System Mask Program r1ask o
o 7 8 11 12 15 16 17 18 19 20 23 24 31
o Instruction Address
32 39 40 63
The fields of the PSW are: Bits o
1
2-4
5
6
7
8-11
12
13
14
15
16-17
18-19 20-23 24-39 40-63 contents
Must be zero. PER (Program Event Recording) enabled.
Must be zero.
Address translation. Summary I/O mask. Summary extension.
The protection key determines if information can be stored
or fetched from a particular location.
Extended control mode.
The machine check flag is set to 1 if machine check
interruptions are enabled.
The wait state flag is set to 1 when the CPU is in the wait state.
The problem state flag is set to 1 when the CPU is operating in the problem rather than the supervisor state.
Must be zero.
The condition code reflects the result of a previous
arithmetic, logical, or I/O operation.
The program mask indicates whether or not various program
exceptions are allowed to cause program interrupts. st be zero. The instruction address gives the location of the next
instruction to be executed for program interrupts or of
the instruction last executed for external interrupts.
Figure 74. The Extended Control PSW (Program Status Word)
Appendix A. System/370 Information 541

Appendix B. VM/SP Monitor Tape Fornlat and Content
Header Record
Each time a monitor call interrupt occurs, VM/SP Monitor receives control and
collects data appropriate for the particular class and code of MONITOR CALL. (Or, for USER, PERFORM, or DASTAP classes, VM/SP Monitor gets control at
periodic intervals to collect data.) The data is formatted into records that are col­
lected sequentially in the order that each interrupt occurred. The tape data format
is standard Variable Blocked (VB) format. Data is written at the default tape drive
density. Maximum block and record lengths are 4096 bytes. The formats and con­
tents of all the kinds of data records for the currently implemented classes and
codes of MONITOR CALL are listed below.
All values described in the following records are binary unless otherwise noted.
lindicates that the field is EBCDIC.
2Indicates that the field is in special timer format described below. 3See VM/SP Data Areas and Control Block Logic, Volume 1 for field format defi­
nition.
Every data record is preceded by the following 12-byte header:
Number DSECT
of Variable
Data Item Bytes Name
Total bytes in record 2 MNHRECS7.
Zeros (standard V format record) 2 MONITOR CALL class number 1 MNHCLASS MONITOR CALL code number 2 MNHCODE Time of Day -5 MNHTOD Note: Time of day occupies 2 fullwords in storage, with the rightmost 12 bits
zeros. The rightmost 2 bytes and the leftmost byte are ignored, giving
16-microsecond accuracy instead of 1-microsecond.
The first 4 bytes of this header are the standard variable-format record field.
542 VM/SP System Programmer's Guide