Additional Source Code Guidelines for Run-Time Efficiency

In addition to data alignment and the efficient use of arrays and I/O, other source coding guidelines can be implemented to improve run-time performance.

The amount of improvement in run-time performance is related to the number of times a statement is executed. For example, improving an arithmetic expression executed within a loop many times has the potential to improve performance, more than improving a similar expression executed once outside a loop.

Suggested guidelines for improving source code efficiency are provided in the following sections:

• Avoid Small Integer and Small Logical Data Items (ia64 only)
• Avoid Mixed Data Type Arithmetic Expressions
• Use Efficient Data Types
• Avoid Using Slow Arithmetic Operators
• Avoid EQUIVALENCE Statement Use
• Use Statement Functions and Internal Subprograms
• Code DO Loops for Efficiency