EVM兼容性

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：

交易类型

目前 eSpace 仅支持 155 类型 交易。 暂不支持 1559 类型交易。

EVM 操作码

• BLOCKHASH 操作码只能接受 NUMBER-1 作为输入。 （与以太坊不同的是，以太坊可以接受 NUMBER-256 到 NUMBER-1 之间的任何整数作为输入）。 这是唯一的中断操作码.。

区块时间

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。

区块的生成速率是每个区块 1.25 秒（主网），与 Core Space Epoch 时间相同。

合约大小

合约最大代码大小是 49152 ，是以太坊的两倍。

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 (15,000,000).

EVM Precompiles

All standard precompiles are supported.

Address	ID	名称	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",
      ...
    }
  ],
  ...
}

其他资源

• EVM opcodes reference