From 64e020182a84740fd1aa90b717f578920143f535 Mon Sep 17 00:00:00 2001
From: Gericom <fnouwt2@gmail.com>
Date: Sat, 27 Dec 2025 12:44:00 +0100
Subject: [PATCH] Added check to CardiTaskThreadPatch that the required slot is
 actually mapped to arm7. Fixes #60

---
 .../patches/arm7/CardiTaskThreadPatchAsm.h    |  1 +
 .../patches/arm7/CardiTaskThreadPatchAsm.s    | 70 +++++++++----------
 arm9/source/patches/arm7/VerifySaveAsm.s      |  8 +--
 .../arm7/sdk2to4/CardiTaskThreadPatch.cpp     | 10 +++
 .../arm7/sdk5/CardiDoTaskFromArm9Patch.cpp    | 10 +++
 arm9/source/patches/platform/LoaderPlatform.h |  5 ++
 .../patches/platform/LoaderPlatformType.h     | 11 +++
 .../platform/ace3ds/Ace3DSLoaderPlatform.h    |  2 +
 .../acekard-common/IoRPGLoaderPlatform.h      |  2 +
 .../platform/dspico/DSPicoLoaderPlatform.h    |  2 +
 .../platform/dstt/DSTTLoaderPlatform.h        |  2 +
 .../patches/platform/ezp/EZPLoaderPlatform.h  |  2 +
 .../platform/g003/G003LoaderPlatform.h        |  2 +
 .../platform/isnitro/IsNitroLoaderPlatform.h  |  2 +
 .../platform/m3ds/M3DSLoaderPlatform.h        |  2 +
 .../platform/melonds/MelonDSLoaderPlatform.h  |  2 +
 .../patches/platform/r4/R4LoaderPlatform.h    |  2 +
 .../supercard/SuperCardLoaderPlatform.h       |  2 +
 18 files changed, 95 insertions(+), 42 deletions(-)
 create mode 100644 arm9/source/patches/platform/LoaderPlatformType.h

diff --git a/arm9/source/patches/arm7/CardiTaskThreadPatchAsm.h b/arm9/source/patches/arm7/CardiTaskThreadPatchAsm.h
index 29ac1b7..b67be3c 100644
--- a/arm9/source/patches/arm7/CardiTaskThreadPatchAsm.h
+++ b/arm9/source/patches/arm7/CardiTaskThreadPatchAsm.h
@@ -8,6 +8,7 @@ extern "C" void __patch_carditaskthread_entry_sdk4();
 
 extern u16 __patch_carditaskthread_mov_cardicommon_to_r4;
 extern u16 __patch_carditaskthread_mov_command_to_r0;
+extern u16 __patch_carditaskthread_lsls_exmemstat_bit_to_r1;
 
 extern u32 __patch_carditaskthread_failoffset;
 extern u32 __patch_carditaskthread_successoffset;
diff --git a/arm9/source/patches/arm7/CardiTaskThreadPatchAsm.s b/arm9/source/patches/arm7/CardiTaskThreadPatchAsm.s
index 22de3ba..64a7c03 100644
--- a/arm9/source/patches/arm7/CardiTaskThreadPatchAsm.s
+++ b/arm9/source/patches/arm7/CardiTaskThreadPatchAsm.s
@@ -21,30 +21,34 @@ __patch_carditaskthread_mov_cardicommon_to_r4:
 __patch_carditaskthread_mov_command_to_r0:
     ldr r0, [r4, #4] // r0 = command
 
+    ldr r1,= 0x04000204
+    ldrh r1, [r1]
+.global __patch_carditaskthread_lsls_exmemstat_bit_to_r1
+__patch_carditaskthread_lsls_exmemstat_bit_to_r1:
+    lsls r1, r1, #20
+    mvns r1, r1
+    lsrs r1, r1, #31 // r1 = 0 when slot mapped to arm7, 1 when slot not mapped to arm7
+
     cmp r0, #2
-    beq identify_backup
-
+        beq end_success // identify
     cmp r0, #6
-    beq read_backup
-
+        beq read_backup
     cmp r0, #7
-    beq write_backup
-
+        beq write_backup
     cmp r0, #8
-    beq write_backup
-
+        beq write_backup
     cmp r0, #9
-    beq verify_backup
+        beq verify_backup
 
