From 178a9b683c5246fae3f5ddad4b53dfc3670ed7cb Mon Sep 17 00:00:00 2001
From: kub <derkub@gmail.com>
Date: Fri, 19 May 2023 14:10:22 +0000
Subject: [PATCH] mcd, fixes and improvements by mcd-verificator

---
 pico/cart.c      |  12 +++-
 pico/cd/cdc.c    | 118 ++++++++++++++++++++++----------------
 pico/cd/mcd.c    |   6 +-
 pico/cd/memory.c | 144 ++++++++++++++++++++++++-----------------------
 pico/cd/sek.c    |   2 +
 pico/pico_int.h  |   1 +
 6 files changed, 160 insertions(+), 123 deletions(-)

diff --git a/pico/cart.c b/pico/cart.c
index 86cab1d7..526ea442 100644
--- a/pico/cart.c
+++ b/pico/cart.c
@@ -404,7 +404,9 @@ size_t pm_read(void *ptr, size_t bytes, pm_file *stream)
 {
   int ret;
 
-  if (stream->type == PMT_UNCOMPRESSED)
+  if (stream == NULL)
+    return -1;
+  else if (stream->type == PMT_UNCOMPRESSED)
   {
     ret = fread(ptr, 1, bytes, stream->file);
   }
@@ -514,8 +516,10 @@ size_t pm_read(void *ptr, size_t bytes, pm_file *stream)
 
 size_t pm_read_audio(void *ptr, size_t bytes, pm_file *stream)
 {
+  if (stream == NULL)
+    return -1;
 #if !(CPU_IS_LE)
-  if (stream->type == PMT_UNCOMPRESSED)
+  else if (stream->type == PMT_UNCOMPRESSED)
   {
     // convert little endian audio samples from WAV file
     int ret = pm_read(ptr, bytes, stream);
@@ -542,7 +546,9 @@ size_t pm_read_audio(void *ptr, size_t bytes, pm_file *stream)
 
 int pm_seek(pm_file *stream, long offset, int whence)
 {
-  if (stream->type == PMT_UNCOMPRESSED)
+  if (stream == NULL)
+    return -1;
+  else if (stream->type == PMT_UNCOMPRESSED)
   {
     fseek(stream->file, offset, whence);
     return ftell(stream->file);
diff --git a/pico/cd/cdc.c b/pico/cd/cdc.c
index 70914636..f7ae04c2 100644
--- a/pico/cd/cdc.c
+++ b/pico/cd/cdc.c
@@ -244,65 +244,66 @@ int cdc_context_load_old(uint8 *state)
 #undef old_load
 }
 
-static void do_dma(enum dma_type type, int words_in)
+static void do_dma(enum dma_type type, int bytes_in)
 {
-	int dma_addr = (Pico_mcd->s68k_regs[0x0a] << 8) | Pico_mcd->s68k_regs[0x0b];
+  int dma_addr = (Pico_mcd->s68k_regs[0x0a] << 8) | Pico_mcd->s68k_regs[0x0b];
   int src_addr = cdc.dac & 0x3ffe;
   int dst_addr = dma_addr;
-  int words = words_in;
+  int bytes = bytes_in;
+  int words = bytes_in >> 1;
   int dst_limit = 0;
   uint8 *dst;
   int len;
 
   elprintf(EL_CD, "dma %d %04x->%04x %x",
-    type, cdc.dac, dst_addr, words_in);
+    type, cdc.dac, dst_addr, bytes_in);
 
   switch (type)
   {
     case pcm_ram_dma_w:
       dst_addr = (dst_addr << 2) & 0xffc;
-      if (dst_addr + words * 2 > 0x1000) {
+      if (dst_addr + bytes > 0x1000) {
         elprintf(EL_ANOMALY, "pcm dma oflow: %x %x", dst_addr, words);
-        words = (0x1000 - dst_addr) / 2;
+        bytes = 0x1000 - dst_addr;
       }
       dst = Pico_mcd->pcm_ram_b[Pico_mcd->pcm.bank];
       dst = dst + dst_addr;
-      while (words > 0)
+      while (bytes > 0)
       {
-        if (src_addr + words * 2 > 0x4000) {
+        if (src_addr + bytes > 0x4000) {
           len = 0x4000 - src_addr;
           memcpy(dst, cdc.ram + src_addr, len);
           dst += len;
           src_addr = 0;
-          words -= len / 2;
+          bytes -= len;
           continue;
         }
-        memcpy(dst, cdc.ram + src_addr, words * 2);
+        memcpy(dst, cdc.ram + src_addr, bytes);
         break;
       }
       goto update_dma;
 
