1 files changed, 135 insertions, 0 deletions
diff --git a/sid/sidplay-libs-2.1.0/libsidplay/src/sid6526/sid6526.cpp b/sid/sidplay-libs-2.1.0/libsidplay/src/sid6526/sid6526.cpp
new file mode 100644
index 00000000..8737f7f0
--- /dev/null
+++ b/sid/sidplay-libs-2.1.0/libsidplay/src/sid6526/sid6526.cpp
@@ -0,0 +1,135 @@
+/***************************************************************************
+                          sid6526.cpp  -  description
+                             -------------------
+    begin                : Wed Jun 7 2000
+    copyright            : (C) 2000 by Simon White
+    email                : s_a_white@email.com
+ ***************************************************************************/
+
+/***************************************************************************
+ *                                                                         *
+ *   This program is free software; you can redistribute it and/or modify  *
+ *   it under the terms of the GNU General Public License as published by  *
+ *   the Free Software Foundation; either version 2 of the License, or     *
+ *   (at your option) any later version.                                   *
+ *                                                                         *
+ ***************************************************************************/
+/***************************************************************************
+ *  $Log: sid6526.cpp,v $
+ *  Revision 1.7  2002/10/02 19:48:15  s_a_white
+ *  Make CIA control register reflect that the timer cannot be disabled.
+ *
+ *  Revision 1.6  2002/03/11 18:00:29  s_a_white
+ *  Better mirror sidplay1s handling of random numbers.
+ *
+ *  Revision 1.5  2002/03/03 22:03:49  s_a_white
+ *  Tidy.
+ *
+ *  Revision 1.4  2001/10/02 18:01:36  s_a_white
+ *  Support for cleaned c64env.
+ *
+ *  Revision 1.3  2001/09/18 02:22:37  jpaana
+ *  Fixed include filename to lowercase
+ *
+ *  Revision 1.2  2001/09/03 22:24:09  s_a_white
+ *  New counts for timer A are correctly formed.
+ *
+ *  Revision 1.1  2001/09/01 11:11:19  s_a_white
+ *  This is the old fake6526 code required for sidplay1 environment modes.
+ *
+ ***************************************************************************/
+
+#include <time.h>
+#include "sidendian.h"
+#include "sid6526.h"
+
+const char * const SID6526::credit =
+{   // Optional information
+    "*SID6526 (SIDPlay1 Fake CIA) Emulation:\0"
+    "\tCopyright (C) 2001 Simon White <sidplay2@email.com>\0"
+};
+
+SID6526::SID6526 (c64env *env)
+:m_env(*env),
+ m_eventContext(m_env.context ()),
+ rnd(0),
+ m_taEvent(*this)
+{
+    clock (0xffff);
+    reset ();
+}
+
+void SID6526::reset (void)
+{
+    locked = false;
+    ta   = ta_latch = m_count;
+    cra  = 0;
+    rnd += time(NULL) & 0xff;
+    m_accessClk = 0;
+}
+
+uint8_t SID6526::read (uint_least8_t addr)
+{
+    if (addr > 0x0f)
+        return 0;
+
+    switch (addr)
+    {
+    case 0x04:
+    case 0x05:
+    case 0x11:
+    case 0x12:
+        rnd = rnd * 13 + 1;
+        return (uint8_t) (rnd >> 3);
+    break;
+    default:
+        return regs[addr];
+    }
+}
+
+void SID6526::write (uint_least8_t addr, uint8_t data)
+{
+    if (addr > 0x0f)
+        return;
+
+    regs[addr] = data;
+
+    if (locked)
+        return; // Stop program changing time interval
+
+    {   // Sync up timer
+        event_clock_t cycles;
+        cycles       = m_eventContext.getTime (m_accessClk);
+        m_accessClk += cycles;
+        ta          -= cycles;
+    }
+
+    switch (addr)
+    {
+    case 0x4: endian_16lo8 (ta_latch, data); break;
+    case 0x5:
+        endian_16hi8 (ta_latch, data);
+        if (!(cra & 0x01)) // Reload timer if stopped
+            ta = ta_latch;
+    break;
+    case 0x0e:
+        cra = data | 0x01;
+        if (data & 0x10)
+        {
+            cra &= (~0x10);
+            ta   = ta_latch;
+        }
+        m_eventContext.schedule (&m_taEvent, (event_clock_t) ta + 1);
+    break;
+    default:
+    break;
+    }
+}
+
+void SID6526::event (void)
+{   // Timer Modes
+    m_accessClk = m_eventContext.getTime ();
+    ta = ta_latch;
+    m_eventContext.schedule (&m_taEvent, (event_clock_t) ta + 1);
+    m_env.interruptIRQ (true);
+}