     // erase
     cmp r0, #10
-    beq end_success
+        beq end_success
     cmp r0, #11
-    beq end_success
+        beq end_success
     cmp r0, #12
-    beq end_success
+        beq end_success
     cmp r0, #15
-    beq end_success
+        beq end_success
 
 end_fail:
     ldr r0, __patch_carditaskthread_failoffset
@@ -58,18 +62,8 @@ end:
     adds r3, r0
     bx r3
 
-identify_backup:
-    b end_success
-
 read_backup:
-    ldr r0, [r4]
-    movs r1, #0
-    str r1, [r0] // result
-    ldr r1, [r0, #0xC] // src
-    ldr r2, [r0, #0x10] // dst
-    ldr r3, [r0, #0x14] // len
-    cmp r3, #0
-        beq end_success
+    bl read_write_verify_backup_common
 
     ldr r0, __patch_carditaskthread_readsave_asm_address
     bl blx_r0
@@ -77,14 +71,7 @@ read_backup:
     b end_success
 
 write_backup:
-    ldr r0, [r4]
-    movs r1, #0
-    str r1, [r0] // result
-    ldr r1, [r0, #0xC] // src
-    ldr r2, [r0, #0x10] // dst
-    ldr r3, [r0, #0x14] // len
-    cmp r3, #0
-        beq end_success
+    bl read_write_verify_backup_common
 
     ldr r0, __patch_carditaskthread_writesave_asm_address
     bl blx_r0
@@ -92,12 +79,7 @@ write_backup:
     b end_success
 
 verify_backup:
-    ldr r0, [r4]
-    ldr r2, [r0, #0xC] // src
-    ldr r1, [r0, #0x10] // dst
-    ldr r3, [r0, #0x14] // len
-    cmp r3, #0
-        beq end_success
+    bl read_write_verify_backup_common
 
     push {r0}
     ldr r0, __patch_carditaskthread_verifysave_asm_address
@@ -106,6 +88,18 @@ verify_backup:
     str r0, [r1] // result
     b end_success
 
+read_write_verify_backup_common:
+    ldr r0, [r4]
+    str r1, [r0] // result
+    cmp r1, #0
+        bne end_success
+    ldr r1, [r0, #0xC] // src
+    ldr r2, [r0, #0x10] // dst
+    ldr r3, [r0, #0x14] // len
+    cmp r3, #0
+        beq end_success
+    bx lr
+
 blx_r0:
     bx r0
 
diff --git a/arm9/source/patches/arm7/VerifySaveAsm.s b/arm9/source/patches/arm7/VerifySaveAsm.s
index 6f01f54..2a8468a 100644
--- a/arm9/source/patches/arm7/VerifySaveAsm.s
+++ b/arm9/source/patches/arm7/VerifySaveAsm.s
@@ -3,16 +3,16 @@
 .syntax unified
 .thumb
 
