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Routines |
| Prev: B833 | Up: Map | Next: B8CF |
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Used by the routine at UpdateSpecialShot.
Builds the picture of a shot from one of the six patterns in the table at ShotPatternTable, picked by the bottom four bits of offset 15, which go round from zero to five as the shot is updated. The picture is made in the buffer at F800 and its size is stored in A1D7. MakeShotColumn does the same for the buffer at BuildTables_Buffer and A1D8.
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| MakeShotRow | B897 | LD DE,$F800 | Use F800. | |||||
| B89A | CALL FindShotPattern | Call FindShotPattern. | ||||||
| B89D | LD A,(IX+$15) | Read offset 15 of IX. | ||||||
| B8A0 | AND %00001111 | Keep the bits of A that are set in 0F. | ||||||
| B8A2 | INC A | Advance A. | ||||||
| B8A3 | CP $06 | Jump to MakeShotRow_Store if A is not 06. | ||||||
| B8A5 | JR NZ,MakeShotRow_Store | |||||||
| B8A7 | XOR A | Clear A. | ||||||
| MakeShotRow_Store | B8A8 | OR %10000000 | Set the bits of A that are set in 80. | |||||
| B8AA | LD (IX+$15),A | Write A to offset 15 of IX. | ||||||
| B8AD | EX DE,HL | Swap DE and HL. | ||||||
| B8AE | LD A,(DE) | Read DE. | ||||||
| B8AF | LD ($A1D7),A | The rows of the shot picture. | ||||||
| B8B2 | JP BuildShotPattern | Jump to BuildShotPattern. | ||||||
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This entry point is used by the routine at UpdateSpecialShot.
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| MakeShotColumn | B8B5 | LD DE,$F880 | The build buffer. | |||||
| B8B8 | CALL FindShotPattern | Call FindShotPattern. | ||||||
| B8BB | EX DE,HL | Swap DE and HL. | ||||||
| B8BC | LD A,(DE) | Read DE. | ||||||
| B8BD | LD ($A1D8),A | The rows of the shot column. | ||||||
| B8C0 | JP BuildShotPattern | Jump to BuildShotPattern. | ||||||
| FindShotPattern | B8C3 | LD A,(IX+$15) | Read offset 15 of IX. | |||||
| B8C6 | AND %00001111 | Keep the bits of A that are set in 0F. | ||||||
| B8C8 | LD C,A | C=A. | ||||||
| B8C9 | LD HL,$B8CF | The shot pattern table. | ||||||
| B8CC | JP GetTableEntry | Jump to GetTableEntry. | ||||||
| Prev: B833 | Up: Map | Next: B8CF |