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Routines |
| Prev: A12D | Up: Map | Next: A20D |
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The handler for entity types 3C to 3F, which are the shots that the robot fires using the first weapon. A shot moves across the map until it hits something or has run out of range. The shot destroys the contents of the cell that it hits, apart from the cells that are solid.
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| MoveSpark | A144 | CALL NextSpriteNumber | Move on to the next sprite using NextSpriteNumber. | |||||
| A147 | CALL GetPosition | Fetch the position of the shot. | ||||||
| A14A | LD B,$60 | The shot can take up to 60 steps in this frame. | ||||||
| MoveSpark_Step | A14C | CALL TryMove | Take a step using TryMove. | |||||
| A14F | JR NZ,MoveSpark_Hit | Jump if the shot has hit something. | ||||||
| A151 | LD A,E | Jump if the shot is not at the start of a cell. | ||||||
| A152 | OR L | |||||||
| A153 | JR NZ,MoveSpark_Store | |||||||
| A155 | LD A,(IX+$07) | Fetch the range of the shot... | ||||||
| A158 | SUB $10 | ...take away one cell... | ||||||
| A15A | LD (IX+$07),A | ...and store it. | ||||||
| A15D | AND $F0 | Jump to explode the shot if it has run out of range. | ||||||
| A15F | JR Z,MoveSpark_Explode | |||||||
| A161 | LD A,B | Loop back to take another step if there are steps left. | ||||||
| A162 | AND A | |||||||
| A163 | JR NZ,MoveSpark_Step | |||||||
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This entry point is used by the routine at MovePellet.
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| MoveSpark_Store | A165 | CALL SetPosition | Store the new position of the shot. | |||||
| A168 | CALL CheckShotHit | Check whether it has hit an enemy using CheckShotHit. | ||||||
| A16B | LD A,(IX+$00) | Fetch the type of the shot, and draw it using AddEntity unless it has become smoke. | ||||||
| A16E | CP $38 | |||||||
| A170 | JP NZ,AddEntity | |||||||
| A173 | LD A,(IY+$08) | Fetch the item that the enemy was carrying, and draw the shot if it was not carrying any. | ||||||
| A176 | AND A | |||||||
| A177 | JP Z,AddEntity | |||||||
| A17A | LD C,A | Keep the item. | ||||||
| A17B | LD HL,($962E) | Fetch the address of the cell that the shot was in. | ||||||
| A17E | LD A,(HL) | Fetch the contents of the cell. | ||||||
| A17F | AND $F0 | Keep the initial type of the cell and use the item as the current type, so that the enemy drops it. | ||||||
| A181 | OR C | |||||||
| A182 | LD (HL),A | Store the new contents of the cell. | ||||||
| A183 | XOR A | Clear the item that the enemy was carrying... | ||||||
| A184 | LD (IY+$08),A | ...and store it. | ||||||
| A187 | JP AddEntity | Draw the shot using AddEntity. | ||||||
| MoveSpark_Explode | A18A | LD (IX+$00),$38 | Turn the shot into smoke by changing its type to 38. | |||||
| A18E | JR MoveSpark_Store | Store the position. | ||||||
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The shot has hit something.
