h6. [[OS SWI Calls]] h6(. » [[OS_FSControl]] h6((. » OS_FSControl 46 h2. OS_ FSControl 46 h5. (SWI &29) |_<^{width:4em}. Entry | | |<^. R0 |<^. 46 (&2E) | |<^. R1 |<^. Pointer to name of image (null terminated) | |<^. R2 |<^. Pointer to buffer | |<^. R5 |<^. Buffer size | |_<^{width:4em}. Exit | | |\2<^. All registers preserved| h4. Use The purpose of this call is to returns an image file’s used space map. h4. Notes This SWI writes the image used space map to the buffer, 1 bits signifying used blocks, 0 bits free blocks. Bit 0 in a byte comes before bit 7. This SWI sets bits up to min( buffer size, file size / block size ). Block size for a file can be read with [[OS_File 24]]. For a non-image file the buffer will be filled with ones. h4. See also * [[OS_FSControl]] * [[OS_File 24]]