2 3 4 Result
of
Shift
- a No overflow on left shift.
- Overflow on
left
shift.
Searching shift terminated with
Ra
equal to 1.
At
the
completion
of
right shifts,
the
condition
code
is
set
as follows:
2 3 4
a a
Logical Shift, Single Register
If the shift
count,
C,
is
positive,
the
contents
of
register R
are
shifted
left
C
places,
the
O's
copied
into
vacated
bit
positions on the right. (Bits shifted past
RO
are
lost.)
If C
is
negative,
the
contents
of
register R
are
shifted right
Ici
places,
with O's
copied
into
vacated
bit
positions on
the
left.
(Bits
shifted past
R31
are
lost.)
Affected:
(R),
CC1, CC2
Logical Shift, Double Register
o 1 2
nr
£.,J
If
the shift
count,
C, is
positive,
the
contents
of
registers
Rand
Ru1
are
shifted
left
C
places,
with
O's
copied
into
vacated
bit
positions on the right. Bits shifted past
bit
position a
of
register
Ru1
are
copied
into
bit
position
31
of
register
R.
(Bits shifted past
RO
are
lost.)
If C is
nega-
tive,
the
contents
of
registers
Rand
Ru1
are
shifted right
Ici
places
with
O's
copied
into
vacated
bit
positions on the
left.
Bits
shifted past
bit
position
31
of
register
Rare
copied
into
bit
position a
of
register
Ru
1. (Bits shifted
past
Ru
131
are
lost.)
Affected:
(R),
(Ru1), CC1,
CC2
Circular
Shift, Single Register
If the shift
count,
C,
is positive,
the
contents
of
register R
are
shifted
left
C
places.
Bits
shifted 'past
bit
position 0
are
copied
into
bit
position 31. (No bits
are
lost.)
If
C
is
negative,
the
contents
of
register R
are
shifted right
lei
places.
Bits
shifted past
bit
position
31
are
copied
into
bit
position
O.
(No bits
are
lost.)
Affected:
(R),
CC1, CC2
Circular
Shift, Double Register
If
the
shift
count,
C,
is
positive,
the
contents
of
registers R
and
Rul
are
shifted
left
C
places.
Bits shifted past
bit
position a
of
register
R
are
copied
into
bit
position
31
of
reg i
ster
Ru
1.
(No bi ts
are
lost.)
If
Cis
negati
ve,
the
contents
of
registers
Rand
Rul
are
shifted right
lei
places.
Bits shifted past
bit
position
31
of
register
Ru1
are
copied
into
bit
position 0
of
register
R.
(No bits
are
lost.)
Affected:
(R),
(Rul), CC1,
CC2
Arithmetic
Shift, Single Register
If
the
shift
count,
C, is
positive,
the
contents
of
register
R
are
shifted
left
C
places,
with O's
copied
into
vacated
bit
positions on
the
right. (Bits shifted past
RO
are
lost.)
If
C
is
negative,
the
contents
of
register
R
are
shifted right
lei
places,
with
the
contents
of
bit
position a
copied
into
va-
cated
bit
positions on the left. (Bits shifted past
R31
are
lost.)
Affected:
(R),
CC1, CC2
Arithmetic
Shift, Double Register
If the shift
count,
C,
is
positive,
the
contents
of
register R
and
Rul
are
shifted
left
C
places,
with O's
copied
into
va-
cated
bit
positions on
the
right. Bits shifted past
bit
posi-
tion a
of
register
Ru1
are
copied
into
bit
position
31
of
register
R.
(Bits shifted past
RO
are
lost.)
If
C
is
negative,
the
contents
of
registers
Rand
Ru1
are
shifted right
Ici
places,
with the contents
of
bit
position a
of
register R
copied
into
vacated
bit
positions on the left. Bits shifted
past
bit
position
31
of
register R
are
copied
into
bit
posi-
tion a
of
register Ru1. (Bits shifted past
Ru131
are
lost.)
Affected:
(R),
(Rul), CC1,
CC2
Searching Shift, Single Register
The
searching
shift
is
circular
in
either
direction.
If the
shift
count,
C,
is
positive,
the
contents
of
register
Rare
shifted
left
C
bit
positions
or
unti I a 1 appears in
bit
posi-
tion
O.
If C is
negative,
the
contents
are shifted right
Ici
positions or unti I a 1
appears
in
bit
position
O.
When the
shift is
terminated,
the remaining
count
is
stored in
regis-
ter
1, which
is
dedicated
to the searching shift instruction.
Shift Instructions
71
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