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Convert assembly to C using Replace some groups with Regex in C#

I want to convert asm to c(assembly to C)
I saw http://www.textmaestro.com/InfoEx_17_Convert_Assembly.htm
(please the page)
page on web and easily after that i try to Do this job using find and Replace with Regex in C#
i am not computer field student so i am not professional at Regex.
I am working 5 days and after this time now i know that i cant do this.i wrote very code but without any success
sample program:
mov r1,1;
mov r2,2;
convert to :
r1=1;
r2=2;
please help me to do this correctly

OP has (painfully) learned that regexps are not a good solution to problems that involve analysis or translation of software. Processing strings simply is not the same as building context-sensitive analyses of text with complex structure.
People keep re-learning this lesson. It is true that you can use repeated regex to simulate Post rewriting systems, and Post systems, being Turing capable, can technically do anything. It is also true that nobody really wants to, or more importantly, nobody can write a very complex program for a real Turing machine [or an equivalent Post system]. This is why we have all these other computer languages and tools. [The TextMaestro system to which OP refers is trying to be exactly that Post system.]
However, the task he wants to do is possible and practical with the proper tools: program transformation systems (PTS).
In particular, he should see this technical paper for a description of precisely how this has been done with one particular PTS: See Pigs from sausages? Reengineering from assembler to C via FermaT transformations. Such a tool in effect is a custom compiler from assembly source code to the target language, and includes parsing, name (label) resolution, often data flow analysis and complex code generation and optimization. A PTS is used because they make it relatively easy to build that kind of compiler. This tool has been used for at least Intel assembly to C, and mainframe (System 360/370/Z) assembly to C, for large-scale tasks. (I have no relationship to this tool but do have huge respect for the authors).
The naysayers in the comments seem to think this is impossible to do except for extremely constrained circumstances. It is true that the more one knows about the assembly code in terms of idioms, the somewhat easier this gets, but the technical approach in the paper is not limited to specific compiler output by any means. It is also true that truly arcane assembler code (especially self-modifying or having runtime code generation) is extremely difficult to translate.

Accessing math coprocessor from C#

How can I access math coprocessor from C# code? I would like to make some calculations on integers as fast as it's possible. I know it's possible under C++ compliers to use Assembler code inside it, but what about .Net?

The JIT compiler knows about the math coprocessor and will use it. What you really want is to use the SIMD engine, not the math coprocessor. This was part of the promise of JIT-compilation, that the runtime could pick the fastest hardware acceleration available on each computer, but I don't think .NET actually does that, at least in v4.
Or are you using the term "math coprocessor" to mean something other than the x87 FPU? There are some FPGA boards marketed as accelerator/coprocessor systems. If that's what you mean, you'll need to consult the programming manual that comes with the particular product. There are no special CPU instructions for accessing those, inline assembler wouldn't be helpful in this case.
For example, the GPU is even faster at math on large datasets than the CPU's SIMD engine, and you can access that from .NET using DirectX Compute Shaders (or p/invoking OpenCL), no assembler required.

I don't think that this would be possible to do directly from managed code. You could still call unmanaged code which does those calculations but whether the cost of interop marshaling is worth it is difficult to say. You will have to minimize it as much as possible and do all the calculations in unmanaged code and do only a single call to minimize overhead.

No, you cannot directly use inline assembler in C# managed code.
Your best bet is to make sure your general approach/algorithm is clean and efficient, and your math operations are clean and efficient, and then rely on the compiler to make efficient use of the available coprocessor.

This is not natively supported by C# as a language, nor .NET as a framework.
If you need that kind of speed or prowess, use something else altogether.

I know this is an old post, but for those coming here for similar reason of speeding up maths operations, for example a large number of vector operations.
To get the greatest speed from C# in maths you should convert your formulae to the logarithmic equivalent. This takes some practice, but once you have the idea you can do it with every formulae. Then decide to keep your values in log form, only converting to human readable form for those values the user needs to see.
The reason logs work faster is because they are all addition and subtraction (subtraction just being the addition of a compliment number), your processors can do these in large numbers with ease.
If you have not done this sort of maths before there are lessons online that will lead you through it, it has a learning curve but for maths/graphics programmers the learning curve is worth it.

