall internal contract. Such transactions can change CFX balances and contract storage in both spaces, core and eSpace.

As EVM clients are not aware of Conflux space transactions (the two spaces use different transaction formats), we construct one or more phantom transactions (aka virtual transactions) for each call to the CrossSpaceCall internal contract. These phantom transactions are derived from the corresponding core space transaction, they do not exist in the ledger. Phantom transactions have the following special properties:

• 其中，gas 和 gasPrice 值均为 0。 跨空间交易的 gas 费用将在Core Space中收取。 因此，相应的 phantom 交易不会消耗任何 gas。
• 无效的签名（r、s、v、standardV）。 Conflux 协议无法代表跨空间交易的发送者签名交易。 因此，phantom 交易使用一个伪造的签名，而这个签名无法通过 ECDSA 验证。

示例

When we retrieve epoch 0x72819 in the Conflux core space, we see it contains a single Conflux transaction.

cfx_getBlockByEpochNumber(0x72819, true)

{
  "epochNumber": "0x72819",
  "hash": "0x7440c9e8ebb2e87a7d187e4ad6d09027d860b3948cf4364bb883c028b6c3a858",
  "transactions": [
    {
      "hash": "0xe89ef4b61434ec331b621b8687033f9e4058e76759a3522bdc50e0cb358f505e",
      "blockHash": "0x7440c9e8ebb2e87a7d187e4ad6d09027d860b3948cf4364bb883c028b6c3a858",
      "from": "NET8888:TYPE.USER:AAJFT5SK5RGK2KTJPMPUEJ69989N15KCCY7JAJEUP2",
      "to": "NET8888:TYPE.CONTRACT:ACAP3N9KXZ7C4TU5NUU8G65FJ7A09MG1FY77ZAYSVW",
      "gasPrice": "0x1",
      "gas": "0x8b28d",
      "storageLimit": "0x54",
      "r": "0x2b943e84111cd5f95fbdf15667329ac546c9e5b99548d3c3702aeced4f07de6d",
      "s": "0x2f47ae3c15ec2d1cbcf5bde3870aa21e1df54e8b7b926840a54faa9951cb3321",
      "v": "0x0",
      ...
    }
  ],
  ...
}

When we retrieve the corresponding block in the eSpace, we see it contains two phantom transactions.

eth_getBlockByNumber(0x72819, true)

{
  "hash": "0x7440c9e8ebb2e87a7d187e4ad6d09027d860b3948cf4364bb883c028b6c3a858",
  "number": "0x72819",
  "transactions": [
    {
      "hash": "0xfcdcf304b6b9dc263625b0924efaf3a7eb7044a17d27c0b8d631025b55d1147e",
      "blockHash": "0x7440c9e8ebb2e87a7d187e4ad6d09027d860b3948cf4364bb883c028b6c3a858",
      "from": "0x0000000000000000000000000000000000000000",
      "to": "0xf709629eee416c2d2a53692d38f1568538d8022f",
      "gasPrice": "0x0",
      "gas": "0x0",
      "r": "0x1",
      "s": "0x1",
      "v": "0x4593",
      ...
    },
    {
      "hash": "0xca2f5c5848458bea556f99e626db7108377d600e24add1920c4106358a1a5502",
      "blockHash": "0x7440c9e8ebb2e87a7d187e4ad6d09027d860b3948cf4364bb883c028b6c3a858",
      "from": "0xf709629eee416c2d2a53692d38f1568538d8022f",
      "to": "0xdacf3af269b55ece5fe3239626a27f2a76c48245",
      "gasPrice": "0x0",
      "gas": "0x0",
      "r": "0x1",
      "s": "0x1",
      "v": "0x4593",
      ...
    }
  ],
  ...
}