Addressing Modes MCQ Quiz in मराठी - Objective Question with Answer for Addressing Modes - मोफत PDF डाउनलोड करा

If the code is position-dependent, then a suitable addressing mode is a relative addressing mode.

The effective address is computed from X (PC, X bytes away from the address pointed by the program counter.

Relative addressing mode uses a program counter and indexed addressing mode uses and general-purpose register.

Answer: Option 1

Explanation: 

We have given a cache memory organization with m lines in which the cache is divided into v sets, each of which consists of k lines.

Consider m = 8, v = 4, k = 2

Representation for this organization is:

To reduce it to direct mapping:

Make v = m, because in both direct mapping and set associative mapping, we have to take the mod operation to find the line number and set number respectively.

Also, make k = 1, because each set starts behaving like a line as in the case of direct mapping.

The skip instruction does not need an address field and is therefore a zero-address instruction.

A conditional skip instruction will skip the next instruction if the condition is met. This is accomplished by incrementing the program counter during the execute phase in addition to its being incremented during the fetch phase.

If the condition is not met, control proceeds with the next instruction in sequence where the programmer inserts an unconditional branch instruction.

PUSH B:

• Store the contents of register pair BC on top two locations of the stack
• Address are defined by stack pointer
• So, it is register indirect addressing mode

Base addressing:
The operand’s offset is the sum of an 8 bit or 16-bit displacement and the contents of the base register BX or BP.

Effective address =  Base register + Content = 140 + 40 = 180

PC relative base addressing:

The effective address for a PC - relative instruction address is the offset parameter added to the address of the next instruction. This offset is usually signed to allow reference to code both before and after the instruction.

Effective address = Program Counter + Base register + Content = 80 + 140 + 40 = 260

An instruction code is a group of bits that instruct the computer to perform a specific operation.

The operation code of an instruction is a group of bits that define such operations as add, subtract, multiply, shift, and complement.

Answer: Option 3

Concept: 

Implied/Implicit addressing mode:

In implied/implicit addressing mode the operand is hidden and the data to be operated is available in the instruction itself.

Register addressing mode:

It is the simplest addressing mode in which the source or destination is a data register or an address register. Content of the register provides the operand. Here, only one register reference is required to access the data.

Index addressing mode:

The address of the operand is obtained by adding to the contents of the general register (index register) a constant value. Index mode is used to access an array whose elements are in successive memory locations.

Direct addressing mode:

The data to be operated is available inside a memory location and that memory location is directly specified as an operand. The operand is directly available in the instruction itself.

Relative addressing mode:

Contents of the program counter are added to the address of an instruction to find the effective address.

Immediate addressing mode:

In this, the operand is specified in the instruction itself. It has an operand field and data is present in the address field of instruction. 

Base addressing mode:

In this, an effective address is found by adding the displacement with the base register. It is a type of displacement addressing mode.

Indirect addressing mode:

The address field of an instruction specifies the address of a memory location that contains the address of the operand.

In this, the address field of instruction gives the address where an effective address is stored. It is helpful to handle pointers.

Absolute addressing mode:

In this, the address part specifies the effective address of the operand. It is also known as direct addressing. If A = contents of an address field in instruction then Effective address = A. It is used to declare global variables in a program and used for branch instructions.

PC relative base addressing mode:

The effective address for a PC - relative instruction address is the offset parameter added to the address of the next instruction. This offset is usually signed to allow reference to code both before and after the instruction.

Concept:

Relative addressing mode:

In this addressing mode, effective address is obtained by adding the next instruction address with the address field.

Effective address (EA) = PC + operand part

where PC is the program counter register

Therefore Relative mode of addressing is most relevant to writing position-independent code

In implied mode, the operands are specified implicitly in the definition of the instruction.

For example,

the instruction "complement accumulator" is an implied-mode instruction because the operand in the accumulator register is implied in the definition of the instruction.

In fact, all register reference instructions that use an accumulator are implied-mode instructions.

Important Points

Addressing modes of 8085:

Immediate addressing mode:

In immediate addressing mode, the source operand is always data. If the data is 8-bit, then the instruction will be of 2 bytes, if the data is of 16-bit then the instruction will be of 3 bytes.

Register addressing mode:

In register addressing mode, the data to be operated is available inside the register(s) and register(s) is(are) operands. Therefore, the operation is performed within various registers of the microprocessor.

Direct addressing mode:

Indirect addressing mode, the data to be operated is available inside a memory location and that memory location is directly specified as an operand. The operand is directly available in the instruction itself.

Register indirect addressing mode:

In register indirect addressing mode, the data to be operated is available inside a memory location and that memory location is indirectly specified by a register pair.

Implied/Implicit addressing mode:

In implied/implicit addressing mode the operand is hidden and the data to be operated is available in the instruction itself.

Addressing modes of 8085:

Immediate addressing mode:

In immediate addressing mode, the source operand is always data. If the data is 8-bit, then the instruction will be of 2 bytes, if the data is of 16-bit then the instruction will be of 3 bytes.

Register addressing mode:

In register addressing mode, the data to be operated is available inside the register(s) and register(s) is(are) operands. Therefore, the operation is performed within various registers of the microprocessor.

Direct addressing mode:

Indirect addressing mode, the data to be operated is available inside a memory location and that memory location is directly specified as an operand. The operand is directly available in the instruction itself.

Register indirect addressing mode:

In register indirect addressing mode, the data to be operated is available inside a memory location and that memory location is indirectly specified by a register pair.

Implied/Implicit addressing mode:

In implied/implicit addressing mode the operand is hidden and the data to be operated is available in the instruction itself.