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Use OSi_IrqVBlank for cheat patching (#156)

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This commit is contained in:
Mow
2026-03-29 05:43:14 -04:00
committed by GitHub
parent bac98b4405
commit 4e67225bc3
4 changed files with 34 additions and 161 deletions
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173
arm9/source/patches/arm7/cheats/CheatEnginePatch.cpp
View File

@@ -3,89 +3,38 @@
#include "CheatEnginePatchCode.h"
#include "CheatEnginePatch.h"
// sdk2-4
static const u32 sVBlankIntrPatternArm0[] = { 0xE92D4000u, 0xE24DD004u, 0xE59F0018u, 0xE5900000u };
static const u32 sVBlankIntrPatternArm1[] = { 0xE92D4008u, 0xE59F0014u, 0xE5900000u, 0xE3500000u };
static const u32 sVBlankIntrPatternThumb0[] = { 0x00000000u, 0xB081B500u, 0x68004804u, 0xD0012800u }; // +4
static const u32 sVBlankIntrPatternThumb1[] = { 0x46C04770u, 0x027FFE1Du, 0x4804B508u, 0x28006800u }; // +8
static const u32 sVBlankIntrPatternThumb2[] = { 0x46C04718u, 0x0000FFFFu, 0x4804B508u, 0x28006800u }; // +8
static const u32 sVBlankIntrPatternThumb3[] = { 0xE51FF004u, 0x037FD67Cu, 0x4804B508u, 0x28006800u }; // +8
static const u32 sVBlankIntrPatternThumb4[] = { 0x46C04770u, 0x02FFFE1Du, 0x4804B508u, 0x28006800u }; // +8
static const u32 sVBlankIntrPatternThumb5[] = { 0xE51FF004u, 0x037FA868u, 0x4804B508u, 0x28006800u }; // +8
static const u32 sOSiIrqVBlankPattern0[] = { 0xE92D4008u, 0xE59F2038u, 0xE59F0038u, 0xE5921000u };
static const u32 sOSiIrqVBlankPattern1[] = { 0xE92D4000u, 0xE24DD004u, 0xE59F003Cu, 0xE5902060u };
static const u32 sOSiIrqVBlankPatternThumb0[] = { 0x4809B508u, 0x69024909u, 0x1C406808u, 0x2A006008u };
bool CheatEnginePatch::FindPatchTarget(PatchContext& patchContext)
{
_vblankIrqHandler = patchContext.FindPattern32(sVBlankIntrPatternArm0, sizeof(sVBlankIntrPatternArm0));
_vblankIrqHandler = patchContext.FindPattern32(sOSiIrqVBlankPattern0, sizeof(sOSiIrqVBlankPattern0));
if (_vblankIrqHandler)
{
_foundPattern = sVBlankIntrPatternArm0;
_foundPattern = sOSiIrqVBlankPattern0;
}
if (!_vblankIrqHandler)
{
_vblankIrqHandler = patchContext.FindPattern32(sVBlankIntrPatternArm1, sizeof(sVBlankIntrPatternArm1));
_vblankIrqHandler = patchContext.FindPattern32(sOSiIrqVBlankPattern1, sizeof(sOSiIrqVBlankPattern1));
if (_vblankIrqHandler)
{
_foundPattern = sVBlankIntrPatternArm1;
_foundPattern = sOSiIrqVBlankPattern1;
}
}
if (!_vblankIrqHandler)
{
_vblankIrqHandler = patchContext.FindPattern32(sVBlankIntrPatternThumb0, sizeof(sVBlankIntrPatternThumb0));
_vblankIrqHandler = patchContext.FindPattern32(sOSiIrqVBlankPatternThumb0, sizeof(sOSiIrqVBlankPatternThumb0));
if (_vblankIrqHandler)
{
_foundPattern = sVBlankIntrPatternThumb0;
_vblankIrqHandler += 1;
}
}
if (!_vblankIrqHandler)
{
_vblankIrqHandler = patchContext.FindPattern32(sVBlankIntrPatternThumb1, sizeof(sVBlankIntrPatternThumb1));
if (_vblankIrqHandler)
{
_foundPattern = sVBlankIntrPatternThumb1;
_vblankIrqHandler += 2;
}
}
if (!_vblankIrqHandler)
{
_vblankIrqHandler = patchContext.FindPattern32(sVBlankIntrPatternThumb2, sizeof(sVBlankIntrPatternThumb2));
if (_vblankIrqHandler)
{
_foundPattern = sVBlankIntrPatternThumb2;
_vblankIrqHandler += 2;
}
}
if (!_vblankIrqHandler)
{
_vblankIrqHandler = patchContext.FindPattern32(sVBlankIntrPatternThumb3, sizeof(sVBlankIntrPatternThumb3));
if (_vblankIrqHandler)
{
_foundPattern = sVBlankIntrPatternThumb3;
_vblankIrqHandler += 2;
}
}
if (!_vblankIrqHandler)
{
_vblankIrqHandler = patchContext.FindPattern32(sVBlankIntrPatternThumb4, sizeof(sVBlankIntrPatternThumb4));
if (_vblankIrqHandler)
{
_foundPattern = sVBlankIntrPatternThumb4;
