Specifications
EXCEPTIONS & INTERRUPTS
All
two-hundred
fift~-six
68000
interrupts
and
exceptions
are
suPPorted
b~
the
microcode,
whether
or
not
they
can
be
expected
to
occur.
The
68000
provides
two
kinds
of
interrupts;
Auto-Vectored
and
Device-Vectored.
The
VS100
utilises
the
Auto-Vector
system.
All
unimplemented
interrupts
and
exceptions
result
in
the
~eneration
of
an
error
code/messase.
EXCEPTIONS
Bus_Errors
are
~enerated
by
accessin~
non-existant
Unibus
memory
(if
NXM
is
set),
when
the
link
Soes
down
while
accessin~
le~itimat~
Unibus
memor~
(not
includin~
CSR's,
which
are
alwa~s
considered
to
be
accessible),
or
when
the
retrY
counter
overflows.
Address_Errors
occur
when
a
word
or
Ions-word
operand
is
accessed
at
an
odd
address.
Other
exceptions
are
initialised
even
thouSh
unused,
in
order
to
insure
asainst
hardware/firmware/microcode
buss.
All
exceptions
other
than
bus
errors
.re
recovered
from
by
use
of
the
rte
instruction.