2 files changed, 14 insertions, 48 deletions
diff --git a/engine/math/math.asm b/engine/math/math.asm
index cdac2d37..d5df3c34 100755
--- a/engine/math/math.asm
+++ b/engine/math/math.asm
@@ -1,11 +1,10 @@
-_Multiply:: ; 67bd
-
+_Multiply::
 ; hMultiplier is one byte.
 	ld a, 8
 	ld b, a
 
 	xor a
-	ldh [hProduct], a
+	ldh [hMultiplicand - 1], a
 	ldh [hMathBuffer + 1], a
 	ldh [hMathBuffer + 2], a
 	ldh [hMathBuffer + 3], a
@@ -37,7 +36,7 @@ _Multiply:: ; 67bd
 
 	ldh a, [hMathBuffer + 1]
 	ld c, a
-	ldh a, [hProduct]
+	ldh a, [hMultiplicand - 1]
 	adc c
 	ldh [hMathBuffer + 1], a
 
@@ -59,9 +58,9 @@ _Multiply:: ; 67bd
 	rla
 	ldh [hMultiplicand + 0], a
 
-	ldh a, [hProduct]
+	ldh a, [hMultiplicand - 1]
 	rla
-	ldh [hProduct], a
+	ldh [hMultiplicand - 1], a
 
 	jr .loop
 
@@ -80,7 +79,7 @@ _Multiply:: ; 67bd
 
 	ret
 
-_Divide:: ; 681d
+_Divide::
 	xor a
 	ldh [hMathBuffer + 0], a
 	ldh [hMathBuffer + 1], a
@@ -173,18 +172,18 @@ _Divide:: ; 681d
 
 .done
 	ldh a, [hDividend + 1]
-	ldh [hDivisor], a
+	ldh [hRemainder], a
 
 	ldh a, [hMathBuffer + 4]
-	ldh [hDividend + 3], a
+	ldh [hQuotient + 3], a
 
 	ldh a, [hMathBuffer + 3]
-	ldh [hDividend + 2], a
+	ldh [hQuotient + 2], a
 
 	ldh a, [hMathBuffer + 2]
-	ldh [hDividend + 1], a
+	ldh [hQuotient + 1], a
 
 	ldh a, [hMathBuffer + 1]
-	ldh [hDividend + 0], a
+	ldh [hQuotient + 0], a
 
 	ret
diff --git a/engine/math/sine.asm b/engine/math/sine.asm
index e22d785a..5db3bd60 100644
--- a/engine/math/sine.asm
+++ b/engine/math/sine.asm
@@ -1,40 +1,7 @@
-_Sine:: ; 8ac9 (2:4ac9)
+_Sine::
+; a = d * sin(e * pi/256)
 	ld a, e
-	and $3f
-	cp $20
-	jr nc, .negative
-	call .GetSine
-	ld a, h
-	ret
-.negative
-	and $1f
-	call .GetSine
-	ld a, h
-	xor $ff
-	inc a
-	ret
-
-.GetSine: ; 8adf (2:4adf)
-	ld e, a
-	ld a, d
-	ld d, $0
-	ld hl, .SineWave
-	add hl, de
-	add hl, de
-	ld e, [hl]
-	inc hl
-	ld d, [hl]
-	ld hl, $0
-.loop
-	srl a
-	jr nc, .no_add
-	add hl, de
-.no_add
-	sla e
-	rl d
-	and a
-	jr nz, .loop
-	ret
+	calc_sine_wave .SineWave
 
 .SineWave:
 	sine_table $100