DIAGNOSE X'5Q.!. = Save the 3701 Control progry Image DIAGNOSE code X'50' (Privilege class A, B, or C only) invokes the CP .odule D!KSNC to (1) validate the parameter list and (2) write the
page-for.at i.age of the 370X control prograa to the appropriate system voluae. When a 370X control program load module is created, the C!S service program SAVEBCP builds a co •• unications controller list (CCPAR!) of
control infor.ation. It passes this information to CP via a DIAGNOSE code X'50'. The register specified as Rx contains the virtual address of the
para.eter list (CCPAR!). The Ry register is ignored on entry. Upon return, the By register contains the following error codes: 044 171
178
179
435 'ncpname' was not found in system name table.
Syste. volu.e specified not currently available.
Insufficient space reserved for program and system control
infor.a tion. Syste. volu.e specified is not a CP-owned volume. P aging error while writing sa ved systea. Code :.:. Contr.2! Fun£ti,Q!! .Q!: the FUDc,!:io!! Key DIAGNOSE code X'54' controls the function of the PA2 function key. The PA2 function key can be used either to simulate an external interrupt to
a virtual machine or to clear the output area of a display screen.
The function perfor.ed depends upon how Rx is specified when DIAGNOSE code X'54' is issued. If Rx contains a nonzero value, the PA2 key
si.ulates an external interrupt to the virtual .achine. If Rx contains
a value of zero, the PA2 key clears the output area of the display
screen.
The external interrupt is si.ulated only when the display screen is
in the ,5 REiD, BOLD, or MORE status and the lPt OJ cossand has been issued. = 3270 Virtual Console Execution of DIAGNOSE code X'58' allows a virtual machine to display
large amounts of data on a 3270 in a very rapid fashion. The interface
can display the entire 3270 screen with one write operation instead of
22 writes (one for each line in the output area of a 3270 screen).
The register specified as Rx contains the address of the console CCi string. The By register contains (in bits 16 through 31) the device
address of the virtual console.
To specify the special display CCi , use the following asse.bler
language instructions: DS OD DC X'19', AL3 (dataddr), lL1(flags), lL1(ctl), lL2(count) dataddr is the beginning address of the data to be displayed.
CP Introduction 1-65

flags
ctl
count
is the standard CCW flag field with the suppress incorrect
length indication (SLI) bit on.
is a control byte that indicates the starting output display
line. If the high order bit is on, the entire 3270 output
display area is erased before the new data is displayed. A value of X'FF' clears the screen, but writes nothing.
is a two byte field indicating the number of bytes to be
displayed. The maximum number of bytes for the 3278 Bodel 2A is 1440. For other types it is 1760. When the DIAGIOSB is executed with a valid CCW string, a buffer
(whose length is the nuaber of bytes specified by is built in
free storage. The data pointed to by is loaded into the buffer.
Data chaining may be specified in the CCW to link noncontiguous data
areas; however, command chaining is an end of data indication for the
current buffer. Using the starting output line (ctl) and the number of bytes of
output (count), CP checks that the data will fit on the screen. CP then
does the display. A zero condition code indicates the I/O operation
completed successfully; a nonzero condition code indicates an I/O error
occurred. lote: An I/O error occurs when the display screen is placed in BORE status and the PA2 key is pressed to allow screen display.
Execution of DIAGIOSE code X'SC' causes the editing of an error message according to the user's setting of the BBSG function: Rx contains the address of the message to be edited. Ry contains the length of the aessage to be edited. DMKBVC tests the VMMLBVBL field of the V!BLOK and returns to the caller
with Rx and Ry modified as follows: VM!LBVBL Registers on Return VMMCODB I V!MTBXT Rx Ry I 01 I 01 no change no change I 01 I OFF no change 10 (length of I code) I OFF I ON pointer to text length of text I part of message alone I OFF I OFF I/A 0 lote: DIAGNOSE code X'SC' does not write the message; it merely rearranges the starting pointer and length. Par CBS error aessages, a
console write is performed following the DIAGNOSE unless Ry is returned with a value of O. 1-66 IBM VM/310 System Logic and Problem Determination--VoluBe 1