Macro factors out sine code, just like sine data, since it's used 5 times

engine/routines/sine.asm

@@ -1,48 +1,4 @@
 _Sine:: ; 84d9
-; A simple sine function.
-; Return d * sin(e) in hl.
-
-; e is a signed 6-bit value.
+; a = d * sin(e * pi/32)
 	ld a, e
-	and %111111
-	cp  %100000
-	jr nc, .negative
-	call .ApplySineWave
-	ld a, h
-	ret
-
-.negative
-	and %011111
-	call .ApplySineWave
-	ld a, h
-	xor $ff
-	inc a
-	ret
-
-.ApplySineWave: ; 84ef
-	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
-; Factor amplitude
-.multiply
-	srl a
-	jr nc, .even
-	add hl, de
-.even
-	sla e
-	rl d
-	and a
-	jr nz, .multiply
-	ret
-
-.sinewave ; 850b
-; A 32-word table representing a sine wave.
-; sin(90 degrees) is index $10 with an amplitude of $100.
-	sine_wave 32
+	calc_sine_wave