From 0ed46cc2b1ff6939fcfe18b243591fdc941726f6 Mon Sep 17 00:00:00 2001
From: Near <77224854+near-san@users.noreply.github.com>
Date: Wed, 24 Jun 2020 09:25:00 +0000
Subject: [PATCH] Update to ares v114r08 release.

  - PlayStation: fixed a bug in the SLLV instruction
  - PlayStation: implemented interrupts
---
 ares/ares/information.hpp          |   2 +-
 ares/ps1/cpu/core/core.cpp         |  14 ++-
 ares/ps1/cpu/core/decoder.hpp      |   2 +-
 ares/ps1/cpu/core/disassembler.hpp |   2 +-
 ares/ps1/cpu/cpu.cpp               |   1 +
 ares/ps1/cpu/cpu.hpp               |  45 ++++++++-
 ares/ps1/cpu/dma.cpp               |  28 +++++-
 ares/ps1/cpu/interrupt.cpp         | 146 +++++++++++++++++++++++++++++
 ares/ps1/gpu/gpu.cpp               |   5 +
 ares/ps1/gpu/gpu.hpp               |   9 +-
 ares/ps1/gpu/io.cpp                |  31 +++++-
 ares/ps1/memory/bus.hpp            |   5 +-
 ares/ps1/memory/memory.hpp         |  37 --------
 ares/ps1/spu/io.cpp                |  52 ++++++++++
 ares/ps1/spu/spu.cpp               |   2 +
 ares/ps1/spu/spu.hpp               |  20 ++++
 16 files changed, 346 insertions(+), 55 deletions(-)
 create mode 100644 ares/ps1/cpu/interrupt.cpp
 create mode 100644 ares/ps1/spu/io.cpp

diff --git a/ares/ares/information.hpp b/ares/ares/information.hpp
index 6778e2f34..83c08c376 100644
--- a/ares/ares/information.hpp
+++ b/ares/ares/information.hpp
@@ -2,7 +2,7 @@
 
 namespace ares {
   static const string Name       = "ares";
-  static const string Version    = "114.7";
+  static const string Version    = "114.8";
   static const string Copyright  = "ares team";
   static const string License    = "BY-NC-ND 4.0";
   static const string LicenseURI = "https://creativecommons.org/licenses/by-nc-nd/4.0/";
diff --git a/ares/ps1/cpu/core/core.cpp b/ares/ps1/cpu/core/core.cpp
index 068ff671f..979045ece 100644
--- a/ares/ps1/cpu/core/core.cpp
+++ b/ares/ps1/cpu/core/core.cpp
@@ -26,13 +26,21 @@ auto CPU::raiseException(uint code, uint coprocessor) -> void {
 auto CPU::instruction() -> void {
   auto address = PC;
 
+  if(auto interrupts = scc.cause.interruptPending & scc.status.interruptMask) {
+    if(interrupt.line & scc.status.frame[0].interruptEnable) {
+      scc.cause.interruptPending = interrupts;
+      step(1);
+      return raiseException(0);
+    }
+  }
+
   if constexpr(1) {
     pipeline.address = address;
     pipeline.instruction = bus.readWord(address);
   //instructionDebug();
     decoderEXECUTE();
     instructionEpilogue();
-    step(1);
+    step(2);
   }
 }
 
@@ -65,8 +73,8 @@ auto CPU::instructionEpilogue() -> bool {
 }
 
 auto CPU::instructionDebug() -> void {
-  pipeline.address = PC;
-  pipeline.instruction = bus.readWord(pipeline.address);
+//pipeline.address = PC;
+//pipeline.instruction = bus.readWord(pipeline.address);
 
