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The Java language allows platforms to use available floating-point hardware that can provide /extended floating-point support/ with exponents that contain more bits than the standard Java primitive type double (in the absence of the strictfp modifier). Consequently, these platforms can represent a superset of the values that can be represented by the standard floating-point types. Floating-point computations on such platforms can produce different results than would be obtained if the floating-point computations were restricted to the standard representations of float and double. According to the Java Language Specification (JLS), §15.4, "FP-strict Expressions":

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Using the strictfp modifier leaves execution unchanged on platforms that lack platform-specific, extended floating-point behaviorsupport. It can have substantial impact, however, on both the efficiency and the result values of floating-point computations when executing on platforms that implement platform-specific provide extended floating-point behaviorsupport. On these platforms, using the strictfp modifier increases the likelihood that intermediate operations will overflow or underflow because it restricts the range that can be represented and the precision of intermediate values; it can also reduce computational efficiency. These issues are unavoidable when portability is the main concern.

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Noncompliant Code Example

On platforms whose Some platforms provide extended floating-point support in which their native floating-point hardware provides greater precision than double. On these platforms, the JIT is permitted to use floating-point registers to hold values of type float or type double (in the absence of the strictfp modifier), even though the registers support values with greater exponent range than that of the primitive types. Consequently, conversion from float to double can cause an effective loss of magnitude.

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Failure to use the strictfp modifier can result in nonportable, implementation-defined behavior with respect to the behavior of floating-point operations.

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