|
Routines |
| Prev: 874E | Up: Map | Next: 8866 |
| 8751 | LD HL,$C596 | Point HL at the start of the nasty buffer. (C596) | ||
| 8754 | LD B,$06 | Maximum of six characters on screen. | ||
| 8756 | NOP | |||
| 8757 | PUSH BC | Remember character count. | ||
| 8758 | PUSH HL | Swap HL for IX so the buffer can be indexed. | ||
| 8759 | POP IX | |||
| 875B | LD A,(IX+$00) | Get the type flag. | ||
| 875E | OR A | If the type is not 0, skip forward. | ||
| 875F | JP NZ,$887D | |||
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Move a simple nasty. This entry point is used by the routine at 8964.
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| 8762 | LD L,(IX+$0C) | Put the current X co-ordinate in L. | ||
| 8765 | LD H,(IX+$0D) | Put the current Y co-ordinate in H. | ||
| 8768 | LD ($8962),HL | Store this in 8962. | ||
| 876B | LD A,(IX+$0B) | Get the current direction. | ||
| 876E | OR A | Is it down? | ||
| 876F | JR NZ,$87A6 | No, so jump forward. | ||
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Moving up.
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| 8771 | LD B,(IX+$11) | Increment the Y co-ordinate by the speed. | ||
| 8774 | LD A,(IX+$0D) | |||
| 8777 | ADD A,B | |||
| 8778 | LD (IX+$0D),A | |||
| 877B | LD L,(IX+$01) | Put the "up" graphic in HL. | ||
| 877E | LD H,(IX+$02) | |||
| 8781 | LD A,(IX+$10) | Decrement the distance to travel. | ||
| 8784 | DEC A | |||
| 8785 | JR NZ,$8797 | Skip the next code if it is not zero. | ||
| 8787 | LD L,(IX+$03) | Put the "down" graphic in HL. | ||
| 878A | LD H,(IX+$04) | |||
| 878D | LD A,(IX+$0B) | Change the direction to "down". | ||
| 8790 | INC A | |||
| 8791 | LD (IX+$0B),A | |||
| 8794 | LD A,(IX+$0E) | Set the distance to travel back to the default. | ||
| 8797 | LD (IX+$10),A | |||
| 879A | LD A,(IX+$0F) | Increment the animation frame, looping from 0 - 7. | ||
| 879D | INC A | |||
| 879E | AND $07 | |||
| 87A0 | LD (IX+$0F),A | |||
| 87A3 | JP $8827 | Move forward to draw the nasty. | ||
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Moving down.
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| 87A6 | CP $01 | Is the direction up? | ||
| 87A8 | JR NZ,$87D2 | No, so jump forward. | ||
| 87AA | LD A,(IX+$0D) | Decrement the Y co-ordinate by the speed. | ||
| 87AD | LD B,(IX+$11) | |||
| 87B0 | SUB B | |||
| 87B1 | LD (IX+$0D),A | |||
| 87B4 | LD A,(IX+$10) | Get the distance to travel. | ||
| 87B7 | LD L,(IX+$03) | Put the "down" graphic in HL. | ||
| 87BA | LD H,(IX+$04) | |||
| 87BD | DEC A | Decrement the distance to travel. | ||
| 87BE | JR NZ,$8797 | Skip the next code if it is not zero. | ||
| 87C0 | LD L,(IX+$01) | Put the "up" graphic in HL. | ||
| 87C3 | LD H,(IX+$02) | |||
| 87C6 | LD A,(IX+$0B) | Change the direction to "up". | ||
| 87C9 | DEC A | |||
| 87CA | LD (IX+$0B),A | |||
| 87CD | LD A,(IX+$0E) | Set the distance to travel back to the default | ||
| 87D0 | JR $8797 | Jump back to draw the nasty. | ||
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Moving left.
