Data Registers

Processor Registers

Basic theoretical information

MULTIPLICATION IN ASSEMBLY LANGUAGE

INTRODUCTION

TROUBLESHOOTING........................................................................ 6

MULTIPLICATION IN ASSEMBLY LANGUAGE........................... 6

TASK

It is necessary to develop an algorithm (in the form of a flowchart) and write a program for this algorithm in Assembler microprocessor Intel x86. The topic of the homework is chosen from Table 1,according to my 20^th variant in students list.

Table 1. Tasks for HW

Variant number	Topic
	Investigation of logic opetarors(1, 2 and more bytes).

CONTENT

TASK......................................................................................................... 3

INTRODUCTION...................................................................................... 5

1.1 Basic theoretical information............................................................. 6

1.2 Rules of block diagram representation............................................... 7

1.3 Structure of assembly program Mult.exe........................................... 9

CONCLUSION........................................................................................ 24

REFERENCES........................................................................................ 25

An assembly language is a low-level programming language for microprocessors and other programmable devices. It is not just a single language, but rather a group of languages. Assembly language implements a symbolic representation of the machine code needed to program a given CPU architecture.

Also known as assembly code. The term is often also used synonymously with 2GL.

Assembly languages generally lack high-level conveniences such as variables and functions, and they arenot portable between various families of processors. It has the same structures and set of commands as machine language, but it allows a programmer to use names instead of numbers. This language is still useful for programmers when speed is necessary or when they need to carry out an operation that is not possible in high-level languages.

Processor operations mostly involve processing data. This data can be stored in memory and accessed from thereon. However, reading data from and storing data into memory slows down the processor, as it involves complicated processes of sending the data request across the control bus and into the memory storage unit and getting the data through the same channel.

To speed up the processor operations, the processor includes some internal memory storage locations, called registers.

The registers store data elements for processing without having to access the memory. A limited number of registers are built into the processor chip.

There are ten 32-bit and six 16-bit processor registers in IA-32 architecture. The registers are grouped into three categories −

• General registers,
• Control registers, and
• Segment registers.

The general registers are further divided into the following groups −

• Data registers,
• Pointer registers, and
• Index registers.

Four 32-bit data registers are used for arithmetic, logical, and other operations. These 32-bit registers can be used in three ways −

· As complete 32-bit data registers: EAX, EBX, ECX, EDX.

· Lower halves of the 32-bit registers can be used as four 16-bit data registers: AX, BX, CX and DX.

· Lower and higher halves of the above-mentioned four 16-bit registers can be used as eight 8-bit data registers: AH, AL, BH, BL, CH, CL, DH, and DL.

Some of these data registers have specific use in arithmetical operations.

AX is the primary accumulator; it is used in input/output and most arithmetic instructions. For example, in multiplication operation, one operand is stored in EAX or AX or AL register according to the size of the operand.

BX is known as the base register, as it could be used in indexed addressing.

CX is known as the count register, as the ECX, CX registers store the loop count in iterative operations.

DX is known as the data register. It is also used in input/output operations. It is also used with AX register along with DX for multiply and divide operations involving large values.

Дата добавления: 2017-01-14