     case prg_ram_dma_w:
       dst_addr <<= 3;
-		  dst = Pico_mcd->prg_ram + dst_addr;
+      dst = Pico_mcd->prg_ram + dst_addr;
       dst_limit = 0x80000;
       break;
 
     case word_ram_0_dma_w:
       dst_addr = (dst_addr << 3) & 0x1fffe;
-			dst = Pico_mcd->word_ram1M[0] + dst_addr;
+      dst = Pico_mcd->word_ram1M[0] + dst_addr;
       dst_limit = 0x20000;
       break;
 
     case word_ram_1_dma_w:
       dst_addr = (dst_addr << 3) & 0x1fffe;
-			dst = Pico_mcd->word_ram1M[1] + dst_addr;
+      dst = Pico_mcd->word_ram1M[1] + dst_addr;
       dst_limit = 0x20000;
       break;
 
     case word_ram_2M_dma_w:
       dst_addr = (dst_addr << 3) & 0x3fffe;
-			dst = Pico_mcd->word_ram2M + dst_addr;
+      dst = Pico_mcd->word_ram2M + dst_addr;
       dst_limit = 0x40000;
       break;
 
@@ -329,13 +330,15 @@ static void do_dma(enum dma_type type, int words_in)
     break;
   }
 
+  bytes_in &= ~1; // Todo leftover byte?
+
 update_dma:
   /* update DMA addresses */
-  cdc.dac += words_in * 2;
+  cdc.dac += bytes_in;
   if (type == pcm_ram_dma_w)
-    dma_addr += words_in >> 1;
+    dma_addr += bytes_in >> 2;
   else
-    dma_addr += words_in >> 2;
+    dma_addr += bytes_in >> 3;
 
   Pico_mcd->s68k_regs[0x0a] = dma_addr >> 8;
   Pico_mcd->s68k_regs[0x0b] = dma_addr;
@@ -348,7 +351,7 @@ void cdc_dma_update(void)
   {
     /* transfer remaining words using 16-bit DMA */
     //cdc.dma_w((cdc.dbc + 1) >> 1);
-    do_dma(cdc.dma_w, (cdc.dbc + 1) >> 1);
+    do_dma(cdc.dma_w, cdc.dbc + 1);
 
     /* reset data byte counter (DBCH bits 4-7 should be set to 1) */
     cdc.dbc = 0xf000;
@@ -356,24 +359,26 @@ void cdc_dma_update(void)
     /* clear !DTEN and !DTBSY */
     cdc.ifstat |= (BIT_DTBSY | BIT_DTEN);
 
-    /* pending Data Transfer End interrupt */
-    cdc.ifstat &= ~BIT_DTEI;
+    /* clear DSR bit & set EDT bit (SCD register $04) */
+    Pico_mcd->s68k_regs[0x04+0] = (Pico_mcd->s68k_regs[0x04+0] & 0x07) | 0x80;
 
-    /* Data Transfer End interrupt enabled ? */
-    if (cdc.ifctrl & BIT_DTEIEN)
-    {
-      /* level 5 interrupt enabled ? */
-      if (Pico_mcd->s68k_regs[0x32+1] & PCDS_IEN5)
+    if (cdc.ifstat & BIT_DTEI) {
+      /* pending Data Transfer End interrupt */
+      cdc.ifstat &= ~BIT_DTEI;
+
+      /* Data Transfer End interrupt enabled ? */
+      if (cdc.ifctrl & BIT_DTEIEN)
       {
-        /* update IRQ level */
-        elprintf(EL_INTS, "cdc DTE irq 5");
-        pcd_irq_s68k(5, 1);
+        /* level 5 interrupt enabled ? */
+        if (Pico_mcd->s68k_regs[0x32+1] & PCDS_IEN5)
+        {
+          /* update IRQ level */
+          elprintf(EL_INTS, "cdc DTE irq 5");
+          pcd_irq_s68k(5, 1);
+        }
       }
     }
 
