| Routines

6CEE: Get the x-coordinate range within which a character can see or be seen

Used by the routines at 6D62 and 6D7D. Returns with C and B holding the lower and upper x-coordinates of the range within which the target character can see or be seen. This routine is called with H holding either (a) the character number of a teacher (to determine where kids must be in order to get lines), or (b) the character number of a kid (to determine where a teacher must be in order to give lines).
Input
H | Target character's number
6CEE | LD L,$02 | Point HL at byte 0x02 of the character's buffer
6CF0 | LD D,(HL) | D=character's y-coordinate
6CF1 | DEC L | L=0x01
6CF2 | LD E,(HL) | E=character's x-coordinate
6CF3 | LD C,$00 | Prepare a lower limit of 0 in case E<10
6CF5 | LD A,E | A=X (character's x-coordinate)
6CF6 | SUB $0A |
6CF8 | JR C,$6CFB |
6CFA | LD C,A | C=max(0, X-10) (lower limit of the range)
6CFB | ADD A,$14 |
6CFD | LD B,A | B=X+10 (upper limit of the range)
6CFE | RET |