This instruction can generate a floating-point exception. Depending on the settings in FPCR, the exception results in either a flag being set in FPSR or a synchronous exception being generated. For more information, see Floating-point exception traps.
integer d = UInt(Rd); integer n = UInt(Rn); if !HaveFJCVTZSExt() then UNDEFINED;
Is the 32-bit name of the general-purpose destination register, encoded in the "Rd" field.
Is the 64-bit name of the SIMD&FP source register, encoded in the "Rn" field.