Fixed Accuracy Arithmetic Functions

This chapter describes functions that perform arithmetic operations at a chosen level of accuracy.

These functions provide flexible specification of accuracy and support IEEE-754 standards. Choice of accuracy level is based on practical experience and application requirements.

Options are specified by a function name suffix:

The options for the single-precision data format are A11, A21, and A24.

The options for the double-precision data format are A50 and A53.

For single precision data:

Suffix_A11 guarantees 11 correctly rounded bits of significand, or at least three exact decimal digits.

Suffix_A21 guarantees 21 correctly rounded bits of significand, or four ulps, or approximately six exact decimal digits.

Suffix_A24 guarantees 24 correctly rounded bits of significand, including the implied bit, with the maximum guaranteed error within one ulp.

For double precision data:

Suffix_A50 guarantees 50 correctly rounded bits of significand, or four ulps, or approximately 15 exact decimal digits.

Suffix_A53 guarantees 53 correctly rounded bits of significand, including the implied bit, with the maximum guaranteed error within one ulp.

This chapter contains the following function definitions.