   static vector<bool> mask;
   if(!mask) mask.resize(0x0800'0000);
diff --git a/ares/ps1/cpu/core/decoder.hpp b/ares/ps1/cpu/core/decoder.hpp
index 62066eb9b..a2b274121 100644
--- a/ares/ps1/cpu/core/decoder.hpp
+++ b/ares/ps1/cpu/core/decoder.hpp
@@ -87,7 +87,7 @@
   op(0x01, INVALID);
   op(0x02, SRL, RD, RT, SA);
   op(0x03, SRA, RD, RT, SA);
-  op(0x04, SLLV, RD, RT, SA);
+  op(0x04, SLLV, RD, RT, RS);
   op(0x05, INVALID);
   op(0x06, SRLV, RD, RT, RS);
   op(0x07, SRAV, RD, RT, RS);
diff --git a/ares/ps1/cpu/core/disassembler.hpp b/ares/ps1/cpu/core/disassembler.hpp
index 5ac535c6e..d266a901a 100644
--- a/ares/ps1/cpu/core/disassembler.hpp
+++ b/ares/ps1/cpu/core/disassembler.hpp
@@ -7,7 +7,7 @@
     auto disassemble(u32 address, u32 instruction) -> string;
     template<typename... P> auto hint(P&&... p) const -> string;
 
-    bool showColors = true;
+    bool showColors = false;
     bool showValues = true;
 
   //private:
diff --git a/ares/ps1/cpu/cpu.cpp b/ares/ps1/cpu/cpu.cpp
index 21b52d067..fcbffc649 100644
--- a/ares/ps1/cpu/cpu.cpp
+++ b/ares/ps1/cpu/cpu.cpp
@@ -4,6 +4,7 @@ namespace ares::PlayStation {
 
 CPU cpu;
 #include "core/core.cpp"
+#include "interrupt.cpp"
 #include "dma.cpp"
 #include "serialization.cpp"
 
diff --git a/ares/ps1/cpu/cpu.hpp b/ares/ps1/cpu/cpu.hpp
index ea389509f..2c5ff36fa 100644
--- a/ares/ps1/cpu/cpu.hpp
+++ b/ares/ps1/cpu/cpu.hpp
@@ -19,14 +19,57 @@ struct CPU : Thread {
 
   #include "core/core.hpp"
 
-  struct DMA : Memory::IO<DMA> {
+  struct Interrupt {
+    enum : uint { Vblank, GPU, CDROM, DMA, Timer0, Timer1, Timer2, Peripheral, SIO, SPU, PIO };
+
+    CPU& self;
+    Interrupt(CPU& self) : self(self) {}
+
+    //interrupt.cpp
+    auto poll() -> void;
+    auto pulse(uint source) -> void;
+    auto raise(uint source) -> void;
+    auto lower(uint source) -> void;
+
+    auto readByte(u32 address) -> u8;
+    auto readHalf(u32 address) -> u16;
+    auto readWord(u32 address) -> u32;
+    auto writeByte(u32 address, u8 data) -> void;
+    auto writeHalf(u32 address, u16 data) -> void;
+    auto writeWord(u32 address, u32 data) -> void;
+
+    struct Source {
+      uint1 line = 0;
+      uint1 stat = 0;
+      uint1 mask = 0;
+    };
+
+    uint1  line = 0;
+    Source vblank;
+    Source gpu;
+    Source cdrom;
+    Source dma;
+    Source timer0;
+    Source timer1;
+    Source timer2;
+    Source peripheral;
+    Source sio;
+    Source spu;
+    Source pio;
+  } interrupt{*this};
+
+  struct DMA {
     enum : uint { MDECIN, MDECOUT, GPU, CDROM, SPU, PIO, OTC };  //channels
 
     CPU& self;
     DMA(CPU& self) : self(self) {}
 
     //dma.cpp
+    auto readByte(u32 address) -> u8;
+    auto readHalf(u32 address) -> u16;
     auto readWord(u32 address) -> u32;
+    auto writeByte(u32 address, u8 data) -> void;
+    auto writeHalf(u32 address, u16 data) -> void;
     auto writeWord(u32 address, u32 data) -> void;
     auto transferLinear(uint c) -> void;
     auto transferLinked(uint c) -> void;
diff --git a/ares/ps1/cpu/dma.cpp b/ares/ps1/cpu/dma.cpp
index 2ddef3045..936bd0461 100644
--- a/ares/ps1/cpu/dma.cpp
+++ b/ares/ps1/cpu/dma.cpp
@@ -1,20 +1,28 @@
+auto CPU::DMA::readByte(u32 address) -> u8 {
+  return 0;
+}
+
+auto CPU::DMA::readHalf(u32 address) -> u16 {
+  return 0;
+}
+
 auto CPU::DMA::readWord(u32 address) -> u32 {
   uint32 data = 0;
   uint32 c = address >> 4 & 7;
 
