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Routines |
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| F650 | LD HL,$7FFB | 7FFB holds ERIC's status flags | ||
| F653 | BIT 7,(HL) | Is ERIC sitting or lying down? | ||
| F655 | RET NZ | Return if so | ||
| F656 | CALL $6648 | Is ERIC on a staircase? | ||
| F659 | RET NZ | Return if so | ||
| F65A | CP $A9 | Is ERIC on the bottom floor? | ||
| F65C | RET Z | Return if so | ||
| F65D | CP $9B | Set the zero flag if ERIC's on the top floor | ||
| F65F | LD BC,$302C | C=44, B=48 (x-coordinates of the edges of the 'writing zone' for the Reading Room blackboard) | ||
| F662 | LD A,E | A=ERIC's x-coordinate | ||
| F663 | JR Z,$F66F | Jump if ERIC's on the top floor | ||
| F665 | LD BC,$201C | C=28, B=32 (x-coordinates of the edges of the writing zone for the White Room blackboard) | ||
| F668 | CP $28 | Is ERIC to the left of the White Room wall? | ||
| F66A | JR C,$F66F | Jump if so | ||
| F66C | LD BC,$2F2B | C=43, B=47 (x-coordinates of the edges of the writing zone for the Exam Room blackboard) | ||
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Now C and B hold the x-coordinates of the left and right edges of the writing zone for the blackboard closest to ERIC.
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| F66F | CP C | Return if ERIC is not standing close enough to the blackboard to write on it | ||
| F670 | RET C | |||
| F671 | CP B | |||
| F672 | RET NC | |||
| F673 | SET 5,(HL) | Set bit 5 of ERIC's status flags at 7FFB: ERIC is writing on a blackboard | ||
| F675 | LD H,$AC | 0xAC=ERIC | ||
| F677 | CALL $7128 | Get the blackboard identifier in A | ||
| F67A | LD L,A | HL=7FED (Reading Room), 7FEF (White Room) or 7FF1 (Exam Room) | ||
| F67B | LD H,$7F | |||
| F67D | INC L | |||
| F67E | SUB $B4 | B=0x38 (Reading Room), 0x3A (White Room) or 0x3C (Exam Room) | ||
| F680 | LD B,A | |||
| F681 | LD A,(HL) | A=number of the character who last wrote on this board | ||
| F682 | LD (HL),$AC | Signal that ERIC (0xAC) wrote on this board | ||
| F684 | XOR $80 | C=0x80 (bit 7 set) if the board is clean, <0x80 (bit 7 reset) if not | ||
| F686 | LD C,A | |||
| F687 | LD A,B | HL=7FA8 (Reading Room blackboard), 7FAE (White Room blackboard), or 7FB4 (Exam Room blackboard) | ||
| F688 | ADD A,A | |||
| F689 | ADD A,B | |||
| F68A | LD L,A | |||
| F68B | LD B,$04 | Prepare the 4 slots in the blackboard buffer that will store the first 4 characters written on the board by ERIC; each slot will have bit 7 set if the board was clean before ERIC started writing | ||
| F68D | LD (HL),C | |||
| F68E | INC L | |||
| F68F | DJNZ $F68D | |||
| F691 | LD (HL),$01 | ERIC will start writing at pixel column 1 | ||
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This entry point is used by the routine at F6AA.
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| F693 | LD HL,$AC60 | Point HL at byte 0x60 of ERIC's buffer | ||
| F696 | LD B,(HL) | Pick up ERIC's animatory state in B, and his coordinates in DE | ||
| F697 | INC L | |||
| F698 | LD D,(HL) | |||
| F699 | INC L | |||
| F69A | LD E,(HL) | |||
| F69B | LD A,$57 | Set 7FFC (which holds the ASCII code of the last keypress) to 'W' (upper case, so ERIC can write fast) | ||
| F69D | LD ($7FFC),A | |||
| F6A0 | LD H,D | Copy ERIC's coordinates to HL | ||
| F6A1 | LD L,E | |||
| F6A2 | LD A,B | A=ERIC's current animatory state | ||
| F6A3 | AND $80 | A=0x0D or 0x8D: ERIC with arm up, as if writing | ||
| F6A5 | ADD A,$0D | |||
| F6A7 | JP $653C | Raise ERIC's arm | ||
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