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authorobscuren <geffobscura@gmail.com>2014-03-21 02:50:53 +0800
committerobscuren <geffobscura@gmail.com>2014-03-21 02:50:53 +0800
commitc68ff9886bdd59294bc2bf0a6b8bf9b83645cc9a (patch)
treeb824abb6ae17acc68801d58440929e57751c569b /ethchain/vm.go
parentf21eb88ad1cf54b342187e8d3b55374a695cd524 (diff)
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Fixed MSTORE and added some more commets
Diffstat (limited to 'ethchain/vm.go')
-rw-r--r--ethchain/vm.go46
1 files changed, 34 insertions, 12 deletions
diff --git a/ethchain/vm.go b/ethchain/vm.go
index 861b041d8..2fa78a748 100644
--- a/ethchain/vm.go
+++ b/ethchain/vm.go
@@ -18,6 +18,8 @@ type Vm struct {
mem map[string]*big.Int
vars RuntimeVars
+
+ state *State
}
type RuntimeVars struct {
@@ -32,7 +34,11 @@ type RuntimeVars struct {
txData []string
}
-func (vm *Vm) RunClosure(closure *Closure, state *State, vars RuntimeVars) []byte {
+func NewVm(state *State, vars RuntimeVars) *Vm {
+ return &Vm{vars: vars, state: state}
+}
+
+func (vm *Vm) RunClosure(closure *Closure) []byte {
// If the amount of gas supplied is less equal to 0
if closure.GetGas().Cmp(big.NewInt(0)) <= 0 {
// TODO Do something
@@ -71,17 +77,28 @@ func (vm *Vm) RunClosure(closure *Closure, state *State, vars RuntimeVars) []byt
}
switch op {
- case oSTOP:
+ case oSTOP: // Stop the closure
return closure.Return(nil)
- case oPUSH:
+ case oPUSH: // Push PC+1 on to the stack
pc++
val := closure.GetMem(pc).BigInt()
stack.Push(val)
- case oMSTORE:
+ case oMSTORE: // Store the value at stack top-1 in to memory at location stack top
// Pop value of the stack
- val := stack.Pop()
- // Set the bytes to the memory field
- mem = append(mem, ethutil.BigToBytes(val, 256)...)
+ val, mStart := stack.Popn()
+ // Ensure that memory is large enough to hold the data
+ // If it isn't resize the memory slice so that it may hold the value
+ bytesLen := big.NewInt(32)
+ totSize := new(big.Int).Add(mStart, bytesLen)
+ lenSize := big.NewInt(int64(len(mem)))
+ if totSize.Cmp(lenSize) > 0 {
+ // Calculate the diff between the sizes
+ diff := new(big.Int).Sub(totSize, lenSize)
+ // Create a new empty slice and append it
+ newSlice := make([]byte, diff.Int64()+1)
+ mem = append(mem, newSlice...)
+ }
+ copy(mem[mStart.Int64():mStart.Int64()+bytesLen.Int64()+1], ethutil.BigToBytes(val, 256))
case oCALL:
// Pop return size and offset
retSize, retOffset := stack.Popn()
@@ -93,20 +110,25 @@ func (vm *Vm) RunClosure(closure *Closure, state *State, vars RuntimeVars) []byt
gas, value := stack.Popn()
// Closure addr
addr := stack.Pop()
-
- contract := state.GetContract(addr.Bytes())
- closure := NewClosure(closure, contract, state, gas, value)
- ret := vm.RunClosure(closure, state, vars)
+ // Fetch the contract which will serve as the closure body
+ contract := vm.state.GetContract(addr.Bytes())
+ // Create a new callable closure
+ closure := NewClosure(closure, contract, vm.state, gas, value)
+ // Executer the closure and get the return value (if any)
+ ret := closure.Call(vm, nil)
// Ensure that memory is large enough to hold the returned data
+ // If it isn't resize the memory slice so that it may hold the value
totSize := new(big.Int).Add(retOffset, retSize)
lenSize := big.NewInt(int64(len(mem)))
- // Resize the current memory slice so that the return value may fit
if totSize.Cmp(lenSize) > 0 {
+ // Calculate the diff between the sizes
diff := new(big.Int).Sub(totSize, lenSize)
+ // Create a new empty slice and append it
newSlice := make([]byte, diff.Int64()+1)
mem = append(mem, newSlice...)
}
+ // Copy over the returned values to the memory given the offset and size
copy(mem[retOffset.Int64():retOffset.Int64()+retSize.Int64()+1], ret)
case oRETURN:
size, offset := stack.Popn()