先决条件–地址绑定方法
地址绑定是程序指令和数据与实际物理内存位置的关联。操作系统中有多种类型的地址绑定。
地址绑定有3种类型:
- 编译时地址绑定
- 加载时间地址绑定
- 执行时间地址绑定
在这里,我们比较加载时间和执行时间地址绑定,如下所示。
加载时间地址绑定:
在将程序加载到内存后,将完成这种地址绑定。加载时间地址绑定将通过操作内存管理器来完成。
执行时间或动态地址绑定:
即使将程序加载到内存中,地址绑定也将被推迟。程序将不断更改内存中的位置,直到执行程序为止。这种地址绑定类型将在程序执行时由处理器完成。
加载时间和执行时间地址绑定之间的区别:
Load Time Address Binding | Execution Time Address Binding |
---|---|
Loader is responsible for the load time address binding. | Execution time address binding is done by processor. |
It generates physical address. | It generates dynamic absolute address. |
Load time address binding is done after loading the program into memory. | Execution time address binding is done at the time of program execution. |
Absolute address is converted to relocatable address. | It helps in execution. |
Instructions are loaded in memory. | From memory instructions are executed by CPU. |
It works with physical address. | It works with dynamic absolute address. |
It is static address binding. | It is dynamic address binding. |
It is done by operating system memory manager itself. | It is done by processor at the time of program execution. |