A data processor having multiple execution units for processing plural classes of instructions in parallel

Claim 1

In a data processing system including a plurality of execution units selectively coupled to a memory and to a plurality of registers, for processing a sequence of instructions which include an op code, a source location reference and a result location reference, the op code of each instruction being classified into one of a plurality of classes, means for executing each instruction in a corresponding one of said plurality of execution units according to the class of the op code thereof, comprising: an instruction dispatcher having an input coupled to receive said sequence of instructions and an output connected to each of said plurality of execution units, for identifying the class of an op code in an instruction in said sequence and dispatching the instruction to one of said plurality of execution units corresponding to the identified class; a control unit having an input connected to said instruction dispatcher and also having an input connected from and an output connected to each of said plurality of execution units; said control unit storing a result location associated with a first occurring instruction in said sequence to be executed in a first one of said plurality of execution units; said control unit comparing said result location of said first occurring instruction with a source location associated with a second occurring instruction in said sequence to be executed in a second one of said plurality of execution units; said control unit delaying the execution of said second instruction until the completion of execution of said first instruction, if said associated source location matches said associated result location indicating that the execution of said second instruction depends on the result produced by the execution of said first instruction; said control unit enabling executing said first instruction in said first one of said plurality of execution units asynchronously with the execution of said second instruction in said second one of said plurality of execution units, if said associated source location does not match said associated result location indicating that said second instruction is independent of said first instruction; whereby mutually dependent instructions of different classes can be executed sequentially and mutually independent instructions of different classes can be executed asynchronously.