Описание тега eip

EIP is the official name of the special register holding the address of the next machine instruction to be executed (not the instruction currently being executed), in 32-bit x86 assembly language. It is an acronym for Extended Instruction Pointer. The name is historical: when the 8086 architecture was extended to 32-bit word size, all the formerly 16-bit registers grew an "E" prefix on their names, whether or not it was useful to be able to refer to the low 16 bits of the register separately. (It is not possible to use "IP" in 32-bit code to read the low 16 bits of the instruction pointer.) The same pattern was repeated more recently: in 64-bit code this register is referred to as "RIP".

Most non-x86 architectures call their analogous register PC (for Program Counter) and do not bother encoding its size into the name.