27 Oct
2011
27 Oct
'11
1:40 p.m.
On 27 Oct 2011 at 16:08, David Riley wrote:
It's an "assembly-compatible" 68K
variant, which means the opcodes
have been shuffled around to optimize silicon area in the decoder, but
all the mnemonics are still there aside from a few bits of
functionality they decided were unnecessary or extremely seldom-used.
Early Coldfires didn't have separate user and supervisor stack
pointers like the real 68K, but modern ones all do and I never had to
work with any without. It's not object-code compatible with the 68K,
but reassembling generally does the trick and most of the SPRs are
pretty much the same.
Didn't Motorola start this idea with the 6809? I seem to remember
that they advertised it as being "assembly-compatible" with the 6800,
even though the instruction sets were very different.
--Chuck