Routines
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65D4: Check whether a character is beside a chair
Used by the routines at 6697, 7974 and F3FC. The value returned in A is as follows:
A Meaning
0x00 Character is facing left and standing beside a chair
0x03 Character must walk to the next chair to the left
0x04 Character must walk to the rightmost chair
0xFF Character is not in a classroom
Input
H Character number (0xB7-0xD2)
65D4 LD L,$02 Point HL at byte 0x02 of the character's buffer
65D6 LD A,(HL) A=character's y-coordinate
65D7 LD DE,$D332 The table at D332 contains the x-coordinates of the left ends of the classrooms
65DA LD B,$03 There are three sets of chairs on the top floor
65DC CP B Is the character on the top floor?
65DD JR Z,$65E6 Jump if so
65DF DEC B B=2 (two sets of chairs on the middle floor)
65E0 CP $0A Is the character on the middle floor?
65E2 JR NZ,$65F5 Jump if not
65E4 LD E,$35 DE=D335
65E6 DEC L
65E7 LD A,(HL) A=character's x-coordinate
65E8 EX DE,HL HL=D332 if the character is on the top floor, D335 if he's on the middle floor
65E9 CP (HL) Is the character to the left of this classroom?
65EA JR C,$65F1 Jump if so
65EC INC H Point HL at the x-coordinate of the right end of the classroom (in the table at D432)
65ED CP (HL) Is the character in this classroom?
65EE JR C,$65F8 Jump if so
65F0 DEC H
65F1 INC L
65F2 DJNZ $65E9
65F4 EX DE,HL
65F5 LD A,$FF Signal: the character is not in a classroom
65F7 RET
The character is in a classroom. But is he beside a chair?
65F8 INC H Point HL at the x-coordinate of the leftmost seat in the classroom (in the table at D532)
65F9 CP (HL) Is the character to the right of the leftmost chair?
65FA JR NC,$6600 Jump if so
65FC LD A,$04 Signal: the character must walk to the rightmost chair
65FE EX DE,HL
65FF RET
6600 INC H Point HL at the x-coordinate of the rightmost seat in the classroom (in the table at D632)
6601 CP (HL) Is the character to the left of the rightmost chair?
6602 JR C,$6608 Jump if so
6604 LD A,$03 Signal: the character must walk to the next chair to the left
6606 EX DE,HL
6607 RET
The character is between the leftmost and rightmost chairs in the classroom.
6608 DEC E E=0
6609 LD A,(DE) A=character's animatory state
660A INC E E=1
660B RLCA
660C JR C,$65FC Jump if the character is facing right
660E LD A,(DE) A=character's x-coordinate
660F XOR (HL) The chairs in a classroom have either all odd or all even x-coordinates; is the character standing beside one?
6610 RRCA
6611 JR NC,$6604 Jump if not
6613 EX DE,HL
6614 XOR A Signal: the character is facing left and standing beside a chair
6615 RET
The contents of the classroom/chairs location tables are as follows:
Room Chairs
0 23 11 22 Blue Room
40 63 50 61 Yellow Room
159 180 168 179 Top-floor room in the girls' skool
30 54 40 53 Science Lab
159 179 167 178 Middle-floor room in the girls' skool
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