From: notaz <notasas@gmail.com>
Date: Fri, 4 Oct 2013 20:24:36 +0000 (+0300)
Subject: cd: fix cycle overflow issue
X-Git-Tag: v1.91~18
X-Git-Url: https://notaz.gp2x.de/cgi-bin/gitweb.cgi?p=picodrive.git;a=commitdiff_plain;h=a6523294e28d7e6c119a578eb65b91af8da77f8d

cd: fix cycle overflow issue
---

diff --git a/pico/32x/32x.c b/pico/32x/32x.c
index b8a84d9..26162e4 100644
--- a/pico/32x/32x.c
+++ b/pico/32x/32x.c
@@ -547,6 +547,9 @@ void PicoFrame32x(void)
   p32x_sh2_poll_event(&msh2, SH2_STATE_VPOLL, 0);
   p32x_sh2_poll_event(&ssh2, SH2_STATE_VPOLL, 0);
 
+  if (PicoAHW & PAHW_MCD)
+    pcd_prepare_frame();
+
   PicoFrameStart();
   PicoFrameHints();
   sh2_drc_frame();
diff --git a/pico/cd/mcd.c b/pico/cd/mcd.c
index 8451a1c..24e99e4 100644
--- a/pico/cd/mcd.c
+++ b/pico/cd/mcd.c
@@ -11,7 +11,9 @@
 
 extern unsigned char formatted_bram[4*0x10];
 
-static unsigned int m68k_cycle_mult;
+static unsigned int mcd_m68k_cycle_mult;
+static unsigned int mcd_m68k_cycle_base;
+static unsigned int mcd_s68k_cycle_base;
 
 void (*PicoMCDopenTray)(void) = NULL;
 void (*PicoMCDcloseTray)(void) = NULL;
@@ -116,14 +118,14 @@ static void pcd_set_cycle_mult(void)
 {
   // ~1.63 for NTSC, ~1.645 for PAL
   if (Pico.m.pal)
-    m68k_cycle_mult = ((12500000ull << 16) / (50*312*488));
+    mcd_m68k_cycle_mult = ((12500000ull << 16) / (50*312*488));
   else
-    m68k_cycle_mult = ((12500000ull << 16) / (60*262*488)) + 1;
+    mcd_m68k_cycle_mult = ((12500000ull << 16) / (60*262*488)) + 1;
 }
 
 unsigned int pcd_cycles_m68k_to_s68k(unsigned int c)
 {
-  return (long long)c * m68k_cycle_mult >> 16;
+  return (long long)c * mcd_m68k_cycle_mult >> 16;
 }
 
 /* events */
@@ -234,10 +236,13 @@ static void pcd_run_events(unsigned int until)
 int pcd_sync_s68k(unsigned int m68k_target, int m68k_poll_sync)
 {
   #define now SekCycleCntS68k
-  unsigned int s68k_target =
-    (unsigned long long)m68k_target * m68k_cycle_mult >> 16;
+  unsigned int s68k_target;
   unsigned int target;
 
+  target = m68k_target - mcd_m68k_cycle_base;
+  s68k_target = mcd_s68k_cycle_base +
+    ((unsigned long long)target * mcd_m68k_cycle_mult >> 16);
+
   elprintf(EL_CD, "s68k sync to %u, %u->%u",
     m68k_target, now, s68k_target);
 
@@ -307,12 +312,21 @@ void pcd_run_cpus_lockstep(int m68k_cycles)
 #include "../pico_cmn.c"
 
 
+void pcd_prepare_frame(void)
+{
+  pcd_set_cycle_mult();
+
+  // need this because we can't have direct mapping between
+  // master<->slave cycle counters because of overflows
+  mcd_m68k_cycle_base = SekCycleAim;
+  mcd_s68k_cycle_base = SekCycleAimS68k;
+}
+
 PICO_INTERNAL void PicoFrameMCD(void)
 {
-  if (!(PicoOpt&POPT_ALT_RENDERER))
-    PicoFrameStart();
+  PicoFrameStart();
 
-  pcd_set_cycle_mult();
+  pcd_prepare_frame();
   PicoFrameHints();
 }
 
diff --git a/pico/pico.c b/pico/pico.c
index 6888080..8535d48 100644
--- a/pico/pico.c
+++ b/pico/pico.c
@@ -285,8 +285,11 @@ int z80_scanline_cycles;  /* cycles done until z80_scanline */
 /* sync z80 to 68k */
 PICO_INTERNAL void PicoSyncZ80(unsigned int m68k_cycles_done)
 {
+  int m68k_cnt;
   int cnt;
-  z80_cycle_aim += cycles_68k_to_z80(m68k_cycles_done - last_z80_sync);
+
+  m68k_cnt = m68k_cycles_done - last_z80_sync;
+  z80_cycle_aim += cycles_68k_to_z80(m68k_cnt);
   cnt = z80_cycle_aim - z80_cycle_cnt;
   last_z80_sync = m68k_cycles_done;
 
diff --git a/pico/pico_int.h b/pico/pico_int.h
index 41dc59d..a8bf7ee 100644
--- a/pico/pico_int.h
+++ b/pico/pico_int.h
@@ -664,6 +664,7 @@ enum pcd_event {
 extern unsigned int pcd_event_times[PCD_EVENT_COUNT];
 void pcd_event_schedule(unsigned int now, enum pcd_event event, int after);
 void pcd_event_schedule_s68k(enum pcd_event event, int after);
+void pcd_prepare_frame(void);
 unsigned int pcd_cycles_m68k_to_s68k(unsigned int c);
 int  pcd_sync_s68k(unsigned int m68k_target, int m68k_poll_sync);
 void pcd_run_cpus(int m68k_cycles);