C# running faster than C++?

A friend and I have written an encryption module and we want to port it to multiple languages so that it's not platform specific encryption. Originally written in C#, I've ported it into C++ and Java. C# and Java will both encrypt at about 40 MB/s, but C++ will only encrypt at about 20 MB/s. Why is C++ running this much slower? Is it because I'm using Visual C++?
What can I do to speed up my code? Is there a different compiler that will optimize C++ better?
I've already tried optimizing the code itself, such as using x >> 3 instead of x / 8 (integer division), or y & 63 instead of y % 64 and other techniques. How can I build the project differently so that it is more performant in C++ ?
EDIT:
I must admit that I have not looked into how the compiler optimizes code. I have classes that I will be taking here in College that are dedicated to learning about compilers and interpreters.
As for my code in C++, it's not very complicated. There are NO includes, there is "basic" math along with something we call "state jumping" to produce pseudo random results. The most complicated things we do are bitwise operations that actually do the encryption and unchecked multiplication during an initial hashing phase. There are dynamically allocated 2D arrays which stay alive through the lifetime of the Encryption object (and properly released in a destructor). There's only 180 lines in this. Ok, so my micro-optimizations aren't necessary, but I should believe that they aren't the problem, it's about time. To really drill the point in, here is the most complicated line of code in the program:
input[L + offset] ^= state[state[SIndex ^ 255] & 63];
I'm not moving arrays, or working with objects.
Syntactically the entire set of code runs perfect and it'll work seamlessly if I were to encrypt something with C# and decrypt it with C++, or Java, all 3 languages interact as you'd expect they would.
I don't necessarily expect C++ to run faster then C# or Java (which are within 1 MB/s of each other), but I'm sure there's a way to make C++ run just as fast, or at least faster then it is now. I admit I'm not a C++ expert, I'm certainly not as seasoned in it as many of you seem to be, but if I can cut and paste 99% of the code from C# to C++ and get it to work in 5 mins, then I'm a little put out that it takes twice as long to execute.
RE-EDIT:
I found an optimization in Visual Studio I forgot to set before. Now C++ is running 50% faster then C#. Thanks for all the tips, I've learned a lot about compilers in my research.

Without source code it's difficult to say anything about the performance of your encryption algorithm/program.
I reckon though that you made a "mistake" while porting it to C++, meaning that you used it in a inefficient way (e.g. lots of copying of objects happens). Maybe you also used VC 6, whereas VC 9 would/could produce much better code.
As for the "x >> 3" optimization... modern compilers do convert integer division to bitshifts by themselves. Needless to say that this optimization may not be the bottleneck of your program at all. You should profile it first to find out where you're spending most of your time :)

The question is extreamly broad. Something that's efficient in C# may not be efficient in C++ and vice-versa.
You're making micro-optimisations, but you need to examine the overall design of your solution to make sure that it makes sense in C++. It may be a good idea to re-design large parts of your solution so that it works better in C++.
As with all things performance related, profile the code first, then modify, then profile again. Repeat until you've got to an acceptable level of performance.

Things that are 'relatively' fast in C# may be extremely slow in C++.
You can write 'faster' code in C++, but you can also write much slower code. Especially debug builds may be extremely slow in C++. So look at the type of optimizations by your compiler.
Mostly when porting applications, C# programmers tend to use the 'create a million newed objects' approach, which really makes C++ programs slow. You would rewrite these algorithm to use pre-allocated arrays and run with tight loops over these.
With pre-allocated memory you leverage the strengths of C++ in using pointers to memory by casting these to the right pod structured data.
But it really depends on what you have written in your code.
So measure your code an see where the implementations burn the most cpu, and then structure your code to use the right algorithms.

