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Routines |
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Used by the routine at Draw_Room.
Draws the right wall of the room if bit 2 of the frame flags is set, or clears its area if it is not.
The wall is made of two tiles, each three bytes wide and 56 lines high, which are drawn from top to bottom at x position 232 and y position 48. The tiles come from the table at Right_Wall_Tile_Table, indexed by the sum of the room x and the room y. The routine is also used to draw the left wall (see Draw_Left_Wall).
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| Draw_Right_Wall | 39606 | PUSH DE | Stash the frame flags on the stack. | |||||||
| 39607 | BIT 2,E | Test bit 2 of the frame flags (the right wall). | ||||||||
| 39609 | LD HL,12520 | Set the x position to 232 and the y position to 48 (12520). | ||||||||
| 39612 | LD DE,39856 | Point at the table of wall tiles (Right_Wall_Tile_Table). | ||||||||
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This entry point is used by the routine at Draw_Left_Wall.
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| Draw_Right_Wall_Check_Present | 39615 | JP Z,Clear_Tall_Panel | Jump to Clear_Tall_Panel if the wall is not present. | |||||||
| Draw_Wall_Tiles | 39618 | LD B,2 | Set the number of tiles to 2. | |||||||
| 39620 | PUSH HL | Stash the position on the stack. | ||||||||
| 39621 | CALL ScreenAddress | Convert the position into a screen address. | ||||||||
| 39624 | LD A,(IX+2) | Fetch the room x of Sabreman. | ||||||||
| 39627 | ADD A,(IX+4) | Add the room y of Sabreman. | ||||||||
| 39630 | RLCA | Double the sum to make an offset into the table of word pointers. | ||||||||
| Draw_Right_Wall_Tile_Loop | 39631 | AND %00000110 | Keep the offset within the table (four entries). | |||||||
| 39633 | LD C,A | Store the offset in C. | ||||||||
| 39634 | PUSH BC | Stash the tile counter and the offset on the stack. | ||||||||
| 39635 | EX DE,HL | Exchange the registers so that HL holds the address of the table. | ||||||||
| 39636 | PUSH HL | Stash the address of the table on the stack. | ||||||||
| 39637 | LD B,0 | Clear the high byte of the offset. | ||||||||
| 39639 | ADD HL,BC | Add the offset to the address of the table. | ||||||||
| 39640 | LD A,(HL) | Fetch the low byte of the address of the tile. | ||||||||
| 39641 | INC HL | Move on to the high byte. | ||||||||
| 39642 | LD H,(HL) | Fetch the high byte of the address of the tile. | ||||||||
| 39643 | LD L,A | Copy the low byte to L. | ||||||||
| 39644 | EX DE,HL | Exchange the registers so that DE holds the address of the tile and HL the screen address. | ||||||||
| 39645 | CALL Draw_Tile | Draw the tile. | ||||||||
| 39648 | POP DE | Restore the address of the table into DE. | ||||||||
| 39649 | POP BC | Restore the tile counter and the offset. | ||||||||
| 39650 | LD A,C | Copy the offset to A. | ||||||||
| 39651 | ADD A,2 | Move on to the next entry of the table. | ||||||||
| 39653 | DJNZ Draw_Right_Wall_Tile_Loop | Decrease the tile counter and loop back until both tiles are drawn. | ||||||||
| 39655 | POP HL | Restore the position of the area. | ||||||||
| 39656 | LD BC,880 | Set the size of the area to 880. | ||||||||
| 39659 | CALL Set_Area_Attributes | Set the attributes of the area. | ||||||||
| 39662 | POP DE | Restore the frame flags from the stack. | ||||||||
| 39663 | RET | Return. | ||||||||
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