-    /* clear DSR bit & set EDT bit (SCD register $04) */
-    Pico_mcd->s68k_regs[0x04+0] = (Pico_mcd->s68k_regs[0x04+0] & 0x07) | 0x80;
-
     /* disable DMA transfer */
     cdc.dma_w = 0;
   }
@@ -456,8 +461,11 @@ void cdc_reg_w(unsigned char data)
 #ifdef LOG_CDC
   elprintf(EL_STATUS, "CDC register %X write 0x%04x", Pico_mcd->s68k_regs[0x04+1] & 0x0F, data);
 #endif
-  switch (Pico_mcd->s68k_regs[0x04+1] & 0x0F)
+  switch (Pico_mcd->s68k_regs[0x04+1] & 0x1F)
   {
+    case 0x00:
+      break;
+
     case 0x01:  /* IFCTRL */
     {
       /* pending interrupts ? */
@@ -498,7 +506,7 @@ void cdc_reg_w(unsigned char data)
 
     case 0x03:  /* DBCH */
       cdc.dbc &= 0x00ff;
-      cdc.dbc |= data << 8;
+      cdc.dbc |= (data & 0x0f) << 8;
       Pico_mcd->s68k_regs[0x04+1] = 0x04;
       break;
 
@@ -638,6 +646,10 @@ void cdc_reg_w(unsigned char data)
       /* set CRCOK bit only if decoding is enabled */
       cdc.stat[0] = data & BIT_DECEN;
 
+      /* reset DECI if decoder turned off */
+      if (!cdc.stat[0])
+        cdc.ifstat |= BIT_DECI;
+
       /* update decoding mode */
       if (data & BIT_AUTORQ)
       {
@@ -692,17 +704,22 @@ void cdc_reg_w(unsigned char data)
 
     case 0x0f:  /* RESET */
       cdc_reset();
+      Pico_mcd->s68k_regs[0x04+1] = 0x10;
       break;
 
     default:  /* by default, SBOUT is not used */
+      Pico_mcd->s68k_regs[0x04+1] = (Pico_mcd->s68k_regs[0x04+1] + 1) & 0x1f;
       break;
   }
 }
 
 unsigned char cdc_reg_r(void)
 {
-  switch (Pico_mcd->s68k_regs[0x04+1] & 0x0F)
+  switch (Pico_mcd->s68k_regs[0x04+1] & 0x01F)
   {
+    case 0x00:
+      return 0xff;
+
     case 0x01:  /* IFSTAT */
       Pico_mcd->s68k_regs[0x04+1] = 0x02;
       return cdc.ifstat;
@@ -778,11 +795,12 @@ unsigned char cdc_reg_r(void)
       }
 #endif
 
-      Pico_mcd->s68k_regs[0x04+1] = 0x00;
+      Pico_mcd->s68k_regs[0x04+1] = 0x10;
       return data;
     }
 
     default:  /* by default, COMIN is always empty */
+      Pico_mcd->s68k_regs[0x04+1] = (Pico_mcd->s68k_regs[0x04+1] + 1) & 0x1f;
       return 0xff;
   }
 }
@@ -815,23 +833,27 @@ unsigned short cdc_host_r(void)
       /* clear !DTEN and !DTBSY */
       cdc.ifstat |= (BIT_DTBSY | BIT_DTEN);
 
-      /* pending Data Transfer End interrupt */
-      cdc.ifstat &= ~BIT_DTEI;
+      /* clear DSR bit & set EDT bit (SCD register $04) */
+      Pico_mcd->s68k_regs[0x04+0] = (Pico_mcd->s68k_regs[0x04+0] & 0x07) | 0x80;
+    } else if ((int16)cdc.dbc <= 2) {
+      if (cdc.ifstat & BIT_DTEI) {
+        /* pending Data Transfer End interrupt */
+        cdc.ifstat &= ~BIT_DTEI;
 
