FATANA

Operation

Approximates arctangent in radians for finite values and signed infinity.

Assembler Syntax

FATANA.{S|D}(z) Fn(s), Fn(d)

Privilege

Unprivileged

Required CPUID flags

FP

FPTRANSA

Repeat eligibility

REP eligible

Computes the \(\operatorname{atan}(x)\) reference in radians over all finite values and signed infinity after DAZ and writes an implementation-bounded S- or D-format approximation under the selected FPTRANSA accuracy contract.

The required FPTRANSA_ACCURACY contract is 0x0013.

Special values

• Zero source: the result is the source.

Exact anchors

• \(\operatorname{atan}(+0) = +0\)

• \(\operatorname{atan}(-0) = -0\)

Required properties

• odd

• monotonically increasing

• finite results are in \([-\pi/2, \pi/2]\)

2.75in

Encodings

FATANA.{S|D}(z) Fn(s), Fn(d)

Format: Instruction format for FATANA.{S|D}(z) Fn(s), Fn(d)