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tesjo

Member

Registered: 2007-11-30

Posts: 164

What's this C++ function?

I thought I would see how gcc calculates a simple function like sqrt(). In the cmath header I find

sqrt(float __x)
  { return __builtin_sqrtf(__x); }

This 'builtin' function doesn't seem to be in another header that I can find. So can someone tell me how this works? Is it delegated to the cpu or is that a bad guess?

Please don't post a sqrt code, thats not what I'm looking for.

Cerebral

Forum Fellow

From: Waterloo, ON, CA

Registered: 2005-04-08

Posts: 3,108

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Re: What's this C++ function?

I think that falls back to a compiler-builtin function.  It's probably written in assembly or something of that sort.