From d2c98639a8a1169a0ed8fa6390998b6ec8aba966 Mon Sep 17 00:00:00 2001
From: Connor McLaughlin <stenzek@gmail.com>
Date: Thu, 17 Dec 2020 23:33:00 +1000
Subject: [PATCH] Cheats: Add extension 32-bit instructions variants

---
 src/core/cheats.cpp | 74 +++++++++++++++++++++++++++++++++++++++++++++
 src/core/cheats.h   | 14 ++++++++-
 2 files changed, 87 insertions(+), 1 deletion(-)

diff --git a/src/core/cheats.cpp b/src/core/cheats.cpp
index 8fe7cccf5..c9a17933c 100644
--- a/src/core/cheats.cpp
+++ b/src/core/cheats.cpp
@@ -880,6 +880,13 @@ void CheatCode::Apply() const
       }
       break;
 
+      case InstructionCode::ExtConstantWrite32:
+      {
+        DoMemoryWrite<u32>(inst.address, inst.value32);
+        index++;
+      }
+      break;
+
       case InstructionCode::ScratchpadWrite16:
       {
         DoMemoryWrite<u16>(CPU::DCACHE_LOCATION | (inst.address & CPU::DCACHE_OFFSET_MASK), inst.value16);
@@ -887,6 +894,29 @@ void CheatCode::Apply() const
       }
       break;
 
+      case InstructionCode::ExtScratchpadWrite32:
+      {
+        DoMemoryWrite<u32>(CPU::DCACHE_LOCATION | (inst.address & CPU::DCACHE_OFFSET_MASK), inst.value32);
+        index++;
+      }
+      break;
+
+      case InstructionCode::ExtIncrement32:
+      {
+        const u32 value = DoMemoryRead<u32>(inst.address);
+        DoMemoryWrite<u32>(inst.address, value + inst.value32);
+        index++;
+      }
+      break;
+
+      case InstructionCode::ExtDecrement32:
+      {
+        const u32 value = DoMemoryRead<u32>(inst.address);
+        DoMemoryWrite<u32>(inst.address, value - inst.value32);
+        index++;
+      }
+      break;
+
       case InstructionCode::Increment16:
       {
         const u16 value = DoMemoryRead<u16>(inst.address);
@@ -919,6 +949,46 @@ void CheatCode::Apply() const
       }
       break;
 
+      case InstructionCode::ExtCompareEqual32:
+      {
+        const u32 value = DoMemoryRead<u32>(inst.address);
+        if (value == inst.value32)
+          index++;
+        else
+          index = GetNextNonConditionalInstruction(index);
+      }
+      break;
+
+      case InstructionCode::ExtCompareNotEqual32:
+      {
+        const u32 value = DoMemoryRead<u32>(inst.address);
+        if (value != inst.value32)
+          index++;
+        else
+          index = GetNextNonConditionalInstruction(index);
+      }
+      break;
+
+      case InstructionCode::ExtCompareLess32:
+      {
+        const u32 value = DoMemoryRead<u32>(inst.address);
+        if (value < inst.value32)
+          index++;
+        else
+          index = GetNextNonConditionalInstruction(index);
+      }
+      break;
+
+      case InstructionCode::ExtCompareGreater32:
+      {
+        const u32 value = DoMemoryRead<u32>(inst.address);
+        if (value > inst.value32)
+          index++;
+        else
+          index = GetNextNonConditionalInstruction(index);
+      }
+      break;
+
       case InstructionCode::CompareEqual16:
       {
         const u16 value = DoMemoryRead<u16>(inst.address);
@@ -1009,6 +1079,7 @@ void CheatCode::Apply() const
       break;
 
       case InstructionCode::SkipIfNotEqual16:      // C0
+      case InstructionCode::ExtSkipIfNotEqual32:   // A4
       case InstructionCode::SkipIfButtonsNotEqual: // D5
       case InstructionCode::SkipIfButtonsEqual:    // D6
       {
@@ -1020,6 +1091,9 @@ void CheatCode::Apply() const
           case InstructionCode::SkipIfNotEqual16: // C0
             activate_codes = (DoMemoryRead<u16>(inst.address) == inst.value16);
             break;
+          case InstructionCode::ExtSkipIfNotEqual32: // A4
+            activate_codes = (DoMemoryRead<u32>(inst.address) == inst.value32);
+            break;
           case InstructionCode::SkipIfButtonsNotEqual: // D5
             activate_codes = (GetControllerButtonBits() == inst.value16);
             break;
diff --git a/src/core/cheats.h b/src/core/cheats.h
index 200c05fa9..b6d69e4b1 100644
--- a/src/core/cheats.h
+++ b/src/core/cheats.h
@@ -44,7 +44,18 @@ struct CheatCode
     CompareLess8 = 0xE2,
     CompareGreater8 = 0xE3,
     Slide = 0x50,
-    MemoryCopy = 0xC2
+    MemoryCopy = 0xC2,
+
+    // Extension opcodes, not present on original GameShark.
+    ExtConstantWrite32 = 0x90,
+    ExtScratchpadWrite32 = 0xA5,
+    ExtCompareEqual32 = 0xA0,
+    ExtCompareNotEqual32 = 0xA1,
+    ExtCompareLess32 = 0xA2,
+    ExtCompareGreater32 = 0xA3,
+    ExtSkipIfNotEqual32 = 0xA4,
+    ExtIncrement32 = 0x60,
+    ExtDecrement32 = 0x61,
   };
 
   union Instruction
@@ -59,6 +70,7 @@ struct CheatCode
 
     BitField<u64, InstructionCode, 32 + 24, 8> code;
     BitField<u64, u32, 32, 24> address;
+    BitField<u64, u32, 0, 32> value32;
     BitField<u64, u16, 0, 16> value16;
     BitField<u64, u8, 0, 8> value8;
   };