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| MoveSpark_Hit | A190 | PUSH DE | Save the X position. | |||||
| A191 | LD DE,$0010 | Each entity is 10 bytes long. | ||||||
| A194 | LD B,$02 | There are two entities that are used for puffs of smoke. | ||||||
| A196 | LD IY,$98B0 | Point IY at CloudEntities. | ||||||
| MoveSpark_FindPuff | A19A | LD A,(IY+$00) | Fetch its type, and jump if it is not being used. | |||||
| A19D | AND A | |||||||
| A19E | JR Z,MoveSpark_Unused | |||||||
| A1A0 | ADD IY,DE | Move on to the next one. | ||||||
| A1A2 | DJNZ MoveSpark_FindPuff | Loop back until both have been tried. | ||||||
| A1A4 | POP DE | Restore the X position. | ||||||
| A1A5 | JR MoveSpark_Explode | Make the shot explode without hitting the cell, as there is no puff to use. | ||||||
| MoveSpark_Unused | A1A7 | POP DE | Restore the X position. | |||||
| A1A8 | PUSH HL | Save the Y position. | ||||||
| A1A9 | LD HL,($962E) | Fetch the address of the cell that was hit. | ||||||
| A1AC | LD A,(HL) | Fetch its contents. | ||||||
| A1AD | AND $0F | Keep the current type of the cell. | ||||||
| A1AF | CP $05 | Jump to explode the shot if the type is 05. | ||||||
| A1B1 | JR Z,MoveSpark_Restore | |||||||
| A1B3 | CP $04 | Jump to explode the shot if the type is 04. | ||||||
| A1B5 | JR Z,MoveSpark_Restore | |||||||
| A1B7 | CP $01 | Jump to explode the shot if the type is 01. | ||||||
| A1B9 | JR Z,MoveSpark_Restore | |||||||
| A1BB | CP $07 | Jump to explode the shot if the type is 07. | ||||||
| A1BD | JR Z,MoveSpark_Restore | |||||||
| A1BF | CP $08 | Jump to explode the shot if the type is 08. | ||||||
| A1C1 | JR Z,MoveSpark_Restore | |||||||
| A1C3 | CP $09 | Jump to explode the shot if the type is 09. | ||||||
| A1C5 | JR Z,MoveSpark_Restore | |||||||
| A1C7 | CP $0C | Jump to explode the shot if the type is 0C. | ||||||
| A1C9 | JR Z,MoveSpark_Restore | |||||||
| A1CB | CP $0E | Jump to explode the shot if the type is 0E. | ||||||
| A1CD | JR Z,MoveSpark_Restore | |||||||
| A1CF | LD A,(HL) | Fetch the contents of the cell again... | ||||||
| A1D0 | AND $F0 | ...and keep the initial type, so that the cell is emptied. | ||||||
| A1D2 | JR MoveSpark_Destroy | |||||||
| MoveSpark_Replace | A1D4 | LD (HL),A | Store the new contents of the cell. | |||||
| A1D5 | LD (IY+$00),$54 | Start a puff of smoke... | ||||||
| A1D9 | LD HL,($962C) | ...at the position of the cell. | ||||||
| A1DC | LD (IY+$02),L | Set the X cell of the puff... | ||||||
| A1DF | LD (IY+$04),H | ...and then its Y cell. | ||||||
| MoveSpark_Restore | A1E2 | POP HL | Restore the Y position. | |||||
| A1E3 | JR MoveSpark_Explode | Make the shot explode. | ||||||
| MoveSpark_Destroy | A1E5 | LD C,A | Keep the initial type of the cell. | |||||
| A1E6 | LD A,(HL) | Fetch the contents of the cell... | ||||||
| A1E7 | AND $0F | ...and keep its current type. | ||||||
| A1E9 | CP $02 | Jump to empty the cell if it is not type 02 (an installed program). | ||||||
| A1EB | LD A,C | |||||||
| A1EC | JR NZ,MoveSpark_Replace | |||||||
| A1EE | PUSH AF | Save the contents... | ||||||
| A1EF | PUSH DE | ...and the X position... | ||||||
| A1F0 | PUSH HL | ...and the Y position. | ||||||
| A1F1 | CALL FindSector | Find the sector that the cell is in using FindSector. | ||||||
| A1F4 | LD E,D | Use the sector number as an index. | ||||||
| A1F5 | LD D,$00 | |||||||
| A1F7 | LD HL,$965B | Point HL at SectorFlags. | ||||||
| A1FA | ADD HL,DE | Add the index. | ||||||
| A1FB | LD A,(HL) | Fetch the flag, and jump if the sector has been activated (as its programs are safe). | ||||||
| A1FC | AND A | |||||||
| A1FD | JR NZ,MoveSpark_Safe | |||||||
| A1FF | CALL ReduceSectorEnergy | Otherwise take one unit of energy off the sector using ReduceSectorEnergy. | ||||||
| A202 | POP HL | Restore the Y position... | ||||||
| A203 | POP DE | ...and the X position... | ||||||
| A204 | POP AF | ...and the contents. | ||||||
| A205 | JR MoveSpark_Replace | Jump back to empty the cell. | ||||||
| MoveSpark_Safe | A207 | POP HL | Restore the Y position... | |||||
| A208 | POP DE | ...and the X position... | ||||||
| A209 | POP AF | ...and the contents. | ||||||
| A20A | LD A,(HL) | Fetch the contents of the cell, which are left as they are. | ||||||
| A20B | JR MoveSpark_Replace | Jump back to start the puff of smoke. | ||||||
| Prev: A12D | Up: Map | Next: A20D |