Assembler

Assembler:

1. A program that converts an assembly language source file into machine code.  In a higher level language, we have programs called compilers that convert the high level language into machine code.  An assembler is different because it’s not interpreting high level concepts to form large machine code equivalents.  Instead, it just takes the instructions, one at a time, and converts each into one actual machine code instruction.  It’s a different and simpler process, so it is not called a compiler and is just an assembler.
2. A language, not to be confused with Assembly!!!!  This language is NOT Assembly Language!  Though, the majority of programmers incorrectly use the terms “assembly” and “assembler” interchangeably.  Assembler is a language that’s specific to a particular vendor’s assembler.  For example, when you’re writing an Assembly Language program, you may need to leave an instruction in the source code that tells the Assembler (the program that converts your source code) how to convert some instructions.  You may want the assembler to generate 64 bit versions of your instructions rather than 32 bit versions.  This instruction left in the source code is NOT a machine instruction.  It’s an instruction for the Assembler that only has meaning during assembly time.  It does NOT get translated into a machine code.  Since this is a special instruction for the Assembler program, the language for those types of NON-MACHINE instructions are called Assembler Language.  As you can see, this is quite different from Assembly Language, which is an actual instruction for the hardware CPU.