1. A computer program product for executing a machine instruction, the computer program product comprising: a non-transitory 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 having associated therewith: 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 an operand to be used by the machine instruction; and executing the machine instruction, the executing comprising: obtaining a modifier indicator from a register associated with the machine instruction; based on the modifier indicator 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 operand, the obtaining including forming the seed material based, in part, on a value of a reseed counter of a parameter block associated with the machine instruction; using a selected hash technique and the seed material to provide one or more seed values; and storing the one or more seed values in the parameter block associated with the machine instruction.