Your timing results are definitely not what I'd expect with well-written C++ and well-written C#. You're almost certainly writing inefficient C++. (Either that, or you're not compiling with the same sort of options. Make sure you're testing the release build, and check the optimization options.
However, micro-optimizations, like you mention, are going to do effectively nothing to improve the performance. You're wasting your time doing things that the compiler will do for you.
Usually you start by looking at the algorithm, but in this case we know the algorithm isn't causing the performance issue. I'd advise using a profiler to see if you can find a big time sink, but it may not find anything different from in C# or Java.
I'd suggest looking at how C++ differs from Java and C#. One big thing is objects. In Java and C#, objects are represented in the same way as C++ pointers to objects, although it isn't obvious from the syntax.
If you're moving objects about in Java and C++, you're moving pointers in Java, which is quick, and objects in C++, which can be slow. Look for where you use medium or large objects. Are you putting them in container classes? Those classes move objects around. Change those to pointers (preferably smart pointers, like std::tr1::shared_ptr<>).
If you're not experienced in C++ (and an experienced and competent C++ programmer would be highly unlikely to be microoptimizing), try to find somebody who is. C++ is not a really simple language, having a lot more legacy baggage than Java or C#, and you could be missing quite a few things.

Free C++ profilers:
What's the best free C++ profiler for Windows?

"Porting" performance-critical code from one language to another is usually a bad idea. You tend not to use the target language (C++ in this case) to its full potential.
Some of the worst C++ code I've seen was ported from Java. There was "new" for almost everything - normal for Java, but a sure performance killer for C++.
You're usually better off not porting, but reimplementing the critical parts.

The main reason C#/Java programs do not translate well (assuming everything else is correct). Is that C#/Java developers have not grokked the concept of objects and references correctly. Note in C#/Java all objects are passed by (the equivalent of) a pointer.
Class Message
{
char buffer[10000];
}
Message Encrypt(Message message) // Here you are making a copy of message
{
for(int loop =0;loop < 10000;++loop)
{
plop(message.buffer[loop]);
}
return message; // Here you are making another copy of message
}
To re-write this in a (more) C++ style you should probably be using references:
Message& Encrypt(Message& message) // pass a reference to the message
{
...
return message; // return the same reference.
}
The second thing that C#/Java programers have a hard time with is the lack of Garbage collection. If you are not releasing any memory correctly, you could start running low on memory and the C++ version is thrashing. In C++ we generally allocate objects on the stack (ie no new). If the lifetime of the object is beyond the current scope of the method/function then we use new but we always wrap the returned variable in a smart pointer (so that it will be correctly deleted).
void myFunc()
{
Message m;
// read message into m
Encrypt(m);
}
void alternative()
{
boost::shared_pointer<Message> m(new Message);
EncryptUsingPointer(m);
}

Show your code. We can't tell you how to optimize your code if we don't know what it looks like.
You're absolutely wasting your time converting divisions by constants into shift operations. Those kinds of braindead transformations can be made even by the dumbest compiler.
Where you can gain performance is in optimizations that require information the compiler doesn't have. The compiler knows that division by a power of two is equivalent to a right-shift.
Apart from this, there is little reason to expect C++ to be faster. C++ is much more dependent on you writing good code. C# and Java will produce pretty efficient code almost no matter what you do. But in C++, just one or two missteps will cripple performance.
And honestly, if you expected C++ to be faster because it's "native" or "closer to the metal", you're about a decade too late. JIT'ed languages can be very efficient, and with one or two exceptions, there's no reason why they must be slower than a native language.
You might find these posts enlightening.
They show, in short, that yes, ultimately, C++ has the potential to be faster, but for the most part, unless you go to extremes to optimize your code, C# will be just as fast, or faster.
If you want your C++ code to compete with the C# version, then a few suggestions:
Enable optimizations (you've hopefully already done this)
Think carefully about how you do disk I/O (IOStremas isn't exactly an ideal library to use)
Profile your code to see what needs optimizing.
Understand your code. Study the assembler output, and see what can be done more efficiently.
Many common operations in C++ are surprisingly slow. Dynamic memory allocation is a prime example. It is almost free in C# or Java, but very costly in C++. Stack-allocation is your friend.
Understand your code's cache behavior. Is your data scattered all over the place? It shouldn't be a surprise then that your code is inefficient.