-      /* Data Transfer End interrupt enabled ? */
-      if (cdc.ifctrl & BIT_DTEIEN)
-      {
-        /* level 5 interrupt enabled ? */
-        if (Pico_mcd->s68k_regs[0x32+1] & PCDS_IEN5)
+        /* Data Transfer End interrupt enabled ? */
+        if (cdc.ifctrl & BIT_DTEIEN)
         {
-          /* update IRQ level */
-          elprintf(EL_INTS, "cdc DTE irq 5");
-          pcd_irq_s68k(5, 1);
+          /* level 5 interrupt enabled ? */
+          if (Pico_mcd->s68k_regs[0x32+1] & PCDS_IEN5)
+          {
+            /* update IRQ level */
+            elprintf(EL_INTS, "cdc DTE irq 5");
+            pcd_irq_s68k(5, 1);
+          }
         }
       }
-
-      /* clear DSR bit & set EDT bit (SCD register $04) */
-      Pico_mcd->s68k_regs[0x04+0] = (Pico_mcd->s68k_regs[0x04+0] & 0x07) | 0x80;
+      /* set DSR and EDT bit (SCD register $04) */
+      Pico_mcd->s68k_regs[0x04+0] = (Pico_mcd->s68k_regs[0x04+0] & 0x07) | 0xc0;
     }
 
     return data;
diff --git a/pico/cd/mcd.c b/pico/cd/mcd.c
index 840f916c..50c85ac1 100644
--- a/pico/cd/mcd.c
+++ b/pico/cd/mcd.c
@@ -166,7 +166,7 @@ static void pcd_int3_timer_event(unsigned int now)
 
   if (Pico_mcd->s68k_regs[0x31] != 0)
     pcd_event_schedule(now, PCD_EVENT_TIMER3,
-      Pico_mcd->s68k_regs[0x31] * 384);
+      (Pico_mcd->s68k_regs[0x31]+1) * 384);
 }
 
 static void pcd_dma_event(unsigned int now)
@@ -190,13 +190,13 @@ void pcd_event_schedule(unsigned int now, enum pcd_event event, int after)
 {
   unsigned int when;
 
-  when = now + after;
-  if (when == 0) {
+  if ((now|after) == 0) {
     // event cancelled
     pcd_event_times[event] = 0;
     return;
   }
 
+  when = now + after;
   when |= 1;
 
   elprintf(EL_CD, "cd: new event #%u %u->%u", event, now, when);
diff --git a/pico/cd/memory.c b/pico/cd/memory.c
index e51ea240..b26b6295 100644
--- a/pico/cd/memory.c
+++ b/pico/cd/memory.c
@@ -100,9 +100,9 @@ static u32 m68k_reg_read16(u32 a)
 
