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Advantages of Inline Assembly

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Because the inline assembler doesn’t require separate assembly and link steps, it is more convenient than a separate assembler. Inline assembly code can use any C variable or function name that is in scope, so it is easy to integrate it with your program’s C code. Because the assembly code can be mixed inline with C or C++ statements, it can do tasks that are cumbersome or impossible in C or C++.

The uses of inline assembly include:

  • Writing functions in assembly language.

  • Spot-optimizing speed-critical sections of code.

  • Making direct hardware access for device drivers.

  • Writing prolog and epilog code for “naked” calls.

Inline assembly is a special-purpose tool. If you plan to port an application to different machines, you’ll probably want to place machine-specific code in a separate module. Because the inline assembler doesn’t support all of Microsoft Macro Assembler’s (MASM) macro and data directives, you may find it more convenient to use MASM for such modules.