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FLDLN2

Loads the natural logarithm of the value of an 80-bit extended precision floating-point number (divided by 2) onto the ST(0) register. The instruction computes $y = \ln(x) / 2$ where $x$ is the operand.

The table below covers what the source and destinations can be.

DO NOT support LOCK

This instruction is available in 64-bit mode only when executing in compatibility mode. In true 64-bit mode, the x87 FPU instructions are generally supported, but specific legacy behaviors may vary; however, this instruction specifically targets the x87 FPU stack.

The operand MUST be a valid 80-bit extended precision floating-point number. If the input value is negative or NaN, the instruction SHALL generate #I. If the input value is zero, it SHALL generate #Z. To avoid precision loss or unexpected exceptions, ensure the input is normalized and within the representable range of f80.