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U-reg
R-reg
U-reg
02 High
=
0000 0000
= 0000 0111 = Reg
15
Byte
2
data
result
=
0000 0111
S3 will remain 0 as there is no
carryout.
Local storage is again addressed by
the expression T->N LS.
The data read
is 00000000.
This is the data from byte
1 of register 15.
Positions 4 and 5 of the S-register
are set to zero (0->S4, S5).
S5 has never been set to one, so the
0,0 branch is taken to address 0140 ..
ADDRESS 0140:
The data from byte
1
of
register 15 is regenerated (WRITE).
The expression LXH + RL->T sets up
the units byte address of general pur-
pose register
II
in the T-register. Reg-
ister 4 is specified by the X2 portion
of our instruction.
Remember, the L-
register contains
Rl
X2
0011
0100.
The A-register input to ALU is set from
the L-register.
The data in the A-
register is
High
Low
0011
0100.
This data is crossed (X) and only the
high portion (H) is used as A source
data, 0100 0000.
In the portion of the expression, RL,
theB-register input to ALU is set from
the CR ROS control field (R).
The value
in the CR field is specified on the E
line.
The data in the B-register is
therefore, 0011 0011.
Only the low
portion(L) is used as B source data.
The data becomes:
3-42
A source data
B source data
=
0100
= 0000
Reg
II
0000
0011
Byte 3
T-register data
= 0100
0011
The next ROS word is at address 0132.
ADDRESS 0132:
The expression R+O+C->DC
transfers the data in the R-register to
the D-register.
The D-register data is
00000000, which comes from register 15
byte
1.
No carries are involved.
Again, core is read (T->N LS).
This
causes the first byte of data to be read
from register 4.
This data is 00101000
because one of the facts of our problem
specified that this register contained
the value of 40 in binary.
The sixth position of the S-register
is set to 1 (1->S6).
The next step is address 0138 at
location A8.
ADDRESS 0138:
The data just read is
regenerated (WRITE).
The T-register is
changed to obtain the address of the
next byte of information.
Reg
II
0100
Byte 2
0010
is the data in the T-register as a
.result of the expression T-O->T.
The next ROS word in sequence is at
address 010A.
ADDRESS 010A:
The data in the V-
register is added to the data in the
R-register.
If a carryout occurs as a
result of the addition, it is allowed to
set S3 (V
+
R->VC).
The data added is:
V-register data
R-register data
=
10101000
=
00101000
V-register result
=
11010000
There is no carryout.
S3 remains zero.
The reading of core is controlled by
T->N .LS.
This causes the data from
register 4 byte 2 to be read.
This data
is 0000 0000.
The branch controls are S6 and O.
S6, if you will recall, was set to a one
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