Thumb Instruction Reference
ARM DUI 0068B Copyright © 2000, 2001 ARM Limited. All r ights reserved. 5-35
5.4.3 BX
Branch, and optionall y exchange instructio n set.
Syntax
BX Rm
where:
Rm
is an ARM register containing the address to branch to.
Bit 0 of
Rm
is not used as part of the address.
If bit 0 of
Rm
is clear:
•bit 1 must also be clear
•the instruction clears the T flag in the CPSR, and the code at the
destination is interpreted as ARM code.
Usage
The
BX
instruction causes a br anch to the address he ld in
Rm
, and changes instruction set
to Thumb if bit 0 of
Rm
is set.
Architectures
This instruction is available in all T variants of the ARM architecture.
Examples
BX r5