SVC os Macro
Number Function
simulation
Routine 00 01 02 03 04 05 06 07 08 09 10 11
13
14
17
18
19 20 21
22
23 24 25
31
35 40 41
42
44
46
47
48
51
56
57 60 62
63
64
68
69
93
94
96 XDAP WAIT POST EXIT GETMAIN FREEMAIN
LINK XCTL LOAD DELETE
GET MAIN/ FREEMAIN
GET POOL TIME ABEND SPIE RESTORE ELDL/FIND OPEN CLOSE STOW OPEN.l TCLOSE DEVTYPE TRKBAL FEOV WTO/WTOR EXTRACT IDENTIFY ATTACH CHAP TTIMER STIMER DEQ SNAP ENQ F3EEDBUF STAB DETACH CHKPT RDJFCB SYNAD BACKSPACE DMSSVT DMSSVN DMSSVN DMSSLN DMSSMN DMSSMN DMSSLN DMSSLN DMSSLN DMSSLN DMSSMN Df"SSMN DMSSVT DMSSAB DMSSVT DMSSVT DMSSVT DMSSOP DMSSOP DMSSVT DMSSOP DMSSOP DMSSVT DMSSVT DMSSVT DMSSVT IJMSSVT DMSSVT DMSSVT DMSSVT DMSSVT DMSSVT DMSSVT DMSSVT DMSSVT DMSSVT DMSSVT DMSSVT DMSSVT DMSSVT DMSSVT DMSSVT GET/PUT DMSSQS READ/WRITE DMSSBS NOTE/POINT DMSSCT CHECK TGET/TPUT TCLEARQ STAX DMsscr DMSSVN DMSSVN DMSSVT -------,
Comments
Reads or writes direct access volumes for an I/O completion Posts the I/O completion
Returns from linked phase
Conditionally acquires user free
storage
Releases user-acquired free storage
Links control to another load phase
Deletes, then links control to another
load phase
Reads another lead phase into storage
Deletes a loaded phase
Manipulates free user storage Simulates an SVC10 Gets the time of day
Terminates processing
Processes program interruptions
Effective NOP Manipulates simulated partitioned data
files
Activates a data file
Deactivates a data file
Manipulates partitioned directories
Activates a data file
Temporarily deactivates a data file Obtains device-type physical
characteristics
Effective NOP Set forced EOV error code
Communicates with the terminal
Effective NOP Adds entry to loader table
Effective LINK
Effective NOP Accesses or cancels timer
Sets timer interval and timer exit
routine
Effective NOP Dumps specified storage areas
Effective NOP Releases a free storage buffer
Allows processing program to decipher
abend condition
Effective NOP Effective NOP Obtains information from FILEDEF
command
Handles data set error conditions
Backs up to the beginning of the
previous record
Manipulates data recoras
Manipulates data blocks
Accesses or changes relative track
address
Tests ECB for completion and errors
Terminal processing
Clears input queue
Adds or deletes an attention exit
level I I J
Figure 22. OS Functions that Simulates efts Method of Operation and Program Organization 2-123
4. Issues the STACK macro to define the terminal as the primary source
of input. Most of the simulated supervisory as control blocks are contained in the
following two CMS control blocks: CMSCVT simulates the communication vector table (CVT). Location 16
contains the address of the CVT control section. CMSCB allocated fro. system free whenever a FILEDEF command or
an OPEN (SVC 19) is issued for a data set. The CMS control block
consists of the CMS file Control block (FCB) for the data file management under CMS, and simulation of the job file control
block (JFCB), input/output block (lOB), and data extent block
(DEB). The name of the data set is contained in the FCB, and is
obtained from the FILEDEF argument list, or from a predetermined
file name supplied by the processing problem program. CMS also utilizes portions of the supplied data control block (DCB) and
the data event control block (DECB). The TSO control blocks utilized
are the command program parameters list (CPPL), user profile table (UPT), protected step control block (PSCB), and environment control
table (ECT). CMS provides a nu.ber of routines to simulate certain operating system functions used by programs such as the Assembler and the FORTRAN and
PL/I compilers. Some of the SVC simulation routines are located in the
disk resident transient module DMSSVT. Whenever one of the SVC routines
in DMSSVT or is invoked, that routine is loaded into the transient area.
The following paragraphs describe how these simulation routines work. Writes and reads the source code spill file, SISUT1, during
language compilation for PL/I Optimizer and ANS COBOL Compilers. WAIT-SVC 1: Causes the active task to wait until one of more event control-blocks (BCBs) have been posted. For each specified BCB that has
been posted one is subtracted from the number of events specified in the WAIT macro. If the number of events is zero by the time the last ECB is control is returned to the user. If the number of events is not
zero after the last ECB is checked and the number of events is not
greater than the number of ECBs, the active task is put into a wait
state until enough ECBs are posted to set the number of events at zero. When the event count reaches zero the wait bits are turn off in any ECEs that have not been posted and control is returned to the user. If the number of events specified is greater than the number of ECBs the system abnormally terminates with an error message. All options of WAIT are
supported. Causes the specified event control block (ECB) to be set to
indicate the occurrence of an event. This event satisfies the
requirements of a WAIT macro instruction. All options of POST are
supported. The bits in the ECB are set as follows: !!,!! o 0 1 1
2-7 Value of specified completion code
2-124 IBM VM/370 System Logic and program Determination--Volume 2
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