-// r1 = save src
-// r2 = memory src
+// r1 = memory src
+// r2 = save src
 // r3 = byte length
 .global verifysave_asm
 .type verifysave_asm, %function
 verifysave_asm:
     push {r4,r5,r6,r7,lr}
     movs r4, r3 // remaining bytes
-    movs r5, r1
-    movs r6, r2
+    movs r5, r2
+    movs r6, r1
 1:
     movs r0, r5 // will be rounded down by function
     ldr r3, verifysave_save_offset_to_sd_sector_asm_address
diff --git a/arm9/source/patches/arm7/sdk2to4/CardiTaskThreadPatch.cpp b/arm9/source/patches/arm7/sdk2to4/CardiTaskThreadPatch.cpp
index 31efa1f..6b9a136 100644
--- a/arm9/source/patches/arm7/sdk2to4/CardiTaskThreadPatch.cpp
+++ b/arm9/source/patches/arm7/sdk2to4/CardiTaskThreadPatch.cpp
@@ -133,6 +133,16 @@ void CardiTaskThreadPatch::ApplyPatch(PatchContext& patchContext)
     __patch_carditaskthread_readsave_asm_address = (u32)readSavePatchCode->GetReadSaveFunction();
     __patch_carditaskthread_writesave_asm_address = (u32)writeSavePatchCode->GetWriteSaveFunction();
     __patch_carditaskthread_verifysave_asm_address = (u32)verifySavePatchCode->GetVerifySaveFunction();
+    if (loaderPlatform->GetPlatformType() == LoaderPlatformType::Slot1)
+    {
+        // Test REG_EXMEMSTAT bit 11
+        __patch_carditaskthread_lsls_exmemstat_bit_to_r1 = THUMB_LSLS_IMM(THUMB_R1, THUMB_R1, 31 - 11);
+    }
+    else
+    {
+        // Test REG_EXMEMSTAT bit 7
+        __patch_carditaskthread_lsls_exmemstat_bit_to_r1 = THUMB_LSLS_IMM(THUMB_R1, THUMB_R1, 31 - 7);
+    }
 
     if (_patchVariant >= PatchVariant::ThumbA)
     {
diff --git a/arm9/source/patches/arm7/sdk5/CardiDoTaskFromArm9Patch.cpp b/arm9/source/patches/arm7/sdk5/CardiDoTaskFromArm9Patch.cpp
index 7f32292..9f9fcf2 100644
--- a/arm9/source/patches/arm7/sdk5/CardiDoTaskFromArm9Patch.cpp
+++ b/arm9/source/patches/arm7/sdk5/CardiDoTaskFromArm9Patch.cpp
@@ -93,6 +93,16 @@ void CardiDoTaskFromArm9Patch::ApplyPatch(PatchContext& patchContext)
     __patch_carditaskthread_readsave_asm_address = (u32)readSavePatchCode->GetReadSaveFunction();
     __patch_carditaskthread_writesave_asm_address = (u32)writeSavePatchCode->GetWriteSaveFunction();
     __patch_carditaskthread_verifysave_asm_address = (u32)verifySavePatchCode->GetVerifySaveFunction();
+    if (loaderPlatform->GetPlatformType() == LoaderPlatformType::Slot1)
+    {
+        // Test REG_EXMEMSTAT bit 11
+        __patch_carditaskthread_lsls_exmemstat_bit_to_r1 = THUMB_LSLS_IMM(THUMB_R1, THUMB_R1, 31 - 11);
+    }
+    else
+    {
+        // Test REG_EXMEMSTAT bit 7
+        __patch_carditaskthread_lsls_exmemstat_bit_to_r1 = THUMB_LSLS_IMM(THUMB_R1, THUMB_R1, 31 - 7);
+    }
 
     u32 patchOffset;
 
diff --git a/arm9/source/patches/platform/LoaderPlatform.h b/arm9/source/patches/platform/LoaderPlatform.h
index 8e843b0..cf0e2ef 100644
--- a/arm9/source/patches/platform/LoaderPlatform.h
+++ b/arm9/source/patches/platform/LoaderPlatform.h
@@ -5,6 +5,7 @@
 #include "SdWritePatchCode.h"
 #include "../PatchHeap.h"
 #include "../PatchCodeCollection.h"
+#include "LoaderPlatformType.h"
 
 /// @brief Abstract class for platform (flashcard or other sd access method) specific parts of the loader.
 class LoaderPlatform
@@ -38,6 +39,10 @@ public:
     virtual const SdReadPatchCode* CreateRomReadPatchCode(
         PatchCodeCollection& patchCodeCollection, PatchHeap& patchHeap) const { return nullptr; }
 
