h6. [[OS SWI Calls]] h6(. » [[OS_Memory]] h6((. » OS_Memory 21 h2. OS_ Memory 21 h5. (SWI &68) |_<^{width:4em}. Entry | | |<^. R0 |<^. 21 (&15), and [[OS_Memory 13 Flags|flags]] | |<^. R1 |<^. Physical address to map in (low 32 bits) | |<^. R2 |<^. Physical address to map in (high 32 bits) | |<^. R3 |<^. Size to map in | |_<^{width:4em}. Exit | | |<^. R0 |<^. Preserved | |<^. R1 |<^. Preserved | |<^. R2 |<^. Preserved | |<^. R3 |<^. Logical address assigned | h4. Use The purpose of this call is to permanently map in a region of IO memory at run-time. This call was introduced in RISC OS 5.27, to improve upon the existing [[OS_Memory 13]] call (which can only deal with 32-bit physical addresses). For compatibility with older OS versions, it's recommended to use OS_Memory 13 whenever 32-bit physical addresses are sufficient. h4. See also * [[OS_Memory]] * [[OS_Memory 13 Flags]] * [[OS_Memory 13]]