DW      PIESLICE        ; Draw an elliptical pie slice

  Input:
     AX         The starting angle of the slice in degrees (0-360)
     BX         The ending angle of the slice in degrees (0-360)
     CX         X radius of the elliptical slice
     DX         Y radius of the elliptical slice

  Return:
     Nothing

PIESLICE draws a filled elliptical pie slice (or wedge) using CP as the
center of the slice, from the given start angle to the given end angle.
The current FILLPATTERN and FILLCOLOR is used to fill the slice and it is
outlined in the current COLOR. To get circular pie slices, the application
(not the driver) must adjust the Y radius as follows:

    YRAD := XRAD * ASPEC / 10000

where ASPEC is the aspect value stored in the driver's DST.