_vblankIrqHandler += 2;
}
}
if (!_vblankIrqHandler)
{
_vblankIrqHandler = patchContext.FindPattern32(sVBlankIntrPatternThumb5, sizeof(sVBlankIntrPatternThumb5));
if (_vblankIrqHandler)
{
_foundPattern = sVBlankIntrPatternThumb5;
_vblankIrqHandler += 2;
_foundPattern = sOSiIrqVBlankPatternThumb0;
_thumb = true;
}
}
if (_vblankIrqHandler)
{
LOG_DEBUG("ARM7 VBlankIntr found at 0x%p\n", _vblankIrqHandler);
LOG_DEBUG("ARM7 OSi_IrqVBlank found at 0x%p\n", _vblankIrqHandler);
}
return _vblankIrqHandler != nullptr;
@@ -102,91 +51,35 @@ void CheatEnginePatch::ApplyPatch(PatchContext& patchContext)
_cheats
);
if (_foundPattern == sVBlankIntrPatternArm0)
int patchOffset;
if (_foundPattern == sOSiIrqVBlankPattern0)
{
// push {lr}
// sub sp, sp, #4
// ldr r0,=
// ldr r0, [r0]
// cmp r0, #0
// beq 1f
// bl
// 1:
// add sp, sp, #4
// pop {lr}
// bx lr
_vblankIrqHandler[7] = 0xE59F0000; // ldr r0,= address
_vblankIrqHandler[8] = 0xE12FFF10; // bx r0
_vblankIrqHandler[9] = (u32)cheatEnginePatchCode->GetCheatEngineFunction(); // address
patchOffset = 0x3C;
}
else if (_foundPattern == sVBlankIntrPatternArm1)
else if (_foundPattern == sOSiIrqVBlankPattern1)
{
// push {r3,lr}
// ldr r0,=
// ldr r0, [r0]
// cmp r0, #0
// beq 1f
// bl
// 1:
// pop {r3,lr}
// bx lr
_vblankIrqHandler[6] = 0xE51FF004; // ldr pc,= address
_vblankIrqHandler[7] = (u32)cheatEnginePatchCode->GetCheatEngineFunctionArm(); // address
patchOffset = 0x40;
}
else if (_foundPattern == sVBlankIntrPatternThumb0)
else if (_foundPattern == sOSiIrqVBlankPatternThumb0)
{
// push {lr}
// sub sp, sp, #4
// ldr r0,=
// ldr r0, [r0]
// cmp r0, #0
// beq 1f
// bl
// 1:
// add sp, sp, #4
// pop {r3}
// bx r3
// nop
((u16*)_vblankIrqHandler)[8] = THUMB_LDR_PC_IMM(THUMB_R1, 0); // ldr r1,= address
((u16*)_vblankIrqHandler)[9] = THUMB_BX(THUMB_R1); // bx r1
_vblankIrqHandler[10 >> 1] = (u32)cheatEnginePatchCode->GetCheatEngineFunction(); // address
}
else if (_foundPattern == sVBlankIntrPatternThumb1
|| _foundPattern == sVBlankIntrPatternThumb2
|| _foundPattern == sVBlankIntrPatternThumb3
|| _foundPattern == sVBlankIntrPatternThumb4
|| _foundPattern == sVBlankIntrPatternThumb5)
{
// push {r3,lr}
// ldr r0,=
// ldr r0, [r0]
// cmp r0, #0
// beq 1f
// bl
// 1:
// pop {r3}
// pop {r3}
// bx r3
// rewrite the function to
// add r1, pc, #4
// ldr r0,=
// ldr r2,= cheatengine_entry_thumb_replace
// bx r2
// beq 1f
// bl
// 1:
// mov pc, r4
// .word cheatengine_entry_thumb_replace
((u16*)_vblankIrqHandler)[0] = THUMB_ADD_PC_IMM(THUMB_R1, 4); // add r1, pc, #4
((u16*)_vblankIrqHandler)[2] = THUMB_LDR_PC_IMM(THUMB_R2, 8); // ldr r2,= cheatengine_entry_thumb_replace
((u16*)_vblankIrqHandler)[3] = THUMB_BX(THUMB_R2); // bx r2
((u16*)_vblankIrqHandler)[7] = THUMB_MOV_HIREG(THUMB_HI_PC, THUMB_R4); // mov pc, r4
_vblankIrqHandler[8 >> 1] = (u32)cheatEnginePatchCode->GetCheatEngineFunctionThumbReplace(); // .word cheatengine_entry_thumb_replace
patchOffset = 0x20;
}
else
{
LOG_ERROR("ARM7 VBlankIntr signature not implemented\n");
LOG_ERROR("ARM7 OSi_IrqVBlank signature not implemented\n");
return;
}
if (_thumb)
{
*(u16*)((u8*)_vblankIrqHandler + patchOffset + 0) = THUMB_LDR_PC_IMM(THUMB_R1, 0); // ldr r1,= address
*(u16*)((u8*)_vblankIrqHandler + patchOffset + 2) = THUMB_BX(THUMB_R1); // bx r1
*(u32*)((u8*)_vblankIrqHandler + patchOffset + 4) = (u32)cheatEnginePatchCode->GetCheatEngineFunction(); // address
}
else
{
*(u32*)((u8*)_vblankIrqHandler + patchOffset + 0) = 0xE51FF004; // ldr pc,= address
*(u32*)((u8*)_vblankIrqHandler + patchOffset + 4) = (u32)cheatEnginePatchCode->GetCheatEngineFunctionArm(); // address
}
LOG_DEBUG("Cheats enabled\n");
}

