Routines
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71AC: Send a policeman to Sam's last known whereabouts
Continues from the routine at 7377. The policeman recently spotted Sam while he was wearing a disguise unknown to the police; this routine sends that policeman back to where he first spotted Sam when the disguise becomes known.
Input
H 0xDE or 0xDF (policeman)
71AC LD L,$1F Pick up byte 0x1F of the policeman's buffer
71AE LD A,(HL)
71AF AND $3F D=Sam's y-coordinate when he was spotted by the policeman while wearing a disguise unknown to the police
71B1 LD D,A
71B2 LD A,(HL) Pick up byte 0x1F again
71B3 LD C,$04 Initialise the destination z-coordinate to 4
71B5 AND $C0 Was Sam's z-coordinate 4 (on the sidewalk or road) when he was spotted?
71B7 JR Z,$71BC Jump if so
71B9 RLCA Move bits 6 and 7 of A into bits 0 and 1
71BA RLCA
71BB LD C,A C=Sam's z-coordinate when he was spotted
71BC DEC L L=0x1E
71BD LD E,(HL) E=Sam's x-coordinate when he was spotted
71BE CALL $7194 Set the policeman's destination coordinates to (E,D)
71C1 CALL $71A3 Copy the destination coordinates and location identifier to 7FDB
71C4 LD L,$1D Point HL at byte 0x1D of the policeman's buffer
This entry point is used by the routine at 7222.
71C6 LD A,(HL) Pick up byte 0x1D of the policeman's buffer
71C7 LD (HL),$00 Set byte 0x1D of the policeman's buffer to 0 now that the disguise Sam was wearing is known to the police
71C9 RLCA Move bits 5-7 of A (which hold the ID of the disguise that Sam was wearing) into bits 0-2
71CA RLCA
71CB RLCA
71CC AND $07 Keep only bits 0-2
71CE ADD A,$A0 Now A=0x40, 0x20, 0x10, 0x08, 0x04, 0x02, or 0x01, with the set bit corresponding to the disguise that Sam was wearing
71D0 LD D,A
71D1 LD E,$15
71D3 LD A,(DE)
71D4 LD DE,$7FE8 7FE8 holds the disguise status flags
71D7 EX DE,HL Set the appropriate bit at 7FE8, making the disguise known to the police
71D8 OR (HL)
71D9 LD (HL),A
71DA JP $7D09 Set the attribute bytes for Sam's current disguise in the bottom right corner of the screen
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