3.1. Processor Operating States

From the programmer’s point of view, the ARM720T can be in one of two states:

ARM state

which executes 32-bit, word-aligned ARM instructions.

THUMB state

which operates with 16-bit, halfword-aligned THUMB instructions. In this state, the PC uses bit 1 to select between alternate halfwords.

Note

Transition between these two states does not affect the processor mode or the contents of the registers.

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