9.2.2 DO Loop Markings

DO loops are graphically displayed in a column headed "DO Loops." Brackets mark the extent of each DO loop up to nest level 10, as shown in the following example:

DO Loops     Line
 +---------  5  DO 99  I = 1,1000
 *           6    A(I,1) = B(1)
 *+--------  7    DO 95 J = 2,1000
 *!          8       A(I,J) = B(J)*A(I,J-1)
 *!________  9    95 CONTINUE
 *_________  10   99  CONTINUE

A statement that is enclosed by n DO loops has n exclamation marks (!) on that line. Loops that have been optimized in a major way have asterisks (*) instead of exclamation points in the source listing.

Note

DIGITAL KAP for DEC Fortran for DIGITAL UNIX recognizes certain operations, such as matrix multiplication, as basic entities. Frequently, the loops forming such operations will not be marked.

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