IAR Embedded Workbench for Arm 9.70.xIAR AssemblerAssembler optionsDescriptions of assembler options‑‑thumb‑‑thumbIn this section: Syntax‑‑thumbDescriptionUse this option to make Thumb (T32 or T in 32-bit mode) the default mode for the assembler directive CODE.See also‑‑cpu_modeCautionTo set this option, use Project>Options>Assembler>Extra Options.