Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!usc!cs.utexas.edu!asuvax!hrc!gtephx!robertsw
From: robertsw@...!asuvax!gtephx (Wild Rider)
Newsgroups: comp.lang.c
Subject: Re: Floating point format conversion?
Message-ID: <1991Apr29.190528.1061@...!asuvax!gtephx>
Date: 29 Apr 91 19:05:28 GMT
References: <1991Apr25.203121.11130@ericsson.se>
Reply-To: robertsw@gtephx.UUCP (Wild Rider)
Organization: AG (formerly GTE) Comm. Sys., Phx, AZ
Lines: 50


	i tried email, but (alas), it bounced; here's the text:

In article <1991Apr25.203121.11130@ericsson.se> writes:
>
>Hi,
>
>I have a data file which was written using Micrsoft binary format for
>floating point numbers.  On a PC this is not a problem because the
>microsoft C libraries have a function to convert the MSC binary format
>to IEEE binary format.
>
>I am looking for a function to perform this same function on a Sun
>workstation running SunOS 4.1.1.  Does anyone have the source code
>for this type of function or know the algorithm for such a conversion?
>

	uh, well, if it were me, being the lazy scumbag that i am :-),
	i'd simply do the conversion on the pc side using the microsoft
	conversion function, then ship the converted data to the sun.

	but, i suppose, you already have the data on the sun & have
	no way of getting it to the pc & back?

	hmm... well, then, you _do_ have a problem, don't you...
	if you have the intestinal fortitude, you can write a
	function in c to do the trick; i had to convert ibm (mainframe)
	floating point to ieee & was able to do it in c pretty
	easily, once i had the specs for the 2 formats.  all you 
	need to do is declare a bitfield struct for each format, 
	then push the bits around as necessary.  for example, i
	believe the following struct pretty much describes an ieee
	floating point value:

		typedef struct {
			ieee_sign	unsigned:1;
			ieee_exp	unsigned:8;
			ieee_mantissa	unsigned:23;
		} ieee_t;

	btw, don't forget the "hidden bit" when you're doing the conversion...
	all this makes more sense when you're looking at the specs.

	hope this helps...
	wr (wild rider)
-- 
Wallace Roberts, AG (formerly GTE) Communication Systems, Phoenix, AZ
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