Assembly language - computer architecture, Computer Engineering

Assignment Help:

Assembly language:

An assembly program has a series of instructions--mnemonics that relate to a stream of executable instructions, when translated by an assembler that may be loaded into memory and then executed.

For an example, an x86/IA-32 processor may execute the following binary instruction as expressed in machine language (see x86 assembly language):

  • Binary: 10110000 01100001 (Hexadecimal: B0 61)

The equivalent assembly language representation is simpler to remember (example in the Intel synta x, more mnemonic):

  • MOV AL, 61h

Means of this instruction:

  • Move the value 61h (or 97 decimal; the h-suffix means hexadecimal; into the processor register named "AL".

The mnemonic "mov" represents the opcode 1011 which moves the value in the second operand into the register specified by the first operand. The mnemonic was selected by the instruction set designer to abbreviate "move", by making it easier for the programmer to remember.  A comma-separated list of parameters or arguments follows the opcode; it is a typical assembly language statement.

In practice many programmers drop the word mnemonic and which is technically incorrect, call "mov" an op code. When they do this they are referring to the underlying binary code which it represents. To put it as a way, a mnemonic such as "mov" is not an op code, but it symbolizes an op code, one can refer to "the op code mov" for instance when one intends to refer to the binary op code it symbolizes rather than to the symbol -- the mnemonic -- itself. As few modern programmers have required being attentive of actually what binary patterns are the op codes for specific instructions, the distinction has in practice become a bit blurred among programmers but not among processor designers.

An assembler transforms assembly language into machine language, and the reverse by disassemble. There is typically a one-to-one correspondence between assembly statements unlike in high-level languages, and the machine language instructions. But, in some cases, an assembler can provide pseudo instructions which expand into various machine language instructions to provide commonly required functionality. For instance, for a machine that lacks a "branch if greater or equal" instruction, an assembler can be used a pseudo instruction that expands to the machine's "branch if zero (on the result of the set instruction)"and "set if less than" and. All the full-featured assemblers also provide a rich macro language mostly (discussed below) which is used by programmers and vendors to generate more difficult code and data sequences.

Each processor architecture and computer architecture has its own machine language. On this level, each instruction is enough simple to be executed by using a relatively small number of electronic circuits. Computers differ by the type and number of operations they support. For instance, a new 64-bit machine would have different circuitry from a 32-bit machine. They can also have different sizes and numbers of registers and different representations of data types in storage. Whereas most general-purpose computers are able to carry out really the same functionality, the ways they do so differ; the equivalent assembly languages reflect these differences.

Multiple sets of assembly-language syntax or mnemonics may exist for a single instruction set, typically instantiated in different assembler programs. In these types of cases, the most popular one is usually that supplied by the manufacturer and used in its documentation.


Related Discussions:- Assembly language - computer architecture

Explain the trackball and thumbwheel devices, Explain the Trackball and Thu...

Explain the Trackball and Thumbwheel devices  Joysticks A joystick consists of a small, vertical lever (called the stick) mounted on a base that is used to steer the screen

Designing the instruction format, Q. Designing the instruction format is a ...

Q. Designing the instruction format is a complex art? Instruction Length Significance: It's the fundamental issue of the format design. It concludes the richness and flex

Show the programmes for parallel systems, Q. Show the Programmes for Parall...

Q. Show the Programmes for Parallel Systems? Adding elements of an array using two processor      int sum, A[ n] ;  //shared variables

Explain vehicle tracking system, Case Study - A taxi company has 200 taxies...

Case Study - A taxi company has 200 taxies. The company provides its services to all the nine districts in Mauritius, about 20 taxies per district. A taxi is normally attached to

Which important terminal required between dte and pstn, An important termin...

An important terminal that is required between DTE and PSTN is (A)  Server                                      (B) MODEM (C)  Relay

What is rambus dram, Q. What is Rambus DRAM? RDRAM which was developed ...

Q. What is Rambus DRAM? RDRAM which was developed by Rambus has been adopted by Intel for its Pentium and Itanium processors. It has become main competitor to SDRAM. RDRAM chip

Advantages of edi (electronic data interchange), Advantages of EDI 1.  ...

Advantages of EDI 1.  EDI replaces paper transactions with electronic transactions therefore it saves times and speeds up transactions. 2.  It gives a legal record of busine

What are the process states in unix, What are the process states in Unix? ...

What are the process states in Unix? As a process implements it changes state according to its circumstances. Unix processes have the following states: Running : The process

Explain the typical functions of operating systems, List the typical functi...

List the typical functions of operating systems. Classical functions of operating system are given as: (1) Process management: A process is a program throughout execution.

Introduction to parallel computing, Introduction  To Parallel Computing ...

Introduction  To Parallel Computing Parallel computing has been a subject of importance in the computing community over the last few years. Ever-growing volume of databases and

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd