Out-of-order executive bus system and operating method thereof

A bus system, comprising:

• a request queue, for receiving and storing a newly received request, wherein the newly received request includes at least a link tag;
• a dependency request link generator, coupled to the request queue, for generating N dependency request links according to dependency constraints of N link tags of the newly received request, wherein N is any positive integer;
• and
• a request selector, coupled to the request queue, for finding M initial requests of the N dependency request link from the unserved requests, and selecting one from the M initial request for execution, wherein each of the M initial requests includes at least a link tag to indicate that the initial request is capable of being served, M and N are positive integers, and M is smaller than N;
• wherein each link tag of the newly received request is to indicates a link relation with respect to an order of the newly received request and a plurality of unserved requests preceding the newly received request.

An operation method applied to a bus system, comprising:

• according to at least a dependency constraint, linking a plurality of requests which utilize the bus system to thereby format least a dependency request link having an order;
• and
• processing the requests according to each dependency request link and the order thereof;
• wherein each of the requests includes at least a tag to indicate if the request is a last request of a corresponding request link to which it belongs, and the step of linking the requests which utilize the bus system to thereby form the dependency request link having the order comprises:
• finding a first request, wherein a first tag included in the first request indicates that the first request is a last request of a first dependency request link;
• linking a newly received request corresponding to the first dependency request link to the first request;
• and
• setting a tag of the newly received request to indicate that the newly received request is the last request of the first dependency request link.

A bus system, comprising:

• a request queue, for receiving and storing a newly received request, wherein the newly received request includes at least a link tag;
• and
• a dependency request link generator, coupled to the request queue, for generating N dependency request links according to dependency constraints of N link tags of the newly received request, wherein N is any positive integer;
• wherein each link tag of the newly received request is to indicate a link relation with respect to an order of the newly received request and a plurality of unserved requests preceding the newly received request, and the dependency request link generator further sets the newly received request as a last request of the N dependency request links according to N tail tags of the newly received request.