Totally of topic but...
I found some info on the encryption module on the homepage you link to from your profile http://www.coreyogburn.com/bigproject.html
(quote)
Put together by my buddy Karl Wessels and I, we believe we have quite a powerful new algorithm.
What separates our encryption from the many existing encryptions is that ours is both fast AND secure. Currently, it takes 5 seconds to encrypt 100 MB. It is estimated that it would take 4.25 * 10^143 years to decrypt it!
[...]
We're also looking into getting a copyright and eventual commercial release.
I don't want to discourage you, but getting encryption right is hard. Very hard.
I'm not saying it's impossible for a twenty year old webdeveloper to develop an encryption algorithm that outshines all existing algorithms, but it's extremely unlikely, and I'm very sceptic, I think most people would be.
Nobody who cares about encryption would use an algorithm that's unpublished. I'm not saying you have to open up your sourcecode, but the workings of the algorithm must be public, and scrutinized, if you want to be taken seriously...

There are areas where a language running on a VM outperforms C/C++, for example heap allocation of new objects. You can find more details here.

There is a somwhat old article in Doctor Dobbs Journal named Microbenchmarking C++, C#, and Java where you can see some actual benchmarks, and you will find that C# sometimes is faster than C++. One of the more extreme examples is the single hash map benchmark. .NET 1.1 is a clear winner at 126 and VC++ is far behind at 537.
Some people will not believe you if you claim that a language like C# can be faster than C++, but it actually can. However, using a profiler and the very high level of fine-grained control that C++ offers should enable you to rewrite your application to be very performant.

When serious about performance you might want to be serious about profiling.
Separately, the "string" object implementation used in C# Java and C++, is noticeably slower in C++.

There are some cases where VM based languages as C# or Java can be faster than a C++ version. At least if you don't put much work into optimization and have a good knowledge of what is going on in the background. One reason is that the VMs can optimize byte-code at runtime and figure out which parts of the program are used often and changes its optimization strategy. On the other hand an old fashioned compiler has to decide how to optimize the program on compile-time and may not find the best solution.

The C# JIT probably noticed at run-time that the CPU is capable of running some advanced instructions, and is compiling to something better than what the C++ was compiled.
You can probably (surely with enough efforts) outperform this by compiling using the most sophisticated instructions available to the designated C.P.U and using knowledge of the algorithm to tell the compiler to use SIMD instructions at specific stages.
But before any fancy changes to your code, make sure are you C++ compiling to your C.P.U, not something much more primitive (Pentium ?).
Edit:
If your C++ program does a lot of unwise allocations and deallocations this will also explain it.

In another thread, I pointed out that doing a direct translation from one language to another will almost always end up in the version in the new language running more poorly.
Different languages take different techniques.

Try the intel compiler. Its much better the VC or gcc. As for the original question, I would be skeptical. Try to avoid using any containers and minimize the memory allocations in the offending function.

[Joke]There is an error in line 13[/Joke]
Now, seriously, no one can answer the question without the source code.
But as a rule of the thumb, the fact that C++ is that much slower than managed one most likely points to the difference of memory management and object ownership issues.
For instance, if your algorithm is doing any dynamic memory allocations inside the processing loop, this will affect the performance. If you pass heavy structures by the value, this will affect the performance. If you do unnecessary copies of objects, this will affect the performance. Exception abuse will cause performance to go south. And still counting.
I know the cases when forgotten "&" after the parameter name resulted in weeks of profiling/debugging:
void DoSomething(const HeavyStructure param); // Heavy structure will be copied
void DoSomething(const HeavyStructure& param); // No copy here
So, check your code to find possible bottlenecks.

C++ is not a language where you must use classes. In my opinion its not logical to use OOP methodologies where it doesnt really help. For a encrypter / decrypter its best not use classes; use arrays, pointers, use as few functions / classes / files possible. Best encryption system consists of a single file containing few functions. After your function works nice you can wrap it into classes if you wish. Also check the release build. There is huge speed difference

Nothing is faster than good machine/assembly code, so my goal when writing C/C++ is to write my code in such a way that the compiler understands my intentions to generate good machine code. Inlining is my favorite way to do this.
First, here's an aside. Good machine code:
uses registers more often than memory
rarely branches (if/else, for, and while)
uses memory more often than functions calls
rarely dynamically allocates any more memory (from the heap) than it already has
If you have a small class with very little code, then implement its methods in the body of the class definition and declare it locally (on the stack) when you use it. If the class is simple enough, then the compiler will often only generate a few instructions to effect its behavior, without any function calls or memory allocation to slow things down, just as if you had written the code all verbose and non-object oriented. I usually have assembly output turned on (/FAs /Fa with Visual C++) so I can check the output.
It's nice to have a language that allows you to write high-level, encapsulated object-oriented code and still translate into simple, pure, lightning fast machine code.

