MPE/iX Commands Reference Manual (32650-90877)

Chapter 12 479
Command List X
Commands SAVE thru SHUTQ
The values in the system-reserved JCWs can be inspected by the user, but not altered.
To display the contents of a JCW use the SHOWJCW or the SHOWVAR command.
JCW Values and Mnemonics
JCWs may be assigned any positive integer value between 0 and 65,535 inclusive (%0 and
%177777). These values are treated as 16-bit unsigned integers by MPE/iX, since all 16
bits are used for numeric information, rather than using the most significant bit as a sign
bit.
MPE/iX treats the two most significant bits of a JCW in a special way: the bits define
"bases" or "steps" of 16K each. Each of these steps is given a mnemonic to simplify
references to it or to the numbers between steps. If the 14 least significant bits are
considered to be zeros, the two "step" bits, step value (in decimal), and mnemonic have the
following relationship:
It is important to remember that these mnemonics are not the names of JCWs. They
cannot be used as user-defined JCW names.
You may use a combination of mnemonics and numbers to indicate numeric values
between steps. If you specify a mnemonic and a number with no intervening spaces, an
implied addition takes place. For example, WARN3 has a value of 16,387, since it is WARN
(16,384) plus 3. The value of the mnemonic plus the appended number value may not
exceed 65,535. Again, no valid value of the form, mnemonic[
number ], may be used as a
valid user-defined
jcwname . An explicit addition or subtraction can also be specified,
using a + or - sign, as in OK+7 (7) or WARN-4 (16,380). A mnemonic may also be added to
another mnemonic, as in WARNFATAL.
The result of a mathematical operation must be in the range of 0 to 65,535, inclusive; if the
number is out of range, an error message is generated, and the value of the JCW remains
unchanged. When the result of an operation is greater than the value of the next "step",
the JCW value displayed by the SHOWJCW command will be the mnemonic of the higher step
plus any offset. For example, the value OK16385 is displayed as WARN1.
User-Defined JCWs
User-defined JCWs are created and initialized to a value by the SETJCW command or
PUTJCW intrinsic. The JCW name contains alphanumeric characters and must begin with
an alphabetic character. The name can be up to 255 characters long. The value assigned to
the JCW must be in the range of 0 to 65,535, inclusive.
The SETJCW command scans the MPE/iX variable table for the name of the specified JCW
(
jcwname ). If the specified name is found, the JCW is set to value. If the jcwname is not
Table 12-1. JCW Values and Mnemonics
Bit Value Step Value Mnemonic
00 0 OK
01 16,384 WARN
10 32,768 FATAL
11 49,152 SYSTEM