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 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 executing the machine instruction, the executing comprising: obtaining a modifier field associated with the machine instruction; based on the modifier field having a first value, performing a deterministic pseudorandom number generate operation, the deterministic pseudorandom number generate operation comprising: for each block of memory of one or more blocks of memory of a first operand located using the machine instruction, generating a hash value using a selected hash technique and at least one seed value of a parameter block associated with the machine instruction, wherein the parameter block is configured to include at least one of: a reseed counter to indicate a number of times the machine instruction has completed with a specific condition code since the parameter block was last instantiated or reseeded; a stream bytes field to track a number of bytes stored based on the generate operation; or a value to indicate an internal state of a random number generator represented by the parameter block; and storing at least a portion of the generated hash value in a corresponding block of memory of the first operand, the generated hash value being at least a portion of a pseudorandom number.