register variable

Chapter 12th APO Programming languageThe APO programming language is based on assembly language and object-oriented programming. There are only 7 basic instructions: assignment instruction, copy instruction, BTX (bit x Test 1, or 0 transfer)

ScopeScope rules tell us the valid range of a variable, where it was created and where it was destroyed (that is, out of scope). The valid scope of a variable starts at its defining point, to the first closing parenthesis of the nearest opening

Auto ordinary local stack variable: is automatic storage, the limit variable can only be used inside the function, this object is automatically created and destroyed, it is recommended that the variable is placed on the stack, the function is called

the scope of a variableThe C language divides variables into local variables and global variables, depending on the scope of the variables.1. Local Variables1> definition: A variable defined inside a function, called a local variable. Formal

Scope rules tell us the valid range of a variable, where it was created and where it was destroyed (that is, out of scope). The valid scope of a variable starts at its defining point, to the first closing parenthesis of the nearest opening brace

Register keyword Register declares the Register variable [try to store the variable in the internal CPU Register, not absolute] CPU reads data: memory -- register -- CPU Although the register speed is very fast, there are limits: The register

Several common methods to optimize C code In terms of performance optimization, we always pay attention to the 80-20 principle, that is, 20% of the program consumes 80% of the running time. Therefore, to improve the efficiency, we mainly consider

Use macro definition In C language, macros are embeddedCode. For embedded systems, macros are a good method to replace functions to meet performance requirements. Write a "standard" macro min, which inputs two parameters and returns a smaller

Keyword OverviewMany of my friends may have doubts. Many other C-language books often start from HelloWorld and Data Types in C language. Why should we start from the keywords of C language? I have two points to note:This chapter is intended for

You can add attribute keywords when defining variables.1) AutoAuto is the default property of the local variable in the C language.Auto indicates that the modified variable is stored on the stackThe compiler defaults to all local variables that are

Storage categories for C + + variables (dynamic storage, static storage, automatic variables, register variables, external variables)dynamic storage mode and static storage mode We've learned about the scope of variables. Scopes are analyzed from

The C language is a total of 32 keywords, listed below:1.auto declaring automatic variablesBy default, all variables of the compiler default are auto2.int declaring integer variables3.double declaring double-precision variables4.long declaring long

1. register variable The keyword regiter requests the compiler to store the variable in the CPU register as much as possible. Note the following points. 1. The register variable must be a type that can be accepted by the CPU register. This usually

I. Basic data types: The data type can be understood as an alias with a fixed memory size. It is a model for creating variables. A variable is an alias for an actual Continuous Bucket. In a program, you can apply for and name a bucket through a

Http://www.cnblogs.com/Ninputer/archive/2011/06/07/2074632.html In the first article of this series, I would like to give an overview of the Compiler Construction and help you understand the purpose of each component in the compiler. I think you

Register modifier implies CompilationProgramThe corresponding variables will be frequently used. If possible, they should be stored in CPU To speed up its storage. For example, the following memory block copyCode, # Ifdef nostructassign

Local variables 1> definition: A variable defined inside a function, called a local variable. Formal parameters also belong to local variables. You must assign a value before you can use the;2> scope: The local variable is only valid inside

0. BackgroundWhile looking at the seventh chapter of Apue, the author analyzes the effect of setjmp and longjmp on different storage type variables, and sees register,auto,volatile,static And so on these keywords is very vague, may also be too

Directory4.1 Basic knowledge of functions 4.2 function external variable 4.4 scope rule returning a non-integer value header file static variable Register variable program block structure Initializes a 4.10 Recursive 4.11 C

int i;for (i=0; iIn order to solve this problem, it is possible to put frequently used variables in the general register of the CPU, so that the use of the variable without access to memory, directly from the register to read, greatly improve the