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⌂ ∞ Elite on the BBC Micro and NES

Drawing the screen: DET1

[Elite-A, Parasite]

       Name: DET1                                                    [Show more]
       Type: Subroutine
   Category: Drawing the screen
    Summary: Show or hide the dashboard (for when we die) by sending a
             write_crtc command to the I/O processor

    Context: See this subroutine in context in the source code
 References: This subroutine is called as follows:
             * DEATH calls DET1




 Arguments:

   X                    The number of text rows to display on the screen (24
                        will hide the dashboard, 31 will make it reappear)



.DET1

 LDA #&95               \ Send command &95 to the I/O processor:
 JSR tube_write         \
                        \   write_crtc(rows)
                        \
                        \ which will update the screen to show the specified
                        \ number of text rows

 TXA                    \ Send the parameter to the I/O processor:
 JMP tube_write         \
                        \   * rows = X
                        \
                        \ and return from the subroutine using a tail call