From 2ec448a8ce6b0d929ba43748462109e46ca0bed4 Mon Sep 17 00:00:00 2001
From: kub <derkub@gmail.com>
Date: Wed, 11 May 2022 00:18:47 +0200
Subject: [PATCH] sound, fix ym2413 fm sound load/save

---
 pico/pico_int.h    |  2 ++
 pico/sound/sound.c | 30 ++++++++++++++++++++++++++----
 pico/state.c       | 23 ++++++++++++++---------
 3 files changed, 42 insertions(+), 13 deletions(-)

diff --git a/pico/pico_int.h b/pico/pico_int.h
index 837953cf..15d151ba 100644
--- a/pico/pico_int.h
+++ b/pico/pico_int.h
@@ -879,6 +879,8 @@ void ym2612_unpack_state(void);
   Pico.t.timer_b_step = TIMER_B_TICK_ZCYCLES * 256; \
   ym2612.OPN.ST.status &= ~3;
 
+void *YM2413GetRegs(void);
+void YM2413UnpackState(void);
 
 // videoport.c
 extern u32 SATaddr, SATmask;
diff --git a/pico/sound/sound.c b/pico/sound/sound.c
index 456d211b..74a40b58 100644
--- a/pico/sound/sound.c
+++ b/pico/sound/sound.c
@@ -29,11 +29,33 @@ extern int *sn76496_regs;
 
 // ym2413
 #define YM2413_CLK 3579545
-OPLL old_opll;
 static OPLL *opll = NULL;
-unsigned YM2413_reg;
+static OPLL old_opll;
+static struct {
+  uint32_t adr;
+  uint8_t reg[sizeof(opll->reg)];
+} opll_buf;
+
+PICO_INTERNAL void *YM2413GetRegs(void)
+{
+  memcpy(opll_buf.reg, opll->reg, sizeof(opll->reg));
+  opll_buf.adr = opll->adr;
+  return &opll_buf;
+}
+
+PICO_INTERNAL void YM2413UnpackState(void)
+{
+  int i;
+
+  for (i = sizeof(opll->reg)-1; i >= 0; i--) {
+    OPLL_writeIO(opll, 0, i);
+    OPLL_writeIO(opll, 1, opll_buf.reg[i]);
+  }
+  opll->adr = opll_buf.adr;
+}
 
 static resampler_t *fmresampler;
+static int (*PsndFMUpdate)(s32 *buffer, int length, int stereo, int is_buf_empty);
 
 PICO_INTERNAL void PsndInit(void)
 {
@@ -57,8 +79,6 @@ PICO_INTERNAL void PsndReset(void)
   timers_reset();
 }
 
-int (*PsndFMUpdate)(s32 *buffer, int length, int stereo, int is_buf_empty);
-
 // FM polyphase FIR resampling
 #define FMFIR_TAPS	9
 
@@ -142,6 +162,8 @@ void PsndRerate(int preserve_state)
     if (preserve_state) memcpy(&old_opll, opll, sizeof(OPLL)); // remember old state
     OPLL_setRate(opll, PicoIn.sndRate);
     OPLL_reset(opll);
+    if (preserve_state) memcpy(&opll->adr, &old_opll.adr, sizeof(OPLL)-20); // restore old state
+    OPLL_forceRefresh(opll);
   }
 
   if (state)
diff --git a/pico/state.c b/pico/state.c
index cd6d4de2..63d2b377 100644
--- a/pico/state.c
+++ b/pico/state.c
@@ -16,7 +16,6 @@
 
 // sn76496 & ym2413
 extern int *sn76496_regs;
-extern OPLL old_opll;
 
 static arearw    *areaRead;
 static arearw    *areaWrite;
@@ -125,7 +124,6 @@ typedef enum {
   CHUNK_DRAM,
   CHUNK_32XPAL,
   CHUNK_32X_EVT,
-  CHUNK_YM2413,   //40
   //rename
   CHUNK_32X_FIRST = CHUNK_MSH2,
   CHUNK_32X_LAST = CHUNK_32X_EVT,
@@ -134,6 +132,7 @@ typedef enum {
   CHUNK_CD_GFX,
   CHUNK_CD_CDC,
   CHUNK_CD_CDD,
+  CHUNK_YM2413,
   //
   CHUNK_DEFAULT_COUNT,
   CHUNK_CARTHW_ = CHUNK_CARTHW,  // 64 (defined in PicoInt)
@@ -225,7 +224,7 @@ static int state_save(void *file)
 {
   char sbuff[32] = "Saving.. ";
   unsigned char buff[0x60], buff_z80[Z80_STATE_SIZE];
-  void *ym2612_regs = YM2612GetRegs();
+  void *ym_regs = YM2612GetRegs();
   void *buf2 = NULL;
   int ver = 0x0191; // not really used..
   int retval = -1;
@@ -245,14 +244,16 @@ static int state_save(void *file)
     CHECKED_WRITE_BUFF(CHUNK_VSRAM, PicoMem.vsram);
     CHECKED_WRITE_BUFF(CHUNK_IOPORTS, PicoMem.ioports);
     ym2612_pack_state();
-    CHECKED_WRITE(CHUNK_FM, 0x200+4, ym2612_regs);
+    ym_regs = YM2612GetRegs();
+    CHECKED_WRITE(CHUNK_FM, 0x200+4, ym_regs);
 
     if (!(PicoIn.opt & POPT_DIS_IDLE_DET))
       SekInitIdleDet();
   }
   else {
     CHECKED_WRITE_BUFF(CHUNK_SMS, Pico.ms);
-    CHECKED_WRITE_BUFF(CHUNK_YM2413, old_opll);
+    ym_regs = YM2413GetRegs();
+    CHECKED_WRITE(CHUNK_YM2413, 0x40+4, ym_regs);
   }
 
   CHECKED_WRITE_BUFF(CHUNK_VRAM,  PicoMem.vram);
@@ -395,7 +396,7 @@ static int state_load(void *file)
   unsigned char buff_sh2[SH2_STATE_SIZE];
   unsigned char *buf = NULL;
   unsigned char chunk;
-  void *ym2612_regs;
+  void *ym_regs;
   int len_check;
   int retval = -1;
   char header[8];
@@ -452,10 +453,14 @@ static int state_load(void *file)
 
       case CHUNK_IOPORTS: CHECKED_READ_BUFF(PicoMem.ioports); break;
       case CHUNK_PSG:     CHECKED_READ2(28*4, sn76496_regs); break;
-      case CHUNK_YM2413:  CHECKED_READ_BUFF(old_opll); break;
+      case CHUNK_YM2413:
+        ym_regs = YM2413GetRegs();
+        CHECKED_READ2(0x40+4, ym_regs);
+        YM2413UnpackState();
+        break;
       case CHUNK_FM:
-        ym2612_regs = YM2612GetRegs();
-        CHECKED_READ2(0x200+4, ym2612_regs);
+        ym_regs = YM2612GetRegs();
+        CHECKED_READ2(0x200+4, ym_regs);
         ym2612_unpack_state();
         break;
 
-- 
2.39.2