About the Unified Assembler Language
Unified Assembler Language (UAL) is a common syntax for A32 and T32 instructions. It supersedes earlier versions of both the ARM and Thumb assembler languages.
Code that is written using UAL can be assembled for A32 or T32 for any ARM processor. armasm faults the use of unavailable instructions.
armasm can assemble code that is written in pre-UAL and UAL syntax.
By default, armasm expects source code
to be written in UAL. armasm accepts UAL syntax if any of
THUMB is used or if you assemble with any
--thumb command-line options.
armasm also accepts source code that is written in
pre-UAL ARM assembly language when you assemble with
armasm accepts source code that is
written in pre-UAL Thumb assembly language when you assemble using the
--16 command-line option, or the
CODE16 directive in the source code.