Performance Issues
Some systems handle denormal values in hardware, in the same way as normal values. Others leave the handling of denormal values to system software, only handling normal values and zero in hardware. Handling denormal values in software always leads to a significant decrease in performance. But even when denormal values are entirely computed in hardware, the speed of computation is significantly reduced on most modern processors; in extreme cases, instructions involving denormal operands may run as much as 100 times slower.
Some applications need to contain code to avoid denormal numbers, either to maintain accuracy, or in order to avoid the performance penalty in some processors. For instance, in audio processing applications, denormal values usually represent a signal so quiet that it is out of the human hearing range. Because of this, a common measure to avoid denormals on processors where there would be a performance penalty is to cut the signal to zero once it reaches denormal levels or mix in an extremely quiet noise signal. Other methods of preventing denormal numbers include adding a DC offset, quantizing numbers, adding a nyquist signal, etc. Since the SSE2 processor extension, Intel has provided such a functionality in CPU hardware, which rounds denormalized numbers to zero.
Read more about this topic: Denormal Number
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