From 57273620e6e61f6691c41d29745cece7a3110ac3 Mon Sep 17 00:00:00 2001
From: Gregory Alexander <yakovlev@grandecom.net>
Date: Thu, 7 Feb 2002 21:22:55 +0000
Subject: [PATCH] Added an experimental realtime PIT to the mix.

This is basically the opposite of the slowdown timer.  Instead
of trying to keep the PIT ticks in sync with bochs time, we
keep them in sync with REAL time.  This is bad because it creates
unreproducible fails, but it's good if you want to run bochs at
maximum speed on your machine.  However, bochs will take all of
the available resources from the machine also.

DO NOT use this with the slowdown timer.  Results would be
unpredictable.
---
 bochs/config.h.in       |  1 +
 bochs/iodev/pit_wrap.cc | 79 ++++++++++++++++++++++++++++++++++++++---
 bochs/iodev/pit_wrap.h  | 14 ++++++--
 3 files changed, 88 insertions(+), 6 deletions(-)

diff --git a/bochs/config.h.in b/bochs/config.h.in
index 9ae64c610..62025491c 100644
--- a/bochs/config.h.in
+++ b/bochs/config.h.in
@@ -184,6 +184,7 @@
 
 // Use Greg Alexander's new PIT model (summer 2001) instead of the original.
 #define BX_USE_NEW_PIT 0
+#define BX_USE_REALTIME_PIT 0
 
 #define BX_USE_SLOWDOWN_TIMER 0
 #define BX_HAVE_SLEEP 0
diff --git a/bochs/iodev/pit_wrap.cc b/bochs/iodev/pit_wrap.cc
index 0f26bca12..f0fdaa21e 100644
--- a/bochs/iodev/pit_wrap.cc
+++ b/bochs/iodev/pit_wrap.cc
@@ -1,5 +1,5 @@
 /////////////////////////////////////////////////////////////////////////
-// $Id: pit_wrap.cc,v 1.13 2002-01-31 17:26:26 yakovlev Exp $
+// $Id: pit_wrap.cc,v 1.14 2002-02-07 21:22:55 yakovlev Exp $
 /////////////////////////////////////////////////////////////////////////
 //
 //  Copyright (C) 2002  MandrakeSoft S.A.
@@ -42,12 +42,27 @@ bx_pit_c bx_pit;
 #  undef OUT
 #endif
 
+#define TIME_DIVIDER (4)
+#define TIME_MULTIPLIER (1)
+#define TIME_HEADSTART (1)
+//USEC_ALPHA is multiplier for the past.
+//USEC_ALPHA_B is 1-USEC_ALPHA, or multiplier for the present.
+#define USEC_ALPHA (.8)
+#define USEC_ALPHA_B (.2)
+
 //How many timer ticks per usecond.
 //1.193181MHz Clock
 //1193/1000 Ticks Per usecond.
+#define TICKS_PER_SECOND (1193181)
+#define USEC_PER_SECOND (1000000)
 #define TIME_MULT 1.193
-#define TICKS_TO_USEC(a) ( ((a)*1000000)/1193181 )
-#define USEC_TO_TICKS(a) ( ((a)*1193181)/1000000 )
+#if BX_USE_REALTIME_PIT
+#  define TICKS_TO_USEC(a) ( ((a)*BX_PIT_THIS s.usec_per_second)/BX_PIT_THIS s.ticks_per_second )
+#  define USEC_TO_TICKS(a) ( ((a)*BX_PIT_THIS s.ticks_per_second)/BX_PIT_THIS s.usec_per_second )
+#else
+#  define TICKS_TO_USEC(a) ( ((a)*USEC_PER_SECOND)/TICKS_PER_SECOND )
+#  define USEC_TO_TICKS(a) ( ((a)*TICKS_PER_SECOND)/USEC_PER_SECOND )
+#endif
 #define MAX(a,b) ( ((a)>(b))?(a):(b) )
 
 bx_pit_c::bx_pit_c( void )
@@ -105,9 +120,17 @@ bx_pit_c::init( bx_devices_c *d )
   BX_PIT_THIS s.last_next_event_time = BX_PIT_THIS s.timer.get_next_event_time();
   BX_PIT_THIS s.last_usec=bx_pc_system.time_usec();
 
-  BX_PIT_THIS s.total_usec=0;
   BX_PIT_THIS s.total_ticks=0;
 
+#if BX_USE_REALTIME_PIT
+  BX_PIT_THIS s.usec_per_second=USEC_PER_SECOND;
+  BX_PIT_THIS s.ticks_per_second=TICKS_PER_SECOND;
+  BX_PIT_THIS s.total_sec=0;
+  BX_PIT_THIS s.last_time=(time(NULL)*TIME_MULTIPLIER/TIME_DIVIDER)+TIME_HEADSTART;
+#else
+  BX_PIT_THIS s.total_usec=0;
+#endif
+
   BX_DEBUG(("pit: finished init"));
 
   BX_DEBUG(("s.last_usec=%d",BX_PIT_THIS s.last_usec));
@@ -360,6 +383,11 @@ bx_pit_c::periodic( Bit32u   usec_delta )
   Boolean want_interrupt = 0;
   Bit32u ticks_delta = 0;
 
