sine_wave macro parameterizes table size, not frequency ("amplitude" was an incorrect comment)

macros/data.asm

@@ -31,29 +31,29 @@ dbwww: MACRO
 ENDM
 
 dn: MACRO ; nybbles
-	rept _NARG / 2
+rept _NARG / 2
 	db ((\1) << 4) | (\2)
 	shift
 	shift
-	endr
+endr
 ENDM
 
 dc: MACRO ; "crumbs"
-	rept _NARG / 4
+rept _NARG / 4
 	db ((\1) << 6) | ((\2) << 4) | ((\3) << 2) | (\4)
 	shift
 	shift
 	shift
 	shift
-	endr
+endr
 ENDM
 
 dx: MACRO
 x = 8 * ((\1) - 1)
-	rept \1
+rept \1
 	db ((\2) >> x) & $ff
 x = x + -8
-	endr
+endr
 ENDM
 
 dt: MACRO ; three-byte (big-endian)
@@ -69,17 +69,17 @@ bigdw: MACRO ; big-endian word
 ENDM
 
 dba: MACRO ; dbw bank, address
-	rept _NARG
+rept _NARG
 	dbw BANK(\1), \1
 	shift
-	endr
+endr
 ENDM
 
 dab: MACRO ; dwb address, bank
-	rept _NARG
+rept _NARG
 	dwb \1, BANK(\1)
 	shift
-	endr
+endr
 ENDM
 
 dba_pic: MACRO ; dbw bank, address
@@ -112,19 +112,17 @@ ENDM
 
 
 sine_wave: MACRO
-; \1: amplitude
 x = 0
-	rept $20
-	; Round up.
-	dw (sin(x) + (sin(x) & $ff)) >> 8
-x = x + (\1) * $40000
-	endr
+rept \1
+	dw (sin(x) + (sin(x) & $ff)) >> 8 ; round up
+x = x + (32768.0 / \1) ; a circle has 65536.0 "degrees"
+endr
 ENDM
 
 
 bcd: MACRO
-	rept _NARG
+rept _NARG
 	dn ((\1) % 100) / 10, (\1) % 10
 	shift
-	endr
+endr
 ENDM