| 摘要 |
PROBLEM TO BE SOLVED: To improve the coding efficiency of an instruction by controlling the number and order of operations with the number of operation fields and a format field specifying the order of the operations and placing in parallel operation simple decoders which decode only operations for specific functions depending upon an operation executing mechanism. SOLUTION: The number and order of operations are controlled according to the number of operation fields and the format field specifying the order of the operations and the simple decoders which decode only operations for specific functions depending upon the operation executing mechanism are placed in parallel operation. For example, three operation fields of three operation instructions in, for example, format 1 each specify one operation code in 20-bit short type format respectively. Operation fields 14 and 15 of two operation instructions in format 2 specify one operation code each, i.e., two operation codes in total. A format filed 10 specifies the order of respective operations in addition to a discrimination between the format 1 of the three operation instructions and the format 2 of the two operation instructions. |
