Topic summary
Indirection bit
Extracted from the Wikipedia article Addressing mode.
Multi-level memory indirect
If the word size is larger than the address, then the word referenced for memory-indirect addressing could itself have an indirect flag set to indicate another memory indirect cycle. This flag is referred to as an indirection bit, and the resulting pointer is a tagged pointer, the indirection bit tagging whether it is a direct pointer or an indirect pointer. Care is needed to ensure that a chain of indirect addresses does not refer to itself; if it does, one can get an infinite loop while trying to resolve an address.