How to: Inline assembler in C++ (under Visual Studio 2010)

Question

I\'m writing a performance-critical, number-crunching C++ project where 70% of the time is used by the 200 line core module.

I\'d like to optimize the core using inl

Answer 1

Nothing is in the registers. as the _asm block is executed. You need to move stuff into the registers. If there is a variable: 'a', then you would need to

__asm {
  mov eax, [a]
}

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It is worth pointing out that VS2010 comes with Microsofts assembler. Right click on a project, go to build rules and turn on the assembler build rules and the IDE will then process .asm files.

this is a somewhat better solution as VS2010 supports 32bit AND 64bit projects and the __asm keyword does NOT work in 64bit builds. You MUST use external assembler for 64bit code :/