Generating the Precompile

# Change to root
cd ..
 
# Generate go files
./scripts/generate_precompile.sh --abi ./contracts/abis/ICalculatorPlus.abi --type Calculatorplus --pkg calculatorplus --out ./calculatorplus

// Code generated
// This file is a generated precompile contract config with stubbed abstract functions.
// The file is generated by a template. Please inspect every code and comment in this file before use.
 
package calculatorplus
 
import (
    "errors"
    "fmt"
    "math/big"
 
    "github.com/ava-labs/subnet-evm/accounts/abi"
    "github.com/ava-labs/subnet-evm/precompile/contract"
    "github.com/ava-labs/subnet-evm/vmerrs"
 
    _ "embed"
 
    "github.com/ethereum/go-ethereum/common"
)
 
const (
    // Gas costs for each function. These are set to 1 by default.
    // You should set a gas cost for each function in your contract.
    // Generally, you should not set gas costs very low as this may cause your network to be vulnerable to DoS attacks.
    // There are some predefined gas costs in contract/utils.go that you can use.
    ModuloPlusGasCost uint64 = 1 /* SET A GAS COST HERE */
    PowOfThreeGasCost uint64 = 1 /* SET A GAS COST HERE */
    SimplFracGasCost  uint64 = 1 /* SET A GAS COST HERE */
)
 
// CUSTOM CODE STARTS HERE
// Reference imports to suppress errors from unused imports. This code and any unnecessary imports can be removed.
var (
    _ = abi.JSON
    _ = errors.New
    _ = big.NewInt
    _ = vmerrs.ErrOutOfGas
    _ = common.Big0
)
 
// Singleton StatefulPrecompiledContract and signatures.
var (
    // CalculatorplusRawABI contains the raw ABI of Calculatorplus contract.
    //go:embed contract.abi
    CalculatorplusRawABI string
 
    CalculatorplusABI = contract.ParseABI(CalculatorplusRawABI)
 
    CalculatorplusPrecompile = createCalculatorplusPrecompile()
)
 
type ModuloPlusInput struct {
    Dividend *big.Int
    Divisor  *big.Int
}
 
type ModuloPlusOutput struct {
    Multiple  *big.Int
    Remainder *big.Int
}
 
type PowOfThreeOutput struct {
    SecondPow *big.Int
    ThirdPow  *big.Int
    FourthPow *big.Int
}
 
type SimplFracInput struct {
    Numerator   *big.Int
    Denominator *big.Int
}
 
type SimplFracOutput struct {
    SimplNum   *big.Int
    SimplDenom *big.Int
}
 
// UnpackModuloPlusInput attempts to unpack [input] as ModuloPlusInput
// assumes that [input] does not include selector (omits first 4 func signature bytes)
func UnpackModuloPlusInput(input []byte) (ModuloPlusInput, error) {
    inputStruct := ModuloPlusInput{}
    err := CalculatorplusABI.UnpackInputIntoInterface(&inputStruct, "moduloPlus", input)
 
    return inputStruct, err
}
 
// PackModuloPlus packs [inputStruct] of type ModuloPlusInput into the appropriate arguments for moduloPlus.
func PackModuloPlus(inputStruct ModuloPlusInput) ([]byte, error) {
    return CalculatorplusABI.Pack("moduloPlus", inputStruct.Dividend, inputStruct.Divisor)
}
 
// PackModuloPlusOutput attempts to pack given [outputStruct] of type ModuloPlusOutput
// to conform the ABI outputs.
func PackModuloPlusOutput(outputStruct ModuloPlusOutput) ([]byte, error) {
    return CalculatorplusABI.PackOutput("moduloPlus",
        outputStruct.Multiple,
        outputStruct.Remainder,
    )
}
 
// UnpackModuloPlusOutput attempts to unpack [output] as ModuloPlusOutput
// assumes that [output] does not include selector (omits first 4 func signature bytes)
func UnpackModuloPlusOutput(output []byte) (ModuloPlusOutput, error) {
    outputStruct := ModuloPlusOutput{}
    err := CalculatorplusABI.UnpackIntoInterface(&outputStruct, "moduloPlus", output)
 
    return outputStruct, err
}
 
func moduloPlus(accessibleState contract.AccessibleState, caller common.Address, addr common.Address, input []byte, suppliedGas uint64, readOnly bool) (ret []byte, remainingGas uint64, err error) {
    if remainingGas, err = contract.DeductGas(suppliedGas, ModuloPlusGasCost); err != nil {
        return nil, 0, err
    }
    // attempts to unpack [input] into the arguments to the ModuloPlusInput.
    // Assumes that [input] does not include selector
    // You can use unpacked [inputStruct] variable in your code
    inputStruct, err := UnpackModuloPlusInput(input)
    if err != nil {
        return nil, remainingGas, err
    }
 
    // CUSTOM CODE STARTS HERE
    _ = inputStruct             // CUSTOM CODE OPERATES ON INPUT
    var output ModuloPlusOutput // CUSTOM CODE FOR AN OUTPUT
    packedOutput, err := PackModuloPlusOutput(output)
    if err != nil {
        return nil, remainingGas, err
    }
 
    // Return the packed output and the remaining gas
    return packedOutput, remainingGas, nil
}
 
// UnpackPowOfThreeInput attempts to unpack [input] into the *big.Int type argument
// assumes that [input] does not include selector (omits first 4 func signature bytes)
func UnpackPowOfThreeInput(input []byte) (*big.Int, error) {
    res, err := CalculatorplusABI.UnpackInput("powOfThree", input)
    if err != nil {
        return new(big.Int), err
    }
    unpacked := *abi.ConvertType(res[0], new(*big.Int)).(**big.Int)
    return unpacked, nil
}
 
