Skool Daze: Routine at F9E5

F9E5: Compare a character's coordinates with ERIC's

Used by the routine at F78E. On entry, the zero flag is set if ERIC's y-coordinate matches that of the character looking for him. On exit, the zero flag is set if the character looking for ERIC is within 3 y-coordinates of ERIC's location and not on a staircase (in which case the routine at F78E checks whether the character is also within 3 x-coordinates of ERIC's location, i.e. has found ERIC).

Input
A	Character's y-coordinate
D	ERIC's y-coordinate
H	Character number (0xA1, 0xA3, 0xA4)
L	0x61

F9E5

JR Z,$F9F2

Jump if ERIC and his chaser are on the same floor

F9E7

SUB D

A=absolute difference between the y-coordinates of ERIC and his chaser

F9E8

JR NC,$F9EC

F9EA

NEG

F9EC

CP $04

Are ERIC and his chaser within 3 y-coordinates of each other?

F9EE

JR C,$F9F2

Jump if so

F9F0

AND A

Reset the zero flag (ERIC has not been found)

F9F1

RET

F9F2

LD A,(HL)

A=y-coordinate of the character looking for ERIC

F9F3

JP $6649

Set the zero flag set if the character is not on a staircase