core/vm: review changes: mod-pad, contract addrs, bn256-arith, f&r

* Right pad return data of  native contract big mod exp to same length
as the modulo input
* Spelling
* Make LOG{n} write operations so the throw during readonly
* Right pad native contracts input with zeros
* Fixed bn256{add, mul}

core/vm/contracts.go

@@ -57,7 +57,7 @@ var PrecompiledContractsMetropolis = map[common.Address]PrecompiledContract{
 	common.BytesToAddress([]byte{4}): &dataCopy{},
 	common.BytesToAddress([]byte{5}): &bigModexp{},
 	common.BytesToAddress([]byte{6}): &bn256Add{},
-	common.BytesToAddress([]byte{6}): &bn256ScalarMul{},
+	common.BytesToAddress([]byte{7}): &bn256ScalarMul{},
 	common.BytesToAddress([]byte{8}): &pairing{},
 }
 
@@ -206,7 +206,7 @@ func (c *bigModexp) Run(input []byte) ([]byte, error) {
 	}
 	mod := new(big.Int).SetBytes(input[:modLen])
 
-	return base.Exp(base, exp, mod).Bytes(), nil
+	return common.LeftPadBytes(base.Exp(base, exp, mod).Bytes(), len(input[:modLen])), nil
 }
 
 type bn256Add struct{}
@@ -220,37 +220,7 @@ func (c *bn256Add) RequiredGas(input []byte) uint64 {
 }
 
 func (c *bn256Add) Run(in []byte) ([]byte, error) {
-	if len(in) != 96 {
+	in = common.RightPadBytes(in, 128)
-		return nil, errBadPrecompileInput
-	}
-
-	g1, onCurve := new(bn256.G1).Unmarshal(in[:64])
-	if !onCurve {
-		return nil, errNotOnCurve
-	}
-	x, y, _, _ := g1.CurvePoints()
-	if x.Cmp(bn256.P) >= 0 || y.Cmp(bn256.P) >= 0 {
-		return nil, errInvalidCurvePoint
-	}
-	g1.ScalarMult(g1, new(big.Int).SetBytes(in[64:]))
-
-	return g1.Marshal(), nil
-}
-
-type bn256ScalarMul struct{}
-
-// RequiredGas returns the gas required to execute the pre-compiled contract.
-//
-// This method does not require any overflow checking as the input size gas costs
-// required for anything significant is so high it's impossible to pay for.
-func (c *bn256ScalarMul) RequiredGas(input []byte) uint64 {
-	return 0 // TODO
-}
-
-func (c *bn256ScalarMul) Run(in []byte) ([]byte, error) {
-	if len(in) != 128 {
-		return nil, errBadPrecompileInput
-	}
 
 	x, onCurve := new(bn256.G1).Unmarshal(in[:64])
 	if !onCurve {
@@ -269,8 +239,35 @@ func (c *bn256ScalarMul) Run(in []byte) ([]byte, error) {
 	if gx.Cmp(bn256.P) >= 0 || gy.Cmp(bn256.P) >= 0 {
 		return nil, errInvalidCurvePoint
 	}
+	x.Add(x, y)
 
-	return x.Add(x, y).Marshal(), nil
+	return x.Marshal(), nil
+}
+
+type bn256ScalarMul struct{}
+
+// RequiredGas returns the gas required to execute the pre-compiled contract.
+//
+// This method does not require any overflow checking as the input size gas costs
+// required for anything significant is so high it's impossible to pay for.
+func (c *bn256ScalarMul) RequiredGas(input []byte) uint64 {
+	return 0 // TODO
+}
+
+func (c *bn256ScalarMul) Run(in []byte) ([]byte, error) {
+	in = common.RightPadBytes(in, 96)
+
+	g1, onCurve := new(bn256.G1).Unmarshal(in[:64])
+	if !onCurve {
+		return nil, errNotOnCurve
+	}
+	x, y, _, _ := g1.CurvePoints()
+	if x.Cmp(bn256.P) >= 0 || y.Cmp(bn256.P) >= 0 {
+		return nil, errInvalidCurvePoint
+	}
+	g1.ScalarMult(g1, new(big.Int).SetBytes(in[64:96]))
+
+	return g1.Marshal(), nil
 }
 
