ZiLOG System 8000 User Manual page 60
Zeus operating system manual
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Also See for System 8000:
- Hardware reference manual (366 pages) ,
- Hardware reference manual (100 pages)
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USER
50
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USER
segmented address
In Z800l CPU's, a 23-bit value
consist-
ing
of a 7-bit segment number and a 16-
bit offset.
segmented mode One of the Running-state
modes
of
the
Z800l
CPU.
In this mode, the CPU gen-
erates addresses that can have different
segment numbers.
shell
A
shell is
a
command
language
inter-
preter.
It
is
possible
for users to
write
and
run
their
own
shells,
as
shells
are
no different from any other
program in terms of system response.
stack
A data
structure
used
for
temporary
storage
or
for procedure and interrupt
serVlce routine linkages.
A stack
uses.
the
last-in,
first-out
concept.
As
items are added to, or pushed onto,
the
stack,
the stack pointer decrements; as
items are removed from, or
popped
off,
the stack, the stack pointer increments.
stack pointer
A general-purpose
register
indicating
the top (lowest address) of a stack.
status
A command normally returns a status when
it finishes.
By convention, a status of
zero indicates
that
the
command
suc-
ceeded.
Commands
can
return non-zero
status to indicate
that
some
abnormal
event has occurred.
status flags
Status flags are set
according
to
the
outcome
of
. certain
instructions
to
direct the subsequent flow of
the
pro-
gram as necessary.
There are six status
flags:
Carry,
Zero,
Sign,
Parity/Overflow, Decimal Adjust and Half
Carry.
The
first
four
are
grouped
together
to
determine
the
condition
code, the last two are used in
programs
manipulating
~
digits.
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