From 69a00a64e6b5aac73f6ff2dd3a0df717b506c6e4 Mon Sep 17 00:00:00 2001
From: Connor McLaughlin <stenzek@gmail.com>
Date: Sat, 30 May 2020 02:19:10 +1000
Subject: [PATCH] Bus: Adjust memory access and MMIO timing

Hasn't broken anything yet, but needs more thorough testing.
---
 src/core/bus.h   |  7 -----
 src/core/bus.inl | 75 +++++++++++++++++++++++++++++++++++-------------
 2 files changed, 55 insertions(+), 27 deletions(-)

diff --git a/src/core/bus.h b/src/core/bus.h
index ba0ff5cf5..609dec2c4 100644
--- a/src/core/bus.h
+++ b/src/core/bus.h
@@ -140,13 +140,6 @@ private:
     MEMCTRL_REG_COUNT = 9
   };
 
-  enum : TickCount
-  {
-    RAM_READ_ACCESS_DELAY = 5,  // Nocash docs say RAM takes 6 cycles to access. Subtract one because we already add a
-                                // tick for the instruction.
-    RAM_WRITE_ACCESS_DELAY = 0, // Writes are free unless we're executing more than 4 stores in a row.
-  };
-
   union MEMDELAY
   {
     u32 bits;
diff --git a/src/core/bus.inl b/src/core/bus.inl
index f8e1e6a06..be3e109a7 100644
--- a/src/core/bus.inl
+++ b/src/core/bus.inl
@@ -44,8 +44,7 @@ TickCount Bus::DoRAMAccess(u32 offset, u32& value)
     }
   }
 
-  // Nocash docs say RAM takes 6 cycles to access.
-  return (type == MemoryAccessType::Read) ? RAM_READ_ACCESS_DELAY : RAM_WRITE_ACCESS_DELAY;
+  return (type == MemoryAccessType::Read) ? 3 : 0;
 }
 
 template<MemoryAccessType type, MemoryAccessSize size>
@@ -109,65 +108,93 @@ TickCount Bus::DispatchAccess(PhysicalMemoryAddress address, u32& value)
   else if (address < (MEMCTRL_BASE + MEMCTRL_SIZE))
   {
     if constexpr (type == MemoryAccessType::Read)
+    {
       value = DoReadMemoryControl(size, address & PAD_MASK);
+      return 1;
+    }
     else
+    {
       DoWriteMemoryControl(size, address & PAD_MASK, value);
-
-    return 0;
+      return 0;
+    }
   }
   else if (address < (PAD_BASE + PAD_SIZE))
   {
     if constexpr (type == MemoryAccessType::Read)
+    {
       value = DoReadPad(size, address & PAD_MASK);
+      return 1;
+    }
     else
+    {
       DoWritePad(size, address & PAD_MASK, value);
-
-    return 0;
+      return 0;
+    }
   }
   else if (address < (SIO_BASE + SIO_SIZE))
   {
     if constexpr (type == MemoryAccessType::Read)
+    {
       value = DoReadSIO(size, address & SIO_MASK);
+      return 1;
+    }
     else
+    {
       DoWriteSIO(size, address & SIO_MASK, value);
-
-    return 0;
+      return 0;
+    }
   }
   else if (address < (MEMCTRL2_BASE + MEMCTRL2_SIZE))
   {
     if constexpr (type == MemoryAccessType::Read)
+    {
       value = DoReadMemoryControl2(size, address & PAD_MASK);
+      return 1;
+    }
     else
+    {
       DoWriteMemoryControl2(size, address & PAD_MASK, value);
-
-    return 0;
+      return 0;
+    }
   }
   else if (address < (INTERRUPT_CONTROLLER_BASE + INTERRUPT_CONTROLLER_SIZE))
   {
     if constexpr (type == MemoryAccessType::Read)
+    {
       value = DoReadInterruptController(size, address & INTERRUPT_CONTROLLER_MASK);
+      return 1;
+    }
     else
+    {
       DoWriteInterruptController(size, address & INTERRUPT_CONTROLLER_MASK, value);
-
-    return 0;
+      return 0;
+    }
   }
   else if (address < (DMA_BASE + DMA_SIZE))
   {
     if constexpr (type == MemoryAccessType::Read)
+    {
       value = DoReadDMA(size, address & DMA_MASK);
+      return 1;
+    }
     else
+    {
       DoWriteDMA(size, address & DMA_MASK, value);
-
-    return 0;
+      return 0;
+    }
   }
   else if (address < (TIMERS_BASE + TIMERS_SIZE))
   {
     if constexpr (type == MemoryAccessType::Read)
+    {
       value = DoReadTimers(size, address & TIMERS_MASK);
+      return 1;
+    }
     else
+    {
       DoWriteTimers(size, address & TIMERS_MASK, value);
-
-    return 0;
+      return 0;
+    }
   }
   else if (address < CDROM_BASE)
   {
@@ -189,20 +216,28 @@ TickCount Bus::DispatchAccess(PhysicalMemoryAddress address, u32& value)
   else if (address < (GPU_BASE + GPU_SIZE))
   {
     if constexpr (type == MemoryAccessType::Read)
+    {
       value = DoReadGPU(size, address & GPU_MASK);
+      return 1;
+    }
     else
+    {
       DoWriteGPU(size, address & GPU_MASK, value);
-
-    return 0;
+      return 0;
+    }
   }
   else if (address < (MDEC_BASE + MDEC_SIZE))
   {
     if constexpr (type == MemoryAccessType::Read)
+    {
       value = DoReadMDEC(size, address & MDEC_MASK);
+      return 1;
+    }
     else
+    {
       DoWriteMDEC(size, address & MDEC_MASK, value);
-
-    return 0;
+      return 0;
+    }
   }
   else if (address < SPU_BASE)
   {