Here's my 2 cents.
I wrote a BlowFish cipher in C (and C#). The C# was almost 'identical' to the C.
How I compiled (i cant remember the numbers now, so just recalled ratios):
C native: 50
C managed: 15
C#: 10
As you can see, the native compilation out performs any managed version. Why?
I am not 100% sure, but my C version compiled to very optimised assembly code, the assembler output almost looked the same as a hand written assembler one I found.

C#'s edge over VB [closed]

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Closed 9 years ago.
What in C#.NET makes it more suitable for some projects than VB.NET?
Performance?, Capabilities?, Libraries/Components?, Reputation?, Reliability? Maintainability?, Ease?
Basically anything C# can do, that is impossible using VB, or vice versa.
Things you just have to consider when choosing C#/VB for a project.

C# and VB are basically the same however there are some minor differences. Aside from the obvious grammar differences you have the following differences:
C# can call unsafe code
VB has optional parameters (Coming in C#4.0)
VB is easier to use when making late bound calls (Coming in C# 4.0) This and number make 2 make using VB to do office automation much cleaner.
VB has a bunch of "helper" functions and class like the My namespace; however, all of this are accessible to C#
VB is case insensitive
C#'s syntax follow a similar grammar to c and java, which make it a much more comfortable transition from those languages, where as VB can be more comfortable to VB users. As far performance, and libraries or components they are nearly identical.
As for which one to choose, unless you have a need to do unsafe operations, then choose the language which is most natural to you. After years of being a VB developer I loved not having to write If yadada then.....End If if (yadaya){....} saves my carpal tunnel a few extra keystrokes (Which can then be used on answering SO questions)
Edit
Just learned one more difference btw C# and VB is that VB supports filtered exceptions so you could something like this pseudo:
try
{
//do something that fails
}
catch(Exception ex when ArgumentException,
ArgumentNullException, FormatException)
{
//Only handle these three types
}
This should not be confused with the ability to do:
try
{
//something that fails
}
catch(ArgumentException)
{
//Log Error
}
catch(ArgumentNullException)
{
//Log Error
}
In this case you are going to handle the exceptions differently in the VB world you could define one piece of code to handle multiple types of Exceptions.
Edit
Some more differences.
VB's Is operator compares two objects to determine if they are the same it compiles to the CEQ IL instruction where as C# compiles to isinst IL. So the following are equivalent statements
c#
if (foo is FooObject){}
vb
If TypeOf foo is FooObject then
Also as mentioned in the comments and I wish I could see them to give you credit but C# doesn't have a like parameter. You need to use the RegEx class.

I think this blog post by Kathleen Dollard provides an excellent overview to the question:
What a C# Coder Should Know Before They Write VB
and her first advice is:
1) Get over the respect thing or quit
before you start. VB is a great
language.

Street cred among geeks.
(And don't pretend that's not important!)

Others have covered a lot of the differences - as has been said several times, they're nearly equivalent languages. A few differences which haven't been covered as far as I've seen:
VB9 has:
XML literals
Mutable anonymous types (urgh)
More LINQ support in the language (C# only covers a few operators)
A whole bunch of extra bits in the language which get compiled down to calls to the Microsoft.VisualBasic assembly. (C# prefers to be a small language with the weight of the .NET framework behind it.)
DateTime literals
C# 3 has:
Better support for lambda expressions: IIRC, you can't write a lambda expression with a block body in VB.
Iterator blocks.
Syntax for extension methods (instead of decorating the method with an attribute)
I suspect there is more, but I thought I'd just throw those into the mix.

When you hit a problem, you'll often be able to Google for a code sample that shows how to solve it in minutes. This is a significant factor in improving productivity. When I was working with Delphi, I had to convert code samples from C into Object Pascal - doable, but tedious, i.e. lots of friction. So don't underestimate the fact that...
The vast majority of .Net code samples are in C# !

