IBM System/7 Functional Characteristics - All about the IBM 1130 ...

11111E111111111 M11111111•11111 11111111.Halt I/0 (Fun=100)The halt I/O command resets the addressed I/O module or control, with the exception ofsensor-based output points and interruption information sent by prepare I/O commands.All other controls, device status, and pending interruptions are reset. The R field isignored.Halt I/O to the processor module (module address = 000000 in the instruction) causesa program check interruption.If the device has an outstanding request in the interruption buffer, that request is notreset by halt I/O. Therefore, an interruption request can be honored by the system eventhough the interrupting source has been reset.Set Interrupt (Fun=101)The set interrupt command is issued to the processor module. One word of data is sent tothe processor interruption controls directing them to establish an interruption requesteither on a specified priority level or to an attached 1130 processor. Both the deviceaddress and module address fields in the set interrupt PIO command must be all 0's,signifying that the processor module is addressed. An interruption request directed to apriority level in the System/7 presents a sublevel of 0 to the processor when the requestis serviced.The data word transmitted from a processor register to the interruption buffer has thefollowing format:0 4 8 15Level0 0 XX 0 0 0 0 X 0 0 0 0 0 0 XIII 1 1 1 1 1 1 1 10-3 0 Oor 4 Oor 1Bits 4 to 7 are O's.Bit 8 is set according to the requirements of the 5024 I/O Attachment Enclosure.Otherwise it is zero.Bits 9 to 14 are 0's.Bit 15 is set according to the following two sections and Chapter 17.Request Interrupt to System/7: Bit 15 set to 0 requests that an interruption request bedirected to the System/7 only. The interruption request is established in the bufferreserved for the priority level indicated by the level field contents in the data word.Two buffers are used for each interruption level: one for general interruptions and oneespecially for set interruptions. If the general interruption buffer is available, the setinterrupt request enters the buffer and is recognized the same as any other interruptionrequest. If the general interruption buffer is full, the set interrupt request enters thespecial set interruption buffer. When the general interruption buffer is again available,the set interrupt request enters the general buffer in competition with any other requestattempting to enter the general buffer for that level. In any case, when the set interruptrequest is recognized by the processor, the request presents a sublevel and.device addressof 0's and a module address of 000111.If a set interrupt request is pending in either buffer, condition code 2 is returned. If noset interrupt request is pending, the set interrupt request enters the general interruptionbuffer (if it is free) or the special set interruption buffer.Condition code settings for this use of the set interrupt command are:00—An interruption request was successfully entered into the appropriate level buffer.01—Does not occur with this use of the command.10—A set interrupt request is already pending on the specified level.11—Does not occur with this use of the command.