Computer IAS
IAS memory
of 1000 storage locations called word which each consist of 40 binary digits
(bits). Data and instructions are also stored here. Because the data and
instruction must be expressed in the form of binary code. Control Units operate
IAS by taking instruction from the instruction memory and mengkesekusinya once.
Both the ALU and control unit contains the location of the storage locations
called registers:
1. Memory
Buffer Register (MBR)
The MBR
contains a word to be stored in memory or used to receive a word from memory.
2. Memory
Address Register (MAR)
MAR is used
to determine the address of a word in memory to be written to or read from MBR
to the MBR.
3.
Instruction Register (IR)
This IR
contains 8-bit instruction code that will be executed.
4. Instruction
Buffer Register (IBR)
IBR is used
to temporarily store right next instruction word in memory.
5. Program
Counter (PC).
PC contains
the address of the next instruction pairs are retrieved from memory.
6.
Accumulator (AC) and Multiplier-Quotient (MQ)
Used to
temporarily store operands and results of operations of the ALU. For example,
the result of multiplying two 40-bit numbers is a 80-bit number; 40 most
significant bit (most significant bit) is stored in the AC and 40 less
significant bits (least significant bit) is stored in the MQ.
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