forked from ontio/ontology
/
func_flowcontrol.go
95 lines (79 loc) · 2.25 KB
/
func_flowcontrol.go
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/*
* Copyright (C) 2018 The ontology Authors
* This file is part of The ontology library.
*
* The ontology is free software: you can redistribute it and/or modify
* it under the terms of the GNU Lesser General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* The ontology is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with The ontology. If not, see <http://www.gnu.org/licenses/>.
*/
package neovm
import (
"github.com/ontio/ontology/vm/neovm/errors"
"math/big"
)
func opNop(e *ExecutionEngine) (VMState, error) {
return NONE, nil
}
func opJmp(e *ExecutionEngine) (VMState, error) {
num, err := e.Context.OpReader.ReadInt16()
if err != nil {
return FAULT, err
}
offset := int(num)
offset = e.Context.GetInstructionPointer() + offset - 3
if offset < 0 || offset > len(e.Context.Code) {
return FAULT, errors.ERR_FAULT
}
var fValue = true
if e.OpCode > JMP {
if EvaluationStackCount(e) < 1 {
return FAULT, errors.ERR_UNDER_STACK_LEN
}
var err error
fValue, err = PopBoolean(e)
if err != nil {
return FAULT, err
}
if e.OpCode == JMPIFNOT {
fValue = !fValue
}
}
if fValue {
e.Context.SetInstructionPointer(int64(offset))
}
return NONE, nil
}
func opCall(e *ExecutionEngine) (VMState, error) {
context := e.Context.Clone()
e.Context.SetInstructionPointer(int64(e.Context.GetInstructionPointer() + 2))
e.OpCode = JMP
e.PushContext(context)
return opJmp(e)
}
func opDCALL(e *ExecutionEngine) (VMState, error) {
context := e.Context.Clone()
e.PushContext(context)
dest, err := PopBigInt(e)
if err != nil {
return FAULT, errors.ERR_DCALL_OFFSET_ERROR
}
if dest.Sign() < 0 || dest.Cmp(big.NewInt(int64(len(e.Context.Code)))) >= 0 {
return FAULT, errors.ERR_DCALL_OFFSET_ERROR
}
target := dest.Int64()
e.Context.SetInstructionPointer(target)
return NONE, nil
}
func opRet(e *ExecutionEngine) (VMState, error) {
e.PopContext()
return NONE, nil
}