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Try to use _control87() (or even __control87_2()) instead of _controlfp().
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Try to use _control87() (or even __control87_2()) instead of _controlfp().

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I have a large project with numerous floating point operations which I am converting from Visual C++ 6 to Visual Studio 2010 c++. &nbsp;I've hit a problem in the different way that VS2010 deals with underflow denormals.<br />
<br />
Consider the following code:<br />
&nbsp; &nbsp; &nbsp; &nbsp; unsigned int cw = _controlfp(0, 0);//this returns &nbsp;589855 in both VC6 and VS2010<br />
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;float abba=12.5;<br />
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;int myin=0;<br />
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;for (myin=0; myin&lt;100; myin ++)<br />
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;{<br />
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;abba = abba/10.1;<br />
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;}<br />
<br />
Both VS2010 and VC6 behave the same up until abba reaches the FLT_MIN lower bound for a float, around 1e-38. &nbsp;After that point in VC6 abba goes to 1e-45, and then to 0.0000. &nbsp;In VS2010, it goes to a garbage 8e-39#DEN value.<br />
<br />
500 points to the person who can show me how to get the VC6 behavior back.<br />
<br />
Notice the _controlfp(0,0) integer in both VS2010 and VC6 they are the same, 589855.
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I have a large project with numerous floating point operations which I am converting from Visual C++ 6 to Visual Studio 2010 c++.  I've hit a problem in the different way that VS2010 deals with underflow denormals.

Consider the following code:
        unsigned int cw = _controlfp(0, 0);//this returns  589855 in both VC6 and VS2010
	float abba=12.5;
	int myin=0;
	for (myin=0; myin<100; myin ++)
	{
		abba = abba/10.1;
	}

Both VS2010 and VC6 behave the same up until abba reaches the FLT_MIN lower bound for a float, around 1e-38.  After that point in VC6 abba goes to 1e-45, and then to 0.0000.  In VS2010, it goes to a garbage 8e-39#DEN value.

500 points to the person who can show me how to get the VC6 behavior back.

Notice the _controlfp(0,0) integer in both VS2010 and VC6 they are the same, 589855.

C++ floating point denormal

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