1. A processing circuit comprising: a plurality of functional units, including a first functional unit and a second functional unit, each configured to perform the same operation in response to a command, wherein the first functional unit has a lower susceptibility to soft errors than the second functional unit; and wherein: the processing circuit includes a configuration to execute the command using the first functional unit if a specified reliability level of the command is high; and the processing circuit includes a configuration to execute the command using the second functional unit if a specified reliability level of the command is low.