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Routines |
| Prev: B853 | Up: Map | Next: B881 |
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Used by the routine at BuildRoomObjects.
Sets the bit for the room that the player is in, in RoomsVisitedBitmap. The bit to set is chosen by changing the opcode of the instruction at VisitRoom_Set.
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| VisitRoom | B863 | LD A,($5B90) | Fetch the room from 5B90. | |
| B866 | LD C,A | Keep it in C. | ||
| B867 | RRCA | Divide the room by eight. | ||
| B868 | RRCA | |||
| B869 | RRCA | |||
| B86A | AND %00011111 | Keep only bits 0 to 4. | ||
| B86C | LD L,A | Keep it in L. | ||
| B86D | LD H,$00 | Set H to 00. | ||
| B86F | LD A,C | Fetch the room again. | ||
| B870 | RLCA | Rotate the room three times. | ||
| B871 | RLCA | |||
| B872 | RLCA | |||
| B873 | AND %00111000 | Keep only bits 3 to 5. | ||
| B875 | OR %11000110 | Make it a SET n,(HL) opcode. |
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| B877 | LD ($B87F),A | Write the opcode to B87F. | ||
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Set the bit in the bitmap.
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| B87A | LD BC,$5B58 | Point HL at RoomsVisitedBitmap plus the byte offset. | ||
| B87D | ADD HL,BC | |||
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This
SET n,(HL) is self-modifying.
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| VisitRoom_Set | B87E | SET 0,(HL) | Set the bit for the room. | |
| B880 | RET | Return. | ||
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View the equivalent code in;
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| Prev: B853 | Up: Map | Next: B881 |
SET n,(HL)opcode.