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Free42 with IEEE 754-2008 decimal floating-point -- interested in a sneak preview?
03-02-2014, 10:59 PM
Post: #39
RE: Free42 with IEEE 754-2008 decimal floating-point - interested in a sneak preview?
(03-02-2014 08:14 PM)Thomas Okken Wrote:  Note that this does mean you'll get a State File Corrupt message when you run these new builds, because of alignment changes inside the file. Also, compatibility when going from 1.4.78 or earlier to 1.4.79 is still broken

I'm going to change the state file format to something EBML-based. This is going to delay the official 1.4.79 by a week or two, but it's long overdue... Every time I change anything about the state, like adding a setting or changing representations, I currently have to break forward compatibility. Also, writing and maintaining the code that has to deal with all these state file variations, to maintain backward compatibility, is a huge pain. Free42 1.4.79 has a lot of problems in this regard, because the BCD20 library's BCDFloat type is an array of eight two-byte integers, while the Intel library's BID_UINT128 type is a struct of two eight-byte integers, and this causes compilers to change the layout of structs that incorporate these types...

With EBML, forward compatibility will be trivial (older versions will simply ignore newer state items they don't recognize), and it will become possible to move state files between devices with different CPU architectures, and that will make it much easier for me to debug problems with state file reading and writing.
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RE: Free42 with IEEE 754-2008 decimal floating-point - interested in a sneak preview? - Thomas Okken - 03-02-2014 10:59 PM



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