Learning high-level languages like Python and Java may help you develop different software and web applications. But with the knowledge of assembly language, a programmer can gain a lot of other benefits as well. Assembly languages have a wide range of applications such as real-time coding systems, boot scripts, low-level embedded systems, reverse engineering, device drivers, and many others. If you wish to learn more about assembly language, then read this blog. Here, we have shared complete details about the features, components, working, and types of assembly languages.
What is Assembly Language?
Assembly is a low-level programming language. However, it is more similar to machine-level language than C. In general, the assembly language is closely related to the architecture’s machine code instructions and is specific to that machine.
An assembler is a software application that translates assembly code into machine code for execution. It converts assembly code’s basic instructions and operations into binary code that a certain type of processor can understand.
With the assemble language, you can alter hardware, address performance issues, and access CPU-specific instructions. Moreover, it is also helpful for programmers to write code that is nearly as readable and understandable as machine code. Machine language is difficult to comprehend and understand because it is made up entirely of numbers. However, assembly language provides absolute control over computer operations.
Assembly language plays a vital role in the development of operating systems, the creation of device drivers, programming embedded systems, and security research.
How is Assembly Language Different from Machine Language?
Machine language is a low-level computer language made up of binary numbers (0 and 1). The only language a computer understands is machine language. However, the computer does not interpret assembly language directly. The assembler converts assembly language to machine language for execution.
Also Read: Low-Level Programming Language Examples
Features of Assembly Language
Listed below are some prominent features of assembly language.
- Declares data using the decimal characters.
- High-level control over numerous hardware operations.
- It is exceptionally quick because it is well-optimized to use only the necessary resources.
- Good memory management.
- It helps with the specification of the symbolic operand by eliminating the requirement to provide the operand’s machine address. It is possible to depict it with a symbol.
- Access memory and hardware registers that are impossible to access using high-level languages.
- Eliminates the need to rely on compilers for code optimization.
- Assembly issues are far easier to discover and fix than compiler bugs.
Working Process of Assembly Language
Assembly languages use mnemonic codes to define what the processor should perform. It primarily transforms mnemonic code created by programmers into machine language (binary code) and executes it. Particularly, to translate assembly code into machine language, it uses an assembler. That machine code will be then placed in an executable file so that it can be executed.
Furthermore, the assembly language permits direct hardware communication between the programmer and registers, memory locations, input/output devices, and other hardware elements. This could enable the programmer to effectively manage resources and exert direct control over hardware components.
Key Components of Assembly Language
The following are the key components of assembly language.
Registers
The fast memory areas found inside the processor are called registers. It facilitates the temporary caching of data and arithmetic operations performed by ALU. Example: Bx, Cx, and Ax (Accumulator).
Instructions
Instructions are mnemonic codes that you give the processor to accomplish certain operations, such as LOAD, ADDITION, and MOVE. Example: ADD.
Commands
A command is an instruction in assembly code that tells the assembler what to do. Assembly language instructions usually use self-descriptive acronyms to simplify vocabulary such as “ADD” for addition and “MOV” for data movement.
Mnemonics
An abbreviation for an assembly language command or the name of a machine function is called a mnemonic. In assembly, every mnemonic refers to a unique machine instruction. An example of one of these machine commands is Add. Other examples include CMP, Mul, and Lea.
Labels
It is a symbolic name or identifier essential for designating a specific location or address in assembly code. For example, FIRST indicates the beginning of the code’s execution.
Macros
Macros are program routines that, once defined, can be called from anywhere in the program. Furthermore, compilers and assemblers are frequently incorporated into it. You should declare it as a directive %macro.
Operands
These are the values or data that you have been given along with instructions on how to handle them. For example, in ADD R1, R2; Here, R1 and R2 are operands.
Opcode
These are mnemonic codes that tell the processor which operation has to be performed. Example: ADD stands for Addition.
Also Read: What are the Different Types of Coding Languages?
Different Types of Assembly Languages
Each CPU type has its own assembly language and set of instructions. However, they all look remarkably similar. Since each CPU type has its own unique characteristics, no two assembly languages are identical. Some examples of distinct CPU architectures include embedded microcontrollers, microcomputers, high-performance servers and workstations, minicomputers, and mainframes.
Generally, at least one assembler will be there for CPU architecture. However, a single CPU architecture can support a large number of different assemblers. Even if all assemblers for a given CPU architecture produce machine code for that architecture, each uses a somewhat different syntax or set of rules.
Aside from that, when programmers develop a program to convert human-readable assembly language to machine code, they can modify the syntax. For example, some assemblers include macro-instructions to save typing; they may have distinct syntax even for the same underlying CPU type. Also, they may even use distinct mnemonics for the same command, such as “JNE” against “BNE” for “jump on not equal” and “branch on not equal”, or “JMP” versus “JUMP”.
If you know the Assembly language for one CPU, then all you need to do is study the instruction set manual and generate code for a different CPU. Regardless of processor type, an assembly language can be classified into three categories.
Basic Assembly Language
It is a type of assembly language that converts instructions to opcodes. The basic assembly language is mostly used for small embedded devices.
Typical/Normal Assembly Language
It performs the same operations as Basic assembly language, but it additionally includes directives and pseudo-instructions for producing data blocks, defining code segments, and much more. This is how a lot of assemblers operate.
Macro Assembly Language
It includes loops, substitutions, and other elements. They could be incredibly powerful in the future. This is illustrated via the IBM 360 Assembler. Mostly, the Microsoft x86/x64 MASM assembler exhibits this.
What are the Different Types of Assemblers?
Some students often confuse the types of assembly languages with the types of assemblers. An assembler is a kind of software that translates assembly language to machine code. Primarily, an assembler is divided into two types. They are One-Pass Assembler and Two-Pass/Multi-Pass Assembler.
One-Pass Assembler
It is a type of assembler that will convert the entire assembly code into machine code in a single pass.
Two-Pass/Multi-Pass Assembler
This assembler type will convert the assembly code into machine code in two passes. First, it processes the code and stores the results in the opcode tables. In the second stage, it builds a machine code using the opcode tables.
Pass 1
- Defines opcode and symbol table
- Keeps track of the location counter
- Processes pseudo instructions
Pass 2
- Translates opcode into numeric opcode
- Generates machine code as per the values of literals and symbols
Also Read: A Beginner’s Guide to Sequel Programming Languages
What are Symbol Table, Location Counter, and Opcode Table?
Symbol tables maintain tabs on the numerical values that correspond to the symbols used in programming languages.
The Opcode table records mnemonics’ values along with their numerical counterparts.
Location Counter stores the current instruction’s storage location’s address.
Conclusion
Hopefully, by now, you will have gained a better understanding of the different types of assembly languages and assemblers. Typically, there is no standard categorization of Assembly language types because the architecture of each machine includes its own assembly language. Moreover, it ranges from very basic (4004, 6502) to quite complicated (VAX-11, etc.).
In case, you have any doubts about assembly language, contact us immediately. On our team, we have numerous assembly language experts to clarify your queries and guide you in strengthening your subject knowledge.