   switch (a) {
     case 0:
-      // here IFL2 is always 0, just like in Gens
-      d = ((Pico_mcd->s68k_regs[0x33] << 13) & 0x8000)
-        | Pico_mcd->m.busreq;
+      pcd_sync_s68k(SekCyclesDone(), 0);
+      d = ((Pico_mcd->s68k_regs[0x33] & PCDS_IEN2) << 13) |
+          (Pico_mcd->m.state_flags & PCD_ST_S68K_IFL2) | Pico_mcd->m.busreq;
       goto end;
     case 2:
       m68k_comm_check(a);
@@ -158,6 +158,8 @@ void m68k_reg_write8(u32 a, u32 d)
   switch (a) {
     case 0:
       d &= 1;
+      Pico_mcd->m.state_flags &= ~PCD_ST_S68K_IFL2;
+      if (d) Pico_mcd->m.state_flags |= PCD_ST_S68K_IFL2;
       if (d && (Pico_mcd->s68k_regs[0x33] & PCDS_IEN2)) {
         elprintf(EL_INTS, "m68k: s68k irq 2");
         pcd_sync_s68k(SekCyclesDone(), 0);
@@ -179,7 +181,7 @@ void m68k_reg_write8(u32 a, u32 d)
       if (!(d & 1))
         Pico_mcd->m.state_flags |= PCD_ST_S68K_RST;
       else if (d == 1 && (Pico_mcd->m.state_flags & PCD_ST_S68K_RST)) {
-        Pico_mcd->m.state_flags &= ~PCD_ST_S68K_RST;
+        Pico_mcd->m.state_flags &= ~(PCD_ST_S68K_RST|PCD_ST_S68K_POLL|PCD_ST_S68K_SLEEP);
         elprintf(EL_CDREGS, "m68k: resetting s68k");
         SekResetS68k();
       }
@@ -193,8 +195,8 @@ void m68k_reg_write8(u32 a, u32 d)
       elprintf(EL_CDREGS, "m68k: prg wp=%02x", d);
       goto write_comm;
     case 3:
-      dold = Pico_mcd->s68k_regs[3];
       elprintf(EL_CDREG3, "m68k_regs w3: %02x @%06x", (u8)d, SekPc);
+      dold = Pico_mcd->s68k_regs[3];
       if ((d ^ dold) & 0xc0) {
         elprintf(EL_CDREGS, "m68k: prg bank: %i -> %i",
           (Pico_mcd->s68k_regs[a]>>6), ((d>>6)&3));
@@ -214,7 +216,6 @@ void m68k_reg_write8(u32 a, u32 d)
         d = (d & 0xc0) | (dold & 0x1c) | Pico_mcd->m.dmna_ret_2m;
       if ((dold ^ d) & 0x1f)
         remap_word_ram(d);
-
       goto write_comm;
     case 6:
       Pico_mcd->bios[MEM_BE2(0x72)] = d; // simple hint vector changer
@@ -224,6 +225,9 @@ void m68k_reg_write8(u32 a, u32 d)
       elprintf(EL_CDREGS, "hint vector set to %04x%04x",
         ((u16 *)Pico_mcd->bios)[0x70/2], ((u16 *)Pico_mcd->bios)[0x72/2]);
       return;
+    case 8:
+      (void) cdc_host_r(); // acts same as reading
+      return;
     case 0x0f:
       a = 0x0e;
     case 0x0e:
@@ -277,7 +281,7 @@ u32 s68k_poll_detect(u32 a, u32 d)
         elprintf(EL_CDPOLL, "s68k poll detected @%06x, a=%02x",
           SekPcS68k, a);
       } else if (cnt > 2)
-        SekEndRunS68k(80);
+        SekEndRunS68k(240);
     }
   }
   Pico_mcd->m.s68k_poll_a = a;
@@ -308,38 +312,47 @@ u32 s68k_reg_read16(u32 a)
 
   switch (a) {
     case 0:
-      return ((Pico_mcd->s68k_regs[0]&3)<<8) | 1; // ver = 0, not in reset state
+      d = ((Pico_mcd->s68k_regs[0]&3)<<8) | 1; // ver = 0, not in reset state
+      goto end;
     case 2:
       d = (Pico_mcd->s68k_regs[2]<<8) | (Pico_mcd->s68k_regs[3]&0x1f);
       elprintf(EL_CDREG3, "s68k_regs r3: %02x @%06x", (u8)d, SekPcS68k);
-      return s68k_poll_detect(a, d);
+      s68k_poll_detect(a, d);
+      goto end;
+    case 4:
+      d = (Pico_mcd->s68k_regs[4]<<8) | (Pico_mcd->s68k_regs[5]&0x1f);
+      goto end;
     case 6:
-      return cdc_reg_r();
+      d = cdc_reg_r();
+      goto end;
     case 8:
-      return cdc_host_r();
+      d = cdc_host_r();
+      goto end;
     case 0xC:
       d = SekCyclesDoneS68k() - Pico_mcd->m.stopwatch_base_c;
       d /= 384;
       d &= 0x0fff;
       elprintf(EL_CDREGS, "s68k stopwatch timer read (%04x)", d);
-      return d;
+      goto end;
     case 0x30:
-      elprintf(EL_CDREGS, "s68k int3 timer read (%02x)", Pico_mcd->s68k_regs[31]);
-      return Pico_mcd->s68k_regs[31];
+      elprintf(EL_CDREGS, "s68k int3 timer read (%02x)", Pico_mcd->s68k_regs[0x31]);
+      d = Pico_mcd->s68k_regs[0x31];
+      goto end;
     case 0x34: // fader
-      return 0; // no busy bit
+      d = 0; // no busy bit
+      goto end;
     case 0x50: // font data (check: Lunar 2, Silpheed)
       READ_FONT_DATA(0x00100000);
-      return d;
+      goto end;
     case 0x52:
       READ_FONT_DATA(0x00010000);
-      return d;
+      goto end;
     case 0x54:
       READ_FONT_DATA(0x10000000);
-      return d;
+      goto end;
     case 0x56:
       READ_FONT_DATA(0x01000000);
-      return d;
+      goto end;
   }
 
