: is a number representinq the last register whose contents are
to be displayed at the terminal. The dask (-) or colon <:)
following reg1 is used to specify a range of register values to be displayed. If req2 is not specified, the contents of
all reqisters from rea1 through the last register of this type
are displayed. The operand, reg2, must be equal to or greater
than rea1. If Greg1 or Xreg1 is specifiei, reg2 may be a
decimal numher from ° to 15 or a hexadecimal number from 0 to
F. If Yrea1 is specified, reg2 may be 0, 2, 4, or 6. The
contents of reqisters reg1 through reg2 are displayed at the
f.1 reqcount PSW CSW is a decimal number from 1 to 16 or a hexadecimal number from
1 to F specifying the number of reqisters (starting with reg1)
whose contents are to be displayed at the terminal. If the 1isplav type G or X is specified, regcount can be a decimal number from 1 to 16 or a hexadecimal number from 1 to F. If display type Y is specified, regcount must be 1, 2, 3, or 4.
The sum of reg1 and regcount must be a number that does not
exceed the maximum reqister number for the type of registers
beinq displayed.
displays the current virtual machine
word) as two hexadecimal words. PSW (program status
displays the contents of the CAW (channel address word at
hexadecimal location 48) as one hexadecimal word.
displays the contents of the CSW (channel status word at
hexadecimal location 40) as two hexadecimal words.
1. First level storage is real main storaqe. Only second-level stor3.ge (storaqe that is real to the virtual machine) can be displayeJ. Operatinq systems runninq in a virtual machine such as DJS/VS and OS/VS have virtual (third level) storage of their own.
This third-level storaqe cannot be displayed directly. The user or
the virtual operating system is responsible for converting any thiri-Ievel storage locations to second-level storage locations
before issuing the command.
2. If a command line with an invalid operand is entered, the DISPLAY commind terminates when it encounters the invalid operand; however, 3.nv previous valid operands are processed before termination
occurs. Multiple storage locations, registers, and control words can be displayed using a single command line. IS' CP Command Beference General Users
3. When multiple operands are entered on a line for location or register displays, the default display type is the same as the
previous explicit display type. The explicit specification of a
display type defines the default for subsequent operands for the current 1isplav function. If a dash or colon is omitted between
the hexloc1 and hexloc2 operands and they are separated by one or mJre blanks, only the storaqe contents at those two specific
locations are displayed. Blanks are used to separate operands or
sets of operands if more than one is entered on the same =ommand line. Blanks must not be used to the right or left of the ranqe or length delimiters (: or -or .), unless it is intended to
take the default value of the missing operand defined by the blank.
For example: display 10 20 T40 80 G12 5 L60-100 displays the respectively:
hexadecimal location 10 hexadecimal location 20 hexadecimal location 40 with EBCDIC translation
hexadecimal location 80 with EBCDIC translation
general register 12
general register 5
hexadecimal locations 60 through 100 4. To terminate the DISPLAY function while data is being displayed at
the terminal, press the attention key (or its equivalent). When the 1isplay terminates, another command may be entered.
5. The command does not distinguish between
nonshared storage; it displays any of the virtual
addressable storage whether shared or not.
shared and
6. Use the DISPLAY command to display the contents of various storage
locations, reqisters, and control words at the terminal. By
examining this type of information during the program's execution, you nay be able to determine the cause of program errors. Usually, an address stop is set to stop the program execution at a specified
point. The system enters the CP environment and you may then issue
the DISPLAY command.
7. When yoa must examine large portions of storage, use the DUMP command rather than the DISPLAY command. Because the terminal
operates at a much slower speed than the printer, only limited
amounts of storaqe should be printed (via the DISPLAY command) at
the terminal.
8. When runninq with a discontiguous saved segment (DCSS), you can
display storage locations outside the range of your virtual machine
size if they are within the Dess. If there exist locations between
the upper limit of your virtual machine and the address at which
the Dess saved, an attempt to display those locations (or
associated keys) results in a "nonaddressable storage" message. One or more of the followinq responses is displayed, depending upon the
operands specified.
Section 5. Format of CP Commands 77
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