+    /// @brief Returns the type of this loader platform.
+    /// @return The type of this loader platform.
+    virtual LoaderPlatformType GetPlatformType() const = 0;
+
     /// @brief Checks if the platform supports rom reads directly.
     /// @return True if the platform supports rom reads, or false otherwise.
     virtual bool HasRomReads() const { return false; }
diff --git a/arm9/source/patches/platform/LoaderPlatformType.h b/arm9/source/patches/platform/LoaderPlatformType.h
new file mode 100644
index 0000000..bf0ca44
--- /dev/null
+++ b/arm9/source/patches/platform/LoaderPlatformType.h
@@ -0,0 +1,11 @@
+#pragma once
+
+/// @brief Enum representing the type of loader platform.
+enum class LoaderPlatformType
+{
+    /// @brief Slot 1 (DS) cartridge.
+    Slot1,
+
+    /// @brief Slot 2 (GBA) cartridge.
+    Slot2
+};
diff --git a/arm9/source/patches/platform/ace3ds/Ace3DSLoaderPlatform.h b/arm9/source/patches/platform/ace3ds/Ace3DSLoaderPlatform.h
index 27f525f..fe3772f 100644
--- a/arm9/source/patches/platform/ace3ds/Ace3DSLoaderPlatform.h
+++ b/arm9/source/patches/platform/ace3ds/Ace3DSLoaderPlatform.h
@@ -34,5 +34,7 @@ public:
         });
     }
 
+    LoaderPlatformType GetPlatformType() const override { return LoaderPlatformType::Slot1; }
+
     bool HasDmaSdReads() const override { return true; }
 };
diff --git a/arm9/source/patches/platform/acekard-common/IoRPGLoaderPlatform.h b/arm9/source/patches/platform/acekard-common/IoRPGLoaderPlatform.h
index c35c4df..3ff5c7f 100644
--- a/arm9/source/patches/platform/acekard-common/IoRPGLoaderPlatform.h
+++ b/arm9/source/patches/platform/acekard-common/IoRPGLoaderPlatform.h
@@ -11,6 +11,8 @@ public:
     explicit IoRPGLoaderPlatform(u8 ioRpgCmdSdioByte)
         : _ioRpgCmdSdioByte(ioRpgCmdSdioByte) { }
 
+    LoaderPlatformType GetPlatformType() const override { return LoaderPlatformType::Slot1; }
+
     bool InitializeSdCard() override;
 
 protected:
diff --git a/arm9/source/patches/platform/dspico/DSPicoLoaderPlatform.h b/arm9/source/patches/platform/dspico/DSPicoLoaderPlatform.h
index a5099b2..1ccf414 100644
--- a/arm9/source/patches/platform/dspico/DSPicoLoaderPlatform.h
+++ b/arm9/source/patches/platform/dspico/DSPicoLoaderPlatform.h
@@ -43,5 +43,7 @@ public:
         });
     }
 
+    LoaderPlatformType GetPlatformType() const override { return LoaderPlatformType::Slot1; }
+
     bool HasDmaSdReads() const override { return true; }
 };
diff --git a/arm9/source/patches/platform/dstt/DSTTLoaderPlatform.h b/arm9/source/patches/platform/dstt/DSTTLoaderPlatform.h
index 8e60432..da6eafb 100644
--- a/arm9/source/patches/platform/dstt/DSTTLoaderPlatform.h
+++ b/arm9/source/patches/platform/dstt/DSTTLoaderPlatform.h
@@ -34,5 +34,7 @@ public:
         });
     }
 
