1. A computer program product for executing a machine instruction, 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, by a processor, a machine instruction for execution, the machine instruction being defined for computer execution according to a computer architecture, the machine instruction comprising: an opcode field to provide an opcode, the opcode to identify a perform pseudorandom number operation; and a register field to be used to identify a register, the register to specify a location in memory of a second operand to be used by the machine instruction; and executing the machine instruction, the executing comprising: obtaining a modifier (M) field of a register associated with the machine instruction; based on the M field having a first value, performing a deterministic pseudorandom number seed operation, the deterministic pseudorandom number seed operation comprising: obtaining seed material based on information included in the second operand; using a 512 bit secure hash technique and the seed material to provide one or more seed values; and storing the one or more seed values in a parameter block associated with the machine instruction.