Abstract: A special inillicode instruction "Load With Access Test" explicitly detects access exceptions for storage operands while retaining control in the current millicode routine to insure exceptions are handled correctly and with the right priority. The millicode Load With Access Test instruction operates similarly to the ESA/390 Load instruction except that access exception code is set, interrupts are blocked and the serialization is forced to purge the instruction pipeline and reset the pipeline control without redirection of the instruction stream.

Abstract: A special Program Status Word (PSW) millicode routine, tests the validity of the PSW with three simple millicode instructions. Testing for access exceptions is executed by a special millicode instruction "Load With Access Test", which explicitly detects access exceptions for storage operands while retaining control in the current millicode routine. A Translate and Test (TRT) routine uses a table of 256 bytes to translate a string of bytes. Each string is used as an index into the table, and the selected table byte is fetched. For Translate and Test, the selected bytes are tested, and the first non-zero table byte selected is returned to the program in a general register along with the address of the string byte which selected it; translate and test also sets the condition code, and does not update storage.

Abstract: A pipelined computer processor in a milli-mode architected state tests the validity of a program status word with a mask stored in a millicode general register. The mask indicates bits in the program status word which are to be zeros if the word is valid. A logical AND operation is performed between correspondingly positioned bits in the word and bits in the mask and in addition the status of at least one other bit in the word is checked, a bit other than a correspondingly positioned bit.