42dfca47cf
Fixes one more instruction being ran when VM FAULTs: NEO-GO-VM > run NEO-GO-VM > error encountered at instruction 6 (ROLL) NEO-GO-VM > runtime error: invalid memory address or nil pointer dereference FAULT NEO-GO-VM > error encountered at instruction 7 (SETITEM) NEO-GO-VM > interface conversion: interface {} is []vm.StackItem, not []uint8 Refs. #96. |
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.. | ||
cli | ||
compiler | ||
tests | ||
context.go | ||
emit.go | ||
emit_test.go | ||
instruction_string.go | ||
instructions.go | ||
interop.go | ||
output.go | ||
README.md | ||
stack.go | ||
stack_item.go | ||
stack_test.go | ||
state.go | ||
state_test.go | ||
vm.go | ||
vm_test.go |
NEO-GO-VM
A cross platform virtual machine implementation for avm
compatible programs.
Installation
With neo-go
Install dependencies.
neo-go
uses dep as its dependency manager. After installing deps
you can run:
make deps
Build the neo-go
cli:
make build
Start the virtual machine:
./bin/neo-go vm
_ ____________ __________ _ ____ ___
/ | / / ____/ __ \ / ____/ __ \ | | / / |/ /
/ |/ / __/ / / / /_____/ / __/ / / /____| | / / /|_/ /
/ /| / /___/ /_/ /_____/ /_/ / /_/ /_____/ |/ / / / /
/_/ |_/_____/\____/ \____/\____/ |___/_/ /_/
NEO-GO-VM >
Standalone
More information about standalone installation coming soon.
Usage
_ ____________ __________ _ ____ ___
/ | / / ____/ __ \ / ____/ __ \ | | / / |/ /
/ |/ / __/ / / / /_____/ / __/ / / /____| | / / /|_/ /
/ /| / /___/ /_/ /_____/ /_/ / /_/ /_____/ |/ / / / /
/_/ |_/_____/\____/ \____/\____/ |___/_/ /_/
NEO-GO-VM > help
COMMAND USAGE
astack show alt stack details
break place a breakpoint (> break 1)
cont continue execution of the current loaded script
estack show evaluation stack details
exit exit the VM prompt
help show available commands
ip show the current instruction
istack show invocation stack details
loadavm load an avm script into the VM (> load /path/to/script.avm)
loadgo compile and load a .go file into the VM (> load /path/to/file.go)
loadhex load a hex string into the VM (> loadhex 006166 )
ops show the opcodes of the current loaded program
run execute the current loaded script
step step (n) instruction in the program (> step 10)
Loading in your script
To load an avm script into the VM:
NEO-GO-VM > loadavm ../contract.avm
READY: loaded 36 instructions
Run the script:
NEO-GO-VM > run
[
{
"value": 1,
"type": "BigInteger"
}
]
You can also directly compile and load .go
files:
NEO-GO-VM > loadgo ../contract.go
READY: loaded 36 instructions
To make it even more complete, you can directly load hex strings into the VM:
NEO-GO-VM > loadhex 54c56b006c766b00527ac46c766b00c391640b006203005a616c756662030000616c7566
READY: loaded 36 instructions
NEO-GO-VM > run
[
{
"value": 10,
"type": "BigInteger"
}
]
Running programs with arguments
You can invoke smart contracts with arguments. Take the following roll the dice smartcontract as example.
package rollthedice
import "github.com/CityOfZion/neo-go/pkg/interop/runtime"
func Main(method string, args []interface{}) int {
if method == "rollDice" {
// args parameter is always of type []interface, hence we need to
// cast it to an int.
rollDice(args[0].(int))
}
return 0
}
func rollDice(number int) {
if number == 0 {
runtime.Log("you rolled 0, better luck next time!")
}
if number == 1 {
runtime.Log("you rolled 1, still better then 0!")
}
if number == 2 {
runtime.Log("you rolled 2, coming closer..")
}
if number == 3 {
runtime.Log("Sweet you rolled 3. This dice has only 3 sides o_O")
}
}
To invoke this contract we need to specify both the method and the arguments.
The first parameter (called method or operation) is always of type string. Notice that arguments can have different types, to make the VM aware of the type we need to specify it when calling run
:
NEO-GO-VM > run rollDice int:1
The method is always of type string, hence we don't need to specify the type.
To add more then 1 argument:
NEO-GO-VM > run someMethod int:1 int:2 string:foo string:bar
Current supported types:
int (int:1 int:100)
string (string:foo string:this is a string)
Debugging
The neo-go-vm
provides a debugger to inspect your program in-depth.
Step 4 instructions.
NEO-GO-VM > step 4
at breakpoint 4 (Opush4)
NEO-GO-VM 4 >
Using just step
will execute 1 instruction at a time.
NEO-GO-VM > step
instruction pointer at 5 (Odup)
NEO-GO-VM 5 >
To place breakpoints:
NEO-GO-VM > break 10
breakpoint added at instruction 10
NEO-GO-VM > cont
at breakpoint 10 (Osetitem)
NEO-GO-VM 10 > cont
Inspecting the evaluation stack:
NEO-GO-VM > estack
[
{
"value": [
null,
null,
null,
null,
null,
null,
null
],
"type": "Array"
},
{
"value": 4,
"type": "BigInteger"
}
]
There are more stacks that you can inspect.
astack
alt stackistack
invocation stack