From 62b9f51e2329507d5e47b4239259067b5fb66240 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Rapha=C3=ABl=20Zumer?= <rzumer@tebako.net>
Date: Sun, 8 Dec 2019 17:56:22 -0500
Subject: [PATCH] Handle GBA cartridge SRAM writes

---
 src/GBACart.cpp | 54 +++++++++++++++++++++++++++++++++++++++++++++++++
 src/GBACart.h   |  4 ++++
 src/NDS.cpp     | 48 +++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 106 insertions(+)

diff --git a/src/GBACart.cpp b/src/GBACart.cpp
index 8ce76ab0..10f51066 100644
--- a/src/GBACart.cpp
+++ b/src/GBACart.cpp
@@ -104,6 +104,60 @@ void RelocateSave(const char* path, bool write)
     fclose(f);
 }
 
+void Write8(u32 addr, u8 val)
+{
+    u8 prev = *(u8*)&SRAM[addr];
+
+    if (prev != val)
+    {
+        *(u8*)&SRAM[addr] = val;/*
+
+        FILE* f = Platform::OpenFile(SRAMPath, "r+b");
+        if (f)
+        {
+            fseek(f, addr, SEEK_SET);
+            fwrite((u8*)&SRAM[addr], 1, 1, f);
+            fclose(f);
+        }*/
+    }
+}
+
+void Write16(u32 addr, u16 val)
+{
+    u16 prev = *(u16*)&SRAM[addr];
+
+    if (prev != val)
+    {
+        *(u16*)&SRAM[addr] = val;/*
+
+        FILE* f = Platform::OpenFile(SRAMPath, "r+b");
+        if (f)
+        {
+            fseek(f, addr, SEEK_SET);
+            fwrite((u8*)&SRAM[addr], 2, 1, f);
+            fclose(f);
+        }*/
+    }
+}
+
+void Write32(u32 addr, u32 val)
+{
+    u32 prev = *(u32*)&SRAM[addr];
+
+    if (prev != val)
+    {
+        *(u32*)&SRAM[addr] = val;/*
+
+        FILE* f = Platform::OpenFile(SRAMPath, "r+b");
+        if (f)
+        {
+            fseek(f, addr, SEEK_SET);
+            fwrite((u8*)&SRAM[addr], 3, 1, f);
+            fclose(f);
+        }*/
+    }
+}
+
 }
 
 
diff --git a/src/GBACart.h b/src/GBACart.h
index 94da0b27..e86ea43d 100644
--- a/src/GBACart.h
+++ b/src/GBACart.h
@@ -29,6 +29,10 @@ namespace GBACart_SRAM
 extern u8* SRAM;
 extern u32 SRAMLength;
 
+void Write8(u32 addr, u8 val);
+void Write16(u32 addr, u16 val);
+void Write32(u32 addr, u32 val);
+
 }
 
 
diff --git a/src/NDS.cpp b/src/NDS.cpp
index da36bdc6..fe66814f 100644
--- a/src/NDS.cpp
+++ b/src/NDS.cpp
@@ -1802,6 +1802,14 @@ void ARM9Write8(u32 addr, u8 val)
     case 0x07000000:
         // checkme
         return;
+
+    case 0x0A000000:
+        if (ExMemCnt[0] & (1<<7)) return; // deselected CPU, skip the write
+        if (GBACart::CartInserted)
+        {
+            GBACart_SRAM::Write8(addr & (GBACart_SRAM::SRAMLength-1), val);
+        }
+        return;
     }
 
     printf("unknown arm9 write8 %08X %02X\n", addr, val);
@@ -1845,6 +1853,14 @@ void ARM9Write16(u32 addr, u16 val)
         if (!(PowerControl9 & ((addr & 0x400) ? (1<<9) : (1<<1)))) return;
         *(u16*)&GPU::OAM[addr & 0x7FF] = val;
         return;
+
+    case 0x0A000000:
+        if (ExMemCnt[0] & (1<<7)) return; // deselected CPU, skip the write
+        if (GBACart::CartInserted)
+        {
+            GBACart_SRAM::Write16(addr & (GBACart_SRAM::SRAMLength-1), val);
+        }
+        return;
     }
 
     //printf("unknown arm9 write16 %08X %04X\n", addr, val);
@@ -1888,6 +1904,14 @@ void ARM9Write32(u32 addr, u32 val)
         if (!(PowerControl9 & ((addr & 0x400) ? (1<<9) : (1<<1)))) return;
         *(u32*)&GPU::OAM[addr & 0x7FF] = val;
         return;
+
+    case 0x0A000000:
+        if (ExMemCnt[0] & (1<<7)) return; // deselected CPU, skip the write
+        if (GBACart::CartInserted)
+        {
+            GBACart_SRAM::Write32(addr & (GBACart_SRAM::SRAMLength-1), val);
+        }
+        return;
     }
 
     printf("unknown arm9 write32 %08X %08X | %08X\n", addr, val, ARM9->R[15]);
@@ -2152,6 +2176,14 @@ void ARM7Write8(u32 addr, u8 val)
     case 0x06800000:
         GPU::WriteVRAM_ARM7<u8>(addr, val);
         return;
+
+    case 0x0A000000:
+        if (!(ExMemCnt[0] & (1<<7))) return; // deselected CPU, skip the write
+        if (GBACart::CartInserted)
+        {
+            GBACart_SRAM::Write8(addr & (GBACart_SRAM::SRAMLength-1), val);
+        }
+        return;
     }
 
     printf("unknown arm7 write8 %08X %02X @ %08X\n", addr, val, ARM7->R[15]);
@@ -2198,6 +2230,14 @@ void ARM7Write16(u32 addr, u16 val)
     case 0x06800000:
         GPU::WriteVRAM_ARM7<u16>(addr, val);
         return;
+
+    case 0x0A000000:
+        if (!(ExMemCnt[0] & (1<<7))) return; // deselected CPU, skip the write
+        if (GBACart::CartInserted)
+        {
+            GBACart_SRAM::Write16(addr & (GBACart_SRAM::SRAMLength-1), val);
+        }
+        return;
     }
 
     //printf("unknown arm7 write16 %08X %04X @ %08X\n", addr, val, ARM7->R[15]);
@@ -2245,6 +2285,14 @@ void ARM7Write32(u32 addr, u32 val)
     case 0x06800000:
         GPU::WriteVRAM_ARM7<u32>(addr, val);
         return;
+
+    case 0x0A000000:
+        if (!(ExMemCnt[0] & (1<<7))) return; // deselected CPU, skip the write
+        if (GBACart::CartInserted)
+        {
+            GBACart_SRAM::Write32(addr & (GBACart_SRAM::SRAMLength-1), val);
+        }
+        return;
     }
 
     //printf("unknown arm7 write32 %08X %08X @ %08X\n", addr, val, ARM7->R[15]);