   //DnMADR: DMA Base Address
-  if((address & 0xffff'ff0f) == 0x1f80'1080 && c < 7) {
+  if((address & 0xffff'ff8f) == 0x1f80'1080 && c < 7) {
     data.bit(0,23) = channel[c].address;
   }
 
   //DnBCR: DMA Block Control
-  if((address & 0xffff'ff0f) == 0x1f80'1084 && c < 7) {
+  if((address & 0xffff'ff8f) == 0x1f80'1084 && c < 7) {
     data.bit( 0,15) = channel[c].length;
     data.bit(16,31) = channel[c].blocks;
   }
 
   //DnCHCR: DMA Channel Control
-  if((address & 0xffff'ff0f) == 0x1f80'1088 && c < 7) {
+  if((address & 0xffff'ff8f) == 0x1f80'1088 && c < 7) {
     data.bit( 0)    = channel[c].direction;
     data.bit( 1)    = channel[c].step;
     data.bit( 2)    = channel[c].chopping.enable;
@@ -68,6 +76,12 @@ auto CPU::DMA::readWord(u32 address) -> u32 {
   return data;
 }
 
+auto CPU::DMA::writeByte(u32 address, u8 value) -> void {
+}
+
+auto CPU::DMA::writeHalf(u32 address, u16 value) -> void {
+}
+
 auto CPU::DMA::writeWord(u32 address, u32 value) -> void {
   uint32 data = value;
   uint32 c = address >> 4 & 7;
@@ -95,12 +109,14 @@ auto CPU::DMA::writeWord(u32 address, u32 value) -> void {
     channel[c].trigger            = data.bit(28);
     channel[c].unknown            = data.bit(29,30);
 
-  //print(c, " ", channel[c].direction, " ", channel[c].synchronization, " ", hex(channel[c].address, 8L), "\n");
-
     if(channel[c].active()) {
+    //u32 base = address & 0xffff'fff0;
+    //print("DMA", c, " ", hex(readWord(base + 8), 8L), " ", hex(readWord(base + 0), 8L), " ", hex(readWord(base + 4), 8L), "\n");
+
       if(channel[c].synchronization == 0) transferLinear(c);
       if(channel[c].synchronization == 1) transferLinear(c);
       if(channel[c].synchronization == 2) transferLinked(c);
+      self.interrupt.pulse(CPU::Interrupt::DMA);
     }
   }
 
@@ -194,6 +210,8 @@ auto CPU::DMA::transferLinked(uint c) -> void {
     address = header & 0xffffff;
     if(address & 0x800000) break;
   } while(--timeout);
+  channel[c].enable  = 0;
+  channel[c].trigger = 0;
 }
 
