-j
In this section:
Syntax
-j
Description
Use this option to enable alternative register names, mnemonics, and operators in order to increase compatibility with other assemblers and, allow porting of code.
See also
Operator synonyms and the chapter Migrating to the IAR Assembler for Arm.
Caution
Project>Options>Assembler>Language>Allow alternative register names, mnemonics and operands