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Routines |
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Used by the routine at 8ABB.
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8BBA | LD C,L | Point BC at the bottom row of pixels of the crumbling floor tile in the screen buffer at 7000 | ||||||||
8BBB | LD A,H | |||||||||
8BBC | ADD A,$1B | |||||||||
8BBE | OR $07 | |||||||||
8BC0 | LD B,A | |||||||||
8BC1 | DEC B | Collect the pixels from the row above in A | ||||||||
8BC2 | LD A,(BC) | |||||||||
8BC3 | INC B | Copy these pixels into the row below it | ||||||||
8BC4 | LD (BC),A | |||||||||
8BC5 | DEC B | Point BC at the next row of pixels up | ||||||||
8BC6 | LD A,B | Have we dealt with the bottom seven pixel rows of the crumbling floor tile yet? | ||||||||
8BC7 | AND $07 | |||||||||
8BC9 | JR NZ,$8BC1 | If not, jump back to deal with the next one up | ||||||||
8BCB | XOR A | Clear the top row of pixels in the crumbling floor tile | ||||||||
8BCC | LD (BC),A | |||||||||
8BCD | LD A,B | Point BC at the bottom row of pixels in the crumbling floor tile | ||||||||
8BCE | ADD A,$07 | |||||||||
8BD0 | LD B,A | |||||||||
8BD1 | LD A,(BC) | Pick up the bottom row of pixels in A | ||||||||
8BD2 | OR A | Is the bottom row clear? | ||||||||
8BD3 | RET NZ | Return if not | ||||||||
The bottom row of pixels in the crumbling floor tile is clear. Time to put a background tile in its place.
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8BD4 | LD A,($8020) | Pick up the attribute byte of the background tile for the current cavern from 8020 | ||||||||
8BD7 | INC H | Set HL to the address of the crumbling floor tile's location in the attribute buffer at 5E00 | ||||||||
8BD8 | INC H | |||||||||
8BD9 | LD (HL),A | Set the attribute at this location to that of the background tile | ||||||||
8BDA | DEC H | Set HL back to the address of the crumbling floor tile's location in the attribute buffer at 5C00 | ||||||||
8BDB | DEC H | |||||||||
8BDC | RET |
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