; calculates the difference |a-b|, setting carry flag if a<b
CalcDifference::
sub b
ret nc
cpl
add $1
scf
ret
MoveSprite::
; move the sprite [hSpriteIndex] with the movement pointed to by de
; actually only copies the movement data to wNPCMovementDirections for later
call SetSpriteMovementBytesToFF
MoveSprite_::
push hl
push bc
call GetSpriteMovementByte1Pointer
xor a
ld [hl], a
ld hl, wNPCMovementDirections
ld c, 0
.loop
ld a, [de]
ld [hli], a
inc de
inc c
cp -1 ; have we reached the end of the movement data?
jr nz, .loop
ld a, c
ld [wNPCNumScriptedSteps], a ; number of steps taken
pop bc
ld hl, wStatusFlags5
set BIT_SCRIPTED_NPC_MOVEMENT, [hl]
pop hl
xor a
ld [wOverrideSimulatedJoypadStatesMask], a
ld [wSimulatedJoypadStatesEnd], a
dec a
ld [wJoyIgnore], a
ld [wUnusedOverrideSimulatedJoypadStatesIndex], a
ret
; divides [hDividend2] by [hDivisor2] and stores the quotient in [hQuotient2]
DivideBytes::
push hl
ld hl, hQuotient2
xor a
ld [hld], a
ld a, [hld]
and a
jr z, .done
ld a, [hli]
.loop
sub [hl]
jr c, .done
inc hl
inc [hl]
dec hl
jr .loop
.done
pop hl
ret
