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The register address specified by the
R .. and R2 fields should be 0, 2, 4, or
6.
Otherwise, a specification exception
is recognized, and a program interrup-
tion is caused.
The storage address of the second
operand should designate word boundaries
for short operands and doubleword boun-
daries for long operands.
Otherwise, a
specification exception is recognized,
and a program interruption is caused.
Results replace the first operand,
except for the storing operations, where
the second operand is replaced.
Except for the storing of the final
result, the contents of all floating-
point or general registers and storage
locations participating in the
addreSSing or execution part of an oper-
ation remain unchanged.
The floating-point instructions are
the only instructions using the
floating-point registers.
DATA
FLOW
SYSTEM CONTROL
•
•
Read Only Storage (ROS) controls
data movement.
Capacitor Cards determine ROS
output.
The System/360 Model 30 uses a Read Only
Storage unit to control the movement of
data throughout the system, Figure 1-25.
This control includes the actual circuit
components for addressing the ReS and
for sensing and decoding the output.
Just as you would follow a sequence of
operations to perform a mathematical
coroputation, the ROS steps through a
series of micro-instructions to perform
a xrachine language instruction.
These
xricro-instructions consist of storage
control, Arithmetic Logic Unit (ALU)
control, register input and output con-
trols, machine status control, ROS
sequencing control, and input-output
controls.
1-31
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