arch/x86/src/README.txt ^^^^^^^^^^^^^^^^^^^^^^^ This directory holds x86_64-specific source files. All x86 source reside in lower-level common, chip-specific, and architecture-specific directories. common/ Directory ^^^^^^^^^^^^^^^^^ This directory holds source files common to all x86_64 architectures. Architecture-Specific Directories ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Architecture-specific directories hold common source files shared for by implementations of specific x86_64 architectures. intel64 This directory holds logic appropriate for any instantiation of the 64-bit intel64 architecture. Chip-Specific directories ^^^^^^^^^^^^^^^^^^^^^^^^^ The same x86 architecture may be realized in different chip implementations. For SoC chips, in particular, on-chip devices and differing interrupt structures may require special, chip-specific definitions in these chip- specific directories. broadwell This is the implementation of NuttX on the Intel Broadwell processors.