   d = (Pico_mcd->s68k_regs[a]<<8) | Pico_mcd->s68k_regs[a+1];
@@ -347,6 +360,7 @@ u32 s68k_reg_read16(u32 a)
   if (a >= 0x0e && a < 0x30)
     return s68k_poll_detect(a, d);
 
+end:
   return d;
 }
 
@@ -361,8 +375,7 @@ void s68k_reg_write8(u32 a, u32 d)
       if (!(d & 1))
         pcd_soft_reset();
       return;
-    case 2:
-      return; // only m68k can change WP
+    case 2: a++; // byte access only, ignores LDS/UDS
     case 3: {
       int dold = Pico_mcd->s68k_regs[3];
       elprintf(EL_CDREG3, "s68k_regs w3: %02x @%06x", (u8)d, SekPcS68k);
@@ -399,33 +412,38 @@ void s68k_reg_write8(u32 a, u32 d)
     }
     case 4:
       elprintf(EL_CDREGS, "s68k CDC dest: %x", d&7);
-      Pico_mcd->s68k_regs[4] = (Pico_mcd->s68k_regs[4]&0xC0) | (d&7); // CDC mode
+      Pico_mcd->s68k_regs[a] = (d&7); // CDC mode
+      Pico_mcd->s68k_regs[0xa] = Pico_mcd->s68k_regs[0xb] = 0; // resets DMA
       return;
     case 5:
-      //dprintf("s68k CDC reg addr: %x", d&0xf);
-      break;
+      //dprintf("s68k CDC reg addr: %x", d&0x1f);
+      Pico_mcd->s68k_regs[a] = (d&0x1f);
+      return;
     case 7:
       cdc_reg_w(d & 0xff);
       return;
     case 0xa:
+    case 0xb:
+      // word access only. 68k sets both bus halves to value d.
       elprintf(EL_CDREGS, "s68k set CDC dma addr");
-      break;
+      Pico_mcd->s68k_regs[0xa] = Pico_mcd->s68k_regs[0xb] = d;
+      return;
     case 0xc:
     case 0xd: // 384 cycle stopwatch timer
       elprintf(EL_CDREGS|EL_CD, "s68k clear stopwatch (%x)", d);
       // does this also reset internal 384 cycle counter?
       Pico_mcd->m.stopwatch_base_c = SekCyclesDoneS68k();
       return;
-    case 0x0e:
-      a = 0x0f;
+    case 0x0e: a++;
     case 0x0f:
       goto write_comm;
+    case 0x30: a++;
     case 0x31: // 384 cycle int3 timer
       d &= 0xff;
       elprintf(EL_CDREGS|EL_CD, "s68k set int3 timer: %02x", d);
       Pico_mcd->s68k_regs[a] = (u8) d;
-      if (d) // d or d+1??
-        pcd_event_schedule_s68k(PCD_EVENT_TIMER3, d * 384);
+      if (d) // XXX: d or d+1? mcd-verificator results suggest d+1
+        pcd_event_schedule_s68k(PCD_EVENT_TIMER3, (d+1) * 384);
       else
         pcd_event_schedule(0, PCD_EVENT_TIMER3, 0);
       break;
@@ -439,6 +457,8 @@ void s68k_reg_write8(u32 a, u32 d)
           pcd_irq_s68k(4, 1);
         }
       }
+      if ((d ^ Pico_mcd->s68k_regs[0x33]) & ~d & PCDS_IEN2)
+	pcd_irq_s68k(2, 0);
       break;
     case 0x34: // fader
       Pico_mcd->s68k_regs[a] = (u8) d & 0x7f;
@@ -478,6 +498,8 @@ void s68k_reg_write8(u32 a, u32 d)
           s[0], s[1], s[2], s[3], s[4], s[5], s[6], s[7], s[8], s[9]);
       }
       return;
+    case 0x4c: a++;
+      break;
     case 0x58:
       return;
   }
@@ -517,11 +539,18 @@ void s68k_reg_write16(u32 a, u32 d)
     goto write_comm;
 
