1 files changed, 76 insertions, 0 deletions
diff --git a/src/InstructionModifierLookup.cpp b/src/InstructionModifierLookup.cpp
new file mode 100644
index 0000000..87c0350
--- /dev/null
+++ b/src/InstructionModifierLookup.cpp
@@ -0,0 +1,76 @@
+#include "InstructionModifierLookup.h"
+
+#include "CPUContext.h"
+#include "Instruction.h"
+#include "Bus.h"
+
+#include <array>
+#include <cstdint>
+#include <utility>
+#include <cstring>
+#include <iostream>
+
+void Mod32_SIB(CPUContext &cc) {
+  std::cout << "[Mod32_SIB] SIB byte encountered." << std::endl; 
+}
+
+void Mod32_LR(CPUContext& cc) {
+  std::cout << "[Mod32_LR] Executed." << std::endl;
+  if (cc.m_Instruction.m_ModRM.m_SIB) {
+    uint32_t src = cc.m_Bus->AccessX<uint32_t>(cc.m_InstructionPointer + cc.m_Instruction.m_Length);
+    std::memcpy(&cc.m_Instruction.m_Displacement, &src, 4);
+    Mod32_SIB(cc);
+  }    
+}
+
+void Mod32_DISP32(CPUContext& cc) {
+  uint32_t src = cc.m_Bus->AccessX<uint32_t>(cc.m_InstructionPointer + cc.m_Instruction.m_Length);
+  std::memcpy(&cc.m_Instruction.m_Displacement, &src, 4);
+  cc.m_Instruction.m_Length += 4;
+  if (cc.m_Instruction.m_ModRM.m_SIB)
+    Mod32_SIB(cc);    
+}
+
+template<uint8_t RM>
+void Mod32_LRDISP32(CPUContext& cc) {
+  uint32_t disp = cc.m_Registers[RM] + cc.m_Bus->AccessX<uint32_t>(cc.m_Instruction.m_Length);
+  std::memcpy(&cc.m_Instruction.m_Displacement, &disp, 4);
+  cc.m_Instruction.m_Length += 4;
+  if (cc.m_Instruction.m_ModRM.m_SIB)
+    Mod32_SIB(cc);    
+ }
+
+template<uint8_t RM>
+void Mod32_LRDISP8(CPUContext& cc) {
+  uint32_t disp = cc.m_Registers[RM] + cc.m_Bus->AccessX<uint8_t>(cc.m_Instruction.m_Length);
+  cc.m_Instruction.m_Displacement[0] = disp;
+  cc.m_Instruction.m_Length += 1;
+  if (cc.m_Instruction.m_ModRM.m_SIB)
+    Mod32_SIB(cc);  
+}
+
+void Mod32_R(CPUContext& cc) {
+  std::cout << "[Mod32_R] Executed." << std::endl;
+}
+  
+template<uint8_t...Is>
+static constexpr std::array<ModifierEntry, 256> GenerateModRM32(std::integer_sequence<uint8_t, Is...>) {
+  return std::array<ModifierEntry, 256>{
+    ([]<uint8_t I>() {
+      constexpr auto modrm = x86::ProcessMODRM(I);
+
+      switch (modrm.m_State) {
+      case x86::ModRMState::LR:           return Mod32_LR;
+      case x86::ModRMState::LR_DISP32:    return Mod32_LRDISP32<modrm.m_Rm>;
+      case x86::ModRMState::LR_DISP8:     return Mod32_LRDISP8<modrm.m_Rm>;
+      case x86::ModRMState::DISP32:       return Mod32_DISP32;
+      case x86::ModRMState::R:            return Mod32_R;
+      }
+
+    }.template operator()<Is>())... // provide the lambda with a proper template argument
+  };
+}
+
+static constexpr std::array<ModifierEntry, 256> s_ModRM32 = GenerateModRM32(std::make_integer_sequence<uint8_t, 255>{});
+
+std::array<ModifierEntry, 256> GetMod32Table() { return s_ModRM32; }