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Routines |
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Used by the routine at Draw_Room.
Sets up the rope for the room that has just been drawn, using the map entry of the room (see Read_World_Map). Bit 3 of the second byte says whether the room has a rope.
The rope is the object in record 3 (type 17).
The length of the rope is stored in Rope_Length. It is half of the sum of FF (or A0 if bit 2 is reset) and 0100 times the two low bits of the second byte.
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| Set_Up_Rope | AE81 | CALL Read_World_Map | Read the world map entry of the room into DE. | |
| AE84 | LD A,E | Copy the room flags to A. | ||
| AE85 | LD ($AAAC),A | Store the room flags in Room_Flags. | ||
| AE88 | XOR A | Clear the displacement of the end of the rope in pixels (Rope_Displacement_Pixels). | ||
| AE89 | LD ($AAA4),A | |||
| AE8C | LD ($AAA3),A | Clear the fraction of the displacement of the end of the rope (Rope_Displacement). | ||
| AE8F | BIT 3,D | Jump to Set_Up_Rope_Remove_Rope if there is no rope in this room (bit 3 of the second byte of the world map entry is clear). | ||
| AE91 | JR Z,Set_Up_Rope_Remove_Rope | |||
| AE93 | LD A,$17 | Use the type of the rope (17). | ||
| AE95 | LD ($8F2A),A | Store it as the type of record 3 (the rope). | ||
| AE98 | LD HL,$0000 | Clear the previous position of the end of the rope (Previous_Rope_End_Position). | ||
| AE9B | LD ($AA97),HL | |||
| AE9E | BIT 2,D | Jump to Set_Up_Rope_Set_Length if the rope is a short one (bit 2 of the second byte of the world map entry is clear). | ||
| AEA0 | JR Z,Set_Up_Rope_Set_Length | |||
| AEA2 | LD L,$FF | Set the low byte of the length of a long rope to FF. | ||
| Set_Up_Rope_Fetch_Second_Byte | AEA4 | LD A,D | Fetch the second byte of the world map entry. | |
| AEA5 | AND %00000011 | Keep only the two low bits (the number of rooms down the rope). | ||
| AEA7 | LD H,A | Store them in the high byte of the length. | ||
| AEA8 | SRA H | Halve the length of the rope. | ||
| AEAA | RR L | |||
| AEAC | LD ($AAA5),HL | Store the length of the rope in Rope_Length. | ||
| AEAF | RET | Return. | ||
| Set_Up_Rope_Remove_Rope | AEB0 | XOR A | Remove the rope by clearing the type of record 3. | |
| AEB1 | LD ($8F2A),A | |||
| AEB4 | RET | Return. | ||
| Set_Up_Rope_Set_Length | AEB5 | LD L,$A0 | Set the low byte of the length of a short rope to A0. | |
| AEB7 | JR Set_Up_Rope_Fetch_Second_Byte | Jump to Set_Up_Rope_Fetch_Second_Byte. | ||
| Prev: AE71 | Up: Map | Next: AEB9 |