From 1475d55da1b88c457061a56abb4d7306bc4de31d Mon Sep 17 00:00:00 2001
From: beirich <beirich@4bbf4f03-6f44-549e-7e59-35d4b0962838>
Date: Sat, 16 Jul 2011 21:09:44 +0000
Subject: [PATCH] blegh

---
 .../Consoles/PC Engine/Compat.txt             |  3 +-
 .../Consoles/PC Engine/MemoryMap.Populous.cs  | 62 +++++++++++++++++++
 2 files changed, 63 insertions(+), 2 deletions(-)
 create mode 100644 BizHawk.Emulation/Consoles/PC Engine/MemoryMap.Populous.cs

diff --git a/BizHawk.Emulation/Consoles/PC Engine/Compat.txt b/BizHawk.Emulation/Consoles/PC Engine/Compat.txt
index 9681043f30..c8c36472a1 100644
--- a/BizHawk.Emulation/Consoles/PC Engine/Compat.txt	
+++ b/BizHawk.Emulation/Consoles/PC Engine/Compat.txt	
@@ -23,7 +23,6 @@ Madoo Granzort    - Graphics issues because SGX VPC renderer is not using new fr
 MML Demo          - Echo channels are too loud (equal volume!)
 Outrun            - OK currently but timing sensitive game for future testing
 Paranoia          - Game hits BREAK on 3rd level. need to investigate
-Populous          - Game freezes on starting new game - unclear if related to battery RAM
 Power Drift       - Timing glitch... starting new game runs slower than it should
 Power Tennis      - Elaborate intro screen doesnt display right
 Raiden            - Sprites and BG get out of sync with current timing
@@ -52,7 +51,7 @@ Side Arms         - Screen is like 4 pixels too tall
 Stuff I Fixed That's Not In Other Docs:
 
 + Street Fighter II special mapper
-+ Populous has special BRAM / saveRAM (I have not yet fixed this)
++ Populous has special SaveRAM, 32k starting at page $40.
 + After Burner - There is a 1-instruction delay on changes to IRQ Control Byte taking effect
 + There is a one-instruction delay on changes to the I flag taking effect
   - Affects (Not a complete list): Blodia, Body Conquest 2, Champions Forever Boxing,
diff --git a/BizHawk.Emulation/Consoles/PC Engine/MemoryMap.Populous.cs b/BizHawk.Emulation/Consoles/PC Engine/MemoryMap.Populous.cs
new file mode 100644
index 0000000000..256b606715
--- /dev/null
+++ b/BizHawk.Emulation/Consoles/PC Engine/MemoryMap.Populous.cs	
@@ -0,0 +1,62 @@
+namespace BizHawk.Emulation.Consoles.TurboGrafx
+{
+    public partial class PCEngine
+    {
+        // The Populous HuCard is the only traditional HuCard to have battery-backed saveRAM
+        // built into it. There is 32k of save-RAM mapped at pages $40 - $44.
+        
+        private byte[] PopulousRAM;
+
+        private byte ReadMemoryPopulous(int addr)
+        {
+            if (addr >= 0x80000 && addr < 0x88000)
+                return PopulousRAM[addr & 0x7FFF];
+            
+            if (addr < 0xFFFFF) // read ROM
+                return RomData[addr % RomLength];
+
+            if (addr >= 0x1F0000 && addr < 0x1F8000) // read RAM
+                return Ram[addr & 0x1FFF];
+
+            if (addr >= 0x1FE000) // hardware page.
+            {
+                if (addr < 0x1FE400)         return VDC1.ReadVDC(addr);
+                if (addr < 0x1FE800)         { Cpu.PendingCycles--; return VCE.ReadVCE(addr); }
+                if (addr < 0x1FEC00)         return IOBuffer;
+                if (addr < 0x1FF000)         { IOBuffer = (byte)(Cpu.ReadTimerValue() | (IOBuffer & 0x80)); return IOBuffer; }
+                if (addr >= 0x1FF000 &&
+                    addr < 0x1FF400)         { IOBuffer = ReadInput(); return IOBuffer; }
+                if ((addr & ~1) == 0x1FF400) return IOBuffer;
+                if (addr == 0x1FF402)        { IOBuffer = (byte)(Cpu.IRQControlByte | (IOBuffer & 0xF8)); return IOBuffer; }
+                if (addr == 0x1FF403)        { IOBuffer = (byte)(Cpu.ReadIrqStatus() | (IOBuffer & 0xF8)); return IOBuffer; }
+            }
+
+            Log.Error("MEM", "UNHANDLED READ: {0:X6}", addr);
+            return 0xFF;
+        }
+
+        private void WriteMemoryPopulous(int addr, byte value)
+        {
+            if (addr >= 0x1F0000 && addr < 0x1F8000) // write RAM.
+                Ram[addr & 0x1FFF] = value;
+
+            else if (addr >= 0x1FE000) // hardware page.
+            {
+                     if (addr <  0x1FE400)     VDC1.WriteVDC(addr, value);
+                else if (addr <  0x1FE800)     { Cpu.PendingCycles--; VCE.WriteVCE(addr, value); }
+                else if (addr <  0x1FEC00)     { IOBuffer = value; PSG.WritePSG((byte)addr, value, Cpu.TotalExecutedCycles); }
+                else if (addr == 0x1FEC00)     { IOBuffer = value; Cpu.WriteTimer(value); }
+                else if (addr == 0x1FEC01)     { IOBuffer = value; Cpu.WriteTimerEnable(value); }
+                else if (addr >= 0x1FF000 && 
+                         addr <  0x1FF400)     { IOBuffer = value; WriteInput(value); }
+                else if (addr == 0x1FF402)     { IOBuffer = value; Cpu.WriteIrqControl(value); }
+                else if (addr == 0x1FF403)     { IOBuffer = value; Cpu.WriteIrqStatus(); }
+                else Log.Error("MEM", "unhandled hardware write [{0:X6}] : {1:X2}", addr, value);
+            }
+            else if (addr >= 0x80000 && addr < 0x88000)
+                PopulousRAM[addr & 0x7FFF] = value;
+            else 
+                Log.Error("MEM","UNHANDLED WRITE: {0:X6}:{1:X2}",addr,value);
+        }
+    }
+}
\ No newline at end of file