
188 Compilers – Principles and Practice
We may further note that in case of RISC processors, which generally have a large register file,
consisting of say 32, 64 or even more full-length registers, the whole of the current AR may be kept
in some of these registers for fast access. Even in CISC processors, special purpose registers like
Program Counter (PC) or Instruction Pointer (IP), Stack Pointer (SP), Frame Pointer (called Base
Pointer on Intel x86 machines) are used to store some of the fields of the current AR.
An important aspect of the Run-Time environment is deciding the protocol for invoking a
subroutine. The following are included ...