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Old 23 August 2015, 14:34   #245
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Join Date: May 2014
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Originally Posted by meynaf View Post
So Gunnar's excuses for rejecting my MOVEM.B idea were invalid
(and the removal of MOVEM.W in the coldfire doesn't look very smart either)
Didn't Coldfire remove many word sized operations?

If DIV is no big deal, would an integer SQR be a problem ?
Not really. It was a looong time since I've touched something like that but a Newton-Rapson started by a table lookup should IIRC be enough. It requires resources that may be better spent though.

Too bad. Why did you stop doing your 68k implementation, btw ?
Many reasons. It wasn't a good fit to support a full 68k instruction set, while it could support (this was never implemented) virtual memory it wouldn't be compatible with existing software. It was designed for a certain family of FPGA without any thought on portability, while fast clock wise some relatively common code patterns would be slow (somewhat like the Pentium 4). This and other things meant I simply lost interest in it.

If I'll ever restart the design it would probably be translated to a VLIW type design with code morphing in Transmeta style.

Other 68k instructions need microcode as well. Oh, wait. They're the 020+ insns everyone removes too
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