From 34bba2589e3ddbe94642dd3325a49179cdf27f82 Mon Sep 17 00:00:00 2001
From: Jaklyy <102590697+Jaklyy@users.noreply.github.com>
Date: Thu, 10 Oct 2024 20:51:52 -0400
Subject: [PATCH] tcm (and cache?) reads dont trigger write buffer drains

additionally drains are triggered even in no cache + no buffer regions despite documentation not specifying such
---
 src/CP15.cpp | 24 ++++++++++--------------
 1 file changed, 10 insertions(+), 14 deletions(-)

diff --git a/src/CP15.cpp b/src/CP15.cpp
index 1d082f04..3ea67f3f 100644
--- a/src/CP15.cpp
+++ b/src/CP15.cpp
@@ -1014,9 +1014,6 @@ u32 ARMv5::CodeRead32(u32 addr, bool branch)
         return 0;
     }
 
-    if ((PU_Map[addr>>12] & 0x30))
-        WriteBufferDrain();
-
     if (addr < ITCMSize)
     {
         CodeCycles = 1;
@@ -1039,6 +1036,8 @@ u32 ARMv5::CodeRead32(u32 addr, bool branch)
         //return *(u32*)&CurICacheLine[addr & 0x1C];
     }
 
+    WriteBufferDrain();
+
     NDS.ARM9Timestamp = NDS.ARM9Timestamp + ((1<<NDS.ARM9ClockShift)-1) & ~((1<<NDS.ARM9ClockShift)-1);
 
     if ((addr >> 24) == 0x02)
@@ -1066,9 +1065,6 @@ bool ARMv5::DataRead8(u32 addr, u32* val)
         DataCycles = 1;
         return false;
     }
-    
-    if ((PU_Map[addr>>12] & 0x30))
-        WriteBufferDrain();
 
     if (addr < ITCMSize)
     {
@@ -1085,6 +1081,8 @@ bool ARMv5::DataRead8(u32 addr, u32* val)
         *val = *(u8*)&DTCM[addr & (DTCMPhysicalSize - 1)];
         return true;
     }
+    
+    WriteBufferDrain();
 
     NDS.ARM9Timestamp = NDS.ARM9Timestamp + ((1<<NDS.ARM9ClockShift)-1) & ~((1<<NDS.ARM9ClockShift)-1);
     
@@ -1114,8 +1112,6 @@ bool ARMv5::DataRead16(u32 addr, u32* val)
     }
 
     addr &= ~1;
-    if ((PU_Map[addr>>12] & 0x30))
-        WriteBufferDrain();
 
     if (addr < ITCMSize)
     {
@@ -1133,6 +1129,8 @@ bool ARMv5::DataRead16(u32 addr, u32* val)
         return true;
     }
 
+    WriteBufferDrain();
+
     NDS.ARM9Timestamp = NDS.ARM9Timestamp + ((1<<NDS.ARM9ClockShift)-1) & ~((1<<NDS.ARM9ClockShift)-1);
     
     DataCycles = MemTimings[addr >> 12][1];
@@ -1162,9 +1160,6 @@ bool ARMv5::DataRead32(u32 addr, u32* val)
 
     addr &= ~3;
 
-    if ((PU_Map[addr>>12] & 0x30))
-        WriteBufferDrain();
-
     if (addr < ITCMSize)
     {
         DataCycles = 1;
@@ -1181,6 +1176,8 @@ bool ARMv5::DataRead32(u32 addr, u32* val)
         return true;
     }
 
+    WriteBufferDrain();
+
     NDS.ARM9Timestamp = NDS.ARM9Timestamp + ((1<<NDS.ARM9ClockShift)-1) & ~((1<<NDS.ARM9ClockShift)-1);
     
     DataCycles = MemTimings[addr >> 12][2];
@@ -1209,9 +1206,6 @@ bool ARMv5::DataRead32S(u32 addr, u32* val)
 
     addr &= ~3;
 
-    if ((PU_Map[addr>>12] & 0x30))
-        WriteBufferDrain();
-
     if (addr < ITCMSize)
     {
         DataCycles += 1;
@@ -1228,6 +1222,8 @@ bool ARMv5::DataRead32S(u32 addr, u32* val)
         return true;
     }
 
+    WriteBufferDrain();
+
     NDS.ARM9Timestamp += DataCycles;
 
     if (!(addr & 0x3FF)) return DataRead32(addr, val); // bursts cannot cross a 1kb boundary