83h DP$CSET set the clock-display status
Input B register - position of clock on screen.
     Bit 7 set to switch clock off.
Output B register - previous clock position and status.
Description Sets the clock-display status.

The B register specifies where on the screen the clock will appear as a position 0 to 74 (max 26 in 2 line mode). If the top bit of B is set, no clock will be displayed.

The clock is printed when DP$CSET is called and is updated in the keyboard interrupt. The interrupt just re-defines the UDGs and does not write to the screen.

The current screen status (cursor position etc) is always preserved.

Note that 5 UDGs (chars 3 to 7) are used to print the underlined clock and 6 if in 12 hour mode - UDG 1 is used for am/pm indicator and will overwrite any UDGs previously defined.

The clock is always right justified in a field of 6 characters (a UDG "_" is used to justify).

This call is not available on CM/XP machines.

Example Print a title line with the clock in the top right-hand corner.
UDG 0 has been defined as an icon, UDG 1 as an underscore character.
        LDX     #TOP_TITLE
        PSHX
        OS      UT$DISP
        DB      12
        ASCIZ   "%s"            ;print top-line
        LDAB    #15             ;UDG clock in top-right hand corner
        OS      DP$CSET         ;set to clock mode
        PSHB
        OS      KB$GETK         ;wait for key (clock will be updated)
        PULB
        OS      DP$CSET         ;restore clock status
        RTS

TOP_TITLE:
        DB      20
        DB      0,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1

Errors - none -