MAS281 Dynex, MAS281 Datasheet - Page 3

• Manufacturer Part Number: MAS281
• Description: MIL-STD-1750A Microprocessor
• Manufacturer: Dynex

1.1.3 PARALLEL MULTIPLIER/ACCUMULATOR
accumulates the product in a single machine cycle. Only four
iterations through the multiplier are required to complete a 16-
bit by 16-bit multiply.
1.1.4 BARREL SHIFTER
network. The barrel shifter allows multibit shifts to be
accomplished in a single machine cycle and is used by the
microcode for all shift, rotate, and normalise operations.
1.1.5 STATUS REGISTER
P, Z, and N; the 4-bit address state (AS) field; and the 4bit
processor state (PS) field. The CS bits are updated after each
logical, shift, and arithmetic operation performed by the ALU.
This multiplies a 24-bit multiplicand by a 4-bit multiplier and
This shifter is a 32-bit input, 16-bit output right-shift
This 16-bit register holds the condition status (CS) bits C,
The CU interrogates these bits during conditional
Figure 2: MAS281 Architecture
operations to determine which course of action to follow. The
AS field is used during expanded memory access to define the
page register set to be used for instruction and operand
memory references. The PS field is used during memory
protect operations to define the access key used for memory
accesses. The PS field is also used during execution of
privileged instructions. PS must be zero for such operations to
be legal. Figure 3 depicts the status register format
1.1.6 STATE SEQUENCER
oscillator, to generate processor timing and control signals.
These signals constitute the lowest level of control available
within the module, and provide the framework for basic
operations, such as selecting the next microinstruction to be
executed, sequencing bus control signals to effect a memory
transfer, or performing an operation within the ALU. Each
complete pass through the state machine corresponds to one
such operation and constitutes a machine cycle.
The EU utilises a state machine, clocked by the system
MAS281
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