Version analysis of hm - Elite on the 6502

This code appears in the following versions (click to see it in the source code):

Cassette, Disc (flight), Disc (docked), 6502 Second Processor, Master and Electron

Code variations between these versions are shown below.

       Name: hm
       Type: Subroutine
   Category: Charts
    Summary: Select the closest system and redraw the chart crosshairs


 Set the system closest to galactic coordinates (QQ9, QQ10) as the selected
 system, redraw the crosshairs on the chart accordingly (if they are being
 shown), and, if this is not a space view, clear the bottom three text rows of
 the screen.


.hm

 JSR TT103              \ Draw small crosshairs at coordinates (QQ9, QQ10),
                        \ which will erase the crosshairs currently there

 JSR TT111              \ Select the system closest to galactic coordinates
                        \ (QQ9, QQ10)

 JSR TT103              \ Draw small crosshairs at coordinates (QQ9, QQ10),
                        \ which will draw the crosshairs at our current home
                        \ system

Code variation 1 of 1Specific to an individual platform

Tap on a block to expand it, and tap it again to revert.

Cassette, Electron
Flight, Docked, 6502SP, Master
 LDA QQ11               \ If this is a space view, return from the subroutine
 BEQ SC5                \ (as SC5 contains an RTS)

                        \ Otherwise fall through into CLYNS to clear space at
                        \ the bottom of the screen
 JMP CLYNS              \ Clear the bottom three text rows of the upper screen,
                        \ and move the text cursor to the first cleared row

                        \ Return from the subroutine using a tail call