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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 23).
The length of the rope is stored in Rope_Length. It is half of the sum of 255 (or 160 if bit 2 is reset) and 256 times the two low bits of the second byte.
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| Set_Up_Rope | 44673 | CALL Read_World_Map | Read the world map entry of the room into DE. | |
| 44676 | LD A,E | Copy the room flags to A. | ||
| 44677 | LD (43692),A | Store the room flags in Room_Flags. | ||
| 44680 | XOR A | Clear the displacement of the end of the rope in pixels (Rope_Displacement_Pixels). | ||
| 44681 | LD (43684),A | |||
| 44684 | LD (43683),A | Clear the fraction of the displacement of the end of the rope (Rope_Displacement). | ||
| 44687 | 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). | ||
| 44689 | JR Z,Set_Up_Rope_Remove_Rope | |||
| 44691 | LD A,23 | Use the type of the rope (23). | ||
| 44693 | LD (36650),A | Store it as the type of record 3 (the rope). | ||
| 44696 | LD HL,0 | Clear the previous position of the end of the rope (Previous_Rope_End_Position). | ||
| 44699 | LD (43671),HL | |||
| 44702 | 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). | ||
| 44704 | JR Z,Set_Up_Rope_Set_Length | |||
| 44706 | LD L,255 | Set the low byte of the length of a long rope to 255. | ||
| Set_Up_Rope_Fetch_Second_Byte | 44708 | LD A,D | Fetch the second byte of the world map entry. | |
| 44709 | AND %00000011 | Keep only the two low bits (the number of rooms down the rope). | ||
| 44711 | LD H,A | Store them in the high byte of the length. | ||
| 44712 | SRA H | Halve the length of the rope. | ||
| 44714 | RR L | |||
| 44716 | LD (43685),HL | Store the length of the rope in Rope_Length. | ||
| 44719 | RET | Return. | ||
| Set_Up_Rope_Remove_Rope | 44720 | XOR A | Remove the rope by clearing the type of record 3. | |
| 44721 | LD (36650),A | |||
| 44724 | RET | Return. | ||
| Set_Up_Rope_Set_Length | 44725 | LD L,160 | Set the low byte of the length of a short rope to 160. | |
| 44727 | JR Set_Up_Rope_Fetch_Second_Byte | Jump to Set_Up_Rope_Fetch_Second_Byte. | ||
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