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Routines |
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This iterates over itemstructs, testing to see if each item is within the range (-1..22, 0..15) of the current map position. If it is it sets the flags itemstruct_ROOM_FLAG_NEARBY_6 and itemstruct_ROOM_FLAG_NEARBY_7 on the item, otherwise it clears both of those flags.
This is similar to is_item_discoverable_interior in that it iterates over all item_structs.
Used by the routines at setup_movable_items and main_loop.
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| mark_nearby_items | DB9E | LD A,($68A0) | Get the global current room index | |
| DBA1 | CP $FF | Is it room_NONE? | ||
| DBA3 | JR NZ,mni_room_set | Jump if not | ||
| DBA5 | XOR A | Otherwise set it to room_0_OUTDOORS | ||
| mni_room_set | DBA6 | LD C,A | Preload the room index into C | |
| DBA7 | LD DE,($81BB) | Point DE at the map position | ||
| DBAB | LD B,$10 | Set B for 16 iterations (item__LIMIT) | ||
| DBAD | LD HL,$76C9 | Point HL at the first item_struct's room member | ||
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Start loop
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| mni_loop | DBB0 | PUSH HL | Preserve item_struct pointer | |
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Compare room
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| DBB1 | LD A,(HL) | Load the room index and flags | ||
| DBB2 | AND $3F | Extract the room index | ||
| DBB4 | CP C | Same room? | ||
| DBB5 | JR NZ,mni_reset | Jump if not | ||
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Is the item's X coordinate within (-1..22) of the map's X position?
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| DBB7 | INC HL | Advance HL to itemstruct.iso_pos.x | ||
| DBB8 | INC HL | |||
| DBB9 | INC HL | |||
| DBBA | INC HL | |||
| DBBB | LD A,E | Copy map X position into A | ||
| DBBC | DEC A | Reduce it by 2 | ||
| DBBD | DEC A | |||
| DBBE | CP (HL) | Compare it to itemstruct.iso_pos.x | ||
| DBBF | JR Z,mni_chk_x_hi | Jump if equal (continuing test) | ||
| DBC1 | JR NC,mni_reset | Reset if under lower bound | ||
| mni_chk_x_hi | DBC3 | ADD A,$19 | Add 25 to make (map X position + 23) | |
| DBC5 | CP (HL) | Compare to X value in itemstruct | ||
| DBC6 | JR C,mni_reset | Reset if over upper bound | ||
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Is the item's Y coordinate within (0..15) of the map's Y position?
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| DBC8 | LD A,D | Copy map Y position into A | ||
| DBC9 | INC HL | Advance HL to itemstruct.iso_pos.y | ||
| DBCA | DEC A | Reduce it by 1 | ||
| DBCB | CP (HL) | Compare it to itemstruct.iso_pos.y | ||
| DBCC | JR Z,mni_chk_y_hi | Jump if equal (continuing test) | ||
| DBCE | JR NC,mni_reset | Reset if under lower bound | ||
| mni_chk_y_hi | DBD0 | ADD A,$11 | Add 17 to make (map Y position + 16) | |
| DBD2 | CP (HL) | Compare to Y value in itemstruct | ||
| DBD3 | JR C,mni_reset | Reset if over upper bound | ||
| mni_set | DBD5 | POP HL | Restore itemstruct pointer | |
| DBD6 | SET 7,(HL) | Set itemstruct_ROOM_FLAG_NEARBY_6 and itemstruct_ROOM_FLAG_NEARBY_7 | ||
| DBD8 | SET 6,(HL) | |||
| DBDA | JR mni_advance | Jump to next iteration | ||
| mni_reset | DBDC | POP HL | Restore itemstruct pointer | |
| DBDD | RES 7,(HL) | Clear itemstruct_ROOM_FLAG_NEARBY_6 and itemstruct_ROOM_FLAG_NEARBY_7 | ||
| DBDF | RES 6,(HL) | |||
| mni_advance | DBE1 | LD A,$07 | Advance HL by stride | |
| DBE3 | ADD A,L | |||
| DBE4 | LD L,A | |||
| DBE5 | JR NC,mni_next | |||
| DBE7 | INC H | |||
| mni_next | DBE8 | DJNZ mni_loop | ...loop | |
| DBEA | RET | Return | ||
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