Routines
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40240: Draw Beam
Used by the routine at UpdateBeams.
Records a beam in the table at BeamTable and draws it.
Input
B Number of bytes
C Pattern of each byte
HL Screen address of the first byte
IY Address of the entry in the table
DrawBeam 40240 LD (IY+0),L Record the low byte of the screen address.
40243 LD (IY+1),H Record the high byte of the screen address.
40246 LD (IY+2),B Record the number of bytes.
40249 LD (IY+3),C Record the pattern.
DrawBeam_Loop 40252 LD A,C Fetch the pattern.
40253 OR (HL) Set the pixels.
40254 LD (HL),A
40255 INC L Move on to the next byte of the row.
40256 DJNZ DrawBeam_Loop Loop back to DrawBeam_Loop for each byte.
40258 RET Return.
Prev: 40239 Up: Map Next: 40259