OSWORD &89

OSWORD &89 (137) - Read teletext pixel Dump Out 3

The control block is incorrectly defined for the OSWORD protocol,
and will work incorrectly if called from a coprocessor.
On entry:
 XY+0..1=X coord 0-1279
 XY+2..3=Y coord 0-1024
 XY?11  =&FF on first call to check for double height
On exit:
 XY?4     =Pixel colour or &80 if off-screen
 XY?5     =Y position with character cell
 XY?6     =foregound colour
 XY?7     =background colour
 XY?8     =character column containing pixel
 XY?9     =character row containing pixel
 XY?10    =character containing the pixel
 XY+11..13=double height table
 XY+12    =attribute: b1=held separated, b2=separated,
   b3=hold, b4=conceal, b5=double height, b6=graphic,
   b7=flash
 XY?15    =current hold character.

See Also

• http://mdfs.net/Docs/Comp/BBC/Oswords

Jgharston 14:17, 26 May 2009 (UTC)