Asynchronous pipeline control interface using tag values to control passing data through successive pipeline stages

A system for externally managing data within an asynchronous pipeline, wherein said asynchronous pipeline includes a plurality of pipeline stages, and a data path and a control path traversing said plurality of pipeline stages in unison, said system comprising:

• processing means for assigning a respective data tag value to each of a plurality of data sets, each said data set for input to said asynchronous pipeline in a respective input interval;
• processing means for sending each said respective data tag value into said control path when said data set to which the respective data tag value is assigned is sent into said data path such that said respective data tag value passes through each successive stage of said plurality of stages of said asynchronous pipeline in unison with said data set to which the respective data tag value is assigned, each said respective data tag value always being in the same pipeline stage as the data set to which the respective data tag value is assigned;
• and
• logic means for comparing each said data tag value with a respective control tag value associated with a given stage of said asynchronous pipeline, and in response to a data tag value matching a respective control tag value, permitting said matching data tag value and the data set to which said matching data tag value is assigned to pass in unison to the next stage within said asynchronous pipeline, wherein passing of each said data tag value and the data set to which said matching data tag value is assigned to respective next stages of said plurality of pipeline stages within said asynchronous pipeline is not synchronized to a common global clock signal.

An asynchronous pipeline apparatus for a digital data processing system, comprising:

• plurality of ordered stages traversed in parallel by a data path and a control path, said data path transmitting data sets through successive said ordered stages of said pipeline, each data set entering said pipeline in a respective input interval, said control path transmitting data tags through successive said ordered stages of said pipeline, each data tag corresponding to a respective data set, each data tag being transmitted through each successive said ordered stage of said pipeline in unison with its corresponding data set, each said data tag always being in the same ordered stage of said pipeline as its corresponding data set;
• and
• stage advance control logic which controls the advancing of each said data set and its corresponding data tag through successive said ordered stages of said asynchronous pipeline, said stage advance control logic allowing each data set and its corresponding data tag to advance from a current stage to a successor stage upon satisfaction of a respective logical stage transition condition associated with each stage transition, wherein for at least some stage transitions, said logical stage transition condition includes the condition that the data tag at the current stage to matches a control tag value associated with the stage transition, wherein advancing of each data set and its corresponding data tag to respective successive stages of said plurality of ordered stages of said pipeline is not synchronized to a common global clock signal.