h6. [[OS SWI Calls]] h6(. » OS_Word h2. OS_Word h5. (SWI &07) |_<^{width:4em}. Entry | | |<^. R0 |<^. "Reason code":#reason| |\2<^. All other registers dependent on reason code| |_<^{width:4em}. Exit | | |<^. R0 |<^. Preserved| |\2<^. All other registers dependent on reason code| h4. Use The purpose of this call is to provide a number of general operations. h4. Notes The action performed depends on the reason code value in R0. h4(#reason). Reason Codes |_<^{width:4em}. #|_<^{width:4em}. Hex #|_<^. Action| |<^. 0|<^. &00|<^. [[OS_Word 0|Read line from input stream]]| |<^. 1|<^. &01|<^. [[OS_Word 1|Read system clock]]| |<^. 2|<^. &02|<^. [[OS_Word 2|Write system clock]]| |<^. 3|<^. &03|<^. [[OS_Word 3|Read interval timer]]| |<^. 4|<^. &04|<^. [[OS_Word 4|Write interval timer]]| |<^. 7|<^. &07|<^. [[OS_Word 7|Make a SOUND]]| |<^. 9|<^. &09|<^. [[OS_Word 9|Read pixel logical colour]]| |<^. 10|<^. &0A|<^. [[OS_Word 10|Read a character definition]]| |<^. 11|<^. &0B|<^. [[OS_Word 11|Read palette]]| |<^. 12|<^. &0C|<^. [[OS_Word 12|Write palette]]| |<^. 13|<^. &0D|<^. [[OS_Word 13|Read current and last graphics cursors]]| |<^. 14|<^. &0E|<^. [[OS_Word 14|Read CMOS clock]]| |<^. 15|<^. &0F|<^. [[OS_Word 15|Write CMOS clock]]| |<^. 21|<^. &15|<^. [[OS_Word 21|Define pointer and mouse parameters]]| |<^. 22|<^. &16|<^. [[OS_Word 22|Write screen base address]]| h6. Controlling sources: "Hdr:OsWords":https://gitlab.riscosopen.org/RiscOS/Sources/Programmer/HdrSrc/-/blob/master/hdr/OsWords managed by the "allocations manager":/content/allocate