Datasheet

Floating-point Support

(For readers familiar with the IEEE 754 specification, the ARM choice of

implementation options are to detect tininess after rounding, and to detect

loss of accuracy as a denormalization loss.)

If Underflow is not trapped, the result is rounded to one of the two nearest

representable denormal numbers, according to the current rounding mode.

The loss of precision is ignored and the system returns the best result it can.

— The Inexact Result exception happens whenever the result of an operation

requires rounding. This would cause significant loss of speed if it had to be

detected on every operation in software, so the ordinary floating-point

libraries do not support the Inexact Result exception. The enhanced

floating-point libraries, and hardware floating-point systems, all support

Inexact Result.

If Inexact Result is not trapped, the system rounds the result in the usual

way.

The flag for Inexact Result is also set by Overflow and Underflow if either

one of those is not trapped.

All exceptions are untrapped by default.