________ holds address of next instruction that A will be executed TMP ________ contains address of memory word to read S or write PC ________ a place to hold memory addresses for indirect IR loads and stores MAR ________ where the data to be written to memory is held MBR and where data being read from memory is first put ________ the second operand of arithmetic operations ________ the first operand of arithmetic operations and where the result it put ________ holds the instruction currently being executed