Computer Organization: CPU and Stack Concepts

A data structure that follows the Last In, First Out (LIFO) principle, similar to a stack of trays where the last item placed on top is the first to be removed.

The operation of adding a new item to the top of a stack.

The operation of removing the top item from a stack.

A special register that stores the memory address of the top element in a stack.

A stack can be implemented using a designated portion of main memory or as a collection of registers.

A stack with a fixed number of storage locations, often implemented using a set of dedicated registers.

The number of elements that can be stored in a stack is limited by its size.

An attempt to add an element to a full stack, causing it to overflow and potentially lose data.

A segment of memory dedicated to storing stack data.

Special registers used to define the upper and lower limits of a stack in memory.

The process of adding a new element to the top of the stack, increasing the SP's value.

The process of removing an element from the top of the stack, decreasing the SP's value.

Instruction format that uses three address fields representing two input operands and a destination address to store the result.

The number of address fields present in an instruction, determining the number of operands an instruction can operate on.

A set of instructions that a processor understands and can execute. It defines the types of operations, the number of operands, and the addressing modes.

A memory addressing mode that combines direct addressing and register indirect addressing, where the effective address (EA) is calculated by adding a value (A) from an address field to the contents of a register (R).

A type of displacement addressing where the program counter (PC) is used as the reference register. The EA is calculated by adding the address field value to the current instruction address.

A type of displacement addressing where the reference register holds a base memory address, and the address field contains a displacement from that address. The register reference can be explicit or implicit.

A type of displacement addressing where the address field points to a main memory address, and the reference register contains a positive displacement (index) from that address. The register reference can be explicit or implicit.

A type of indexing where the index register is automatically incremented or decremented after each reference, often used in iterative tasks.

Auto-indexing where the index register is automatically incremented after each reference, useful for processing arrays in a sequential manner.

Auto-indexing where the index register is automatically decremented after each reference, useful for processing arrays in reverse order.

A type of auto-indexing where the index register is incremented or decremented by a value other than 1, allowing for larger or smaller steps in array processing.

In One-Address machines, instructions only require specifying the address of a single operand (the source).

The accumulator is a special register in a One-Address machine where intermediate results of calculations are stored.

The accumulator holds the operand used in One-Address instructions like 'load' and 'add'.

In One-Address instructions, the address of the operand is directly specified. For instance, 'load addr' copies the value at address 'addr' into the accumulator.

Zero-Address machines assume operands are located in a default location, typically the stack.

A stack is a data structure that follows the LIFO (Last-In, First-Out) principle, similar to stacking plates where the last one placed on top is the first to be removed.

In Zero-Address machines, both operands are retrieved from the stack, and the calculation result is returned to the stack.

Zero-Address instructions operate on stack data, avoiding the need to specify operand addresses.

In this addressing mode, the address field directly contains the memory address of the operand. It involves a single memory access without any calculations.

Instead of directly pointing to the operand, the address field points to another memory location containing the actual operand address. This requires an extra step where memory locations are accessed twice.

The address field points to a register that holds the operand's value. It requires only one operation because the operand is already in the register.

The address field points to a register, and that register contains the memory address of the operand. This involves two steps: first accessing the register and then using its content to access the memory.

Direct addressing limits the address range due to the fixed size of the address field.

It involves one fewer memory access compared to indirect addressing because the initial address is directly stored in the faster registers.

Register addressing has a smaller address space compared to other addressing modes because it only uses registers for storage.

Overall, the choice of addressing mode depends on factors like address range requirements, speed, and efficiency of execution. The address mode selected affects the instruction format and performance of the system.