// PackPowOfThree packs [base] of type *big.Int into the appropriate arguments for powOfThree.
// the packed bytes include selector (first 4 func signature bytes).
// This function is mostly used for tests.
func PackPowOfThree(base *big.Int) ([]byte, error) {
    return CalculatorplusABI.Pack("powOfThree", base)
}
 
// PackPowOfThreeOutput attempts to pack given [outputStruct] of type PowOfThreeOutput
// to conform the ABI outputs.
func PackPowOfThreeOutput(outputStruct PowOfThreeOutput) ([]byte, error) {
    return CalculatorplusABI.PackOutput("powOfThree",
        outputStruct.SecondPow,
        outputStruct.ThirdPow,
        outputStruct.FourthPow,
    )
}
 
// UnpackPowOfThreeOutput attempts to unpack [output] as PowOfThreeOutput
// assumes that [output] does not include selector (omits first 4 func signature bytes)
func UnpackPowOfThreeOutput(output []byte) (PowOfThreeOutput, error) {
    outputStruct := PowOfThreeOutput{}
    err := CalculatorplusABI.UnpackIntoInterface(&outputStruct, "powOfThree", output)
 
    return outputStruct, err
}
 
func powOfThree(accessibleState contract.AccessibleState, caller common.Address, addr common.Address, input []byte, suppliedGas uint64, readOnly bool) (ret []byte, remainingGas uint64, err error) {
    if remainingGas, err = contract.DeductGas(suppliedGas, PowOfThreeGasCost); err != nil {
        return nil, 0, err
    }
    // attempts to unpack [input] into the arguments to the PowOfThreeInput.
    // Assumes that [input] does not include selector
    // You can use unpacked [inputStruct] variable in your code
    inputStruct, err := UnpackPowOfThreeInput(input)
    if err != nil {
        return nil, remainingGas, err
    }
 
    // CUSTOM CODE STARTS HERE
    _ = inputStruct             // CUSTOM CODE OPERATES ON INPUT
    var output PowOfThreeOutput // CUSTOM CODE FOR AN OUTPUT
    packedOutput, err := PackPowOfThreeOutput(output)
    if err != nil {
        return nil, remainingGas, err
    }
 
    // Return the packed output and the remaining gas
    return packedOutput, remainingGas, nil
}
 
// UnpackSimplFracInput attempts to unpack [input] as SimplFracInput
// assumes that [input] does not include selector (omits first 4 func signature bytes)
func UnpackSimplFracInput(input []byte) (SimplFracInput, error) {
    inputStruct := SimplFracInput{}
    err := CalculatorplusABI.UnpackInputIntoInterface(&inputStruct, "simplFrac", input)
 
    return inputStruct, err
}
 
// PackSimplFrac packs [inputStruct] of type SimplFracInput into the appropriate arguments for simplFrac.
func PackSimplFrac(inputStruct SimplFracInput) ([]byte, error) {
    return CalculatorplusABI.Pack("simplFrac", inputStruct.Numerator, inputStruct.Denominator)
}
 
// PackSimplFracOutput attempts to pack given [outputStruct] of type SimplFracOutput
// to conform the ABI outputs.
func PackSimplFracOutput(outputStruct SimplFracOutput) ([]byte, error) {
    return CalculatorplusABI.PackOutput("simplFrac",
        outputStruct.SimplNum,
        outputStruct.SimplDenom,
    )
}
 
// UnpackSimplFracOutput attempts to unpack [output] as SimplFracOutput
// assumes that [output] does not include selector (omits first 4 func signature bytes)
func UnpackSimplFracOutput(output []byte) (SimplFracOutput, error) {
    outputStruct := SimplFracOutput{}
    err := CalculatorplusABI.UnpackIntoInterface(&outputStruct, "simplFrac", output)
 
    return outputStruct, err
}
 
func simplFrac(accessibleState contract.AccessibleState, caller common.Address, addr common.Address, input []byte, suppliedGas uint64, readOnly bool) (ret []byte, remainingGas uint64, err error) {
    if remainingGas, err = contract.DeductGas(suppliedGas, SimplFracGasCost); err != nil {
        return nil, 0, err
    }
    // attempts to unpack [input] into the arguments to the SimplFracInput.
    // Assumes that [input] does not include selector
    // You can use unpacked [inputStruct] variable in your code
    inputStruct, err := UnpackSimplFracInput(input)
    if err != nil {
        return nil, remainingGas, err
    }
 
    // CUSTOM CODE STARTS HERE
    _ = inputStruct            // CUSTOM CODE OPERATES ON INPUT
    var output SimplFracOutput // CUSTOM CODE FOR AN OUTPUT
    packedOutput, err := PackSimplFracOutput(output)
    if err != nil {
        return nil, remainingGas, err
    }
 
    // Return the packed output and the remaining gas
    return packedOutput, remainingGas, nil
}
 
// createCalculatorplusPrecompile returns a StatefulPrecompiledContract with getters and setters for the precompile.
 
func createCalculatorplusPrecompile() contract.StatefulPrecompiledContract {
    var functions []*contract.StatefulPrecompileFunction
 
    abiFunctionMap := map[string]contract.RunStatefulPrecompileFunc{
        "moduloPlus": moduloPlus,
        "powOfThree": powOfThree,
        "simplFrac":  simplFrac,
    }
 
    for name, function := range abiFunctionMap {
        method, ok := CalculatorplusABI.Methods[name]
        if !ok {
            panic(fmt.Errorf("given method (%s) does not exist in the ABI", name))
        }
        functions = append(functions, contract.NewStatefulPrecompileFunction(method.ID, function))
    }
    // Construct the contract with no fallback function.
    statefulContract, err := contract.NewStatefulPrecompileContract(nil, functions)
    if err != nil {
        panic(err)
    }
    return statefulContract
}