instruction sets. Therefore, studying a single assembly language is sufficient to learn: I) the basic concepts; II) to recognize situations where the use of assembly language might be appropriate; and III) to see how efficient executable code can be created from high-level languages. Typical applications Assembly language is typically used in a system's boot code, the low-level code that initializes and tests the system hardware prior to booting the operating system and is often stored in ROM. (BIOS on IBM-compatible PC systems and CP/M is an example.) Assembly language is often used for low-level code, for instance for operating system kernels, which cannot rely on the availability of pre-existing system calls and must indeed implement them for the particular processor architecture on which the system will be running. Some compilers translate high-level languages into assembly first before fully compiling, allowing the assembly code to be viewed for debugging and optimization purposes. Some compilers for relatively low-level languages, such as Pascal or C, allow the programmer to embed assembly language directly in the source code (so called inline assembly). Programs using such facilities can then construct abstractions using different assembly language on each hardware platform. The system's portable code can then use these processor-specific components through a uniform interface. Assembly language is useful in reverse engineering. Many programs are distributed only in machine code form which is straightforward to translate into assembly language by a disassembler, but more difficult to translate into a higher-level language through a decompiler. Tools such as the Interactive Disassembler make extensive use of disassembly for such a purpose. This technique is used by hackers to crack commercial software, and competitors to produce software with similar results from competing companies. Assembly language is used to enhance speed of execution, especially in early personal computers with limited processing power and RAM. Assemblers can be used to generate blocks of data, with no high-level language overhead, from formatted and commented source code, to be used by other code. See also Compiler Comparison of assemblers Disassembler Hexadecimal Instruction set architecture Little man computer – an educational computer model with a base-10 assembly language Nibble Typed assembly language Notes References Further reading (2+xiv+270+6 pages) Kann, Charles W. (2021). "Introduction to Assembly Language Programming: From Soup to Nuts: ARM Edition" ("An online book full of helpful ASM info, tutorials and code examples" by the ASM Community, archived at the internet archive.) External