You can switch the operating state of the processor between:
ARM state and
Thumb state using the BX and BLX instructions,
and loads to the PC. Switching state is described in the ARM
Architecture Reference Manual.
Thumb state and ThumbEE state using the ENTERX and LEAVEX instructions.
Exceptions cause the processor to enter ARM or Thumb state
according to the value held in the TE bit within the system control
coprocessor. Normally, on exiting an exception handler, the processor
restores the original contents of the T and J bits.
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