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== Overview == | == Overview == | ||
− | In the first few versions of [[ARM]], the [[Program Counter]] was | + | In the first few versions of [[ARM]], the [[Program Counter]] was only 26 bits, allowing it to access 64 MiB of memory. The high 6 bits were actually used for the {{arm|Processor Status Register}}. With the introduction of the {{arm|ARMv3}}, the ISA moved to a full 32-bit address space. ARMv3 consequently introduced a compatibility mode to support the older architectures (except for {{arm|ARMv3G}}). With the introduction of {{arm|ARMv4}}, the mode became optional on all non-T variants. {{arm|ARMv5}} dropped 26-bit compatibility entirely. |
=== Major Differences === | === Major Differences === |