1. A computer program product for stalling processing in a processor, the computer program product comprising: a computer readable storage medium readable by a processing circuit and storing instructions for execution by the processing circuit for performing a method comprising: obtaining an extended DRAIN instruction to stall processing within the processor, the extended DRAIN instruction including an opcode field identifying said extended DRAIN instruction, a stall field separate from the opcode field that specifies a processing stage in which to stall processing, and a field that specifies a delay; and executing the extended DRAIN instruction, said executing stalling processing at the processing stage specified by the stall field of the extended DRAIN instruction, and wherein the executing comprises stalling processing specified by the delay indicated in the field of the extended DRAIN instruction, wherein the stalling begins after one or more specified conditions have been satisfied that would have allowed processing to continue absent the delay.