+    LoaderPlatformType GetPlatformType() const override { return LoaderPlatformType::Slot1; }
+
     bool InitializeSdCard() override;
 };
diff --git a/arm9/source/patches/platform/ezp/EZPLoaderPlatform.h b/arm9/source/patches/platform/ezp/EZPLoaderPlatform.h
index 86bb8d6..dfbc3ed 100644
--- a/arm9/source/patches/platform/ezp/EZPLoaderPlatform.h
+++ b/arm9/source/patches/platform/ezp/EZPLoaderPlatform.h
@@ -30,4 +30,6 @@ public:
             return new EZPWriteSectorsPatchCode(patchHeap);
         });
     }
+
+    LoaderPlatformType GetPlatformType() const override { return LoaderPlatformType::Slot1; }
 };
diff --git a/arm9/source/patches/platform/g003/G003LoaderPlatform.h b/arm9/source/patches/platform/g003/G003LoaderPlatform.h
index 9c6c3f5..484cde8 100644
--- a/arm9/source/patches/platform/g003/G003LoaderPlatform.h
+++ b/arm9/source/patches/platform/g003/G003LoaderPlatform.h
@@ -34,5 +34,7 @@ public:
         });
     }
 
+    LoaderPlatformType GetPlatformType() const override { return LoaderPlatformType::Slot1; }
+
     bool HasDmaSdReads() const override { return true; }
 };
diff --git a/arm9/source/patches/platform/isnitro/IsNitroLoaderPlatform.h b/arm9/source/patches/platform/isnitro/IsNitroLoaderPlatform.h
index 43b40e0..818f580 100644
--- a/arm9/source/patches/platform/isnitro/IsNitroLoaderPlatform.h
+++ b/arm9/source/patches/platform/isnitro/IsNitroLoaderPlatform.h
@@ -27,6 +27,8 @@ public:
         });
     }
 
+    LoaderPlatformType GetPlatformType() const override { return LoaderPlatformType::Slot2; }
+
 private:
     u32 GetAgbRamPtr() const
     {
diff --git a/arm9/source/patches/platform/m3ds/M3DSLoaderPlatform.h b/arm9/source/patches/platform/m3ds/M3DSLoaderPlatform.h
index bba8676..08eddf4 100644
--- a/arm9/source/patches/platform/m3ds/M3DSLoaderPlatform.h
+++ b/arm9/source/patches/platform/m3ds/M3DSLoaderPlatform.h
@@ -33,4 +33,6 @@ public:
                 }));
         });
     }
+
+    LoaderPlatformType GetPlatformType() const override { return LoaderPlatformType::Slot1; }
 };
diff --git a/arm9/source/patches/platform/melonds/MelonDSLoaderPlatform.h b/arm9/source/patches/platform/melonds/MelonDSLoaderPlatform.h
index b9667e1..bbc4ac6 100644
--- a/arm9/source/patches/platform/melonds/MelonDSLoaderPlatform.h
+++ b/arm9/source/patches/platform/melonds/MelonDSLoaderPlatform.h
@@ -25,4 +25,6 @@ public:
             return new MelonDSWriteSdPatchCode(patchHeap);
         });
     }
+
+    LoaderPlatformType GetPlatformType() const override { return LoaderPlatformType::Slot1; }
 };
diff --git a/arm9/source/patches/platform/r4/R4LoaderPlatform.h b/arm9/source/patches/platform/r4/R4LoaderPlatform.h
index 4d5b110..106a90e 100644
--- a/arm9/source/patches/platform/r4/R4LoaderPlatform.h
+++ b/arm9/source/patches/platform/r4/R4LoaderPlatform.h
@@ -37,6 +37,8 @@ public:
         });
     }
 
+    LoaderPlatformType GetPlatformType() const override { return LoaderPlatformType::Slot1; }
+
     bool HasRomReads() const override { return true; }
 
     void PrepareRomBoot(u32 romDirSector, u32 romDirSectorOffset) const override;
diff --git a/arm9/source/patches/platform/supercard/SuperCardLoaderPlatform.h b/arm9/source/patches/platform/supercard/SuperCardLoaderPlatform.h
index daa24e5..cffc383 100644
--- a/arm9/source/patches/platform/supercard/SuperCardLoaderPlatform.h
+++ b/arm9/source/patches/platform/supercard/SuperCardLoaderPlatform.h
@@ -99,6 +99,8 @@ public:
         }
     }
 
+    LoaderPlatformType GetPlatformType() const override { return LoaderPlatformType::Slot2; }
+
     bool InitializeSdCard() override;
 
 private: