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Re: [MiNT] EmuTOS for ColdFire



Hi,

Line-A constitutes a pitfall here. This range of opcodes are used for MAC-instructions on the ColdFire. Didier solves this by replacing $a000 with an unused TRAP. This trap should probably be implemented in freemint for "standard" 68k machines as well.

ColdFire stuff should run fairly well on 060 CPUs, since AFAIK complex instructions and address modes are slower than load/store instructions on the 060.

Note: Line-A is a big no-no, I know that, but a lot of applications still rely on the $A000 opcode for some reason. Maybe this is part of some old startup vod or whatever. In a perfect universe, the best way to remedy this would be in the application itself. However, I think the only realistic solution would be to add the TRAP call to the OS instead, because this makes it very easy to patch the applications in question for ColdFire compatibility.

-- PeP


2 maj 2009 kl. 13.38 skrev Markus Fröschle:


Am 02.05.2009 um 13:23 schrieb Vincent Rivière:

I know that, but is a CodFire between a 68000 and 68010? That is what I don´t understand.

Something which hasn't been mentioned yet, but is very important in my opinion when it comes to TOS/MinT compatibility:

Although running MC680xx programs on a CF v4e CPU requires a CPU emulation library, this is not absolutely necessary the other way round. The Coldfire instruction set is more like a subset of the 680xx instruction set than an enhancement and, with some care (only using adressing modes and instructions which are available on both processors), it should be possible to write programs which run natively on 680xx as well as Coldfire processor architectures (although they might not run as fast on the older architecture than they would if written exclusively for them).