   switch (a) {
+    case 0x02:
     case 0x0e:
-      // special case, 2 byte writes would be handled differently
-      // TODO: verify
-      d = (u8)d | (r[0xe] << 8);
-      goto write_comm;
+    case 0x30:
+    case 0x4c:
+      // these are only byte registers, LDS/UDS ignored
+      return s68k_reg_write8(a + 1, d);
+    case 0x08:
+      return (void) cdc_host_r(); // acts same as reading
+    case 0x0a: // DMA address
+      r[0xa] = d >> 8;
+      r[0xb] = d;
+      return;
     case 0x58: // stamp data size
       r[0x59] = d & 7;
       return;
@@ -634,19 +663,19 @@ static void PicoWriteM68k16_cell1(u32 a, u32 d)
 static u32 PicoReadM68k8_ramc(u32 a)
 {
   u32 d = 0;
-  if (a == 0x400001) {
+  if ((a & 0xf00001) == 0x400001) {
     if (Pico.sv.data != NULL)
       d = 3; // 64k cart
     return d;
   }
 
-  if ((a & 0xfe0000) == 0x600000) {
+  if ((a & 0xf00001) == 0x600001) {
     if (Pico.sv.data != NULL)
       d = Pico.sv.data[((a >> 1) & 0xffff) + 0x2000];
     return d;
   }
 
-  if (a == 0x7fffff)
+  if ((a & 0xf00001) == 0x700001)
     return Pico_mcd->m.bcram_reg;
 
   elprintf(EL_UIO, "m68k unmapped r8  [%06x] @%06x", a, SekPc);
@@ -661,15 +690,15 @@ static u32 PicoReadM68k16_ramc(u32 a)
 
 static void PicoWriteM68k8_ramc(u32 a, u32 d)
 {
-  if ((a & 0xfe0000) == 0x600000) {
+  if ((a & 0xf00001) == 0x600001) {
     if (Pico.sv.data != NULL && (Pico_mcd->m.bcram_reg & 1)) {
-      Pico.sv.data[((a>>1) & 0xffff) + 0x2000] = d;
+      Pico.sv.data[((a >> 1) & 0xffff) + 0x2000] = d;
       Pico.sv.changed = 1;
     }
     return;
   }
 
-  if (a == 0x7fffff) {
+  if ((a & 0xf00001) == 0x700001) {
     Pico_mcd->m.bcram_reg = d;
     return;
   }
@@ -902,15 +931,16 @@ static u32 PicoReadS68k16_bram(u32 a)
   u32 d;
   elprintf(EL_ANOMALY, "FIXME: s68k_bram r16: [%06x] @%06x", a, SekPcS68k);
   a = (a >> 1) & 0x1fff;
-  d = Pico_mcd->bram[a++];
-  d|= Pico_mcd->bram[a++] << 8; // probably wrong, TODO: verify
+  d = Pico_mcd->bram[a];
   return d;
 }
 
 static void PicoWriteS68k8_bram(u32 a, u32 d)
 {
-  Pico_mcd->bram[(a >> 1) & 0x1fff] = d;
-  Pico.sv.changed = 1;
+  if (a & 1) {
+    Pico_mcd->bram[(a >> 1) & 0x1fff] = d;
+    Pico.sv.changed = 1;
+  }
 }
 
 static void PicoWriteS68k16_bram(u32 a, u32 d)
@@ -918,7 +948,6 @@ static void PicoWriteS68k16_bram(u32 a, u32 d)
   elprintf(EL_ANOMALY, "s68k_bram w16: [%06x] %04x @%06x", a, d, SekPcS68k);
   a = (a >> 1) & 0x1fff;
   Pico_mcd->bram[a++] = d;
-  Pico_mcd->bram[a++] = d >> 8; // TODO: verify..
   Pico.sv.changed = 1;
 }
 
