unimplemented cpu and fpu emu

pjhutch · 14 December 2013, 16:31

Does any one know what the 'unimplemented cpu and fpu emu' options do?
Are they undocumented cpu features or does it mean it will emulate non-Motorola 680x0 cpus?

Leffmann · 14 December 2013, 19:31

It emulates the 040 and 060 as if they had the complete 680x0 and 68881 instruction sets.

The 040 and 060 are not fully backward-compatible, and Commodore solved this with the 68040.library and 68060.library which are loaded by SetPatch to provide software emulation and achieve backward compatibility.

If you've ever had software crash on your 040 and 060 when you booted without startup-sequence then it's probably because you didn't load SetPatch, and effectively have had an incompatible CPU.

Toni Wilen · 15 December 2013, 16:47

Yeah, options were added when emulation was improved enough to allow full (*) emulation of missing instruction exceptions (It is much more complex than it looks).

Note that even 6888x have "missing" instructions, 68040+ introduced few new FPU instruction variants. (FDxxx and FSxxx)

*) It isn't 100% full, unsupported data type exception is not emulated because it requires quite tricky new stack frame type. (when exception returns, instruction needs to resume!)

14 December 2013, 16:31	#1
pjhutch Peter Join Date: Oct 2004 Location: Sowerby Bridge,UK Age: 57 Posts: 102	unimplemented cpu and fpu emu Does any one know what the 'unimplemented cpu and fpu emu' options do? Are they undocumented cpu features or does it mean it will emulate non-Motorola 680x0 cpus?

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
030 cpu with fpu: Sync or Async?	HeZoR	support.Hardware	18	27 December 2012 18:00
Best CPU and FPU settings	Bloodwych	support.WinUAE	8	29 January 2012 12:54
GUI: FPU selector is grey when cycle-extract or cpu more compatible is selected.	Thom87	support.WinUAE	0	16 August 2011 09:18
060 SysSpeed CPU FPU?	ancalimon	support.Hardware	7	03 January 2010 15:10
Unimplemented error 21	lours	support.WinUAE	1	31 May 2009 00:19

14 December 2013, 19:31	#2
Leffmann Join Date: Jul 2008 Location: Sweden Posts: 2,269	It emulates the 040 and 060 as if they had the complete 680x0 and 68881 instruction sets. The 040 and 060 are not fully backward-compatible, and Commodore solved this with the 68040.library and 68060.library which are loaded by SetPatch to provide software emulation and achieve backward compatibility. If you've ever had software crash on your 040 and 060 when you booted without startup-sequence then it's probably because you didn't load SetPatch, and effectively have had an incompatible CPU.

15 December 2013, 16:47	#3
Toni Wilen WinUAE developer Join Date: Aug 2001 Location: Hämeenlinna/Finland Age: 49 Posts: 26,505	Yeah, options were added when emulation was improved enough to allow full () emulation of missing instruction exceptions (It is much more complex than it looks). Note that even 6888x have "missing" instructions, 68040+ introduced few new FPU instruction variants. (FDxxx and FSxxx) ) It isn't 100% full, unsupported data type exception is not emulated because it requires quite tricky new stack frame type. (when exception returns, instruction needs to resume!)

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)