 auto CPU::DMA::pollIRQ() -> void {
diff --git a/ares/ps1/cpu/interrupt.cpp b/ares/ps1/cpu/interrupt.cpp
new file mode 100644
index 000000000..34f63f977
--- /dev/null
+++ b/ares/ps1/cpu/interrupt.cpp
@@ -0,0 +1,146 @@
+auto CPU::Interrupt::poll() -> void {
+  line = 0;
+  line |= vblank.stat & vblank.mask;
+  line |= gpu.stat & gpu.mask;
+  line |= cdrom.stat & cdrom.mask;
+  line |= dma.stat & dma.mask;
+  line |= timer0.stat & timer0.mask;
+  line |= timer1.stat & timer1.mask;
+  line |= timer2.stat & timer2.mask;
+  line |= peripheral.stat & peripheral.mask;
+  line |= sio.stat & sio.mask;
+  line |= spu.stat & spu.mask;
+  line |= pio.stat & pio.mask;
+  self.scc.cause.interruptPending.bit(2) = line;
+}
+
+auto CPU::Interrupt::pulse(uint source) -> void {
+  raise(source);
+  lower(source);
+}
+
+auto CPU::Interrupt::raise(uint source) -> void {
+  if(source ==  0 && !vblank.line) vblank.line = vblank.stat = 1;
+  if(source ==  1 && !gpu.line) gpu.line = gpu.stat = 1;
+  if(source ==  2 && !cdrom.line) cdrom.line = cdrom.stat = 1;
+  if(source ==  3 && !dma.line) dma.line = dma.stat = 1;
+  if(source ==  4 && !timer0.line) timer0.line = timer0.stat = 1;
+  if(source ==  5 && !timer1.line) timer1.line = timer1.stat = 1;
+  if(source ==  6 && !timer2.line) timer2.line = timer2.stat = 1;
+  if(source ==  7 && !peripheral.line) peripheral.line = peripheral.stat = 1;
+  if(source ==  8 && !sio.line) sio.line = sio.stat = 1;
+  if(source ==  9 && !spu.line) spu.line = spu.stat = 1;
+  if(source == 10 && !pio.line) pio.line = pio.stat = 1;
+  poll();
+}
+
+auto CPU::Interrupt::lower(uint source) -> void {
+  if(source ==  0) vblank.line = 0;
+  if(source ==  1) gpu.line = 0;
+  if(source ==  2) cdrom.line = 0;
+  if(source ==  3) dma.line = 0;
+  if(source ==  4) timer0.line = 0;
+  if(source ==  5) timer1.line = 0;
+  if(source ==  6) timer2.line = 0;
+  if(source ==  7) peripheral.line = 0;
+  if(source ==  8) sio.line = 0;
+  if(source ==  9) spu.line = 0;
+  if(source == 10) pio.line = 0;
+  poll();
+}
+
+auto CPU::Interrupt::readByte(u32 address) -> u8 {
+  uint8 data = 0;
+  print("* read byte ", hex(address, 8L), "\n");
+  return data;
+}
+
+auto CPU::Interrupt::readHalf(u32 address) -> u16 {
+  uint16 data = 0;
+
+  //I_STAT
+  if(address == 0x1f80'1070) {
+    data.bit( 0) = vblank.stat;
+    data.bit( 1) = gpu.stat;
+    data.bit( 2) = cdrom.stat;
+    data.bit( 3) = dma.stat;
+    data.bit( 4) = timer0.stat;
+    data.bit( 5) = timer1.stat;
+    data.bit( 6) = timer2.stat;
+    data.bit( 7) = peripheral.stat;
+    data.bit( 8) = sio.stat;
+    data.bit( 9) = spu.stat;
+    data.bit(10) = pio.stat;
+  }
+
+  //I_MASK
+  if(address == 0x1f80'1074) {
+    data.bit( 0) = vblank.mask;
+    data.bit( 1) = gpu.mask;
+    data.bit( 2) = cdrom.mask;
+    data.bit( 3) = dma.mask;
+    data.bit( 4) = timer0.mask;
+    data.bit( 5) = timer1.mask;
+    data.bit( 6) = timer2.mask;
+    data.bit( 7) = peripheral.mask;
+    data.bit( 8) = sio.mask;
+    data.bit( 9) = spu.mask;
+    data.bit(10) = pio.mask;
+  }
+
+  return data;
+}
+
+auto CPU::Interrupt::readWord(u32 address) -> u32 {
+  uint32 data = 0;
+  data |= readHalf(address & ~3 | 0) <<  0;
+  data |= readHalf(address & ~3 | 2) << 16;
+  return data;
+}
+
+auto CPU::Interrupt::writeByte(u32 address, u8 value) -> void {
+  uint8 data = value;
+  print("* write byte ", hex(address, 8L), "\n");
+}
+
+auto CPU::Interrupt::writeHalf(u32 address, u16 value) -> void {
+  uint16 data = value;
+
+  //I_STAT
+  if(address == 0x1f80'1070) {
+    if(!data.bit( 0)) vblank.stat = 0;
+    if(!data.bit( 1)) gpu.stat = 0;
+    if(!data.bit( 2)) cdrom.stat = 0;
+    if(!data.bit( 3)) dma.stat = 0;
+    if(!data.bit( 4)) timer0.stat = 0;
+    if(!data.bit( 5)) timer1.stat = 0;
+    if(!data.bit( 6)) timer2.stat = 0;
+    if(!data.bit( 7)) peripheral.stat = 0;
+    if(!data.bit( 8)) sio.stat = 0;
+    if(!data.bit( 9)) spu.stat = 0;
+    if(!data.bit(10)) pio.stat = 0;
+    poll();
+  }
+
+  //I_MASK
+  if(address == 0x1f80'1074) {
+    vblank.mask     = data.bit( 0);
+    gpu.mask        = data.bit( 1);
+    cdrom.mask      = data.bit( 2);
+    dma.mask        = data.bit( 3);
+    timer0.mask     = data.bit( 4);
+    timer1.mask     = data.bit( 5);
+    timer2.mask     = data.bit( 6);
+    peripheral.mask = data.bit( 7);
+    sio.mask        = data.bit( 8);
+    spu.mask        = data.bit( 9);
+    pio.mask        = data.bit(10);
+    poll();
+  }
+}
+
+auto CPU::Interrupt::writeWord(u32 address, u32 value) -> void {
+  uint32 data = value;
+  writeHalf(address & ~3 | 0, value >>  0);
+  writeHalf(address & ~3 | 2, value >> 16);
+}
diff --git a/ares/ps1/gpu/gpu.cpp b/ares/ps1/gpu/gpu.cpp
index 9f63ad213..19d7bca81 100644
--- a/ares/ps1/gpu/gpu.cpp
+++ b/ares/ps1/gpu/gpu.cpp
@@ -22,8 +22,13 @@ auto GPU::unload() -> void {
 }
 
