IAR Embedded Workbench for Arm supports the 32-bit and 64-bit Arm architectures by means of execution modes.

In 32-bit mode refers to using IAR Embedded Workbench for Arm configured to generate and debug code for the T32/T and A32 instruction sets, either on an Armv4/5/6/7 core or in the AArch32 execution state on an Arm v8-A core. In 32-bit mode, you can use both the A32 and T32/T instruction sets and switch between them.

In 64-bit mode refers to using IAR Embedded Workbench for Arm configured to generate and debug code for the A64 instruction set in the AArch64 execution state on an Arm v8-A core. Code in 64-bit mode can call code in 32-bit mode, and that code can return back. However, the IAR translator tools do not support this switch being used in a single linked image. Switching between A32/T32/T code and A64 code must be performed by using several images. For example, an OS using 64-bit mode can start applications in either 64-bit or in 32-bit mode.

The AArch32 execution state is compatible with the Arm v7 architecture. The AArch32 execution state is emulated inside the AArch64 execution state.