From 36a1ce556beb972a6bb8827906b33b145c817e30 Mon Sep 17 00:00:00 2001
From: cyberwarriorx <cyberwarriorx@users.sf.net>
Date: Mon, 27 Nov 2006 20:11:20 +0000
Subject: [PATCH] -Rewrote the framebuffer code. Now it supports VRAM blocks
 A-D -Added support for Display Mode 0(Display Off) -Added the basic framework
 for Display Mode 3(Display from Main RAM)

---
 desmume/src/GPU.c | 27 ++++++++++++++++++++++++---
 desmume/src/GPU.h | 42 ++++++++++++++++++++++++++++++------------
 2 files changed, 54 insertions(+), 15 deletions(-)

diff --git a/desmume/src/GPU.c b/desmume/src/GPU.c
index 498dfbf15..4ac57af66 100644
--- a/desmume/src/GPU.c
+++ b/desmume/src/GPU.c
@@ -2,6 +2,8 @@
     yopyop156@ifrance.com
     yopyop156.ifrance.com
 
+    Copyright (C) 2006 Theo Berkau
+
     This file is part of DeSmuME
 
     DeSmuME is free software; you can redistribute it and/or modify
@@ -123,11 +125,30 @@ void GPU_DeInit(GPU * gpu)
      free(gpu);
 }
 
-/* NOTICE: the name of function is unclear, but it's about writing in DISPLAY_CR */
+/* Sets up LCD control variables for Display Engines A and B for quick reading */
 void GPU_setVideoProp(GPU * gpu, u32 p)
 {
 	gpu->prop = p;
-	
+
+        gpu->dispMode = p >> 16;
+        if (gpu->lcd == 0)
+           gpu->dispMode &= 0x3;
+        else
+           gpu->dispMode &= 0x1;
+        switch (gpu->dispMode)
+        {
+           case 0: // Display Off
+              return;
+           case 1: // Display BG and OBJ layers
+              break;
+           case 2: // Display framebuffer
+              gpu->vramBlock = (p >> 18) & 0x3;
+              return;
+           case 3: // Display from Main RAM
+              LOG("FIXME: Display Mode 3 not supported(Display from Main RAM)\n");
+              return;
+        }
+
 	gpu->nbBGActif = 0;
 	if(p & DISPLAY_SPR_1D_LAYOUT)
 	{
@@ -1127,7 +1148,7 @@ void sprite2D(GPU * gpu, u16 l, u8 * dst, u8 * prioTab)
           size sprSize = sprSizeTab[(aux->attr1>>14)][(aux->attr0>>14)];
           
           u32 lg = sprSize.x;
-          
+
           if(sprY>192)
                sprY = (s32)((s8)(aux->attr0 & 0xFF));
 
diff --git a/desmume/src/GPU.h b/desmume/src/GPU.h
index bca2ee99b..861a8ee73 100644
--- a/desmume/src/GPU.h
+++ b/desmume/src/GPU.h
@@ -2,6 +2,8 @@
     yopyop156@ifrance.com
     yopyop156.ifrance.com
 
+    Copyright (C) 2006 Theo Berkau
+
     This file is part of DeSmuME
 
     DeSmuME is free software; you can redistribute it and/or modify
@@ -80,7 +82,10 @@ struct _GPU
 
        u8 lcd;
 		 u8 core;
-       
+
+       u8 dispMode;
+       u8 vramBlock;
+
        u8 nbBGActif;
        u8 BGIndex[4];
        u8 ordre[4];
@@ -137,20 +142,33 @@ static INLINE void GPU_ligne(Screen * screen, u16 l)
      u8 i8;
      u16 i16;
 
-     /* FIXME I've just quickly added mic's framebuffer patch here.
-      * I'm really not sure it's correct.
-      */
-     if (gpu->lcd == 0) {
-        u32 mainlcdcnt = T1ReadLong(ARM9Mem.ARM9_REG, 0);
-        int ii = l * 256;
-
-        if ((mainlcdcnt & 0x10000) == 0) {
-           for (i=0; i<256; i++) {
-	       T2WriteWord(dst, i << 1, T1ReadWord(ARM9Mem.ARM9_LCD, ii << 1));
-               ii++;
+     // This could almost be changed to use function pointers
+     switch (gpu->dispMode)
+     {
+        case 1: // Display BG and OBJ layers
+           break;
+        case 0: // Display Off(Display white)
+        {
+           for (i=0; i<256; i++)
+           {
+              T2WriteWord(dst, i << 1, 0x7FFF);
            }
            return;
         }
+        case 2: // Display framebuffer
+        {
+           int ii = l * 256 * 2;
+           for (i=0; i<(256 * 2); i+=2)
+           {
+              u8 * vram = ARM9Mem.ARM9_LCD + (gpu->vramBlock * 0x20000);
+
+              T2WriteWord(dst, i, T1ReadWord(vram, ii));
+              ii+=2;
+           }
+           return;
+        }
+        case 3: // Display from Main RAM(FIX ME)
+           return;
      }
      
      u32 c = T1ReadWord(ARM9Mem.ARM9_VMEM, gpu->lcd * 0x400);