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Routines |
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Used by the routine at 25008. Sets the bits in the screen refresh buffer (SRB) that correspond to the four tiles in the left, middle or right column of a sprite.
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| 27008 | LD B,4 | There are 4 rows (and 3 columns) in a sprite | ||||||||
| 27010 | LD A,(DE) | Pick up a sprite UDG reference | ||||||||
| 27011 | INC D | Next row of the sprite | ||||||||
| 27012 | AND A | Is this the blank UDG? | ||||||||
| 27013 | JR Z,27017 | Jump if so (no need to update this SRB byte) | ||||||||
| 27015 | SET 0,(HL) | Set the appropriate bit in the SRB byte; this instruction is modified by the routine at 25008 before this routine is called | ||||||||
| 27017 | LD A,4 | Point HL at the byte of the SRB corresponding to the next row of the screen | ||||||||
| 27019 | ADD A,L | |||||||||
| 27020 | LD L,A | |||||||||
| 27021 | DJNZ 27010 | Jump back until all 4 squares in the column are done | ||||||||
| 27023 | BIT 3,D | Return with the zero flag reset if we have just updated the SRB for the rightmost column of the sprite | ||||||||
| 27025 | RET | |||||||||
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