| Routines

8DF8: Move and draw Eugene in Eugene's Lair

Used by the routine at 870E. First we move Eugene up or down, or change his direction.
8DF8 | LD A,($8074) | Pick up the attribute of the last item drawn from 8074
8DFB | OR A | Have all the items been collected?
8DFC | JR Z,$8E0F | Jump if so
8DFE | LD A,($80DB) | Pick up Eugene's direction from 80DB
8E01 | OR A | Is Eugene moving downwards?
8E02 | JR Z,$8E0F | Jump if so
8E04 | LD A,($80DC) | Pick up Eugene's pixel y-coordinate from 80DC
8E07 | DEC A | Decrement it (moving Eugene up)
8E08 | JR Z,$8E1C | Jump if Eugene has reached the top of the cavern
8E0A | LD ($80DC),A | Update Eugene's pixel y-coordinate at 80DC
8E0D | JR $8E24 |
8E0F | LD A,($80DC) | Pick up Eugene's pixel y-coordinate from 80DC
8E12 | INC A | Increment it (moving Eugene down)
8E13 | CP $58 | Has Eugene reached the portal yet?
8E15 | JR Z,$8E1C | Jump if so
8E17 | LD ($80DC),A | Update Eugene's pixel y-coordinate at 80DC
8E1A | JR $8E24 |
8E1C | LD A,($80DB) | Toggle Eugene's direction at 80DB
8E1F | XOR $01
8E21 | LD ($80DB),A
Now that Eugene's movement has been dealt with, it's time to draw him.
8E24 | LD A,($80DC) | Pick up Eugene's pixel y-coordinate from 80DC
8E27 | AND $7F | Point DE at the entry in the screen buffer address lookup table at 8300 that corresponds to Eugene's y-coordinate
8E29 | RLCA
8E2A | LD E,A
8E2B | LD D,$83
8E2D | LD A,(DE) | Point HL at the address of Eugene's location in the screen buffer at 6000
8E2E | OR $0F
8E30 | LD L,A
8E31 | INC DE
8E32 | LD A,(DE)
8E33 | LD H,A
8E34 | LD DE,$80E0 | Draw Eugene to the screen buffer at 6000
8E37 | LD C,$01
8E39 | CALL $8FF4
8E3C | JP NZ,$8D06 | Kill Willy if Eugene collided with him
8E3F | LD A,($80DC) | Pick up Eugene's pixel y-coordinate from 80DC
8E42 | AND $78 | Point HL at the address of Eugene's location in the attribute buffer at 5C00
8E44 | RLCA
8E45 | OR $07
8E47 | SCF
8E48 | RL A
8E4A | LD L,A
8E4B | LD A,$00
8E4D | ADC A,$5C
8E4F | LD H,A
8E50 | LD A,($8074) | Pick up the attribute of the last item drawn from 8074
8E53 | OR A | Set the zero flag if all the items have been collected
8E54 | LD A,$07 | Assume we will draw Eugene with white INK
8E56 | JR NZ,$8E5F | Jump if there are items remaining to be collected
8E58 | LD A,($80BD) | Pick up the value of the game clock at 80BD
8E5B | RRCA | Move bits 2-4 into bits 0-2 and clear the other bits; this value (which decreases by one on each pass through the main loop) will be Eugene's INK colour
8E5C | RRCA
8E5D | AND $07
This entry point is used by the routines at 8E75 (to set the attributes for a Skylab), 8EF1 (to set the attributes for a vertical guardian) and 9135 (to set the attributes for the Kong Beast).
8E5F | LD (HL),A | Save the INK colour in the attribute buffer temporarily
8E60 | LD A,($8020) | Pick up the attribute byte of the background tile for the current cavern from 8020
8E63 | AND $F8 | Combine its PAPER colour with the chosen INK colour
8E65 | OR (HL)
8E66 | LD (HL),A | Set the attribute byte for the top-left cell of the sprite in the attribute buffer at 5C00
8E67 | LD DE,$001F | Prepare DE for addition
8E6A | INC HL | Set the attribute byte for the top-right cell of the sprite in the attribute buffer at 5C00
8E6B | LD (HL),A
8E6C | ADD HL,DE | Set the attribute byte for the middle-left cell of the sprite in the attribute buffer at 5C00
8E6D | LD (HL),A
8E6E | INC HL | Set the attribute byte for the middle-right cell of the sprite in the attribute buffer at 5C00
8E6F | LD (HL),A
8E70 | ADD HL,DE | Set the attribute byte for the bottom-left cell of the sprite in the attribute buffer at 5C00
8E71 | LD (HL),A
8E72 | INC HL | Set the attribute byte for the bottom-right cell of the sprite in the attribute buffer at 5C00
8E73 | LD (HL),A
8E74 | RET |