+#if BX_USE_REALTIME_PIT
+  ticks_delta=(Bit32u)(USEC_TO_TICKS(usec_delta));
+  BX_PIT_THIS s.total_ticks += ticks_delta;
+  second_update_data();
+#else
   BX_PIT_THIS s.total_usec += usec_delta;
   ticks_delta=(Bit32u)((USEC_TO_TICKS((Bit64u)(BX_PIT_THIS s.total_usec)))-BX_PIT_THIS s.total_ticks);
   BX_PIT_THIS s.total_ticks += ticks_delta;
@@ -368,6 +396,7 @@ bx_pit_c::periodic( Bit32u   usec_delta )
     BX_PIT_THIS s.total_ticks -= 1193181;
     BX_PIT_THIS s.total_usec  -= 1000000;
   }
+#endif
 
   while(ticks_delta>0) {
     Bit32u maxchange=BX_PIT_THIS s.timer.get_next_event_time();
@@ -394,4 +423,46 @@ bx_pit_c::periodic( Bit32u   usec_delta )
   return(want_interrupt);
 }
 
+
+#if BX_USE_REALTIME_PIT
+void
+bx_pit_c::second_update_data(void) {
+  Bit64u timediff=(time(NULL)*TIME_MULTIPLIER/TIME_DIVIDER)-BX_PIT_THIS s.last_time;
+  BX_PIT_THIS s.last_time += timediff;
+  if(timediff) {
+    Bit64s tickstemp;
+
+    BX_PIT_THIS s.total_sec += timediff;
+
+    if(timediff==1) printf("1\n");
+
+    printf("timediff: %lld, total_sec: %lld, total_ticks: %lld\n",timediff, BX_PIT_THIS s.total_sec, BX_PIT_THIS s.total_ticks);
+
+    tickstemp = 
+      (((BX_PIT_THIS s.total_sec)*TICKS_PER_SECOND)-BX_PIT_THIS s.total_ticks)
+       + TICKS_PER_SECOND;
+
+//    while((BX_PIT_THIS s.total_sec >= 0) && (BX_PIT_THIS s.total_ticks >= TICKS_PER_SECOND)) {
+//      BX_PIT_THIS s.total_sec -= 1;
+//      BX_PIT_THIS s.total_ticks -= TICKS_PER_SECOND;
+//    }
+
+    if(tickstemp > (TICKS_PER_SECOND*1.5)) {
+      printf("Running WAY too slow. tps:%lld\n",tickstemp);
+      tickstemp = TICKS_PER_SECOND*1.5;
+      printf("..................... tps:%lld\n",tickstemp);
+    } else if(tickstemp < (TICKS_PER_SECOND*0.5)) {
+      printf("Running WAY too fast. tps:%lld\n",tickstemp);
+      tickstemp = TICKS_PER_SECOND*0.5;
+      printf("..................... tps:%lld\n",tickstemp);
+    }
+
+    BX_PIT_THIS s.ticks_per_second = tickstemp;
+
+    BX_PIT_THIS s.usec_per_second = ((bx_pc_system.time_usec()-BX_PIT_THIS s.last_sec_usec)/timediff)*USEC_ALPHA_B + USEC_ALPHA*BX_PIT_THIS s.usec_per_second;
+    BX_PIT_THIS s.last_sec_usec = bx_pc_system.time_usec();
+    printf("Parms: ticks_per_second=%lld, usec_per_second=%lld\n",BX_PIT_THIS s.ticks_per_second, BX_PIT_THIS s.usec_per_second);
+  }
+}
+#endif // #if BX_USE_REALTIME_PIT
 #endif // #if BX_USE_NEW_PIT
diff --git a/bochs/iodev/pit_wrap.h b/bochs/iodev/pit_wrap.h
index 091f4f18c..366ccd8db 100644
--- a/bochs/iodev/pit_wrap.h
+++ b/bochs/iodev/pit_wrap.h
@@ -1,5 +1,5 @@
 /////////////////////////////////////////////////////////////////////////
-// $Id: pit_wrap.h,v 1.7 2002-01-31 16:52:00 yakovlev Exp $
+// $Id: pit_wrap.h,v 1.8 2002-02-07 21:22:55 yakovlev Exp $
 /////////////////////////////////////////////////////////////////////////
 //
 //  Copyright (C) 2001  MandrakeSoft S.A.
@@ -71,8 +71,16 @@ private:
     int  timer_handle[3];
     Bit64u last_usec;
     Bit32u last_next_event_time;
-    Bit64u total_usec;
     Bit64u total_ticks;
+#if BX_USE_REALTIME_PIT
+    Bit64u usec_per_second;
+    Bit64u ticks_per_second;
+    Bit64u total_sec;
+    Bit64u last_time;
+    Bit64u last_sec_usec;
+#else
+    Bit64u total_usec;
+#endif
     } s;
 
   bx_devices_c *devices;
@@ -85,6 +93,8 @@ private:
   BX_PIT_SMF void  latch( unsigned timerid );
   BX_PIT_SMF void  set_GATE(unsigned pit_id, unsigned value);
   BX_PIT_SMF void  start(unsigned timerid);
+
+  BX_PIT_SMF void  second_update_data(void);
 };
 
 extern bx_pit_c bx_pit;