neo-go/pkg/vm/README.md
Anthony De Meulemeester 941bd7e728
VM and compiler update (#63)
* renamed test folders and fixed bug where wrong jump labels would be exectuted for rewrite.

* Added support for Osize (len(string)) and factored out the array tests

* Added current instruction number to VM prompt if program is loaded.

* added support for unary expressions.

* updated README of and sorted the help commands

* updated readme of the compiler

* bumped version -> 0.39.0
2018-04-04 21:41:19 +02:00

170 lines
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Markdown

# NEO-GO-VM
A cross platform virtual machine implementation for `avm` compatible programs.
# Installation
## With neo-go
Install dependencies.
`neo-go` uses [dep](https://github.com/golang/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"
}
]
```
### 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 stack
- `istack` invocation stack