AT&T 6300 Programmer's Manual page 291

IF GOTO ELSE
IF THEN ELSE
Statements
Note: When using IF to test equality for a value
that is the result of a floating-point computa-
tion, remember that the internal representation
of the value may not be exact. Therefore, the
test should be against the range over which the
accuracy of the value may vary. For example, to
test a computed variable A against the value
1.0, use:
IF ABS (A-1.0)< 1.0E-6 THEN ...
This test returns true if the value of A is 1.0
with a relative error of less than 1.0E-6.
7.1
ql;