2.2. Processor operating states

The ARM7EJ-S processor has three operating states:

ARM state

32-bit, word-aligned ARM instructions are executed in this state.

Thumb state

16-bit, halfword-aligned Thumb instructions.

Jazelle state

Variable length, byte-aligned Jazelle instructions.

In Thumb state, bit 1 of the Program Counter (PC) is used to select between alternate halfwords.

In Jazelle state, all instruction fetches are in words.


Transition between ARM, Thumb, and Jazelle states does not affect the processor mode or the register contents.

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