 auto GPU::main() -> void {
+  if(io.vcounter == 240) {
+    cpu.interrupt.raise(CPU::Interrupt::Vblank);
+  }
+
   if(++io.vcounter == 262) {
     io.vcounter = 0;
+    cpu.interrupt.lower(CPU::Interrupt::Vblank);
     refreshed = true;
   }
 
diff --git a/ares/ps1/gpu/gpu.hpp b/ares/ps1/gpu/gpu.hpp
index 4a107108b..a60df8718 100644
--- a/ares/ps1/gpu/gpu.hpp
+++ b/ares/ps1/gpu/gpu.hpp
@@ -1,6 +1,6 @@
 //Graphics Processing Unit
 
-struct GPU : Thread, Memory::IO<GPU> {
+struct GPU : Thread {
   Node::Component node;
   Node::Screen screen;
 
@@ -14,14 +14,19 @@ struct GPU : Thread, Memory::IO<GPU> {
   auto power(bool reset) -> void;
 
   //io.cpp
+  auto readByte(u32 address) -> u8;
+  auto readHalf(u32 address) -> u16;
   auto readWord(u32 address) -> u32;
+  auto writeByte(u32 address, u8 data) -> void;
+  auto writeHalf(u32 address, u16 data) -> void;
   auto writeWord(u32 address, u32 data) -> void;
 
   //serialization.cpp
   auto serialize(serializer&) -> void;
 
   struct IO {
-    u16 vcounter = 0;
+    uint16 vcounter = 0;
+     uint2 dmaDirection = 0;
   } io;
 
 //unserialized:
diff --git a/ares/ps1/gpu/io.cpp b/ares/ps1/gpu/io.cpp
index 0aaa4b1d3..d913fd548 100644
--- a/ares/ps1/gpu/io.cpp
+++ b/ares/ps1/gpu/io.cpp
@@ -1,3 +1,11 @@
+auto GPU::readByte(u32 address) -> u8 {
+  return 0;
+}
+
+auto GPU::readHalf(u32 address) -> u16 {
+  return 0;
+}
+
 auto GPU::readWord(u32 address) -> u32 {
   uint32 data = 0;
 
