FTANHA

Operation

Approximates hyperbolic tangent for finite values and signed infinity.

Assembler Syntax

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

Privilege

Unprivileged

Required CPUID flags

FP

FPTRANSA

Repeat eligibility

REP eligible

Computes the tanh(x) reference 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 0x0023.

Special values

• Infinite source: the result is one with the sign of the source.

• Zero source: the result is the source.

Exact anchors

• tanh(+0) = +0

• tanh(-0) = -0

• tanh(signed infinity) = signed 1

Required properties

• odd

• monotonically increasing

• result is in [-1, 1]

2.75in

Encodings

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

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