2.1. About the programmer’s model

The processor implements the ARM v7-M architecture. This includes the entire 16-bit Thumb instruction set and the base Thumb-2 32-bit instruction set architecture. The processor cannot execute ARM instructions.

The Thumb instruction set is a subset of the ARM instruction set, re-encoded to 16 bits. It supports higher code density and systems with memory data buses that are 16 bits wide or narrower.

Thumb-2 is a major enhancement to the Thumb Instruction Set Architecture (ISA). Thumb-2 enables higher code density than Thumb and offers higher performance with 16/32-bit instructions.

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