QDOS Internals

Anything you never knew you wanted to know about the Sinclair QL.

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This Trap writes a line of blobs to a window.

Call ParametersReturn Parameters
D0.B$74D0.LError return
D1.L x,y start coordinatesD1.LPreserved
D2.Lx,y end coordinatesD2.LPreserved
A0.LWindow IDA0.LPreserved
A1.LPointer to blobA1.LPreserved
A2.LPointer to patternA2.LPreserved


ERR.NOChannel not open
ERR.BPBad data structure


  • All registers not mentioned above are preserved on return.
  • Blobs are written continuously from the start address in D1 to the end address in D2.
  • Blobs wholly or partially outside the window are ignored and no error is signalled.


It is assumed here that A0.L contains the ID of the window.

  lea    blo,a1     ; Address of blob
  lea    pat,a2     ; Address of pattern
  moveq  #0,d1      ; Start at top left
  move.l #$C000C,d2 ; End position
  moveq  #-1,d3     ; Tineout
  moveq  #$74,d0    ; IOP.LBLB
  trap   #3
  tst.l  d0
  bne    OOPS ---->
qdosmsq/pe/lblb.txt · Last modified: 2010/05/13 14:10 by george.gwilt