Database Systems Concepts - Essay Example

One more register, known as program counter register, consists of the address for the next instruction to be processed or executed. The stack pointer register is associated with an automated program stack that is located in the address space. Moreover, it can increase its size to the amount of memory available in the system. Generally, the stack point is triggered by the initial instructions of an application program. The stack representing the data structure increases downwards from high memory to low memory.

The central processing unit consists of many types of registers. General Purpose Registers are utilized for complex arithmetic calculations. A typical 8086 CPU is associated with 8 general purpose registers which are as follows: AX - the accumulator register are separated into AH / AL. They produce shortest machine code and supports arithmetic logic and data transfer. One of the numbers must indicate AL or AX. They also support multiplication and division, inputs and outputs. ‘BX’ the base address register is separated into ‘BH / BL’ and ‘CX’ count register is separated into ‘CH / CL’.

The segmentation of iterative code is conducted by the loop instruction. Moreover, the REP command executes monotonous operations on a string. Furthermore, it helps the counts of bits to transfer and revolve. ‘DX’ the data register is separated into ‘DH / DL’. ‘DX: AX’ concatenated into 32-bit register for some MUL and DIV operations. It specifies ports for enter and exit operations. The ‘SI’ source index register is utilized for indicating the data address. Likewise, it is used as a source in some instructions related to strings.

The addresses containing offsets are relative to DS. The ‘DI’ destination index register is utilized for data addressing indication. In some instructions related to strings, it is also used as destination. The addresses containing offsets are relative to ES. The’ BP’ base pointer register is primarily used for accessing parameters that are passed through the stack (8086 registers). The addresses containing offsets are relative to SS. The stack pointer register always indicates to the item available on the top of the stack.

The addresses containing offsets are relative to SS. It also indicates to word and an empty stack may have ‘SP = FFFEh’ value. Special purpose Accessible Application registers are combined with eight 4-bit registers for holding the status of the previous instruction. Segment Registers are divided in two parts in typical ‘x86’ architecture, named as segment and an offset. Segment registers are utilized to store segment values. The ‘CS’ indicates the segment including the current program.

‘DS’ indicates at segment including variables are. ‘ES’ extra segment register indicates its usage. SS register indicates the segment enclosing the stack. Special Kernel Mode Registers enables the execution of a user within the kernel space (8086 registers). The significant advantage of this procedure is valuable because it is an efficient mechanism for distribution of code and data. For instance, memory can contain only one copy of an editor or a compiler. Editor is a program that can be compared with the word processor.

Although, the main purpose of the editor is to amend the source code. The source code is defined as “Every computer program is written in a programming language,