ARM Architecture Reference Manual ARMv7-A and ARMv7-R edition

Assembler syntax
BX
where:
See Standard assembler syntax fields on page A8-7.
Instruction Details
The register that contains the branch target address and instruction set selection bit. The PC
can be used.
Operation
Note
If is the PC in a Thumb instruction at a non word-aligned address, it results in
UNPREDICTABLE behavior because the address passed to the BXWritePC() pseudocode
function has bits = '10'.
if ConditionPassed() then
EncodingSpecificOperations();
BXWritePC(R[m]);
Exceptions
None.
ARM DDI 0406B Copyright © 1996-1998, 2000, 2004-2008 ARM Limited. All rights reserved. A8-63