The Platform System Interface Specification, or psi-spec, is a collection of documents for hardware and software co-design from a general perspective. It describes how microprocessors set up an environment for an operating system or otherwise bare-metal applications, typically through intermediate, rewritable code that initializes clocks, DRAM and peripherals, commomly referred to as firmware.
In the following sections, psi-spec describes principles and abstractions that apply agnostic of vendors and products.