Dashboard: COMPAS

       Name: COMPAS                                                  [Show more]
       Type: Subroutine
   Category: Dashboard
    Summary: Update the compass
    Context: See this subroutine in context in the source code
 References: This subroutine is called as follows:
             * DIALS (Part 4 of 4) calls COMPAS


.COMPAS

 JSR DOT                ; Call DOT to redraw (i.e. remove) the current compass
                        ; dot

 LDA SSPR               ; If we are inside the space station safe zone, jump to
 BNE SP1                ; SP1 to draw the space station on the compass

 JSR SPS1               ; Otherwise we need to draw the planet on the compass,
                        ; so first call SPS1 to calculate the vector to the
                        ; planet and store it in XX15

 JMP SP2                ; Jump to SP2 to draw XX15 on the compass, returning
                        ; from the subroutine using a tail call