chaos effect range test

AreChaosEffectsBetweenBCAndDEActive::
; input:
; bc: start index
; de: end index
; a: type
; return result in the flagarray wChaosEffectRangeFlagArray (40 flags)
    push hl
    call GetChaosEffectListPointer
.loop
; check for terminator
    ld a, [hli]
    or [hl]
    jr z, .done
; compare bc and [hl]
    ld a, c
    sub [hl]
    dec hl
    ld a, b
    sbc [hl]
; if bc > [hl], try again
    jr c, .notInRange
; compare de and [hl]
    inc hl
    ld a, e
    sub [hl]
    dec hl
    ld a, d
    sbc [hl]
; if equal, we're in the range
    jr z, .inRange
; else, if we're greater, we're not in the range
    jr nc, .notInRange
.inRange
    push hl
    push bc
    inc hl
; read the lower byte of the chaos effect
    ld a, [hl]
; a - c to get difference
; since the maximum difference is only 40 bytes anyway an 8-bit comparison shouldn't affect anything
    sub c
    ld c, a
; flag action predef
    ld hl, wChaosEffectRangeFlagArray
    ld b, FLAG_SET
    predef FlagActionPredef
    pop bc
    pop hl
.notInRange
    inc hl
    inc hl
    jr .loop
.done
    pop hl
    ret