To give a little bit of background, I wanted to study how x86 instructions are encoded/decoded manually. I came across the ModR/M and SIB bytes and it seems that understanding the x86 addressing modes is fundamental to understanding the instruction encoding scheme.
Hence, I did a Google search for x86 addressing modes. Most blogs/videos that the search returned were addressing modes for the 8086 processor. Going through some of them, the different addressing modes were Register, Direct, Indirect, Indexed, Based, and some more. But the blogs use inconsistent names when referring to these addressing modes. Multiple different sources use multiple different addressing modes. The different terms are not even mentioned in the Intel manual here. For example, I can't seem to find anywhere in the Intel manual, an addressing mode called Direct or Indirect. Also, the Mod bits in the ModRM byte is a 2 bit field, which makes me wonder if more than 4 addressing modes are possible.
My question is, are terms like Direct addressing modes, Indirect addressing modes older terms that are no longer used in the Intel manuals, but used by the general public. If the terms technically do exists, where can I find a reference to them in the manuals.