nullsound: pan FX for ADPCM channels

Author: dciabrin

Diff for: nullsound/nss-adpcm-a.s

@@ -30,6 +30,7 @@
         ;; getters for ADPCM-A state
         .lclequ VOL, (state_a_vol-state_a)
         .lclequ OUT_VOL, (state_a_out_vol-state_a)
+        .lclequ PAN, (state_a_pan-state_a)
 
         .equ    NSS_ADPCM_A_INSTRUMENT_PROPS,   4
         .equ    NSS_ADPCM_A_NEXT_REGISTER,      8
@@ -71,6 +72,8 @@ state_a_trigger:                .blkb   TRIGGER_SIZE
 ;;; volume
 state_a_vol:                    .blkb    1      ; configured note volume (attenuation)
 state_a_out_vol:                .blkb    1      ; ym2610 volume after the FX pipeline
+;;; pan
+state_a_pan:                    .blkb    1      ; configured pan (b7: left, b6: right)
 ;;;
 state_a_end:
 ;;; ADPCM-A2
@@ -128,10 +131,15 @@ init_nss_adpcm_state_tracker::
         ld      (state_adpcm_a_channel), a
         ;; set default
         ld      ix, #state_a1
+        ld      bc, #ADPCM_A_STATE_SIZE
         ld      d, #6
 _a_init:
         ld      a, #0x1f
         ld      VOL(ix), a
+        ld      a, #0xc0
+        ld      PAN(ix), a
+
+        add     ix, bc
         dec     d
         jr      nz, _a_init
         ;; global ADPCM volumes are initialized in the volume state tracker
@@ -228,17 +236,17 @@ _post_load_a_vol:
 
         ;; Pipeline action: load pan+volume register when it is modified
         ld      a, PIPELINE(ix)
-        or      a, #(STATE_LOAD_VOL|STATE_LOAD_PAN)
+        and     a, #(STATE_LOAD_VOL|STATE_LOAD_PAN)
         jr      z, _post_load_a_pan_vol
         res     BIT_LOAD_VOL, PIPELINE(ix)
         res     BIT_LOAD_PAN, PIPELINE(ix)
 
-        ;; c: volume + default pan (L/R)
+        ;; c: volume + pan
         ld      a, OUT_VOL(ix)
-        or      #0xc0
+        add     PAN(ix)
         ld      c, a
 
-        ;; set pan+volume for channel in the YM2610
+        ;; set volume + pan for channel in the YM2610
         ;; b: ADPCM-A channel
         ld      a, (state_adpcm_a_channel)
         add     a, #REG_ADPCM_A1_PAN_VOLUME
@@ -620,3 +628,17 @@ adpcm_a_retrigger::
 
         ld      a, #1
         ret
+
+
+;;; ADPCM_A_PAN
+;;; Set the pan (l/r) for the current ADPCM-A channel
+;;; ------
+;;; [ hl ]: pan (b7: left, b6: right)
+adpcm_a_pan::
+        ld      a, (hl)
+        inc     hl
+        ld      PAN(ix), a
+        set     BIT_LOAD_PAN, PIPELINE(ix)
+
+        ld      a, #1
+        ret

Diff for: nullsound/nss-adpcm-b.s

@@ -34,6 +34,7 @@
         .lclequ DELTA_N, (state_b_note_delta_n-state_b)
         .lclequ VOL, (state_b_vol-state_b)
         .lclequ OUT_VOL, (state_b_out_vol-state_b)
+        .lclequ PAN, (state_b_pan-state_b)
         .lclequ INSTR, (state_b_instr-state_b)
         .lclequ START_CMD, (state_b_instr_start_cmd-state_b)
 
@@ -85,6 +86,8 @@ state_b_instr_start_cmd:        .blkb   1       ; instrument play command (with
 ;;; volume
 state_b_vol:                    .blkb   1       ; configured note volume (attenuation)
 state_b_out_vol:                .blkb   1       ; ym2610 volume after the FX pipeline
+;;; pan
+state_b_pan:                    .blkb    1      ; configured pan (b7: left, b6: right)
 ;;;
 state_b_end:
 
@@ -176,9 +179,18 @@ _b_post_check_playing:
         ld      b, #REG_ADPCM_B_VOLUME
         ld      c, OUT_VOL(ix)
         call    ym2610_write_port_a
-
+        res     BIT_LOAD_VOL, PIPELINE(ix)
 _post_load_b_vol:
 
