What is Code

Collection of code

About code

Sometimes I got confused by some concepts, such as machine code and object code. Here’s a collection of “code” definitions

Source code: (.c file)

Any collection of code, with or without comments, written using a human-readable programming language, usually as plain text.

Assembly code (.s file)

is plain-text and (somewhat) human read-able source code that mostly has a direct 1:1 analog with machine instructions. This is accomplished using mnemonics for the actual instructions, registers, or other resources. Examples include JMP and MULT for the CPU’s jump and multiplication instructions. Unlike machine code, the CPU does not understand assembly code. You convert assembly code to machine code with the use of an assembler or a compiler, though we usually think of compilers in association with high-level programming language that are abstracted further from the CPU instructions.

Machine code (1000101)

  • Machine language is made up of instructions and data that can be executed directly by the CPU. They are all binary code. (Basically 0 and 1)
  • Machine language is normally displayed in hexadecimal form so that it is a little bit easier to read.
  • If you open a machine code file in a text editor you would see garbage, including unprintable characters

Object code (.o file)

is a portion of machine code not yet linked into a complete program. It’s the machine code for one particular library or module that will make up the completed product. It may also contain placeholders or offsets not found in the machine code of a completed program. The linker will use these placeholders and offsets to connect everything together.