Control Data Corporation 3300 Reference Manual page 129

"'"---
60229400
Entrance
(from statement previously executed)
~
Set CNT
=
1
Set AMNT
=
ORIG
J
,
I
CNT
=
100
I
True
To statement following
I
PERFORM statement
{ False
I
I
True
AMNT> 250
I l
+
False
Execute CALCULATION
J
i
Set AMNT
=
ORIG
Augment AMNT BY DIFF
,
Augment CNT by 1
+
At termination of the PERFORM statement, AMNT contains its initial value.
CNT has a value that exceeds the last used setting by an increment or decre-
ment, unless condition-1 was true when the PERFORM statement was entered,
in which case CNT and AMNT contain their initial values.
For three identifiers, the mechanism is the same as for two identifiers except
that identifier-7 goes through a complete cycle each time that identifier-4 is
augmented by identifier-6 or literal-6, which in turn goes through acorn plete
cycle each time identifier-1 is varied.
Exampl~
of PERFORM varying three identifiers:
PERFORM PROC-1 THRU PROC-2 VARYING ID-1 FROM ID-2 BY ID-3
UNTIL ill-I EQUAL TO TERM-1 AFTER ID-4 FROM ID-5 BY ID-6
UNTIL ID-4 GREATER LIMIT-2 AFTER ID-7 FROM ID-8 BY 1 UNTIL
ID-7
=
5.
4-49