This content has not been validated; it was AI-generated following the x86-64 ISA Documentation generation process to maintain high quality. However, as no human has verified this data, errors may exist. If the accuracy of this data is critical, please consult the Intel SDM. The model used to generate this is gemma4:31b
FPATAN
Computes the arctangent of the value in the ST(0) register using a polynomial approximation and stores the result in ST(0).
The table after the description covers what the source and destinations can be.
| source | destination(s) |
|---|---|
| reg (ST(0)) | reg (ST(0)) |
DO NOT support LOCK
This instruction is only available in x86-64 when the processor is operating in compatibility mode. It is not supported in 64-bit mode.
The result of the approximation is less precise than the results of typical transcendental instructions. It MAY produce #I, #Z, #D, #O, #U, or #P exceptions depending on the input value and the current rounding mode. If the input is a NaN, #I is signaled.