|  | # Device Software | 
|  |  | 
|  | ## Reference Firmware Images | 
|  |  | 
|  | The OpenTitan Reference Firmware Images together make up the Opentitan Reference Firmware Stack. | 
|  | Different images are used for different boot stages. | 
|  |  | 
|  | The Reference Firmware Images are, in boot order: | 
|  |  | 
|  | 1.  The [ROM](./silicon_creator/rom/README.md) (in `sw/device/silicon_creator/rom`), executed at chip reset; | 
|  | 2.  The ROM_EXT (in `sw/device/silicon_creator/rom_ext`), the second stage Silicon Creator code, executed from flash; and | 
|  |  | 
|  | ### Testing-only Images | 
|  |  | 
|  | There are also some other standalone firmware images in the repository, which are only used for testing. | 
|  |  | 
|  | - [`sw/device/tests`](./tests/README.md) contains several categories of chip-level tests, including smoke, IP integration, and system-level (use case) tests. | 
|  |  | 
|  | - [`sw/device/benchmarks/coremark`](https://github.com/lowRISC/opentitan/tree/master/sw/device/benchmarks/coremark) contains infrastructure for running the [CoreMark](https://github.com/eembc/coremark) benchmark suite on the OpenTitan device. | 
|  | - `sw/device/riscv_compliance_support` contains infrastructure so we can run the [RISC-V Compliance](https://github.com/riscv/riscv-compliance) tests on the OpenTitan core. | 
|  | - `sw/device/sca` contains on-device software used for Side-Channel Analysis. | 
|  | - `sw/device/prebuilt` contains pre-built Tock images, which may not be up-to-date. | 
|  | - `sw/device/examples` contains example images, including a simple [Hello World](https://github.com/lowRISC/opentitan/tree/master/sw/device/examples/hello_world). | 
|  |  | 
|  | There are also prototype versions of some of the boot stages, now only used for testing: | 
|  |  | 
|  | - [`sw/device/lib/testing/test_rom`](https://github.com/lowRISC/opentitan/tree/master/sw/device/lib/testing/test_rom) is a previous, testing-only version of the ROM. | 
|  | - `sw/device/exts` contains software for our prototype second boot stage images. | 
|  |  | 
|  | ## Documentation Index | 
|  |  | 
|  | {{% sectionContent %}} |