A CLIC Extension Based Fast Interrupt System for Embedded RISC-V Processors

A fast interrupt response time is a very important feature for embedded processors. In this paper, we design a fast interrupt system for embedded RISC-V processors. It is further extended on the Core-Local Interrupt Controller (CLIC) based interrupt system. When an interrupt happens, the general-purpose registers and other interrupt related registers such as Control and Status Registers (CSRs) are pushed to the stack memory automatically. Thus, there is no additional software overhead in the Interrupt Service Routine (ISR), and the real handler code can be executed immediately. The interrupt response time of the interrupt system based on the CLIC extension is shorter than that of a RISC-V processor only employing the CLIC, and is comparable to that of an ARM}