@@ -1079,28 +1108,6 @@ static void remap_prg_window(u32 r1, u32 r3)
 // is reassigned to it (e.g. Mega Race).
 // since DTACK isn't on the expansion port, main cpu accesses are not blocked.
 // XXX is data read/written if main is accessing Word_RAM while not owning it?
-static u32 m68k_wordram_sub_read8(u32 a)
-{
-  return 0xff;
-//  return Pico_mcd->word_ram2M[MEM_BE2(a) & 0x3ffff];
-}
-
-static u32 m68k_wordram_sub_read16(u32 a)
-{
-  return 0xffff;
-//  return ((u16 *)Pico_mcd->word_ram2M)[(a >> 1) & 0x1ffff];
-}
-
-static void m68k_wordram_sub_write8(u32 a, u32 d)
-{
-//  Pico_mcd->word_ram2M[MEM_BE2(a) & 0x3ffff] = d;
-}
-
-static void m68k_wordram_sub_write16(u32 a, u32 d)
-{
-//  ((u16 *)Pico_mcd->word_ram2M)[(a >> 1) & 0x1ffff] = d;
-}
-
 static u32 s68k_wordram_main_read8(u32 a)
 {
   Pico_mcd->m.state_flags |= PCD_ST_S68K_SLEEP;
@@ -1145,9 +1152,7 @@ static void remap_word_ram(u32 r3)
     } else {
       Pico_mcd->m.state_flags &= ~PCD_ST_S68K_SLEEP;
       cpu68k_map_all_ram(0x080000, 0x0bffff, bank, 1);
-      cpu68k_map_all_funcs(0x200000, 0x23ffff,
-          m68k_wordram_sub_read8, m68k_wordram_sub_read16,
-          m68k_wordram_sub_write8, m68k_wordram_sub_write16, 0);
+      m68k_map_unmap(0x200000, 0x23ffff);
     }
     // TODO: handle 0x0c0000
   }
@@ -1236,6 +1241,7 @@ PICO_INTERNAL void PicoMemSetupCD(void)
   cpu68k_map_set(s68k_write16_map, 0xff0000, 0xffffff, PicoWriteS68k16_pr, 1);
 
   // RAMs
+  remap_prg_window(2,1);
   remap_word_ram(1);
 
 #ifdef EMU_C68K
diff --git a/pico/cd/sek.c b/pico/cd/sek.c
index baf0d9e5..9bb72829 100644
--- a/pico/cd/sek.c
+++ b/pico/cd/sek.c
@@ -32,6 +32,8 @@ static int new_irq_level(int level)
 {
   int level_new = 0, irqs;
   Pico_mcd->m.s68k_pend_ints &= ~(1 << level);
+  if (level == 2) // clear pending bit
+    Pico_mcd->m.state_flags &= ~PCD_ST_S68K_IFL2;
   irqs = Pico_mcd->m.s68k_pend_ints;
   irqs &= Pico_mcd->s68k_regs[0x33];
   while ((irqs >>= 1)) level_new++;
diff --git a/pico/pico_int.h b/pico/pico_int.h
index ac8a7ecf..578fcb65 100644
--- a/pico/pico_int.h
+++ b/pico/pico_int.h
@@ -511,6 +511,7 @@ struct mcd_pcm
 #define PCD_ST_S68K_SLEEP   4
 #define PCD_ST_S68K_POLL   16
 #define PCD_ST_M68K_POLL   32
+#define PCD_ST_S68K_IFL2   0x100
 
 struct mcd_misc
 {
-- 
2.39.5