A data processing system includes a processor, a cache memory, a speculative cache memory, and a control circuit. The processor is for executing instructions. The cache memory is coupled to the processor and is for storing the instructions and related data. A speculative cache is coupled to the processor and is for storing only speculative instructions and related data. The control circuit is coupled to the processor, to the cache memory, and to the speculative cache. The control circuit is for causing speculative instructions to be stored in the speculative cache in response to receiving an indication from the processor. Also, a method is provided for speculative execution in the data processing system.