Re: print(268435456 + 1)

["Brian Weed" <bw@...>]

Brian Weed wrote:
> Aaron Brown wrote:
> > Brian Weed wrote:
> >
> > > Is there something about adding numbers that I should know
> > > about?
> >
> > > print(0x10000000)
> > > 268435456
> > >
> > > print(0x10000000 + 0x00000001)
> > > 268435456
> > >
> > > print(0x10000000 + 0x00000002)
> > > 268435456
> >
> > I get 268435456, 268435457, and 268435458.  My first guess
> > is that you're using (single-precision) floats instead of
> > doubles.  What platform are you on?  Did you change
> > LUA_NUMBER when compiling?
> >
> > http://docs.sun.com/source/806-3568/ncg_goldberg.html
> This is on Win32 (Lua is part of our game engine).  We did not modify 
> LUA_NUMBER.  It's still double.
> Lua is compiled as a static lib via Visual C++ 6.0.  The app is 
> compiled via Visual Studio 2005.
>
> Brian

Ok, this is really weird...

The following C code has the same problem (while watching "d" in the 
debugger in Visual C++ 6.0):

double d = 0x10000000;

d = d + 0x00000002;

doubles are supposed to be able to completely represent  a 32bit int right?

Brian