With certain exceptions, flush-to-zero mode has the following effects on floating-point operations:
A denormalized number is treated as 0 when used as an input to a floating-point operation. The source register is not altered.
If the result of a single-precision floating-point operation, before rounding, is in the range -2-126 to +2-126, it is replaced by 0.
If the result of a double-precision floating-point operation, before rounding, is in the range -2-1022 to +2-1022, it is replaced by 0.
An inexact exception occurs whenever a denormalized number is used as an operand, or a result is flushed to zero. Underflow exceptions do not occur in flush-to-zero mode.