1
arm9/source/patches/arm7/cheats/CheatEnginePatch.h
View File

@@ -15,4 +15,5 @@ private:
const void* _cheats;
u32* _vblankIrqHandler = nullptr;
const u32* _foundPattern = nullptr;
u16 _thumb = false;
};

6
arm9/source/patches/arm7/cheats/CheatEnginePatchCode.h
View File

@@ -5,7 +5,6 @@
DEFINE_SECTION_SYMBOLS(patch_cheatengine);
extern "C" void cheatengine_entry_arm(void);
extern "C" void cheatengine_entry_thumb_replace(void);
extern "C" void cheatengine_entry(void);
extern const void* cheatengine_cheatsPtr;
@@ -28,9 +27,4 @@ public:
{
return GetAddressAtTarget((void*)cheatengine_entry_arm);
}
const void* GetCheatEngineFunctionThumbReplace() const
{
return GetAddressAtTarget((void*)cheatengine_entry_thumb_replace);
}
};

15
arm9/source/patches/arm7/cheats/CheatEnginePatchCode.s
View File

@@ -14,21 +14,6 @@ cheatengine_entry_arm:
bx r12
.thumb
.global cheatengine_entry_thumb_replace
.type cheatengine_entry_thumb_replace, %function
cheatengine_entry_thumb_replace:
push {r4, r5, lr} // r5 is a dummy
ldr r0, [r0]
adr r4, cheatengine_entry_thumb_replace_return
cmp r0, #0
mov pc, r1
.balign 4
cheatengine_entry_thumb_replace_return:
pop {r4}
nop
.global cheatengine_entry
.type cheatengine_entry, %function
cheatengine_entry: