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== Overview ==
 
== Overview ==
In the first few versions of [[ARM]], the [[Program Counter]] was 24 bits allowing for a 26-bit address space of up to 64 MiB of memory. The other bits were 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.
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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 ===

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