+        ;; Pipeline action: load pan if requested
+        bit     BIT_LOAD_PAN, PIPELINE(ix)
+        jr      z, _post_load_b_pan
+        ld      b, #REG_ADPCM_B_PAN
+        ld      c, PAN(ix)
+        call    ym2610_write_port_a
+        res     BIT_LOAD_PAN, PIPELINE(ix)
+_post_load_b_pan:
+
         ;; Pipeline action: load note register when the note state is modified
         bit     BIT_LOAD_NOTE, PIPELINE(ix)
         jr      z, _post_load_b_note
@@ -779,3 +791,17 @@ adpcm_b_cut::
 
         ld      a, #1
         ret
+
+
+;;; ADPCM_B_PAN
+;;; Set the pan (l/r) for the channel
+;;; ------
+;;; [ hl ]: pan (b7: left, b6: right)
+adpcm_b_pan::
+        ld      a, (hl)
+        inc     hl
+        ld      PAN(ix), a
+        set     BIT_LOAD_PAN, PIPELINE(ix)
+
+        ld      a, #1
+        ret

Diff for: nullsound/stream.s

@@ -530,6 +530,8 @@ nss_opcodes:
         .nss_op adpcm_b_cut
         .nss_op adpcm_b_delay
         .nss_op adpcm_a_retrigger
+        .nss_op adpcm_a_pan
+        .nss_op adpcm_b_pan
 
 
 

Diff for: tools/nsstool.py

@@ -289,6 +289,8 @@ def register_nss_ops():
         ("b_cut",    ["delay"]),
         ("b_delay",  ["delay"]),
         ("a_retrigger", ["delay"]),
+        ("a_pan",    ["pan_mask"]),
+        ("b_pan",    ["pan_mask"]),
         # reserved opcodes
         ("nss_label", ["pat"])
     )
@@ -301,6 +303,15 @@ def register_nss_ops():
             globals()[cname]=make_dataclass(cname, fields)
 
 
+def convert_pan(fx, fxval):
+    if fx == 0x08:  # pan
+        pan_l = 0x80 if (fxval & 0xf0) else 0
+        pan_r = 0x40 if (fxval & 0x0f) else 0
+    elif fx == 0x80:  # old pan
+        pan_l = 0x80 if fxval in [0x00, 0x80] else 0
+        pan_r = 0x40 if fxval in [0x80, 0xff] else 0
+    return pan_l|pan_r;
+
 
 #
 # Furnace module conversion functions
@@ -317,15 +328,7 @@ def convert_fm_row(row, channel):
             opcodes.append(fm_vol(row.vol))
         # pre-instrument effects
         for fx, fxval in row.fx:
-            if fx == 0x08:  # pan
-                pan_l = 0x80 if (fxval & 0xf0) else 0
-                pan_r = 0x40 if (fxval & 0x0f) else 0
-                opcodes.append(fm_pan(pan_l|pan_r))
-            elif fx == 0x80:  # old pan
-                pan_l = 0x80 if fxval in [0x00, 0x80] else 0
-                pan_r = 0x40 if fxval in [0x80, 0xff] else 0
-                opcodes.append(fm_pan(pan_l|pan_r))
-            elif fx == 0xed:  # note delay
+            if fx == 0xed:  # note delay
                 opcodes.append(fm_delay(fxval))
         # instrument
         if row.ins != -1:
@@ -382,6 +385,9 @@ def convert_fm_row(row, channel):
                 opcodes.append(fm_porta(fxval))
             elif fx == 0xec:  # cut
                 opcodes.append(fm_cut(fxval))
+            elif fx in [0x08, 0x80]: # panning
+                pan_mask = convert_pan(fx, fxval)
+                opcodes.append(fm_pan(pan_mask))
             else:
                 add_unknown_fx('FM', fx)
 
@@ -521,6 +527,9 @@ def convert_a_row(row, channel):
                 opcodes.append(groove(fxval))
             elif fx == 0xec:  # cut
                 opcodes.append(a_cut(fxval))
+            elif fx in [0x08, 0x80]: # panning
+                pan_mask = convert_pan(fx, fxval)
+                opcodes.append(a_pan(pan_mask))
             else:
                 add_unknown_fx('ADPCM-A', fx)
 
@@ -571,6 +580,9 @@ def convert_b_row(row, channel):
                 opcodes.append(b_porta(fxval))
             elif fx == 0xec:  # cut
                 opcodes.append(b_cut(fxval))
+            elif fx in [0x08, 0x80]: # panning
+                pan_mask = convert_pan(fx, fxval)
+                opcodes.append(b_pan(pan_mask))
             else:
                 add_unknown_fx('ADPCM-B', fx)