Hardware square root gcc

I'm trying to use the hardware instructions to compute some mathematical functions. For example the square root (sqrtpd instruction). I'm compiling my C code with GCC.

Does Anybody know what are the gcc options to force to compile with the hardware instructions and not to use the libc? Or if I need to do something special on my source code? (Without writing asm code).

On gcc you should use `__builtin_ia32_sqrtpd`.

The easiest way is to use optimization flags. -O1 generates

`sqrtsd %xmm1, %xmm0`

in assembly code. Try using -S flag with gcc to generate assembly and look how optimization flags works.

Why don't you just write the desired hardware instruction in assembly code directly.

As far as I know, writing assembly code directly in c code is possible. It is called Inline Assembly. [ See here:

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