[a1k0n]

Huh, it has 15 registers? AX, BX, CX, DX, SI, DI, BP, SP; CS, DS, ES, SS, IP, flags. What am I missing?

[kens]

There are two internal registers (IND and OPR) that aren't visible to the programmer. See the block diagram at the bottom of the post. The flags are in the ALU, not in the register file.

[gkolli]

I believe the status register (flag)