@@ -7,14 +15,27 @@ auto GPU::readWord(u32 address) -> u32 {
 
   //GPUSTAT
   if(address == 0x1f80'1814) {
-    data.bit(26) = 1;  //ready to receive command
-    data.bit(27) = 1;  //ready to send VRAM to CPU
-    data.bit(28) = 1;  //ready to receive DMA block
+    switch(io.dmaDirection) {
+    case 0: data.bit(25) = 0; break;
+    case 1: data.bit(25) = 1; break;
+    case 2: data.bit(25) = 1; break;
+    case 3: data.bit(25) = 1; break;
+    }
+    data.bit(26)    = 1;  //ready to receive command
+    data.bit(27)    = 1;  //ready to send VRAM to CPU
+    data.bit(28)    = 1;  //ready to receive DMA block
+    data.bit(29,30) = io.dmaDirection;
   }
 
   return data;
 }
 
+auto GPU::writeByte(u32 address, u8 value) -> void {
+}
+
+auto GPU::writeHalf(u32 address, u16 value) -> void {
+}
+
 auto GPU::writeWord(u32 address, u32 value) -> void {
   uint32 data = value;
 
@@ -24,5 +45,9 @@ auto GPU::writeWord(u32 address, u32 value) -> void {
 
   //GP1
   if(address == 0x1f80'1814) {
+    u8 command = data >> 24;
+    if(command == 0x04) {
+      io.dmaDirection = data.bit(0,1);
+    }
   }
 }
diff --git a/ares/ps1/memory/bus.hpp b/ares/ps1/memory/bus.hpp
index 83270b7e6..9ea63e587 100644
--- a/ares/ps1/memory/bus.hpp
+++ b/ares/ps1/memory/bus.hpp
@@ -5,11 +5,14 @@
   if(address <= 0x1eff'ffff) return unmapped; \
   if(address <= 0x1f7f'ffff) return unmapped; \
   if(address <= 0x1f80'03ff) return cpu.cache.access(__VA_ARGS__); \
-  if(address <= 0x1f80'107f) return unmapped; \
+  if(address <= 0x1f80'106f) return unmapped; \
+  if(address <= 0x1f80'107f) return cpu.interrupt.access(__VA_ARGS__); \
   if(address <= 0x1f80'10ff) return cpu.dma.access(__VA_ARGS__); \
   if(address <= 0x1f80'17ff) return unmapped; \
   if(address <= 0x1f80'180f) return unmapped; \
   if(address <= 0x1f80'181f) return gpu.access(__VA_ARGS__); \
+  if(address <= 0x1f80'1bff) return unmapped; \
+  if(address <= 0x1f80'1fff) return spu.access(__VA_ARGS__); \
   if(address <= 0x1fbf'ffff) return unmapped; \
   if(address <= 0x1fff'ffff) return bios.access(__VA_ARGS__); \
   return unmapped; \
diff --git a/ares/ps1/memory/memory.hpp b/ares/ps1/memory/memory.hpp
index 9cf1f3a2b..5bfd0d88c 100644
--- a/ares/ps1/memory/memory.hpp
+++ b/ares/ps1/memory/memory.hpp
@@ -94,43 +94,6 @@ struct Writable {
   u32 maskWord = 0;
 };
 
-template<typename T>
-struct IO {
-  auto readByte(u32 address) -> u8 {
-    auto data = ((T*)this)->readWord(address);
-    switch(address & 3) {
-    case 0: return data >>  0;
-    case 1: return data >>  8;
-    case 2: return data >> 16;
-    case 3: return data >> 24;
-    } unreachable;
-  }
-
-  auto readHalf(u32 address) -> u16 {
-    auto data = ((T*)this)->readWord(address);
-    switch(address & 2) {
-    case 0: return data >>  0;
-    case 2: return data >> 16;
-    } unreachable;
-  }
-
-  auto writeByte(u32 address, u8 data) -> void {
-    switch(address & 3) {
-    case 0: return ((T*)this)->writeWord(address, data <<  0);
-    case 1: return ((T*)this)->writeWord(address, data <<  8);
-    case 2: return ((T*)this)->writeWord(address, data << 16);
-    case 3: return ((T*)this)->writeWord(address, data << 24);
-    }
-  }
-
-  auto writeHalf(u32 address, u16 data) -> void {
-    switch(address & 2) {
-    case 0: return ((T*)this)->writeWord(address, data <<  0);
-    case 2: return ((T*)this)->writeWord(address, data << 16);
-    }
-  }
-};
-
 }
 
