<s>
While	O
marketed	O
externally	O
as	O
a	O
high-performance	O
microcontroller	B-Architecture
,	O
it	O
has	O
been	O
almost	O
exclusively	O
used	O
combined	O
with	O
the	O
Philips	O
SCC66470	O
VSC	O
(	O
Video	O
-	O
and	O
Systems	O
Controller	O
)	O
in	O
the	O
Philips	B-Device
CD-i	I-Device
interactive	O
entertainment	O
product	O
line	O
.	O
</s>
<s>
Additions	O
to	O
the	O
Motorola	B-Device
68000	I-Device
core	O
include	O
:	O
</s>
<s>
Differences	O
from	O
the	O
Motorola	B-Device
68000	I-Device
core	O
include	O
these	O
:	O
</s>
<s>
The	O
SCC68070	O
has	O
MC68010	B-Device
style	O
bus-error	O
recovery	O
.	O
</s>
<s>
The	O
SCC68070	O
lacks	O
a	O
dedicated	O
address	B-General_Concept
generation	I-General_Concept
unit	I-General_Concept
(	O
AGU	B-General_Concept
)	O
,	O
so	O
operations	O
requiring	O
address	O
calculation	O
run	O
slower	O
due	O
to	O
contention	O
with	O
the	O
shared	O
ALU	O
.	O
</s>
<s>
This	O
means	O
that	O
most	O
instructions	O
take	O
more	O
cycles	O
to	O
execute	O
,	O
for	O
some	O
instructions	O
significantly	O
more	O
,	O
than	O
a	O
68000	B-Device
.	O
</s>
<s>
The	O
MMU	B-General_Concept
is	O
not	O
compatible	O
with	O
the	O
Motorola	B-Device
68451	I-Device
or	O
any	O
other	O
"	O
standard	O
"	O
Motorola	O
MMU	B-General_Concept
,	O
so	O
operating	O
system	O
code	O
dealing	O
with	O
memory	O
protection	O
and	O
address	O
translation	O
is	O
not	O
generally	O
portable	O
.	O
</s>
<s>
Enabling	O
the	O
MMU	B-General_Concept
also	O
costs	O
a	O
wait	O
state	O
on	O
each	O
memory	O
access	O
.	O
</s>
<s>
While	O
the	O
SCC68070	O
is	O
mostly	O
binary	B-General_Concept
compatible	I-General_Concept
with	O
the	O
Motorola	B-Device
68000	I-Device
,	O
there	O
is	O
no	O
equivalent	O
chip	O
in	O
the	O
Motorola	B-Device
680x0	I-Device
series	O
.	O
</s>
<s>
In	O
particular	O
,	O
the	O
SCC68070	O
is	O
not	O
a	O
follow-on	O
to	O
the	O
Motorola	B-General_Concept
68060	I-General_Concept
.	O
</s>
<s>
Even	O
though	O
the	O
SCC68070	O
is	O
a	O
32-bit	O
processor	O
internally	O
,	O
it	O
has	O
a	O
24-bit	O
address	B-Architecture
bus	I-Architecture
,	O
giving	O
it	O
a	O
theoretical	O
16MB	O
maximum	O
RAM	B-Architecture
.	O
</s>
