The control unit (CU) coordinates the sequencing of steps involved in executing

Question

The control unit (CU) coordinates the sequencing of steps involved in executing machine instructions. The ALU performs only addition, subtraction, multiplication, and division operations. Data travels along a bus one bit at a time. The most basic unit of time for machine in is called the machine cycle. The upper half of the EAX register is called AX. The lower half of the EBX register is called BX. The Overflow flag is set based on the results of signed arithmetic. The Zero flag is clear when the result of an arithmetic operation is zero. Registers in the floating-point unit are 80 bits long. Microprograms are interpreted and executed by machine instructions. In Real-address mode, only one program can run at a time. In Virtual-8086 mode, only a single virtual machine can run at one time. In the multi-segment model (Protected mode), each program is given its own local descriptor table. Segment limit and base address are both fields within a segment descriptor. In Protected mode, the total memory used by all running programs can never be larger than the computer's physical memory.

Explanation / Answer

1) True, the control unit coordinates the sequencing of steps involved in executing machine instruction.

2) False, ALU not only performs arithmetic operations (addition, subtraction, multiplication and division) instead it also performs logical operations.

3) False, data travels one byte at a time and not one bit at a time

4) True, basic unit of time for machine instructions is machine cycle.

5) False, AX is the lower half of EAX register and not the upper half.

6) False, BX is not the lower half of EAX, AX is the lower half of EAX register.

7) True, overflow tag is set based on the results of signed arithmetic.

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