  An Application Specific Instruction set Processor (ASIP) is an important
component in designing embedded systems. One of the problems in designing an
instruction set for such processors is determining the number of registers is
needed in the processor that will optimize the computational time and the cost.
The performance of a processor may fall short due to register spilling, which
is caused by the lack of available registers in a processor. In the design
perspective, it will result in processors with great performance and low power
consumption if we can avoid register spilling by deciding a value for the
number of registers needed in an ASIP. However, as of now, it has not clearly
been recognized how the number of registers changes with different application
domains. In this paper, we evaluated whether different application domains have
any significant effect on register spilling and therefore the performance of a
processor so that we could use different number of registers when building
ASIPs for different application domains rather than using a constant set of
registers. Such utilization of registers will result in processors with high
performance, low cost and low power consumption.
