There's a lot of literature that repeats a harmful misnomer. The register is always an instruction pointer, even if the hardware incorrectly calls it a program

There's a lot of literature that repeats a harmful misnomer. The register is always an instruction pointer, even if the hardware incorrectly calls it a program counter. The processor that matters most, by far, is x86. At one point PowerPC wasn't too far behind, and PowerPC still dominates in high-end network gear. Both of these processors are correctly documented. For x86 the name is ip, eip, or rip. For PowerPC the name is usually nip, meaning "next instruction pointer". Sometimes the PowerPC documentation will use "current" instead of "next", or "address" instead of "pointer". All of these are correct.