Scaleable shadow stack for a configurable DSP concept

SoC (System-on-Chip) applications map complex system functions on a single die. The increasing importance of flexibility in SoC applications leads to raising portion implemented in firmware. Therefore, the demand on computational power of the embedded processors in the application is increasing. The newest silicon technologies (e.g. 0.13 μm and lower) help to increase the reachable frequency, but the demand cannot be sufficiently satisfied. One approach to increase the processor frequency is the introduction of pipelining. To guarantee data consistency in deep pipelined processors different methods have been developed. Additional complexity is introduced by the occurrence of interrupts. This paper describes a concept to enable data consistency between the instructions of different pipeline stages in pipelined DSP kernels during interrupt service routines, without the interaction of the DSP itself and with no restrictions concerning the nesting level of the interrupts. The scaleable shadow stack is part of a development project for a configurable DSP concept.