From 5ac99d9adf88799fd2de3ec787409ed1f2255168 Mon Sep 17 00:00:00 2001
From: notaz <notasas@gmail.com>
Date: Wed, 14 Aug 2013 03:36:36 +0300
Subject: [PATCH] 32x: add preliminary hint emulation

---
 pico/32x/32x.c    | 31 +++++++++++++++++++++++++++++++
 pico/32x/memory.c |  6 +++---
 pico/pico_int.h   |  2 ++
 3 files changed, 36 insertions(+), 3 deletions(-)

diff --git a/pico/32x/32x.c b/pico/32x/32x.c
index f461187..0d56b98 100644
--- a/pico/32x/32x.c
+++ b/pico/32x/32x.c
@@ -228,6 +228,25 @@ static void p32x_start_blank(void)
   p32x_sh2_poll_event(&ssh2, SH2_STATE_VPOLL, 0);
 }
 
+void p32x_schedule_hint(SH2 *sh2, int m68k_cycles)
+{
+  // rather rough, 32x hint is useless in practice
+  int after;
+
+  if (!((Pico32x.sh2irq_mask[0] | Pico32x.sh2irq_mask[1]) & 4))
+    return; // nobody cares
+  // note: when Pico.m.scanline is 224, SH2s might
+  // still be at scanline 93 (or so)
+  if (!(Pico32x.sh2_regs[0] & 0x80) && Pico.m.scanline > 224)
+    return;
+
+  after = (Pico32x.sh2_regs[4 / 2] + 1) * 488;
+  if (sh2 != NULL)
+    p32x_event_schedule_sh2(sh2, P32X_EVENT_HINT, after);
+  else
+    p32x_event_schedule(m68k_cycles, P32X_EVENT_HINT, after);
+}
+
 // compare cycles, handling overflows
 // check if a > b
 #define CYCLES_GT(a, b) \
@@ -244,6 +263,13 @@ static void fillend_event(unsigned int now)
   p32x_sh2_poll_event(&ssh2, SH2_STATE_VPOLL, now);
 }
 
+static void hint_event(unsigned int now)
+{
+  Pico32x.sh2irqs |= P32XI_HINT;
+  p32x_update_irls(NULL, now);
+  p32x_schedule_hint(NULL, now);
+}
+
 typedef void (event_cb)(unsigned int now);
 
 unsigned int event_times[P32X_EVENT_COUNT];
@@ -251,6 +277,7 @@ static unsigned int event_time_next;
 static event_cb *event_cbs[] = {
   [P32X_EVENT_PWM]      = p32x_pwm_irq_event,
   [P32X_EVENT_FILLEND]  = fillend_event,
+  [P32X_EVENT_HINT]     = hint_event,
 };
 
 // schedule event at some time 'after', in m68k clocks
@@ -481,10 +508,14 @@ void sync_sh2s_lockstep(unsigned int m68k_target)
 
 void PicoFrame32x(void)
 {
+  Pico.m.scanline = 0;
+
   Pico32x.vdp_regs[0x0a/2] &= ~P32XV_VBLK; // get out of vblank
   if ((Pico32x.vdp_regs[0] & P32XV_Mx) != 0) // no forced blanking
     Pico32x.vdp_regs[0x0a/2] &= ~P32XV_PEN; // no palette access
 
+  if (!(Pico32x.sh2_regs[0] & 0x80))
+    p32x_schedule_hint(NULL, SekCyclesDoneT2());
   p32x_sh2_poll_event(&msh2, SH2_STATE_VPOLL, 0);
   p32x_sh2_poll_event(&ssh2, SH2_STATE_VPOLL, 0);
 
diff --git a/pico/32x/memory.c b/pico/32x/memory.c
index c40a3fd..5d882e3 100644
--- a/pico/32x/memory.c
+++ b/pico/32x/memory.c
@@ -635,13 +635,13 @@ static void p32x_sh2reg_write8(u32 a, u32 d, SH2 *sh2)
       Pico32x.regs[0] |= (d << 8) & P32XS_FM;
       return;
     case 1: // HEN/irq masks
-      if ((d ^ Pico32x.sh2_regs[0]) & 0x80)
-        elprintf(EL_ANOMALY|EL_32X, "HEN");
-      Pico32x.sh2irq_mask[sh2->is_slave] = d & 0x8f;
+      Pico32x.sh2irq_mask[sh2->is_slave] = d & 0x0f;
       Pico32x.sh2_regs[0] &= ~0x80;
       Pico32x.sh2_regs[0] |= d & 0x80;
       if (d & 1)
         p32x_pwm_schedule_sh2(sh2);
+      if (d & 4)
+        p32x_schedule_hint(sh2, 0); 
       p32x_update_irls(sh2, 0);
       return;
     case 5: // H count
diff --git a/pico/pico_int.h b/pico/pico_int.h
index bba13c9..aa8e497 100644
--- a/pico/pico_int.h
+++ b/pico/pico_int.h
@@ -749,6 +749,7 @@ extern struct Pico32x Pico32x;
 enum p32x_event {
   P32X_EVENT_PWM,
   P32X_EVENT_FILLEND,
+  P32X_EVENT_HINT,
   P32X_EVENT_COUNT,
 };
 extern unsigned int event_times[P32X_EVENT_COUNT];
@@ -766,6 +767,7 @@ void p32x_update_irls(SH2 *active_sh2, int m68k_cycles);
 void p32x_reset_sh2s(void);
 void p32x_event_schedule(unsigned int now, enum p32x_event event, int after);
 void p32x_event_schedule_sh2(SH2 *sh2, enum p32x_event event, int after);
+void p32x_schedule_hint(SH2 *sh2, int m68k_cycles);
 
 // 32x/memory.c
 struct Pico32xMem *Pico32xMem;
-- 
2.39.2