From 8ad6f2cecc4bf723053d7bf9e7846ab8ab56aab7 Mon Sep 17 00:00:00 2001
From: MerryMage <MerryMage@users.noreply.github.com>
Date: Fri, 7 Apr 2017 20:54:11 +0100
Subject: [PATCH] AX: Add support for UCodes without LPF

---
 Source/Core/Core/HW/DSPHLE/UCodes/AX.cpp      |  4 +-
 Source/Core/Core/HW/DSPHLE/UCodes/AXStructs.h |  2 +-
 Source/Core/Core/HW/DSPHLE/UCodes/AXVoice.h   | 59 ++++++++++++++++---
 Source/Core/Core/HW/DSPHLE/UCodes/AXWii.cpp   |  4 +-
 4 files changed, 57 insertions(+), 12 deletions(-)

diff --git a/Source/Core/Core/HW/DSPHLE/UCodes/AX.cpp b/Source/Core/Core/HW/DSPHLE/UCodes/AX.cpp
index 7d8e4522f2..7c9e745fd1 100644
--- a/Source/Core/Core/HW/DSPHLE/UCodes/AX.cpp
+++ b/Source/Core/Core/HW/DSPHLE/UCodes/AX.cpp
@@ -422,7 +422,7 @@ void AXUCode::ProcessPBList(u32 pb_addr)
                           m_samples_auxA_right, m_samples_auxA_surround, m_samples_auxB_left,
                           m_samples_auxB_right, m_samples_auxB_surround}};
 
-    ReadPB(pb_addr, pb);
+    ReadPB(pb_addr, pb, m_crc);
 
     u32 updates_addr = HILO_TO_32(pb.updates.data);
     u16* updates = (u16*)HLEMemory_Get_Pointer(updates_addr);
@@ -439,7 +439,7 @@ void AXUCode::ProcessPBList(u32 pb_addr)
         buffers.ptrs[i] += spms;
     }
 
-    WritePB(pb_addr, pb);
+    WritePB(pb_addr, pb, m_crc);
     pb_addr = HILO_TO_32(pb.next_pb);
   }
 }
diff --git a/Source/Core/Core/HW/DSPHLE/UCodes/AXStructs.h b/Source/Core/Core/HW/DSPHLE/UCodes/AXStructs.h
index 96b9543881..098e05073f 100644
--- a/Source/Core/Core/HW/DSPHLE/UCodes/AXStructs.h
+++ b/Source/Core/Core/HW/DSPHLE/UCodes/AXStructs.h
@@ -252,7 +252,7 @@ struct AXPB
   PBADPCMInfo adpcm;
   PBSampleRateConverter src;
   PBADPCMLoopInfo adpcm_loop_info;
-  PBLowPassFilter lpf;
+  PBLowPassFilter lpf;  // Skipped when writing to/reading from MRAM/ARAM for certain AX UCodes
   u16 loop_counter;
 
   u16 padding[24];
diff --git a/Source/Core/Core/HW/DSPHLE/UCodes/AXVoice.h b/Source/Core/Core/HW/DSPHLE/UCodes/AXVoice.h
index 8e77b5ce4a..b7fca29356 100644
--- a/Source/Core/Core/HW/DSPHLE/UCodes/AXVoice.h
+++ b/Source/Core/Core/HW/DSPHLE/UCodes/AXVoice.h
@@ -80,18 +80,63 @@ union AXBuffers
 #endif
 };
 
-// Read a PB from MRAM/ARAM
-void ReadPB(u32 addr, PB_TYPE& pb)
+// Determines if this version of the UCode has a PBLowPassFilter in its AXPB layout.
+bool HasLpf(u32 crc)
 {
-  u16* dst = (u16*)&pb;
-  Memory::CopyFromEmuSwapped<u16>(dst, addr, sizeof(pb));
+  switch (crc)
+  {
+  case 0x4E8A8B21:
+    return false;
+  default:
+    return true;
+  }
+}
+
+// Read a PB from MRAM/ARAM
+void ReadPB(u32 addr, PB_TYPE& pb, u32 crc)
+{
+  if (HasLpf(crc))
+  {
+    u16* dst = (u16*)&pb;
+    Memory::CopyFromEmuSwapped<u16>(dst, addr, sizeof(pb));
+  }
+  else
+  {
+    // The below is a terrible hack in order to support two different AXPB layouts.
+    // We skip lpf in this layout.
+
+    char* dst = (char*)&pb;
+
+    constexpr size_t lpf_off = offsetof(AXPB, lpf);
+    constexpr size_t lc_off = offsetof(AXPB, loop_counter);
+
+    Memory::CopyFromEmuSwapped<u16>((u16*)dst, addr, lpf_off);
+    memset(dst + lpf_off, 0, lc_off - lpf_off);
+    Memory::CopyFromEmuSwapped<u16>((u16*)(dst + lc_off), addr + lpf_off, sizeof(pb) - lc_off);
+  }
 }
 
 // Write a PB back to MRAM/ARAM
-void WritePB(u32 addr, const PB_TYPE& pb)
+void WritePB(u32 addr, const PB_TYPE& pb, u32 crc)
 {
-  const u16* src = (const u16*)&pb;
-  Memory::CopyToEmuSwapped<u16>(addr, src, sizeof(pb));
+  if (HasLpf(crc))
+  {
+    const u16* src = (const u16*)&pb;
+    Memory::CopyToEmuSwapped<u16>(addr, src, sizeof(pb));
+  }
+  else
+  {
+    // The below is a terrible hack in order to support two different AXPB layouts.
+    // We skip lpf in this layout.
+
+    const char* src = (const char*)&pb;
+
+    constexpr size_t lpf_off = offsetof(AXPB, lpf);
+    constexpr size_t lc_off = offsetof(AXPB, loop_counter);
+
+    Memory::CopyToEmuSwapped<u16>(addr, (const u16*)src, lpf_off);
+    Memory::CopyToEmuSwapped<u16>(addr + lpf_off, (const u16*)(src + lc_off), sizeof(pb) - lc_off);
+  }
 }
 
 #if 0
diff --git a/Source/Core/Core/HW/DSPHLE/UCodes/AXWii.cpp b/Source/Core/Core/HW/DSPHLE/UCodes/AXWii.cpp
index 22e2268168..4c77f35224 100644
--- a/Source/Core/Core/HW/DSPHLE/UCodes/AXWii.cpp
+++ b/Source/Core/Core/HW/DSPHLE/UCodes/AXWii.cpp
@@ -451,7 +451,7 @@ void AXWiiUCode::ProcessPBList(u32 pb_addr)
                           m_samples_aux1,      m_samples_wm2,        m_samples_aux2,
                           m_samples_wm3,       m_samples_aux3}};
 
-    ReadPB(pb_addr, pb);
+    ReadPB(pb_addr, pb, m_crc);
 
     u16 num_updates[3];
     u16 updates[1024];
@@ -476,7 +476,7 @@ void AXWiiUCode::ProcessPBList(u32 pb_addr)
                    m_coeffs_available ? m_coeffs : nullptr);
     }
 
-    WritePB(pb_addr, pb);
+    WritePB(pb_addr, pb, m_crc);
     pb_addr = HILO_TO_32(pb.next_pb);
   }
 }