From 22d2b612b89ebbc7adfd9cab73e45214b4e3a487 Mon Sep 17 00:00:00 2001
From: Arisotura <thetotalworm@gmail.com>
Date: Fri, 28 Oct 2022 21:12:01 +0200
Subject: [PATCH] botching Teakra some... not a big success

---
 src/teakra/src/CMakeLists.txt       |  1 +
 src/teakra/src/interpreter.h        | 48 +++++++++++++++++++++++++----
 src/teakra/src/memory_interface.cpp | 16 +++++++---
 src/teakra/src/operand.h            |  2 +-
 4 files changed, 56 insertions(+), 11 deletions(-)

diff --git a/src/teakra/src/CMakeLists.txt b/src/teakra/src/CMakeLists.txt
index b96c500b..2ba05b40 100644
--- a/src/teakra/src/CMakeLists.txt
+++ b/src/teakra/src/CMakeLists.txt
@@ -19,6 +19,7 @@ add_library(teakra
     timer.cpp
     timer.h
     icu.h
+	InstrDecode.h
     interpreter.h
     matcher.h
     memory_interface.cpp
diff --git a/src/teakra/src/interpreter.h b/src/teakra/src/interpreter.h
index 98241a32..22ca5653 100644
--- a/src/teakra/src/interpreter.h
+++ b/src/teakra/src/interpreter.h
@@ -16,6 +16,9 @@
 
 namespace Teakra {
 
+class Interpreter;
+extern void (*InstrTable[65536])(Interpreter& cpu, u16 instr);
+
 class UnimplementedException : public std::runtime_error {
 public:
     UnimplementedException() : std::runtime_error("unimplemented") {}
@@ -60,6 +63,34 @@ public:
         UNREACHABLE();
     }
 
+    u16 OpcodeFetch()
+    {
+        u16 opcode = mem.ProgramRead((regs.pc++) | (regs.prpage << 18));
+        return opcode;
+    }
+
+    void HandleLoops()
+    {
+        if (regs.rep) {
+            if (regs.repc == 0) {
+                regs.rep = false;
+            } else {
+                --regs.repc;
+                --regs.pc;
+            }
+        }
+
+        if (regs.lp && regs.bkrep_stack[regs.bcn - 1].end + 1 == regs.pc) {
+            if (regs.bkrep_stack[regs.bcn - 1].lc == 0) {
+                --regs.bcn;
+                regs.lp = regs.bcn != 0;
+            } else {
+                --regs.bkrep_stack[regs.bcn - 1].lc;
+                regs.pc = regs.bkrep_stack[regs.bcn - 1].start;
+            }
+        }
+    }
+
     void Run(u64 cycles) {
         idle = false;
         for (u64 i = 0; i < cycles; ++i) {
@@ -84,8 +115,8 @@ public:
                 regs.ipv = 1;
             }
 
-            u16 opcode = mem.ProgramRead((regs.pc++) | (regs.prpage << 18));
-            auto& decoder = decoders[opcode];
+            u16 opcode = OpcodeFetch();
+            /*auto& decoder = decoders[opcode];
             u16 expand_value = 0;
             if (decoder.NeedExpansion()) {
                 expand_value = mem.ProgramRead((regs.pc++) | (regs.prpage << 18));
@@ -110,7 +141,8 @@ public:
                 }
             }
 
-            decoder.call(*this, opcode, expand_value);
+            decoder.call(*this, opcode, expand_value);*/
+            InstrTable[opcode](*this, opcode);
 
             // I am not sure if a single-instruction loop is interruptable and how it is handled,
             // so just disable interrupt for it for now.
@@ -1185,14 +1217,16 @@ public:
         // retd is supposed to kick in after 2 cycles
 
         for (int i = 0; i < 2; i++) {
-            u16 opcode = mem.ProgramRead((regs.pc++) | (regs.prpage << 18));
+            /*u16 opcode = mem.ProgramRead((regs.pc++) | (regs.prpage << 18));
             auto& decoder = decoders[opcode];
             u16 expand_value = 0;
             if (decoder.NeedExpansion()) {
                 expand_value = mem.ProgramRead((regs.pc++) | (regs.prpage << 18));
             }
 
-            decoder.call(*this, opcode, expand_value);
+            decoder.call(*this, opcode, expand_value);*/
+            u16 opcode = OpcodeFetch();
+            InstrTable[opcode](*this, opcode);
         }
 
         PopPC();
@@ -3642,7 +3676,9 @@ private:
         return map.at(in);
     }
 
-    const std::vector<Matcher<Interpreter>> decoders = GetDecoderTable<Interpreter>();
+    //const std::vector<Matcher<Interpreter>> decoders = GetDecoderTable<Interpreter>();
 };
 
 } // namespace Teakra
+
+#include "InstrDecode.h"
diff --git a/src/teakra/src/memory_interface.cpp b/src/teakra/src/memory_interface.cpp
index ef30b95a..b771a9d1 100644
--- a/src/teakra/src/memory_interface.cpp
+++ b/src/teakra/src/memory_interface.cpp
@@ -2,6 +2,8 @@
 #include "mmio.h"
 #include "shared_memory.h"
 
+#include "../../DSi.h"
+
 namespace Teakra {
 MemoryInterface::MemoryInterface(SharedMemory& shared_memory,
                                  MemoryInterfaceUnit& memory_interface_unit)
@@ -11,11 +13,17 @@ void MemoryInterface::SetMMIO(MMIORegion& mmio) {
     this->mmio = &mmio;
 }
 
-u16 MemoryInterface::ProgramRead(u32 address) const {
-    return shared_memory.ReadWord(address);
+u16 MemoryInterface::ProgramRead(u32 address) const
+{
+    //return shared_memory.ReadWord(address);
+    u8* ptr = DSi::NWRAMMap_B[2][(address >> 14) & 0x7];
+    return ptr ? *(u16*)&ptr[(address << 1) & 0x7FFF] : 0;
 }
-void MemoryInterface::ProgramWrite(u32 address, u16 value) {
-    shared_memory.WriteWord(address, value);
+void MemoryInterface::ProgramWrite(u32 address, u16 value)
+{
+    //shared_memory.WriteWord(address, value);
+    u8* ptr = DSi::NWRAMMap_B[2][(address >> 14) & 0x7];
+    if (ptr) *(u16*)&ptr[(address << 1) & 0x7FFF] = value;
 }
 u16 MemoryInterface::DataRead(u16 address, bool bypass_mmio) {
     if (memory_interface_unit.InMMIO(address) && !bypass_mmio) {
diff --git a/src/teakra/src/operand.h b/src/teakra/src/operand.h
index 67900bd6..bd761aae 100644
--- a/src/teakra/src/operand.h
+++ b/src/teakra/src/operand.h
@@ -9,7 +9,7 @@ struct Operand {
     static_assert(bits > 0 && bits <= 16);
     static constexpr unsigned Bits = bits;
 
-protected:
+public:
     u16 storage{};
 
     template <typename OperandT, unsigned pos>