Understanding CPU Flags in Computer Architecture

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What is the purpose of the OFFSET assembler directive?

To load the offset value of a variable into a register (correct)

To access elements of an array using an index

To add a constant to the contents of a register to get the final address

To pass a parameter to a procedure

What is the purpose of the indexed addressing mode?

To access elements of an array using an index (correct)

To add a constant to the contents of a register to get the final address

To pass a parameter to a procedure

To load the offset value of a variable into a register

What is the difference between using OFFSET and the lea instruction to load the address of a variable into a register?

OFFSET loads the actual address, while lea loads the effective address

OFFSET is more efficient than lea for loading variable addresses

OFFSET has run-time overhead, while lea has assembly-time overhead

OFFSET can only be used for variables, while lea can be used for more complex addressing modes (correct)

When would you need to use the lea instruction instead of the OFFSET directive?

When the needed data is available at run time only Signup and view all the answers

What is the purpose of the displacement addressing mode?

To add a constant to the contents of a register to get the final address Signup and view all the answers

Which addressing mode is used to access array elements using an index stored in a register?

Indexed addressing mode Signup and view all the answers

What does the CS (Code Segment) register store?

Starting address of the code segment in memory Signup and view all the answers

How are 40-bit numbers stored after multiplication?

Most significant 40 bits in AC, least significant in MQ Signup and view all the answers

What does SS (Stack Segment) register point to?

Starting address of the stack Signup and view all the answers

Which register holds the starting address of an extra data segment?

ES Signup and view all the answers

What is the default size of a quad word?

8 bytes Signup and view all the answers

Which combination represents a default 32-bit segment and offset?

32-bit segment and offset Signup and view all the answers

What does the Trap Flag (T) do when set to 1?

Enables single-step mode for processor operation Signup and view all the answers

When the Direction Flag (D) is set to 1, what happens to the registers during string instructions?

Registers are automatically decremented Signup and view all the answers

What does the Overflow Flag (O) indicate after a signed arithmetic operation?

Overflow of a high-order bit Signup and view all the answers

What is the purpose of the I/O Privilege Level field (IOPL)?

Defines privilege level of current process Signup and view all the answers

What activates the Alignment Check flag bit (AC)?

Word or doubleword addressed on a non-boundary Signup and view all the answers

What does the Nested Task (NT) flag control?

Linking current process to the next process Signup and view all the answers

What is the purpose of the jump operation mentioned in the text?

To specify the address of the next instruction in the program Signup and view all the answers

How many classes of instructions are mentioned in the text?

5 Signup and view all the answers

What is the size of an instruction in the 4-address instruction format?

13 bytes Signup and view all the answers

What is the maximum amount of memory that can be accessed by the 4-address instructions?

16 MB Signup and view all the answers

What type of machine is based on an accumulator register?

Accumulator based machine Signup and view all the answers

Which machine type works on the principle of Last In First Out (LIFO)?

Stacked based machine Signup and view all the answers

What is a characteristic of an Accumulator based machine?

Second term of an operation is fetched from memory Signup and view all the answers

Understanding CPU Flags in Computer Architecture

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