From f3876af7f9da57d1020a974a656db010b1a4ef94 Mon Sep 17 00:00:00 2001
From: kub <derkub@gmail.com>
Date: Wed, 21 Jun 2023 18:15:33 +0000
Subject: [PATCH] sound, fixes for ym2612 (ARM and C)

---
 pico/sound/ym2612.c     |  8 ++++----
 pico/sound/ym2612_arm.S | 20 +++++++++++++++-----
 2 files changed, 19 insertions(+), 9 deletions(-)

diff --git a/pico/sound/ym2612.c b/pico/sound/ym2612.c
index 6d47850c..86dbda25 100644
--- a/pico/sound/ym2612.c
+++ b/pico/sound/ym2612.c
@@ -550,7 +550,7 @@ static INLINE void recalc_volout(FM_SLOT *SLOT)
 {
 	INT16 vol_out = SLOT->volume;
 	if ((SLOT->ssg&0x0c) == 0x0c)
-		vol_out = (0x200 - SLOT->volume) & MAX_ATT_INDEX;
+		vol_out = (0x200 - vol_out) & MAX_ATT_INDEX;
 	SLOT->vol_out = vol_out + SLOT->tl;
 }
 
@@ -880,7 +880,7 @@ static INLINE UINT32 update_ssg_eg_phase(FM_SLOT *SLOT, UINT32 phase)
 			}
 		}
 	}
-//	recalc_volout(SLOT);
+	recalc_volout(SLOT);
 	return phase;
 }
 #endif
@@ -1663,8 +1663,8 @@ static int OPNWriteReg(int r, int v)
 		SLOT->ssg ^= SLOT->ssgn;
 		if (v&0x08) ym2612.ssg_mask |=   1<<(OPN_SLOT(r) + c*4);
 		else        ym2612.ssg_mask &= ~(1<<(OPN_SLOT(r) + c*4));
-//		if (SLOT->state > EG_REL)
-//			recalc_volout(SLOT);
+		if (SLOT->state > EG_REL)
+			recalc_volout(SLOT);
 		break;
 
 	case 0xa0:
diff --git a/pico/sound/ym2612_arm.S b/pico/sound/ym2612_arm.S
index 3b1aa7c7..4d630dd3 100644
--- a/pico/sound/ym2612_arm.S
+++ b/pico/sound/ym2612_arm.S
@@ -198,10 +198,10 @@
     ldrb    r2, [r5,#0x17]                @ state
     ldrh    r3, [r5,#0x1a]                @ volume
     tst     r0, #0x08                     @ ssg enabled &&
-    beq     9f
+    beq     10f
     cmp     r2, #EG_REL+1                 @   state > EG_REL &&
     cmpge   r3, #0x200                    @   volume >= 0x200?
-    blt     9f
+    blt     10f
 
     tst     r0, #0x01
     beq     1f
@@ -245,6 +245,15 @@
     movgt   r2, #EG_ATT
 8:  strb    r2, [r5,#0x17]                @ state
 9:
+    ldrb    r0, [r5,#0x30]                @ ssg
+    ldrh    r2, [r5,#0x18]                @ tl
+    cmp     r0, #0x0c
+    rsbge   r3, r3, #0x200                @ volume = (0x200-volume) & MAX_ATT
+    movge   r3, r3, lsl #22
+    movge   r3, r3, lsr #22
+    add     r3, r3, r2                    @ volume += tl
+    strh    r3, [r5,#0x34]                @ vol_out
+10:
 .endm
 
 @ r5=slot, trashes: r0,r2,r3
@@ -703,11 +712,11 @@ ssg_upd_loop:
     addne   lr, lr, #4
     addne   r5, r5, #SLOT_STRUCT_SIZE
 #else
-    add     lr, lr, #4*2
+    add     lr, lr, #4
     add     r5, r5, #SLOT_STRUCT_SIZE*2
     update_ssg_eg
     subs    r6, r6, #2
-    subne   lr, lr, #4
+    addne   lr, lr, #4
     subne   r5, r5, #SLOT_STRUCT_SIZE
 #endif
     bne     ssg_upd_loop
@@ -861,8 +870,9 @@ crl_smp_loop_end:
     cmn     r1, r0, asr #13
     subne   r0, r1, #0x80000001
     movne   r0, r0, asr #18
-    tst     r4, r1, lsl #7          @ (sample < 0) && dac?
+    tst     r4, #0x80               @ dac?
     bicne   r0, r0, #0x1f
+    tst     r4, r1, lsl #7          @ (sample < 0) && dac?
     subne   r0, r0, #7<<5
     tst     r12, #1
     beq     ctl_sample_mono
-- 
2.39.5