Version analysis of TT208 - Elite on the 6502

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

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

Code variations between these versions are shown below.

       Name: TT208
       Type: Subroutine
   Category: Market

Code variation 1 of 5A variation in the comments only

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Cassette, Docked, 6502SP, Master
Electron
    Summary: Show the Sell Cargo screen (red key f2)
    Summary: Show the Sell Cargo screen (FUNC-3)



.TT208

Code variation 2 of 5Related to the 6502SP version

In the 6502SP version, you can send the Sell Cargo screen to the printer by pressing CTRL-f2.

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Cassette, Docked, Electron
Master
6502SP
 LDA #4                 \ Clear the top part of the screen, draw a border box,
 JSR TT66               \ and set the current view type in QQ11 to 4 (Sell
                        \ Cargo screen)
 LDA #4                 \ Clear the top part of the screen, draw a border box,
 JSR TRADEMODE          \ and set up a trading screen with a view type in QQ11
                        \ of 4 (Sell Cargo screen)
 LDA #4                 \ Clear the top part of the screen, draw a border box,
 JSR TRADEMODE          \ and set up a printable trading screen with a view type
                        \ in QQ11 of 4 (Sell Cargo screen)

Code variation 3 of 5Related to a standard feature

The layout of the Sell Cargo screen in the cassette and Electron versions is slightly different to the other versions (it doesn't have a boxed title and the text starts lower down the screen).

See below for more variations related to this code.

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Cassette, Electron
Docked, Master
6502SP
 LDA #4                 \ Move the text cursor to row 4, column 4
 STA YC
 STA XC
 LDA #10                \ Move the text cursor to column 10
 STA XC
 LDA #10                \ Move the text cursor to column 10
 JSR DOXC

Code variation 4 of 5Specific to an individual platform

This variation is blank in the 6502 Second Processor, Master and Electron versions.

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Cassette
Docked
\JSR FLKB               \ This instruction is commented out in the original
                        \ source. It calls a routine to flush the keyboard
                        \ buffer (FLKB) that isn't present in the cassette
                        \ version but is in other versions
 JSR FLKB               \ Flush the keyboard buffer

 LDA #205               \ Print recursive token 45 ("SELL")
 JSR TT27

Code variation 5 of 5Related to a standard feature

See variation 3 above for details.

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Cassette, Electron
Docked, 6502SP, Master
 LDA #206               \ Print recursive token 46 (" CARGO{sentence case}")
 JSR TT68               \ followed by a colon
 LDA #206               \ Print recursive token 46 (" CARGO{sentence case}")
 JSR NLIN3              \ draw a horizontal line at pixel row 19 to box in the
                        \ title

 JSR TT67               \ Print a newline

                        \ Fall through into TT210 to show the Inventory screen
                        \ with the option to sell