In early versions of VB.NET, the difference was more obvious, however with the current version, there are no significant differences.
VB supports XML literals directly in code, which is not supported by C#. C# supports unsafe code and VB don't. Technically these two are the biggest differences. There are many small variations but they are not important. I like C# more because I think the syntax is much less bloated. It's easy to recognize the blocks of code instead of seeing a bunch of keywords, but that's a pure personal preference.
Choose the one you and your team are more familiar with.

VB.Net has a root namespace and C# has a default namespace which is not the same. Because when you have a root namespace in VB.Net it will always add that before the namespace.
For example: if you have a rootnamepsace in VB.Net named namespace1 and then you add this to your file.
Namespace namespace1
Public Class class1
End Class
End Namespace
then you will have to refer to it as namespace1.namespace1.class1
in C# if you have a default namespace called namespace1 and you this in your file.
namespace namespace1{
public class class1{}
}
Then you can still just refer to it as namespace1.class1

My favorite feature of C# that VB doesn't have is the yield statement. It lets you easily return an lazily evaluated IEnumerable from a method.
Here is an article that covers it: http://msdn.microsoft.com/en-us/magazine/cc163970.aspx

VB has a better feedback on errors. In C# you have to compile more often to get all the errors in your syntax.

The big advantage i see with C# is that the vast majority of open source projects, sample code and blog snippets are written in C#. Although it’s easy to convert these to VB.NET with tools (or your head) it is still a monotonous task for VB devs (like me).
Even if you write in VB.NET day to day, you will still need to be able to read C#
Technically, they share the same framework with same performance and memory characteristics and same type systems, so I find it hard to hard to split the two.
Most good developers should be able to shift between the two with a few days adjustment time.
My core frustaration lies with the hundreds of time I have written:
String lastName as String
and wondered why it never compiles!

In C# you can have more fine tuned control over events/delegates. But you rarely need this.
There are a lot more code examples for C#.
In VB.Net it is (a lot) easier to use late binding. For example to COM objects (in C# from version 4.0).
I use C# for 90% in my projects
I use VB.Net for interop to Excel, etc
As soon as I know F# better, I will probably use it for the parts that F# is better suited for.

Performance?
No difference, though VB historically uses a weird indexing in loops which means that you have to subtract 1 from the highest index most of the time:
For i = 0 To someArrayOrString.Length - 1 …
Though I doubt this impacts performance in any measurable way.
On the other hand, due to background compilation, VB actually compiles seemingly faster. Some people claim that this makes the IDE react sluggishly but I've never noticed that myself.
Capabilities?
In a few instances, C#'s yield statement is really useful. VB requires more manual work here. Also, lambdas are much better implemented in C#, especially syntactically. Consider these two statements:
Parallel.For(1, 10000, i => {
// Do something
});
versus
Parallel.For(1, 10000, Sub() _
' Do something '
End Sub)
Besides the fact that VB can't do this yet, and that a comment at this place is forbidden, it's just more clutter and generally a no-go.
Libraries/Components?
Identical.
Reputation?
Not important. “Street cred”? Sorry. Not a factor. Get over it, Nick.
Reliability?
Maintainability?
Ease?
More or less identical. I claim that VB is easier but that may be biased and in any way, it's only marginal.

As I understand it, there are differences between the languages though they are minimal. I would suggest working with the language that you/your developers would feel most comfortable with. If they already have VB experience then I'd suggest VB.Net/vice-versa.
Though I prefer the terse syntax of C# personally. :)

Since C# and VB.Net both compile into MSIL, both have nearly identical Performance, Capabilities, Libraries and Components. Reflection can deassemble MSIL code into either C# or VB.NET (or a number of other languages)
This basically leaves us with, C# looks a lot like Java and C++ which gives it more credibility.

I think Josh gave a good rollup on the language differences.
Tooling Support
There are however also differences in how Visual Studio handles these languages.
Code Snippets are easier to use from the C# editor and the refactoring is better also.
The VB-editor simplifies intellisense by not showing all options at all times.
I'm sure there are more things, but those are the ones that I as a C#'er (doing very little VB) have noticed.

