cpos expression; operation
cpos 35;wmi <- wmi if bit 35 on
cpos /13;wmi <- wmi if bit 13 off
cpos gt5;+5 <- skip four lines if lower
half of PSW > 5
cpos /13;$okay <- go to label "okay" if bit 13 is off
cpos ;9999 <- end the command file successfully
CPOS, written by Bull, is intended to provide a flow of control capability for command file (DRUN or CRUN) applications. It permits either conditional alteration of the normal serial processing of input file responses for a command file application, or conditional execution of a single command based on the contents of the user program switch word (PSW).
The first parameter represents a boolean expression. If this is true, the second expression is evaluated. The condition expression may contain any of the following operands:
Form Is true when: Restriction i bit i of the PSW is on 0 <= i < 36 LTn c(PSW) bits 18-35 is less than n n < 262144 LEn c(PSW) bits 18-35 is <= n n < 262144 GTn c(PSW) bits 18-35 is greater than n n < 262144 GEn c(PSW) bits 18-35 is >= n n < 262144 EQn c(PSW) bits 18-35 is equal to n n < 262144 NEn c(PSW) bits 18-35 is not equal to n n < 262144 DEF this is a DRUN session
Permissible operators include + (or), * (and), - (exclusive or), and / (not). Although / is a unary operator involving only one operand, by convention A/B is taken to mean A*/B.
The second parameter is an operation to perform if the condition is true. If this is a number, then it is a relative line in the command file where execution is to continue. A positive value moves forward, and a negative value move backward. (Zero would result in a jump to the CPOS line itself). A forward move beyond the end of the file (e.g. 9999), terminates the command file normally. If the string starts with a "$", then is is taken as a label for and absolute location in the file marked by a $*$LBL line. Anything else is taken as a TSS command to be executed.
A null expression is always true, and is used for "goto" type actions.
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