| 摘要 |
<p>A programmable controller architecture utilizes specialized processors in a co-processing system so that each function is optimized. The system comprises first and second processors having respective instruction sets and respective associated means for fetching instructions from a common memory. Each of the processors and its instruction set is tailored to a corresponding processor's specialized function. Each processor's instruction set includes a subset of special instructions, the occurrence of one of which signifies that control is to be passed from one processor to the other. Upon encountering a special instruction within its special instruction subset, a given processor invokes associated control passing circuitry for suspending its own operation and commencing the operation of the other processor. The passage of control occurs very quickly so that the speed benefits of switching control are not lost in the overhead of such switching. Since passage of control renders one of the processors inactive, there is no requirement that the actual instructions of one processor be objectively distinguishable from those of the other.</p> |
