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Polish String Interruption for Asynchronous Simulation

IP.com Disclosure Number: IPCOM000042713D
Original Publication Date: 1984-Jun-01
Included in the Prior Art Database: 2005-Feb-04
Document File: 3 page(s) / 45K

Publishing Venue

IBM

Related People

Cheng, DD: AUTHOR [+3]

Abstract

Traditionally, batch-oriented simulations have required a user to manually code and compile a behavioral block description into machine code that can be executed. This is a time-consuming and costly process. One notion of an internal behavioral representation (polish strings) that is generated automatically for the user is known, which is limited to only processing synchronous types of statements. Significant event simulators require the ability to also process asynchronous statement types represented by polish strings. A behavioral description of the functional characteristics of an entity (node) describes the input/output (cause/effect) relationships of an entity. In the case of a sequential circuit, the behavioral description must also describe any externally visible memory elements of the entity.

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Polish String Interruption for Asynchronous Simulation

Traditionally, batch-oriented simulations have required a user to manually code and compile a behavioral block description into machine code that can be executed. This is a time-consuming and costly process. One notion of an internal behavioral representation (polish strings) that is generated automatically for the user is known, which is limited to only processing synchronous types of statements. Significant event simulators require the ability to also process asynchronous statement types represented by polish strings. A behavioral description of the functional characteristics of an entity (node) describes the input/output (cause/effect) relationships of an entity. In the case of a sequential circuit, the behavioral description must also describe any externally visible memory elements of the entity. In addition, it may describe delay/timing characteristics (real or cycled based), or fault characteristics (that is, behavior under failure conditions as well as good machine behavior). The description does not necessarily imply any particular internal organization or algorithms used to implement the entity; it only represents the external (black box) characteristics. Theoretically, it does not use any lower-level entities as components; practically, it may use such components. A description of the functional characteristics of an entity is also known as a behavioral-level description. An application program working with this level of description, such as the simulator, can be called behavioral processing. Inherent to asynchronous simulation (significant events) are delays or timing statements. For many behavioral-level design languages, timing descriptions fall into two categories: (1) wait-type statements which will cause a temporary, or sometimes permanent, pause in the behavioral processing, and (2) synchronization statements which may cause a re- arrangement in the sequential processing of statements designed for parallel execution. For the first case, wait-type statements, special queuing events are used to store information associated with those conditions specifying the length of delay required. For wait statements that are for a specific delay, an event is queued, and at that future specified time, behavioral processing will continue. For conditional wait statements that are pending on successful satisfaction of a condition, a different event is queued. If and when a wait condition becomes satisfied, behavioral processing will continue. A conditional wait "tester" utility may be called each time unit to test the condition's statement if any conditions are pending. The use of these queue e...