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| 87D2 | CP $02 | Is the direction left? | ||
| 87D4 | JR NZ,$87FE | No, so jump forward. | ||
| 87D6 | LD A,(IX+$0C) | Decrement the X co-ordinate by the speed. | ||
| 87D9 | LD B,(IX+$11) | |||
| 87DC | SUB B | |||
| 87DD | LD (IX+$0C),A | |||
| 87E0 | LD A,(IX+$10) | Get the distance to travel. | ||
| 87E3 | LD L,(IX+$05) | Put the "left" graphic in HL. | ||
| 87E6 | LD H,(IX+$06) | |||
| 87E9 | DEC A | Decrement the distance to travel. | ||
| 87EA | JR NZ,$8797 | Skip the next code if it is not zero. | ||
| 87EC | LD L,(IX+$07) | Put the "right" graphic in HL. | ||
| 87EF | LD H,(IX+$08) | |||
| 87F2 | LD A,(IX+$0B) | Change the direction to "right". | ||
| 87F5 | INC A | |||
| 87F6 | LD (IX+$0B),A | |||
| 87F9 | LD A,(IX+$0E) | Set the distance to travel back to default. | ||
| 87FC | JR $8797 | Jump back to draw the nasty. | ||
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Moving right.
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| 87FE | LD A,(IX+$0C) | Increment the X co-ordinate by the speed. | ||
| 8801 | LD B,(IX+$11) | |||
| 8804 | ADD A,B | |||
| 8805 | LD (IX+$0C),A | |||
| 8808 | LD L,(IX+$07) | Put the "right" graphic in HL. | ||
| 880B | LD H,(IX+$08) | |||
| 880E | LD A,(IX+$10) | Decrement the distance to travel. | ||
| 8811 | DEC A | |||
| 8812 | JR NZ,$8797 | Skip the next code if it is not zero. | ||
| 8814 | LD L,(IX+$05) | Put the "left" graphic in HL. | ||
| 8817 | LD H,(IX+$06) | |||
| 881A | LD A,(IX+$0B) | Change the direction to "left". | ||
| 881D | DEC A | |||
| 881E | LD (IX+$0B),A | |||
| 8821 | LD A,(IX+$0E) | Set the distance to travel back to the default. | ||
| 8824 | JP $8797 | Jump back to draw the nasty. | ||
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After updating the position, the nasty can be drawn.
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| 8827 | EX DE,HL | Swap DE and HL over. | ||
| 8828 | RRA | Get the top 3 bits of animation to determine the frame to draw. | ||
| 8829 | AND $03 | |||
| 882B | LD L,A | Put this in HL. | ||
| 882C | LD H,$00 | |||
| 882E | ADD HL,HL | Multiply by 32 to get a address of graphics. | ||
| 882F | ADD HL,HL | |||
| 8830 | ADD HL,HL | |||
| 8831 | ADD HL,HL | |||
| 8832 | ADD HL,HL | |||
| 8833 | ADD HL,DE | Add the basic address of the graphics to get the right one. | ||
| 8834 | LD ($ECE0),HL | Set the graphics to draw. | ||
| 8837 | LD L,(IX+$0C) | Set the co-ordinates. | ||
| 883A | LD H,(IX+$0D) | |||
| 883D | LD ($ECDE),HL | |||
| 8840 | CALL $EBE0 | Draw the graphic. | ||
| 8843 | LD A,(IX+$00) | Is the status 0? | ||
| 8846 | OR A | |||
| 8847 | JR NZ,$8857 | Move on if not. | ||
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The nasty's attributes needs to be drawn.
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| 8849 | LD HL,($8962) | Get the old position. | ||
| 884C | LD C,$47 | Use bright white to erase the old attribute. | ||
| 884E | NOP | |||
| 884F | NOP | |||
| 8850 | NOP | |||
| 8851 | CALL $886F | Draw these specific attributes. | ||
| 8854 | CALL $8866 | Draw the new attributes from the actual nasty data. | ||
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All done with this nasty, move to the next. This entry point is used by the routine at 8964.
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| 8857 | PUSH IX | Add 14 bytes to point to the next nasty data. | ||
| 8859 | POP HL | |||
| 885A | LD DE,$0014 | |||
| 885D | ADD HL,DE | |||
| 885E | POP BC | Restore BC. | ||
| 885F | DJNZ $8863 | Loop back if there are more nasties to look at. | ||
| 8861 | EI | Otherwise re-enable interrupts and return. | ||
| 8862 | RET | |||
| 8863 | JP $8757 | |||
| Prev: 874E | Up: Map | Next: 8866 |