Here is another point not yet covered in this trail:
Higher Degree of Employability + Better (more) Dev Resources
Now I don’t agree with this point of view however:
There are more C# dev shops that VB shops
Some backward c# employers will put you at a serious disadvantage if you are stronger with VB. So maybe C# is the better choice here.
On the flip side, when you go to hire people for your C# project, you will be able to attract more candidates to iterview and get better skills as a result – I don't think detail should be overlooked.

I have to say it's been my experience when using Google to search for examples or documentation that C# examples are of better quality than VB examples. This isn't to say that there aren't bad C# examples, but if you search for something like "dictionary drop down" adding C# will provide a better quality answer higher on the list.
This doesn't apply to examples that display both C# and VB code side by side.

for the moment VB.Net has a very poor implementation of lambda expressions. Meaning that you can't do the neat things that you can in C#. Well you can, but it needs a very ugly workaround in most cases.
This is solved in VB.Net 10.0.

Free from old cruft, array declaration in C# is not padded with extra element. VB.NET array is padded with extra element, so legacy VB6 code migration is easier.
C# is more consistent than VB.NET
Button1.Color() = Color.Red
Button1.Color = Color.Red
I can't give an answer when one student asked me when to use parenthesis on properties of VB.NET. It's hard to give an insightful reasoning for this kind of misfeature.
Consistency with instance and static members. VB.NET allows accessing static members on instance e.g. yarn.Sleep(1000), this is a misfeature. https://stackoverflow.com/questions/312419/language-features-you-should-never-use

C# / F# Performance comparison

Is there any C#/F# performance comparison available on web to show proper usage of new F# language?

Natural F# code (e.g. functional/immutable) is slower than natural (imperative/mutable object-oriented) C# code. However, this kind of F# is much shorter than usual C# code.
Obviously, there is a trade-off.
On the other hand, you can, in most cases, achieve performance of F# code equal to performance of C# code. This will usually require coding in imperative or mutable object-oriented style, profile and remove bottlenecks. You use that same tools that you would otherwise use in C#: e.g. .Net reflector and a profiler.
That having said, it pays to be aware of some high-productivity constructs in F# that decrease performance. In my experience I have seen the following cases:
references (vs. class instance variables), only in code executed billions of times
F# comparison (<=) vs. System.Collections.Generic.Comparer, for example in binary search or sort
tail calls -- only in certain cases that cannot be optimized by the compiler or .Net runtime. As noted in the comments, depends on the .Net runtime.
F# sequences are twice slower than LINQ. This is due to references and the use of functions in F# library to implement translation of seq<_>. This is easily fixable, as you might replace the Seq module, by one with same signatures that uses Linq, PLinq or DryadLinq.
Tuples, F# tuple is a class sorted on the heap. In some case, e.g. a int*int tuple it might pay to use a struct.
Allocations, it's worth remembering that a closure is a class, created with the new operator, which remembers the accessed variables. It might be worth to "lift" the closure out, or replaced it with a function that explicitly takes the accessed variables as arguments.
Try using inline to improve performance, especially for generic code.
My experience is to code in F# first and optimize only the parts that matter. In certain cases, it might be easier to write the slow functions in C# rather that to try to tweak F#. However, from programmer efficiency point of view makes sense to start/prototype in F# then profile, disassemble and optimize.
Bottom line is, your F# code might end-up slower than C# because of program design decisions, but ultimately efficiency can be obtained.

See these questions that I asked recently:
Is a program F# any more efficient (execution-wise) than C#?
How can I use functional programming in the real world?
Is it possible that F# will be optimized more than other .Net languages in the future?

Here are a few links on (or related to) this topic:
http://cs.hubfs.net/forums/thread/3207.aspx
http://strangelights.com/blog/archive/2007/06/17/1588.aspx
http://khigia.wordpress.com/2008/03/30/ocaml-vs-f-for-big-integer-surprising-performance-test/
http://cs.hubfs.net/blogs/f_team/archive/2006/08/15/506.aspx
http://blogs.msdn.com/jomo_fisher/
What I seem to remember from another post on Robert Pickering's blog (or was it Scott Hanselman?) that in the end, because both are sitting on the same framework, you can get the same performance from both, but you sometimes have to 'twist' the natural expression of the language to do so. In the example I recall, he had to twist F# to get comparable performance with C#...