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Routines |
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Used by the routine at SpawnBug.
Creates a new bug in an inactive bug object, at the cubby hole whose number is in BugStart_CubbyHole. The type and the colour are chosen using the level, and the random number (see BugTypeTable). The bug is cancelled if Robbie is too close to it.
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| CreateBug | 29282 | PUSH HL | Stash HL on the stack. | |||||
| 29283 | EX DE,HL | Switch DE and HL. | ||||||
| 29284 | LD HL,24342 | Copy 8 bytes of data from DefaultState_Bug to DE. | ||||||
| 29287 | LD BC,8 | |||||||
| 29290 | LDIR | |||||||
| 29292 | POP IX | Restore IX from the stack (the old value in HL). | ||||||
| 29294 | LD A,(24083) | A=BugStart_CubbyHole. | ||||||
| 29297 | CP 5 | Jump to CreateBug_Right if the cubby hole is on the right. | ||||||
| 29299 | JR NC,CreateBug_Right | |||||||
| 29301 | LD (IX+1),8 | Write 8 to the X position of the bug. | ||||||
| 29305 | SET 6,(IX+0) | Set bit 6 of the state of the bug (this has no effect as the state is overwritten at 29354). | ||||||
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This entry point is used by the routine at CreateBug_Right.
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| CreateBug_Row | 29309 | RRCA | Rotate the row number round so it is in bits 5-7. | |||||
| 29310 | RRCA | |||||||
| 29311 | RRCA | |||||||
| 29312 | AND %11100000 | Keep only bits 5-7. | ||||||
| 29314 | ADD A,55 | Add 55. | ||||||
| 29316 | LD (IX+2),A | Write it to the Y position of the bug. | ||||||
| 29319 | LD A,(24119) | A=the level from ActivePlayer_Level. | ||||||
| 29322 | CP 1 | Jump to CreateBug_Level1 if it is level 1. | ||||||
| 29324 | JR Z,CreateBug_Level1 | |||||||
| 29326 | CP 2 | Jump to CreateBug_Level2 if it is level 2. | ||||||
| 29328 | JR Z,CreateBug_Level2 | |||||||
| 29330 | CP 3 | Jump to CreateBug_Level3 if it is level 3. | ||||||
| 29332 | JR Z,CreateBug_Level3 | |||||||
| 29334 | CP 4 | Jump to CreateBug_Type if it is a lower level. | ||||||
| 29336 | JR C,CreateBug_Type | |||||||
| 29338 | LD A,R | A=the refresh register. | ||||||
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This entry point is used by the routines at CreateBug_Level1, CreateBug_Level2 and CreateBug_Level3.
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| CreateBug_Type | 29340 | AND %00000011 | Keep only bits 0-1. | |||||
| 29342 | LD C,A | C=A. | ||||||
| 29343 | SLA A | Multiply A by two. | ||||||
| 29345 | ADD A,C | Add C to make it three times the bug type. | ||||||
| 29346 | LD C,A | C=the offset into the table (three bytes for each type of bug). | ||||||
| 29347 | LD B,0 | Clear the high byte of the offset in B. | ||||||
| 29349 | LD HL,29417 | HL=BugTypeTable. | ||||||
| 29352 | ADD HL,BC | Add the offset. | ||||||
| 29353 | LD A,(HL) | A=the type of the bug. | ||||||
| 29354 | LD (IX+0),A | Write it to the state of the bug. | ||||||
| 29357 | INC HL | Move onto the first colour. | ||||||
| 29358 | LD A,(24089) | A=the random number from RandomNumber. | ||||||
| 29361 | BIT 6,A | Jump to CreateBug_Colour if bit 6 is not set. | ||||||
| 29363 | JR Z,CreateBug_Colour | |||||||
| 29365 | INC HL | Move onto the second colour. | ||||||
| CreateBug_Colour | 29366 | LD A,(HL) | A=the colour of the bug. | |||||
| 29367 | LD (IX+3),A | Write it to the colour of the bug. | ||||||
| 29370 | LD E,0 | E=0 (no collision). | ||||||
| 29372 | LD HL,24174 | HL=State_Robbie_Pos_Y (the Y position of Robbie). | ||||||
| 29375 | CALL BugCollision_Y | Check whether the bug is on top of Robbie using BugCollision_Y. | ||||||
| 29378 | DEC E | Decrease the collision result in E by one (zero means that the bug is on top of Robbie). | ||||||
| 29379 | JR NZ,CreateBug_Done | Jump to CreateBug_Done if the bug is not on top of Robbie. | ||||||
| 29381 | LD (IX+0),0 | Write 0 to the state of the bug (cancel it). | ||||||
| CreateBug_Done | 29385 | JP SpawnBonusItem | Jump to SpawnBonusItem. | |||||
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