Tube: tube_table

       Name: tube_table                                              [Show more]
       Type: Variable
   Category: Tube
    Summary: Lookup table for Tube commands sent from the parasite to the I/O
             processor
  Deep dive: Tube communication in Elite-A
    Context: See this variable in context in the source code
 References: This variable is used as follows:
             * tube_func uses tube_table


 This table lists all the commands that can be sent from the parasite to the
 I/O processor.

 The hexadecimal number is the number of that command, and is the first byte to
 be sent over the Tube. The parameters shown in brackets are sent next, in the
 order shown, and if the command returns a result (denoted by a leading = sign
 in the command name), then this is then sent back to the parasite.

 Consider the following command, which scans the keyboard or Delta 14B keypad
 for a specific flight key:

   =scan_y(key_offset, delta_14b)

 To run this command, the parasite would first send a value of &96 to the I/O
 processor (using the tube_write routine), then it would send the key_offset
 and delta_14b parameters (in that order), and finally it would wait for the
 result to be returned by calling the tube_read routine.

 Meanwhile, at the other end, the receipt of the &96 value would trigger a call
 to the routine in WRCHV, which is the tube_wrch routine. This routine sees
 that the received value is greater than 127, so it calls the tube_func
 routine, which then looks up the corresponding routine from this table
 (routine scan_y in this case) and calls it to implement the command. The
 scan_y routine then fetches the parameter values using the tube_get routine,
 performs the keyboard or keypad scan according to the command's parameters,
 and finally sends the result back to the parasite using the tube_put routine.


.tube_table

 EQUW LL30              \ &80   draw_line(x1, y1, x2, y2)
 EQUW HLOIN             \ &81   draw_hline(x1, y1, x2)
 EQUW PIXEL             \ &82   draw_pixel(x, y, distance)
 EQUW clr_scrn          \ &83   clr_scrn()
 EQUW CLYNS             \ &84   clr_line()
 EQUW sync_in           \ &85   =sync_in()
 EQUW DILX              \ &86   draw_bar(value, colour, screen_low, screen_high)
 EQUW DIL2              \ &87   draw_angle(value, screen_low, screen_high)
 EQUW MSBAR             \ &88   put_missle(number, colour)
 EQUW scan_fire         \ &89   =scan_fire()
 EQUW write_fe4e        \ &8A   =write_fe4e(value)
 EQUW scan_xin          \ &8B   =scan_xin(key_number)
 EQUW scan_10in         \ &8C   =scan_10in()
 EQUW get_key           \ &8D   =get_key()
 EQUW CHPR              \ &8E   write_xyc(x, y, char)
 EQUW write_pod         \ &8F   write_pod(escp, hfx)
 EQUW draw_blob         \ &90   draw_blob(x, y, colour)
 EQUW draw_tail         \ &91   draw_tail(x, y, base_colour, alt_colour, height)
 EQUW SPBLB             \ &92   draw_S()
 EQUW ECBLB             \ &93   draw_E()
 EQUW UNWISE            \ &94   draw_mode()
 EQUW DET1              \ &95   write_crtc(rows)
 EQUW scan_y            \ &96   =scan_y(key_offset, delta_14b)
 EQUW write_0346        \ &97   write_0346(value)
 EQUW read_0346         \ &98   =read_0346()
 EQUW return            \ &99   return()
 EQUW HANGER            \ &9A   picture_h(line_count, multiple_ships)
 EQUW HA2               \ &9B   picture_v(line_count)

IF _BUG_FIX

 EQUW savews            \ &9C   savews()

ENDIF