FM overhaul

src/def.inc

@@ -210,8 +210,6 @@ SFXPS_CHANNEL_COUNT equ PA_CHANNEL_COUNT
 
 ; FMCNT defs
 FMCNT_CH_ENABLE            equ 1
-FMCNT_VOL_UPDATE           equ 2
-FMCNT_PITCH_SLIDE_ENABLE   equ 4
 
 FMCNT_MIN_FNUM equ $0080
 FMCNT_MAX_FNUM equ $07FF

src/fm.s

@@ -70,37 +70,6 @@ FMCNT_init:
 	pop hl
 	ret
 
-; DOESN'T BACKUP REGISTERS !!!
-FMCNT_irq:
-	ld b,FM_CHANNEL_COUNT
-	ld ix,FM_ch4
-
-loop$:
-	dec b
-		; If the channel's enable bit is 0,
-		; then continue to the next channel
-		ld a,(ix+FM_Channel.enable)
-		bit 0,a
-		jr z,skip_loop$
-
-		; If if FMCNT vol upd. flag is enabled...
-		; (This check is executed inside the function
-		;  too, this is to save time in most scenarios)
-		bit 1,a
-		call nz,FMCNT_update_total_levels
-
-		; Clear all the update bitflags
-		ld a,(ix+FM_Channel.enable)
-		and a,FMCNT_VOL_UPDATE ^ $FF
-		ld (ix+FM_Channel.enable),a 
-
-skip_loop$:
-		ld de,-FM_Channel.SIZE
-		add ix,de
-	inc b
-	djnz loop$
-	ret
-
 ; b:  channel (0~3)
 ; ix: address to FMCNT channel data
 ; (FM_channel_volumes[channel]): volume (0~7F)
@@ -109,17 +78,6 @@ FMCNT_update_total_levels:
 	push bc
 	push hl
 	push af
-		; if the FMCNT vol enable flag
-		; isn't set, return
-		ld a,(ix+FM_Channel.enable)
-		bit 1,a
-		jp z,return$
-
-		; If it is set, clear volume flag
-		; and proceed with the function
-		and a,FMCNT_VOL_UPDATE ^ $FF
-		ld (ix+FM_Channel.enable),a
-
 		ld e,(ix+FM_Channel.algo)
 		ld c,1 ; Prepare operator value
 
@@ -329,6 +287,7 @@ FM_op_register_offsets_LUT:
 ; a:  fbalgo (--FFFAAA; Feedback, Algorithm)
 ; c:  channel (0~3)
 ; ix: Pointer to FMCNT channel data
+; Total levels must be updated afterwards
 FMCNT_set_fbalgo:
 	push de
 	push af
@@ -355,11 +314,6 @@ even_channel$:
 		and a,%00000111 ; --FFFAAA -> 00000AAA
 		rlca ; algorithm *= 2
 		ld (ix+FM_Channel.algo),a
-
-		; Set FM volume update flag
-		ld a,(ix+FM_Channel.enable)
-		or a,FMCNT_VOL_UPDATE
-		ld (ix+FM_Channel.enable),a
 	pop hl
 	pop af
 	pop de
@@ -458,10 +412,6 @@ FMCNT_set_operator:
 	push af
 	push bc
 		push hl
-			ld a,(ix+FM_Channel.enable)
-			or a,FMCNT_VOL_UPDATE
-			ld (ix+FM_Channel.enable),a
-
 			; Load OP register offset in a, then 
 			; add said offset to DTMUL base address.
 			; After that, move result to d
@@ -566,7 +516,6 @@ FMCNT_set_note:
 		or a,b          ; OR block with F-Num 2
 		ld b,a
 
-		; WRITE TO REGISTERS DIRECTLY DO NOT BUFFER IN WRAM FOR NO ABSOLUTE REASON
 		; Write Block and F-Num 2 
 		ld e,b 
 		ld d,REG_FM_CH13_FBLOCK

src/main.s

@@ -197,7 +197,6 @@ execute_tma_tick:
 
 	call FADE_irq
 	call MLM_irq
-	call FMCNT_irq
 	ret
 
 fast_beep:

src/mlm.s

@@ -667,10 +667,8 @@ set_fm_instrument$:
 		call FMCNT_set_operator
 		add hl,de
 
-		; Set volume update flag
-		ld a,(ix+FM_Channel.enable)
-		or a,FMCNT_VOL_UPDATE
-		ld (ix+FM_Channel.enable),a
+		ld b,c
+		call FMCNT_update_total_levels
 	pop ix
 	pop af
 	pop bc
@@ -910,10 +908,8 @@ set_fm_channel_volume$:
 		and a,127 ; Wrap volume inbetween 0 and 127
 		ld (ix+FM_Channel.volume),a
 
-		; set channel volume update flag
-		ld a,(ix+FM_Channel.enable)
-		or a,FMCNT_VOL_UPDATE
-		ld (ix+FM_Channel.enable),a
+		ld b,c
+		call FMCNT_update_total_levels
 	pop ix
 	pop af
 	pop bc
@@ -990,9 +986,8 @@ ch_counter set 0
 			and a,127
 
 			ld (FM_ch1+(ch_counter*FM_Channel.SIZE)+FM_Channel.volume),a
-			ld a,(FM_ch1+(ch_counter*FM_Channel.SIZE)+FM_Channel.enable)
-			or a,FMCNT_VOL_UPDATE
-			ld (FM_ch1+(ch_counter*FM_Channel.SIZE)+FM_Channel.enable),a
+			ld b,ch_counter 
+			call FMCNT_update_total_levels
 ch_counter set ch_counter+1
 		edup
 

src/mlmcom.s

@@ -325,9 +325,9 @@ MLMCOM_FM_TL_set:
 	ld e,a
 	ld hl,FM_ch1+FM_Channel.enable
 	add hl,de
-	ld a,(hl)
-	or a,FMCNT_VOL_UPDATE
-	ld (hl),a
+
+	ld b,c
+	call FMCNT_update_total_levels
 	ret 
 
 ; invalid command, plays a noisy beep

test/sdata/sdata.s

@@ -152,14 +152,15 @@ MLM_song_fm4:
 
 MLM_el_fm:
 	set_inst 2
+	set_vol $FF
 	set_pan PANNING_CENTER,0
 	fm_note NOTE_C,4,24
 	fm_note NOTE_D,4,24
 	note_off 30
-	set_vol $E8
-	set_pan PANNING_LEFT,0
+	set_vol $E0
+	;set_pan PANNING_LEFT,0
 	fm_note NOTE_E,4,24
-	set_pan PANNING_RIGHT,0
+	;set_pan PANNING_RIGHT,0
 	fm_note NOTE_C,4,24
 	note_off 30
 	jump MLM_el_fm-MLM_header