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Routines |
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Used by the routine at UpdateShot.
Updates a shot that has bit 7 of offset 15 set, which is the kind that is made by LaunchShot_Special. The length of the shot is at offset 0E. Purpose of the details not yet known.
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| UpdateSpecialShot | B414 | LD A,(IX+$0E) | The high byte of the vertical acceleration. | |||||
| B417 | AND A | Call PlayFlutterSound if A is not zero. | ||||||
| B418 | CALL NZ,PlayFlutterSound | |||||||
| B41B | INC (IX+$11) | Increase offset 11 of IX by one. | ||||||
| B41E | CALL MakeShotRow | Call MakeShotRow. | ||||||
| B421 | CALL FindObjectScreenAddress | Call FindObjectScreenAddress. | ||||||
| B424 | LD B,(IX+$0E) | The high byte of the vertical acceleration. | ||||||
| B427 | EXX | Switch to the alternate registers. | ||||||
| B428 | BIT 7,(IX+$10) | Jump to UpdateSpecialShot_Shorter if bit 7 of offset 10 of IX is set. | ||||||
| B42C | JR NZ,UpdateSpecialShot_Shorter | |||||||
| B42E | BIT 0,(IX+$11) | Jump to UpdateSpecialShot_Frame if bit 0 of offset 11 of IX is clear. | ||||||
| B432 | JR Z,UpdateSpecialShot_Frame | |||||||
| B434 | LD A,(IX+$12) | The vertical screen position. | ||||||
| B437 | ADD A,(IX+$07) | Add the byte at offset 07 of IX to A. | ||||||
| B43A | LD (IX+$07),A | Write the high byte of the horizontal speed. | ||||||
| B43D | LD A,(IX+$0E) | The high byte of the vertical acceleration. | ||||||
| B440 | CP $08 | Jump to UpdateSpecialShot_Test if A is 08. | ||||||
| B442 | JR Z,UpdateSpecialShot_Test | |||||||
| B444 | INC (IX+$0E) | Increase offset 0E of IX by one. | ||||||
| B447 | BIT 7,(IX+$00) | Jump to UpdateSpecialShot_Test if bit 7 of offset 00 of IX is clear. | ||||||
| B44B | JR Z,UpdateSpecialShot_Test | |||||||
| B44D | LD A,$F8 | A=F8. | ||||||
| B44F | ADD A,(IX+$0B) | Add the byte at offset 0B of IX to A. | ||||||
| B452 | LD (IX+$0B),A | Write the high byte of the horizontal acceleration. | ||||||
| UpdateSpecialShot_Test | B455 | CALL TestShotHitsGround_Wide | Call TestShotHitsGround_Wide. | |||||
| B458 | JR Z,UpdateSpecialShot_Frame | Jump to UpdateSpecialShot_Frame if the zero flag is set. | ||||||
| B45A | LD A,($C8EC) | The high byte of the ship's horizontal speed. | ||||||
| B45D | LD (IX+$07),A | Write the high byte of the horizontal speed. | ||||||
| UpdateSpecialShot_Shorter | B460 | DEC (IX+$0E) | Decrease offset 0E of IX by one. | |||||
| B463 | BIT 7,(IX+$00) | Jump to UpdateSpecialShot_Frame if bit 7 of offset 00 of IX is clear. | ||||||
| B467 | JR Z,UpdateSpecialShot_Frame | |||||||
| B469 | LD A,$08 | A=08. | ||||||
| B46B | ADD A,(IX+$0B) | Add the byte at offset 0B of IX to A. | ||||||
| B46E | LD (IX+$0B),A | Write the high byte of the horizontal acceleration. | ||||||
| UpdateSpecialShot_Frame | B471 | CALL MakeShotColumn | Call MakeShotColumn. | |||||
| B474 | LD A,(IX+$11) | The horizontal screen position. | ||||||
| B477 | CP $16 | Jump to DrawShot if A is not 16. | ||||||
| B479 | JP NZ,DrawShot | |||||||
| B47C | SET 7,(IX+$10) | Set bit 7 of offset 10 of IX. | ||||||
| B480 | JP DrawShot | Jump to DrawShot. | ||||||
| Prev: B403 | Up: Map | Next: B483 |