因為Gcoin EVM是由Ethereum EVM增修而來，此資料夾(Smart-Contract)必須和你安裝的Ethereum放在不同的資料夾。 安裝官方的Ethereum照1的步驟，已安裝過Ethereum請跳到步驟2安裝Gcoin EVM。

1.Building the source (Ethereum)

For prerequisites and detailed build instructions please read the Installation Instructions on the wiki.

Building geth requires both a Go and a C compiler. You can install them using your favourite package manager. Once the dependencies are installed, run

make geth

or, to build the full suite of utilities:

make all

2.Building the source (Gcoin EVM)

假設已經安裝過必須的套件或程式如Go，如未安裝，請到步驟1的連結安裝。確認後直接執行

make evm

Executable

Command	Description
evm	Developer utility version of the EVM (Ethereum Virtual Machine) that is capable of running bytecode snippets within a configurable environment and execution mode. Its purpose is to allow insolated, fine graned debugging of EVM opcodes (e.g. evm --code 60ff60ff --debug).

##Flags

Command	Description
--dump	將evm執行後的結果(state)輸出至standard output
--write [filename]	將evm執行後的結果(state)寫入檔案
--read [filename]	從檔案讀取state
--sender [address]
--receiver [address]
--deploy	若要deploy一個新的contract，要加這個flag才會存下正確的code
--fund '{"[color]":"[value]"}'	生出指定顏色和數量的coin給sender；測試可用
--code [bytecode]	contract的bytecode
--value '{"[color]":"[value]"}'	要附加在Transaction的value
--input [code]	call某一function需要給的code，包含該function的identifier及參數
--time [time]	由Oracle帶入該Transaction所屬的Block的timestamp
使用到color和value時請注意單引號和雙引號

Usage example

The user [User] trying to deploy the contract at [Adr] with money color [5566] and value [500] and save the state into [MyJson.json]:

$sudo ./evm --deploy --sender [User]  --receiver [Adr] --value '{"5566":"500"}' --code [Bytecode] --write [MyJson.json]

The sender must have enough balance before deploy the contract: Suppose [User] has $10000 of color X adding the balance [10000] of color [5566] to the user [User]

sudo ./evm --fund '{"5566":"10000"}' --read [MyJson.json] --sender [User] --write [MyJson.json]

Call a function in a contract

contract example:

contract Information{
  ...
  function setWeather(uint today){
    ...
  }
  ...
}

Keccak256 online

https://emn178.github.io/online-tools/keccak_256.html

take the first 8 bytes of the keccak256 hash of the setWeather(uint256), which is 39b490bd, appended with arguments(64 bits each, if any).

--input 39b490bd00000000000000000000000000000000000000000000000000000020    //setWeather(0x20) == setWeather(32)

Contract example

contract Information{
    uint256 private number;
    address master;
    string asd;
    function Information()
    {
        master = msg.sender;
        number = 0x1fff;
        asd = "ddd";    
    }
    function setWeather(uint today)
    {
        if(msg.sender==master)  number=today;
    }
     function setWeather2(uint today,uint tom)
    {
        if(msg.sender==master)  number=today+1;
        asd="dddd";    

    }
}

Bytecode

 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

Transfer Coins

address.send(amount, color); msg.sender.send(20, 5566); //send 20 units of color 5566 coin to msg.sender

address.balance(color); 0xdf1a92bd1607100075c03f0309c53c9b8671b034.balance(5566); //return the amount of coin 5566 that 0xdf1a92bd1607100075c03f0309c53c9b8671b034 have

msg.value(color); msg.value(5566); //return the amount of coin 5566 that sent along with this transaction

License

The go-ethereum library (i.e. all code outside of the cmd directory) is licensed under the GNU Lesser General Public License v3.0, also included in our repository in the COPYING.LESSER file.

The go-ethereum binaries (i.e. all code inside of the cmd directory) is licensed under the GNU General Public License v3.0, also included in our repository in the COPYING file.