VisualStorms Tools

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VisualStorms Tools

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VisualStorms Tools Another Brick in the Robot . . . Universit degli Studi di Pisa Introduction Lego MindStorms allow building small robots based on the popular Lego ... – PowerPoint PPT presentation

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Title: VisualStorms Tools

1
VisualStorms Tools

Another Brick in the Robot . . .

2
Introduction

Lego MindStorms allow building small robots based
on the popular Lego bricks
A programmable brick allows controlling up to
three devices (motors) and test up to three input
sensors
Programs are expressed in a bytecode interpreted
by an interpreter in the bricks ROM
The execution model is concurrent (up to ten
threads) and there is a (very) small amount of
memory representing the state of the execution

3
Programming the Brick

Lego provides a visual programming system to
program the brick
Other tools have been developed to program
MindStorms a tiny JVM is being written (to
replace the Lego VM), NQC is a C-Like language
for programming the Brick
We have written a library to program MindStorms
with .NET and Visual Studio
The library compiles Intermediate Language (IL)
into Lego bytecode, in this way (almost) any .NET
compiler can be used to program the Brick.

4
Compilation Scheme
C
bcI File
VB
VisualStorms
IL
SML
Brick Downloader
. . .
5
Memory Organization

The compilation process should map a stack based
machine into a register based machine
Class fields are mapped to global variables
Stack of a method is mapped to local variables
starting from index 47 towards 32
Local variables are mapped starting from 32
Thus maxstack locals lt 32

Global variables (0-31)
Task 0 (Main) 32-47
Task 1 (32-47)
Task 9 (32-47)
V1 V2 .. . .
sp
. . .
Stack
46
47
6
Compilation an Example

using System
namespace StormTestAdvanced
public class AracnoBrickTop
VisualStormsTypes.RCX2
public int x
public int y
FunctionType(Function.Task, 0)
public void main()
int i Sensor2()
while(Sensor1() 0)
if (i ! 0)
SetMotorsPower(VisualStormsTypes.Motor.A,
Sensor3())
else
SetMotorsPower(VisualStormsTypes.Motor.C,
Sensor3())

7
Compilation Example IL
SetVar 20 32 9 1 0

IL_0000 ldarg.0
IL_0001 call instance int32
VisualStormsTypes.LegoBrickSensor2()
IL_0006 stloc.0
IL_0007 br.s IL_0028
IL_0009 ldloc.0
IL_000a brfalse.s IL_001b
IL_000c ldarg.0
IL_000d ldc.i4.1
IL_000e ldarg.0
IL_000f call instance int32
VisualStormsTypes.LegoBrickSensor3()
IL_0014 call instance void
LegoBrickSetMotorsPower(Motor, int32)
IL_0019 br.s IL_0028
IL_001b ldarg.0
IL_001c ldc.i4.4
IL_001d ldarg.0
IL_001e call instance int32
VisualStormsTypes.LegoBrickSensor3()
IL_0023 call instance void
LegoBrickSetMotorsPower(Motor, int32)
IL_0028 ldarg.0
IL_0029 call instance int32
VisualStormsTypes.LegoBrickSensor1()

LJump 114 26 0 (26 f)
SetVar 20 47 0 32 0
LCheckDo 149 192 2 47 0 0 9 0 (9 f)
SetPower 19 1 9 2
LJump 114 6 0 (6 f)
SetPower 19 4 9 2
SetVar 20 47 9 0 0
LCheckDo 149 192 2 47 0 0 221 255 (35 b)
8
Compilation Example Output

SetVar 20 32 9 1 0
LJump 114 26 0 (26 f)
SetVar 20 47 0 32 0
LCheckDo 149 192 2 47 0 0 9 0 (9 f)
SetPower 19 1 9 2
LJump 114 6 0 (6 f)
SetPower 19 4 9 2
SetVar 20 47 9 0 0
LCheckDo 149 192 2 47 0 0 221 255 (35 b)

9
Compilation Example NQC

int x
int y
task main ()
int i SENSOR_2
while(SENSOR_1 0)
if (i ! 0)
SetPower (OUT_A,SENSOR_3)
else
SetPower (OUT_C,SENSOR_3)

10
Compilation Example NQCs output
SetVar 20 32 9 1 0 LJump 114 26 0 (26
f) SetVar 20 47 0 32 0 LCheckDo 149 192 2 47
0 0 9 0 (9 f) SetPower 19 1 9 2 LJump 114 6
0 (6 f) SetPower 19 4 9 2 SetVar 20 47 9 0
0 LCheckDo 149 192 2 47 0 0 221 255 (35 b)

Var 0 x
Var 1 y
Var 47 i
Task 0 main
pwr ABC, 7
dir ABC, Fwd
setv var47, Input(1)
jmpl 33
chkl 0 var47, 29
pwr A, Input(2)
jmpl 33
pwr C, Input(2)
chkl 0 Input(0), 14

11
Structure of the System
VisualStudio
User
VisualStorms AddIn
AssemblyLoader
VisualStormsCompiler
SharpStormsLib
CliFileReader
Reflection
SharpSerial
12
Demo
13
Applications

Teaching the ability of programming simple
robots with real world languages allow a gentle
introduction to programming
Use of Lego to prototype robots controlled by
remote programs running on a full fledged PC and
radio controlled
Application of extensible reflection provided by
.NET
It is Possibile to implement emulators and debug
programs in Visual Studio (or guidbg) for .NET

14
Conclusions and Future Work

IL is a rich binary format that can be exploited
for purposes different than execution
The ability of compiling a subset of C programs
to the robot allows a neat environment for
experimenting with easy-to-build robots
In the future the compiler will recognize call to
external methods generating RPC code and
distributing a computation between the robot and
the PC automatically

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