MSIL commands are as follows:
ldstr string :—loads the string constant onto the stack.
call function(parameters) :—calls the static function. Parameters for the function should be loaded onto the stack before this call.
pop :—pops a value from the stack. Used when we don't need to store a value in the variable.
ret :—returns from a function.
I will discuss about MSIL in my next article.
2 :- CLR(Comman Language Runtime) Full form of CLR is Common Language Runtime and it forms the heart of the .NET framework.It is the implementation of CLI .The core runtime engine in the microsoft .net framework for executing assemblies. All Languages have runtime and its the responsibility of the runtime to take care of the code execution of the program. For example VC++ has MSCRT40.DLL,VB6 has MSVBVM60.DLL, Java has Java Virtual Machine etc. Similarly .NET has CLR. Internet Exlorer is the example of hosting CLR. CLR have following qualities :-
Garbage Collection :- CLR automatically manages memory thus eliminating memory leaks. When objects are not referred GC automatically releases those memories thus providing efficient memory management.
Code Access Security :- CAS grants rights to program depending on the security configuration of the machine. Example the program has rights to edit or create a new file but the security configuration of machine does not allow the program to delete a file. CAS will take care that the code runs under the environment of machines security configuration.
Code Verification :- This ensures proper code execution and type safety while the code runs. It prevents the source code to perform illegal operation such as accessing invalid memory locations etc.
IL( Intermediate language )-to-native translators and optimizer’s :- CLR uses JIT and compiles the IL code to machine code and then executes. CLR also determines depending on platform what is optimized way of running the IL
code.
3 :- CTS(Comman Type System) :- In order that two language communicate smoothly CLR has CTS (Common Type System).Example
in VB you have “Integer” and in C++ you have “long” in c u have "int" these datatypes are not compatible so the interfacing between them is very complicated. In order to able that two different languages can 1. Basic .NET Framework communicate Microsoft introduced Common Type System. So “Integer” datatype in VB6 and
“int” datatype in C++ will convert it to System.int32 which is datatype of CTS. CLS which is covered in the coming question is subset of CTS.
4 :-CLS(Common Language Specification) :- This is a subset of the CTS which all .NET languages are expected to support. It was always a
dream of Microsoft to unite all different languages in to one umbrella and CLS is one step towards that. Microsoft has defined CLS which are nothing but guidelines that language to follow so that it can communicate with other .NET languages in a seamless manner.
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It's a good tutorial.I have read your posts it sounds interesting keep it up.
ReplyDeleteJust In Time Compilers (JITers)
ReplyDeleteWhen our IL compiled code needs to be executed, CLR invokes JIT compilers which compile the IL code to native executable code (.exe or .dll) for the specific machine and OS. JITers in many ways are different from traditional compilers as they, as their name suggests, compile the IL to native code only when desired e.g., when a function is called, IL of function’s body is converted to native code; just in time of need. So, the part of code that is not used by particular run is not converted to native code. If some IL code is converted to native code then the next time when its needed to be used, the CLR uses the same copy without re-compiling. So, if a program runs for sometime, then it won’t have any just in time performance penalty. As JITers are aware of processor and OS exactly at runtime, they can optimize the code extremely efficiently resulting in very robust applications. Also, since JITer knows the exact current state of executable code, they can also optimize the code by in-lining small function calls (like replacing body of small function when its called in a loop, saving the function call time). Although, Microsoft stated that C# and .Net are not competing with languages like C++ in efficiency, speed of execution, JITers can make your code even faster than C++ code in some cases when program is run over extended period of time (like web-servers).
Garbage Collector :-
ReplyDeleteCLR also contains Garbage Collector (GC) which runs in a low-priority thread and checks for un-referenced dynamically allocated memory space. If it finds some data that is no more referenced by any variable/reference, it re-claims it and returns the occupied memory back to the Operating System; so that it can be used by other programs as necessary. The presence of standard Garbage Collector frees the programmer from keeping track of dangling data.