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Re: decimal to binary?

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Bryan R Harris
September 23, 2009 12:42
Re: decimal to binary?
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> From: Uri Guttman
>>>>>>> "BM" == Bob McConnell <> writes:
>>   BM> From: Bryan R Harris
>>>> I need to convert a number like this:   -3205.0569059
>>>> ... into an 8-byte double (big and little endian), e.g. 4f 3e 52
> 00 2a
>>   BM> bc 93
>>>> d3  (I just made up those 8 byte values).
>>>> Is this easy in perl?  Are long and short ints easy as well?
>>   BM> The sprintf() family is your friend.
>> that will only generate text (hex and other formats). he needs pack
>> which does exactly what he wants. read perlpacktut for a tutorial on
>> pack/unpack and then perlfunc -f pack for the reference on it.
> That statement just confuses me. His initial value of -3205.0569059 is
> also text. It is the human readable representation of the number, and is
> not anything like what it looks like inside the computer. He just asked
> for a different format for that text. Why is sprintf not a reasonable
> way to do that?

The 8 bytes is an IEEE 754-2008 formatted number -- see here for an

It's not just a simple hex of a decimal...  You've got an exponent and a
sign encoded in there too.

I'm still reading the perlpacktut, but I'm hoping it'll get me to that.

- Bryan

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