The relatively small number of general registers ( also inherited from its 8-bit ancestors ) has made register-relative addressing ( using small immediate offsets ) an important method of accessing operands, especially on the stack.
12.
Instruction relative addressing in 64-bit code ( RIP + displacement, where RIP is the instruction pointer register ) simplifies the implementation of position-independent code ( as used in shared libraries in some operating systems ).
13.
This is a manifestation of the many addressing modes and optimizations such as sub-register addressing, memory operands in ALU instructions, absolute addressing, PC-relative addressing, and register-to-register spills, which these ISAs offer.
14.
Like PC-relative addressing, some CPUs have versions of this addressing mode that only refer to one register ( " skip if reg1 = 0 " ) or no registers, implicitly referring to some previously-set bit in the status register.
15.
The memory space ( or " core " ) is of finite size, but only relative addressing is used, that is, address " 0 " always refers to the currently executing instruction, address " 1 " to the instruction after it, and so on.
16.
The x86-64 architecture and the 64-bit ARMv8-A architecture have PC-relative addressing modes, called " RIP-relative " in x86-64 and " literal " in ARMv8-A . The Motorola 6809, a very advanced 8-bits CPU designed in 1978, also supports a PC-relative addressing mode.
17.
The x86-64 architecture and the 64-bit ARMv8-A architecture have PC-relative addressing modes, called " RIP-relative " in x86-64 and " literal " in ARMv8-A . The Motorola 6809, a very advanced 8-bits CPU designed in 1978, also supports a PC-relative addressing mode.
