From e63fb66b40103c427febfa0b1a8c4119fa4e1a35 Mon Sep 17 00:00:00 2001
From: qeed <qeed@users.sf.net>
Date: Mon, 19 Oct 2009 10:18:20 +0000
Subject: [PATCH] [ES-1064] Qi Long Zhu (C) should be mostly playable now,
 still some graphic glitches though

---
 src/mappers/253.cpp | 25 ++++++++++++-------------
 1 file changed, 12 insertions(+), 13 deletions(-)

diff --git a/src/mappers/253.cpp b/src/mappers/253.cpp
index 964730a3..9fc52b8e 100644
--- a/src/mappers/253.cpp
+++ b/src/mappers/253.cpp
@@ -8,12 +8,16 @@ static int32 irq_enable, irq_counter, irq_latch, irq_clock;
 
 static void Mapper253_IRQHook(int cycles)
 {
+    //basically, this happens at every frame
+    //0x72 is 114 cycles, so like one scanline
+    //happens for 0xff scanlines so 256 scanlines (frame)
     if( irq_enable & 0x02 ) 
     {
         if( (irq_clock+=cycles) >= 0x72 ) 
         {
             irq_clock -= 0x72;
-            if( irq_counter == 0xFF ) 
+            
+            if( irq_counter == 0xFF)  
             {
                 irq_counter = irq_latch;
                 irq_enable = (irq_enable & 0x01) * 3;
@@ -40,22 +44,20 @@ static void	SetBank_PPUSUB(int bank, int page)
     }
     if ((page == 4) || (page == 5)) 
     {
-        printf("Page in 4 5: %d\n", page);
-        if(VRAM_switch == 0)
-            setchr1( bank << 10, page ); //CHR-ROM
-        else 
-            setchr1( bank << 10, page ); //CHR-RAM
+        // [ES-1064] Qi Long Zhu (C).NES game uses CHR-RAM for these pages
+        //and doesn't seem to set VRAM switch so use
+        //CHR-RAM as default for now
+        //if (VRAM_switch == 0)
+        //    setchr1(bank << 10, page); //CHR-ROM
+        else
+            setvramb1(&CHRRAM[page << 10], page << 10, 0); //CHR-RAM
     } 
     else 
-	{
-		printf("Page: %d\n", page);
         setchr1(bank << 10, page);
-	}
 }
 
 static DECLFW(Mapper253_Write)
 {
-    printf("Address: 0x%X V: 0x%X\n", A, V);
     if (A == 0x8010) //8kb select at 0x8000
     {
         setprg8(0x8000, V);
@@ -169,9 +171,6 @@ static DECLFW(Mapper253_Write)
             }
             X6502_IRQEnd(FCEU_IQEXT);
             break;
-        default:
-			break;
-            //printf("Not handled 0x%X 0x%X", A, V);
     }
 }