IEEE 754 Converter

[JF2015]

Hi, i have a problem concerning float values. I receive a 4 Byte value through the serial port in the following order: SEEEEEEE EMMMMMMM MMMMMMMM MMMMMMMM S - Sign E - Exponent M - Mantissa so, for example i have: 43h 89h 80h 00h (h...hexadecimal) which is the decimal value of: 275.0 My question is, if anybody knows a way of converting the 4 Byte value to the float value. Thanks in advance for any help you can provide

[blackjack2150]

In C++, you would write number = (sign ? -1:1) * 2^(exponent) * 1.(mantissa bits)

[Guffa]

Use the BitConverter.ToSingle method.

--- single minded; short sighted; long gone;

[CPallini]

Actually, with C++ you can be more extreme, for instance:

unsigned char myBytes[4]={0x43, 0x89, 0x80, 0x00};
unsigned char myReversedBytes[4];

myReversedBytes[0] = myBytes[3];
myReversedBytes[1] = myBytes[2];
myReversedBytes[2] = myBytes[1];
myReversedBytes[3] = myBytes[0];
float f = *(float *)myReversedBytes;

Note that if you're lucky the original bytes have not to be reversed. :-D

If the Lord God Almighty had consulted me before embarking upon the Creation, I would have recommended something simpler. -- Alfonso the Wise, 13th Century King of Castile.

[CPallini]

Note that, If you intend to use the Guffa solution (that indeed is the correct one), then you have to reverse the order of the bytes to get the correct result. :)

If the Lord God Almighty had consulted me before embarking upon the Creation, I would have recommended something simpler. -- Alfonso the Wise, 13th Century King of Castile.

[Vikram A Punathambekar]

Sounds like you need a union. :)

Cheers, Vıkram.

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After all is said and done, much is said and little is done.

[JF2015]

Thanks a lot. This really helped me. I almost thought i would have to code it on my own.

[JF2015]

Thanks, you guys are a real good source for advice. No wonder that there are lots of people asking anyone of you instead of looking in the msdn documents.:-D

[CPallini]

Vikram A Punathambekar wrote:

Sounds like you need a union.

AFAIK C# doesn't provide it.:)

If the Lord God Almighty had consulted me before embarking upon the Creation, I would have recommended something simpler. -- Alfonso the Wise, 13th Century King of Castile.

[Vikram A Punathambekar]

[bangs head against wall]

Cheers, Vıkram.

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After all is said and done, much is said and little is done.