| Routines

F5B9: Check whether ERIC is standing on a boy who's been knocked out

Used by the routine at F533. Returns with the carry flag set if ERIC is standing on a boy.
Input
B | 11 (there are 11 little boys)
D | 1 + ERIC's y-coordinate
E | ERIC's x-coordinate
H | 0x98 (little boy no. 1)
F5B9 | LD C,E | Set E=x-1 and C=x+2 where x is ERIC's x-coordinate; any boy with an x-coordinate in this range is a potential step for ERIC
F5BA | DEC E
F5BB | INC C
F5BC | INC C
F5BD | LD L,$61 | Byte 0x61 of the boy's buffer holds his y-coordinate
This entry point is also used by the routine at F533 with H=0xA7 (BOY WANDER) and B=0x03 (and E and C already set as above).
F5BF | LD A,D | A=y+1 (y=ERIC's y-coordinate)
F5C0 | CP (HL) | Is there a boy at this y-coordinate?
F5C1 | JR NZ,$F5D4 | Jump if not
F5C3 | DEC L | Collect the boy's animatory state from byte 0x60 of his buffer
F5C4 | LD A,(HL)
F5C5 | INC L | L=0x61
F5C6 | AND $0F | Keep only bits 0-3 of the animatory state
F5C8 | CP $07 | Is the boy lying flat on his back?
F5CA | JR NZ,$F5D4 | Jump if not
F5CC | INC L | Collect the boy's x-coordinate from byte 0x62 of his buffer
F5CD | LD A,(HL)
F5CE | DEC L | L=0x61
F5CF | CP E | Return with the carry flag set if ERIC is standing on this boy; otherwise continue
F5D0 | JR C,$F5D4
F5D2 | CP C
F5D3 | RET C
F5D4 | INC H | Next boy
F5D5 | DJNZ $F5BF | Jump back until all the boys have been checked
F5D7 | AND A | Return with the carry flag reset to indicate that ERIC is not standing on a boy
F5D8 | RET