qdosmsq:traps:trap_3:pana

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qdosmsq:traps:trap_3:pana [2009/05/18 17:53] (current)
george.gwilt created
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 +====== SD_SCROL/​IOW_SCRA etc ======
 +
 +
 +These traps scroll all or part of a window.
 +^Trap^Value in D0.B^Action^
 +|SD_SCROL/​IOW_SCRA|$18|Scroll all of window|
 +|SD_SCRTP/​IOW_SCRT|$19|Scroll top of window|
 +|SD_SCRBT/​IOW_SCRB|$1A|Scroll bottom of window|
 +
 +^Call Parameters^^Return Parameters^^
 +|D0.B|See above|D0.L|Error return.|
 +|D1.W|Distance to scroll |D1.L|Corrupted.|
 +|D3.W|Timeout |D3.L|Preserved.|
 +|A0.L|Channel ID |A0.L|Preserved.|
 +
 +===== Errors =====
 +
 +
 +|ERR_NC|Not complete.|
 +|ERR_NO|Channel not open.|
 +
 +
 +===== Notes =====
 +  * All registers not shown above are not used on entry and are preserved on exit.
 +  * Scrolling means that the area selected will be moved up or down by an integral number of pixels. A positive number in D1.W will cause a downward movement. The vacated rows of pixels will be filled with paper colour.
 +  * The top of a window is defined as all the rows above the line on which the cursor lies (the cursor line).
 +  * The bottom of the window is defined as all the rows below the cursor line.
 +===== Example =====
 +The example below shows the use of this trap call to scroll text up by one line. It is assumed that A0 contains the correct channel ID.
 +
 +<​code>​
 +scroll ​ moveq   #​sd_scrol,​d0 ​   ; $18
 +        moveq   #​-10,​d1 ​        ; Up one line
 +        moveq   #​-1,​d3 ​         ; Timeout
 +        trap    #3              ; Scroll up a line
 +        tst.l   ​d0 ​             ; OK? . .
 +        bne     ​error ​          ; . . no!
 +</​code>​
 +
  
  • qdosmsq/traps/trap_3/pana.txt
  • Last modified: 2009/05/18 17:53
  • by george.gwilt