From 6aa36c2ead2673cc13fe5f3eb6a36b8240f8c1b7 Mon Sep 17 00:00:00 2001
From: Connor McLaughlin <mclaughc@outlook.com>
Date: Tue, 24 Sep 2019 23:55:57 +1000
Subject: [PATCH] SPU: Hook up DMA reads/writes to RAM

---
 src/pse/spu.cpp | 29 ++++++++++++++++++++++++-----
 src/pse/spu.h   |  2 ++
 2 files changed, 26 insertions(+), 5 deletions(-)

diff --git a/src/pse/spu.cpp b/src/pse/spu.cpp
index c8aa7dbbf..55aa8773d 100644
--- a/src/pse/spu.cpp
+++ b/src/pse/spu.cpp
@@ -75,10 +75,9 @@ void SPU::WriteRegister(u32 offset, u16 value)
 
     case 0x1F801DA8 - SPU_BASE:
     {
-      std::memcpy(&m_ram[m_transfer_address], &value, sizeof(value));
       Log_TracePrintf("SPU transfer data register <- 0x%04X (RAM offset 0x%08X)", ZeroExtend32(value),
                       m_transfer_address);
-      m_transfer_address = (m_transfer_address + sizeof(value)) & RAM_MASK;
+      RAMTransferWrite(value);
       return;
     }
 
@@ -107,11 +106,17 @@ void SPU::WriteRegister(u32 offset, u16 value)
 
 u32 SPU::DMARead()
 {
-  Log_ErrorPrintf("SPU DMA READ");
-  return UINT32_C(0xFFFFFFFF);
+  const u16 lsb = RAMTransferRead();
+  const u16 msb = RAMTransferRead();
+  return ZeroExtend32(lsb) | (ZeroExtend32(msb) << 16);
 }
 
-void SPU::DMAWrite(u32 value) {}
+void SPU::DMAWrite(u32 value)
+{
+  // two 16-bit writes to prevent out-of-bounds
+  RAMTransferWrite(Truncate16(value));
+  RAMTransferWrite(Truncate16(value >> 16));
+}
 
 void SPU::UpdateDMARequest()
 {
@@ -119,3 +124,17 @@ void SPU::UpdateDMARequest()
   const bool request = (mode == RAMTransferMode::DMAWrite || mode == RAMTransferMode::DMARead);
   m_dma->SetRequest(DMA::Channel::SPU, request);
 }
+
+u16 SPU::RAMTransferRead()
+{
+  u16 value;
+  std::memcpy(&value, &m_ram[m_transfer_address], sizeof(value));
+  m_transfer_address = (m_transfer_address + sizeof(value)) & RAM_MASK;
+  return value;
+}
+
+void SPU::RAMTransferWrite(u16 value)
+{
+  std::memcpy(&m_ram[m_transfer_address], &value, sizeof(value));
+  m_transfer_address = (m_transfer_address + sizeof(value)) & RAM_MASK;
+}
diff --git a/src/pse/spu.h b/src/pse/spu.h
index e61849669..91a211ad0 100644
--- a/src/pse/spu.h
+++ b/src/pse/spu.h
@@ -82,6 +82,8 @@ private:
 #endif
 
   void UpdateDMARequest();
+  u16 RAMTransferRead();
+  void RAMTransferWrite(u16 value);
 
   System* m_system = nullptr;
   DMA* m_dma = nullptr;