Zero-overhead loop in an embedded digital signal processor

Abstract

A decoding logic method is arranged to execute a zero-overhead loop in an embedded digital signal processor (DSP). In the method, instruction data is fetched from a memory, and a plurality of instruction tokens, which are derived from the instruction data, are stored in a token buffer. A first portion of one or more instruction tokens from the token buffer are passed to a first decode module, which may be an instruction decode module, and a second portion of the one or more instruction tokens from the token buffer are passed to a second decode module, which may be a loop decode module. The second decode module detects a special loop instruction token, and based on the detection of the special loop instruction token, a loop counter is conditionally tested. Using the first decode module, at least one instruction token of an iterative algorithm is assembled into a single instruction, which is executable in a single execution cycle. Based on the conditional test of the loop counter, the first decode module further assembles a loop branch instruction of the iterative algorithm into the single instruction executable in one execution cycle.