h6. [[OS SWI Calls]] h6(. » [[OS_Memory]] h6((. » OS_Memory 9 h2. OS_Memory 9 h5. (SWI &68) |_<^{width:4em}. Entry | | |<^. R0 |<^. 9, all flag bits reserved | |<^. R1 |<^. [[OS_Memory 9 Controller Numbers|Controller number]] | |_<^{width:4em}. Exit | | |<^. R0 |<^. Preserved | |<^. R1 |<^. Controller base logical address, or 0 if not present | h4. Use The purpose of this call is to check for the presence of a given controller and return its base logical address if present. The behaviour of this SWI differs slightly between RISC OS 5 and RISC OS Select/Adjust. Under RISC OS 5 the SWI will return an error if the controller number is unrecognised, or 0 if the controller isn't present. Under RISC OS Select/Adjust the SWI will return an error under both situations. Also under RISC OS Select/Adjust, even if the controller exists there is no guarantee that the memory will have been mapped in by the kernel. Therefore programs should also use [[OS_Memory 25]] where appropriate, in order to allow them to map in the memory themselves. h4. See also * [[OS_Memory]] * [[OS_Memory 9 Controller Numbers]] * [[OS_Memory 25]]