Maths (Geometry): SCALEY2

       Name: SCALEY2                                                 [Show more]
       Type: Subroutine
   Category: Maths (Geometry)
    Summary: Scale the y-coordinate in A (leave it unchanged)
    Context: See this subroutine in context in the source code
 References: This subroutine is called as follows:
             * TT105 calls SCALEY2
             * TT14 calls SCALEY2
             * TT23 calls SCALEY2


 This routine (and the related SCALEY and SCALEX routines) are called from
 various places in the code to scale the value in A. This code is different in
 the Apple II and BBC Master versions, and allows coordinates to be scaled
 correctly on different platforms.

 The original source contains the comment "SCALE Scans by 3/4 to fit in".

 In the Master version, the only scaling routine that does anything is SCALEY,
 which halves the y-coordinates in the Long-range Chart (as the galaxy is half
 as tall as it is wide). The other routines are left over from the Apple II
 version, which uses them to scale the system charts to fit into its smaller
 screen size.


 Returns:

   C flag               The C flag is cleared


.SCALEY2

 RTS                    \ Return from the subroutine