Implementation of External Registers
Original Publication Date: 1979-Mar-01
Included in the Prior Art Database: 2005-Feb-19
There are many complex functions in a system architecture, such as timers and interrupts, that are typically implemented cooperatively by hardware and microcode, A typical implementation of such devices is the IBM System 370 use of "external registers" as the interface between the hardware and microcode, parts of the supportive timers, interrupts and other such functions. The hardware arranges latch bits that are to be written and read by the microcode, so that the microcode can address these bits as if they formed an array of registers. Typically, these bits are implemented in random logic.