h6. [[Programmer's Reference Manuals]] h6(. » [[*Commands]] h6((. » *FX h2. *FX h4. Use This *Command calls [[OS_Byte]] to alter status variables, and to perform other closely-related actions. h4. Syntax *FX _reason_code_ [[,] _r1_ [[,] _r2_]] h4. Parameters |<^{width:8em}. _reason_code_|<^. OS_Byte reason code (0 to 255) | |<^. _r1_|<^. Register value of R1| |<^. _r2_|<^. Register value of R2| h4. Notes The reason code determines which action to perform. See [[OS_Byte]] for the complete list. h4. See also * [[OS_Byte]]