From 4fd456e1583a4c8686c8de87c2aeb1eb78125be1 Mon Sep 17 00:00:00 2001
From: David Guillen Fandos
Date: Wed, 5 May 2021 02:20:00 +0200
Subject: Adding Code Breaker cheat support

This works on both interpreter and dynarec.
Tested in MIPS, ARM and x86, still needs some more testing, some edge
cases can be buggy.
---
 arm/arm_emit.h |  8 ++++++++
 arm/arm_stub.S | 16 ++++++++++++++++
 2 files changed, 24 insertions(+)

(limited to 'arm')

diff --git a/arm/arm_emit.h b/arm/arm_emit.h
index 1432617..4368a80 100644
--- a/arm/arm_emit.h
+++ b/arm/arm_emit.h
@@ -31,6 +31,8 @@ u32 prepare_store_reg(u32 scratch_reg, u32 reg_index);
 void generate_load_reg(u32 ireg, u32 reg_index);
 void complete_store_reg(u32 scratch_reg, u32 reg_index);
 void complete_store_reg_pc_no_flags(u32 scratch_reg, u32 reg_index);
+void thumb_cheat_hook();
+void arm_cheat_hook();
 
 u32 arm_update_gba_arm(u32 pc);
 u32 arm_update_gba_thumb(u32 pc);
@@ -1876,6 +1878,12 @@ u32 execute_store_cpsr_body(u32 _cpsr, u32 store_mask, u32 address)
   generate_indirect_branch_cycle_update(dual_thumb);                          \
 }                                                                             \
 
+#define thumb_process_cheats()                                                \
+  generate_function_call(thumb_cheat_hook);
+
+#define arm_process_cheats()                                                  \
+  generate_function_call(arm_cheat_hook);
+
 #define thumb_swi()                                                           \
   generate_swi_hle_handler(opcode & 0xFF, thumb);                             \
   generate_function_call(execute_swi_thumb);                                  \
diff --git a/arm/arm_stub.S b/arm/arm_stub.S
index 944d36a..222bb21 100644
--- a/arm/arm_stub.S
+++ b/arm/arm_stub.S
@@ -288,6 +288,22 @@ arm_update_gba_builder(idle_arm, arm, add)
 arm_update_gba_builder(idle_thumb, thumb, add)
 
 
+@ Cheat hooks for master function
+@ This is called whenever PC == cheats-master-function
+@ Just calls the C function to process cheats
+
+#define cheat_hook_builder(mode)                                             ;\
+defsymbl(mode##_cheat_hook)                                                  ;\
+  save_flags()                                                               ;\
+  store_registers_##mode()                                                   ;\
+  call_c_function(process_cheats)                                            ;\
+  load_registers_##mode()                                                    ;\
+  restore_flags()                                                            ;\
+  bx lr                                                                      ;\
+
+cheat_hook_builder(arm)
+cheat_hook_builder(thumb)
+
 
 @ These are b stubs for performing indirect branches. They are not
 @ linked to and don't return, instead they link elsewhere.
-- 
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