T
REGISTERS
There
are
sixty-four
64-bit
T
registers
in the computation section.
T
registers
are
used
as
intermediate storage for the S
registers.
The
Data
may
be
transferred
bidirectionally
between
T
and
S
registers
and
between
T
registers
and
memory.
The
transfer
of a value
between
a T
register
and
an
S
register
requires only
one
clock period. T
registers
reference
memory
through block read
and
block write
instructions.
Block
transfers
occur
at
a
maximum
rate
of
one
word
per clock period.
No
reservations are
made
for T
registers
and
no
instructions
can
issue during
block
transfers
to
and
from
T
registers.
In
this
manual, T
registers
are referred to
by
the
letter
T
and
a
2-digit
octal subscript in the range
00
through
77.
Instructions reference T
registers
by
allowing
specification
of the octal subscript
as
the jk
designator
as
described in section 4 of
this
manual.
A
REGISTERS
The
eight 24-bit A
registers
serve a variety of applications.
They
are
primarily
used
as
address
registers
for
memory
references
and
as
index
registers
but also are
used
to provide values for
shift
counts, loop
control,
and
channel
I/O
operations.
In
address applications, they are
used
to index the base address for
scalar
memory
references
and
for
providing both a base address
and
an
index address for vector
memory
references.
The
address functional units support address
and
index generation
by
performing 24-bit integer arithmetic
on
operands obtained
from
A
registers
and
delivering the
results
to A
registers.
Data
can
move
directly
between
memory
and
A
registers
or
can
be
placed in
B
registers
as
an
intermediate step. This allows buffering of the data
between
A
registers
and
memory.
Data
can
also
be
transferred
between
A
and
S
registers.
The
vector length
register
is
set
by
transmitting a value to
it
from
an
A
register.
2240004
3-8
E
To Next Page
Loading...