 struct Bus {
diff --git a/ares/ps1/spu/io.cpp b/ares/ps1/spu/io.cpp
new file mode 100644
index 000000000..f95908d92
--- /dev/null
+++ b/ares/ps1/spu/io.cpp
@@ -0,0 +1,52 @@
+auto SPU::readByte(u32 address) -> u8 {
+  return 0;
+}
+
+auto SPU::readHalf(u32 address) -> u16 {
+  uint16 data = 0;
+
+  //SPURAMCNT
+  if(address == 0x1f80'1dac) {
+    data.bit(1,3) = io.ramTransferType;
+  }
+
+  //SPUSTAT
+  if(address == 0x1f80'1dae) {
+    data.bit(0)   = io.cdAudioEnable;
+    data.bit(1)   = io.externalAudioEnable;
+    data.bit(2)   = io.cdAudioReverb;
+    data.bit(3)   = io.externalAudioReverb;
+    data.bit(4,5) = io.ramTransferMode;
+    data.bit(7)   = io.ramTransferMode.bit(1);  //unverified
+  }
+
+  return data;
+}
+
+auto SPU::readWord(u32 address) -> u32 {
+  return 0;
+}
+
+auto SPU::writeByte(u32 address, u8 value) -> void {
+}
+
+auto SPU::writeHalf(u32 address, u16 value) -> void {
+  uint16 data = value;
+
+  //SPUCNT
+  if(address == 0x1f80'1daa) {
+    io.cdAudioEnable       = data.bit(0);
+    io.externalAudioEnable = data.bit(1);
+    io.cdAudioReverb       = data.bit(2);
+    io.externalAudioReverb = data.bit(3);
+    io.ramTransferMode     = data.bit(4,5);
+  }
+
+  //SPURAMCHT
+  if(address == 0x1f80'1dac) {
+    io.ramTransferType = data.bit(1,3);
+  }
+}
+
+auto SPU::writeWord(u32 address, u32 value) -> void {
+}
diff --git a/ares/ps1/spu/spu.cpp b/ares/ps1/spu/spu.cpp
index d144224f7..5c944cbda 100644
--- a/ares/ps1/spu/spu.cpp
+++ b/ares/ps1/spu/spu.cpp
@@ -3,6 +3,7 @@
 namespace ares::PlayStation {
 
 SPU spu;
+#include "io.cpp"
 #include "serialization.cpp"
 
 auto SPU::load(Node::Object parent) -> void {
@@ -33,6 +34,7 @@ auto SPU::step(uint clocks) -> void {
 
 auto SPU::power(bool reset) -> void {
   Thread::reset();
+  io = {};
 }
 
 }
diff --git a/ares/ps1/spu/spu.hpp b/ares/ps1/spu/spu.hpp
index b30bf70fb..ecb600e7a 100644
--- a/ares/ps1/spu/spu.hpp
+++ b/ares/ps1/spu/spu.hpp
@@ -14,8 +14,28 @@ struct SPU : Thread {
 
   auto power(bool reset) -> void;
 
+  //io.cpp
+  auto readByte(u32 address) -> u8;
+  auto readHalf(u32 address) -> u16;
+  auto readWord(u32 address) -> u32;
+  auto writeByte(u32 address, u8 data) -> void;
+  auto writeHalf(u32 address, u16 data) -> void;
+  auto writeWord(u32 address, u32 data) -> void;
+
   //serialization.cpp
   auto serialize(serializer&) -> void;
+
+  struct IO {
+    //SPUCNT
+    uint1 cdAudioEnable = 0;
+    uint1 externalAudioEnable = 0;
+    uint1 cdAudioReverb = 0;
+    uint1 externalAudioReverb = 0;
+    uint2 ramTransferMode = 0;
+
+    //SPURAMCNT
+    uint3 ramTransferType = 0;
+  } io;
 };
 
 extern SPU spu;