 // pairing implements a pairing pre-compile for the bn256 curve

core/vm/evm.go

@@ -104,8 +104,8 @@ type EVM struct {
 	abort int32
 }
 
-// NewEVM retutrns a new EVM evmironment. The returned EVM is not thread safe
+// NewEVM retutrns a new EVM . The returned EVM is not thread safe and should
-// and should only ever be used *once*.
+// only ever be used *once*.
 func NewEVM(ctx Context, statedb StateDB, chainConfig *params.ChainConfig, vmConfig Config) *EVM {
 	evm := &EVM{
 		Context:     ctx,
@@ -153,7 +153,7 @@ func (evm *EVM) StaticCall(caller ContractRef, addr common.Address, input []byte
 	}
 
 	// initialise a new contract and set the code that is to be used by the
-	// E The contract is a scoped evmironment for this execution context
+	// EVM. The contract is a scoped evmironment for this execution context
 	// only.
 	contract := NewContract(caller, to, new(big.Int), gas)
 	contract.SetCallCode(&addr, evm.StateDB.GetCodeHash(addr), evm.StateDB.GetCode(addr))

core/vm/jump_table.go

@@ -56,43 +56,12 @@ type operation struct {
 }
 
 var (
-	frontierInstructionSet   = NewFrontierInstructionSet()
+	frontierInstructionSet  = NewFrontierInstructionSet()
-	homesteadInstructionSet  = NewHomesteadInstructionSet()
+	homesteadInstructionSet = NewHomesteadInstructionSet()
-	metropolisInstructionSet = NewMetropolisInstructionSet()
 )
 
-func NewMetropolisInstructionSet() [256]operation {
+// NewHomesteadInstructionSet returns the frontier and homestead
-	instructionSet := NewHomesteadInstructionSet()
+// instructions that can be executed during the homestead phase.
-	instructionSet[STATIC_CALL] = operation{
-		execute:       opStaticCall,
-		gasCost:       gasStaticCall,
-		validateStack: makeStackFunc(6, 1),
-		memorySize:    memoryStaticCall,
-		valid:         true,
-	}
-	instructionSet[REVERT] = operation{
-		execute:       opRevert,
-		gasCost:       constGasFunc(GasFastestStep),
-		validateStack: makeStackFunc(2, 0),
-		valid:         true,
-		reverts:       true,
-	}
-	instructionSet[RETURNDATASIZE] = operation{
-		execute:       opReturnDataSize,
-		gasCost:       constGasFunc(0), // TODO
-		validateStack: makeStackFunc(0, 1),
-		valid:         true,
-	}
-	instructionSet[RETURNDATACOPY] = operation{
-		execute:       opReturnDataCopy,
-		gasCost:       gasReturnDataCopy,
-		validateStack: makeStackFunc(3, 0),
-		memorySize:    memoryReturnDataCopy,
-		valid:         true,
-	}
-	return instructionSet
-}
-
 func NewHomesteadInstructionSet() [256]operation {
 	instructionSet := NewFrontierInstructionSet()
 	instructionSet[DELEGATECALL] = operation{
@@ -841,6 +810,7 @@ func NewFrontierInstructionSet() [256]operation {
 			validateStack: makeStackFunc(2, 0),
 			memorySize:    memoryLog,
 			valid:         true,
+			writes:        true,
 		},
 		LOG1: {
 			execute:       makeLog(1),
@@ -848,6 +818,7 @@ func NewFrontierInstructionSet() [256]operation {
 			validateStack: makeStackFunc(3, 0),
 			memorySize:    memoryLog,
 			valid:         true,
+			writes:        true,
 		},
 		LOG2: {
 			execute:       makeLog(2),
@@ -855,6 +826,7 @@ func NewFrontierInstructionSet() [256]operation {
 			validateStack: makeStackFunc(4, 0),
 			memorySize:    memoryLog,
 			valid:         true,
+			writes:        true,
 		},
 		LOG3: {
 			execute:       makeLog(3),
@@ -862,6 +834,7 @@ func NewFrontierInstructionSet() [256]operation {
 			validateStack: makeStackFunc(5, 0),
 			memorySize:    memoryLog,
 			valid:         true,
+			writes:        true,
 		},
 		LOG4: {
 			execute:       makeLog(4),
@@ -869,6 +842,7 @@ func NewFrontierInstructionSet() [256]operation {
 			validateStack: makeStackFunc(6, 0),
 			memorySize:    memoryLog,
 			valid:         true,
+			writes:        true,
 		},
 		CREATE: {
 			execute:       opCreate,