From 443ecb313d55c5ab9b256fa0176d560cc1b521ec Mon Sep 17 00:00:00 2001
From: Jaklyy <102590697+Jaklyy@users.noreply.github.com>
Date: Sun, 15 Dec 2024 19:57:04 -0500
Subject: [PATCH] improve(?) irq handling

...i dont think this fixes anything
---
 src/ARM.cpp | 23 +++++++++++++----------
 src/ARM.h   |  2 ++
 src/NDS.cpp | 16 ++++++++++------
 3 files changed, 25 insertions(+), 16 deletions(-)

diff --git a/src/ARM.cpp b/src/ARM.cpp
index d4e49723..5e6ce172 100644
--- a/src/ARM.cpp
+++ b/src/ARM.cpp
@@ -160,6 +160,7 @@ void ARM::Reset()
     Halted = 0;
     DataCycles = 0;
 
+    IRQTimestamp = -1;
     IRQ = 0;
 
     for (int i = 0; i < 16; i++)
@@ -705,7 +706,7 @@ void ARMv5::StartExecTHUMB()
     else NullFetch = false;
     PC = R[15];
 
-    if (IRQ && !(CPSR & 0x80)) TriggerIRQ<CPUExecuteMode::Interpreter>();
+    if (!(CPSR & 0x80) && (NDS.ARM9Timestamp > IRQTimestamp)) TriggerIRQ<CPUExecuteMode::Interpreter>();
     else if (CurInstr > 0xFFFFFFFF) [[unlikely]] // handle aborted instructions
     {
         PrefetchAbort();
@@ -728,7 +729,7 @@ void ARMv5::StartExecARM()
     NullFetch = false;
     PC = R[15];
 
-    if (IRQ && !(CPSR & 0x80)) TriggerIRQ<CPUExecuteMode::Interpreter>();
+    if (!(CPSR & 0x80) && (NDS.ARM9Timestamp > IRQTimestamp)) TriggerIRQ<CPUExecuteMode::Interpreter>();
     else if (CurInstr & ((u64)1<<63)) [[unlikely]] // handle aborted instructions
     {
         PrefetchAbort();
@@ -771,14 +772,13 @@ void ARMv5::Execute()
         else if (NDS.HaltInterrupted(0))
         {
             Halted = 0;
+            NDS.ARM9Timestamp = IRQTimestamp;
+#ifdef JIT_ENABLED
             if (NDS.IME[0] & 0x1)
             {
-#ifdef JIT_ENABLED
                 if constexpr (mode == CPUExecuteMode::JIT) TriggerIRQ<mode>();
-                else
-#endif
-                    IRQ = 1;
             }
+#endif
         }
         else
         {
@@ -921,7 +921,7 @@ void ARMv4::StartExecTHUMB()
     CodeRead16(R[15]);
     QueueFunction(&ARMv4::UpdateNextInstr1);
 
-    if (IRQ && !(CPSR & 0x80)) TriggerIRQ<CPUExecuteMode::Interpreter>();
+    if (!(CPSR & 0x80) && (NDS.ARM7Timestamp > IRQTimestamp)) TriggerIRQ<CPUExecuteMode::Interpreter>();
     else
     {
         // actually execute
@@ -939,7 +939,7 @@ void ARMv4::StartExecARM()
     CodeRead32(R[15]);
     QueueFunction(&ARMv4::UpdateNextInstr1);
 
-    if (IRQ && !(CPSR & 0x80)) TriggerIRQ<CPUExecuteMode::Interpreter>();
+    if (!(CPSR & 0x80) && (NDS.ARM7Timestamp > IRQTimestamp)) TriggerIRQ<CPUExecuteMode::Interpreter>();
     else if (CheckCondition(CurInstr >> 28)) // actually execute
     {
         u32 icode = ((CurInstr >> 4) & 0xF) | ((CurInstr >> 16) & 0xFF0);
@@ -964,13 +964,16 @@ void ARMv4::Execute()
         else if (NDS.HaltInterrupted(1))
         {
             Halted = 0;
+            NDS.ARM7Timestamp = IRQTimestamp;
             if (NDS.IME[1] & 0x1)
             {
 #ifdef JIT_ENABLED
                 if constexpr (mode == CPUExecuteMode::JIT) TriggerIRQ<mode>();
-                else
 #endif
-                    IRQ = 1;
+            }
+            else
+            {
+                IRQTimestamp = -1;
             }
         }
         else
diff --git a/src/ARM.h b/src/ARM.h
index 21c06813..eabae95b 100644
--- a/src/ARM.h
+++ b/src/ARM.h
@@ -213,6 +213,8 @@ public:
         u32 StopExecution;
     };
 
+    u64 IRQTimestamp;
+
     u32 CodeRegion;
     s32 CodeCycles;
 
diff --git a/src/NDS.cpp b/src/NDS.cpp
index 12a96cb3..c4fb3bbe 100644
--- a/src/NDS.cpp
+++ b/src/NDS.cpp
@@ -1834,7 +1834,7 @@ u32 NDS::RunFrame()
                         if (!MainRAMHandle()) break;
                     }
                 }
-
+                CurCPU = 2;
                 RunSystem(target);
 
                 if (CPUStop & CPUStop_Sleep)
@@ -2156,16 +2156,20 @@ void NDS::SetGBASlotTimings()
 void NDS::UpdateIRQ(u32 cpu)
 {
     ARM& arm = cpu ? (ARM&)ARM7 : (ARM&)ARM9;
+    u64 curtime = ((CurCPU == 2) ? SysTimestamp : ((CurCPU == 1) ? ARM7Timestamp : ((ARM9Timestamp + ((1<<ARM9ClockShift)-1)) >> ARM9ClockShift)));
+    if (!cpu) curtime <<= ARM9ClockShift; 
 
-    if (IME[cpu] & 0x1)
+    if (IME[cpu] & 0x1 || (arm.Halted == 1))
     {
-        arm.IRQ = !!(IE[cpu] & IF[cpu]);
-        if ((ConsoleType == 1) && cpu)
-            arm.IRQ |= !!(IE2 & IF2);
+        //arm.IRQ = !!(IE[cpu] & IF[cpu]);
+        if (IE[cpu] & IF[cpu]) { if (curtime < arm.IRQTimestamp) arm.IRQTimestamp = curtime; }
+        else arm.IRQTimestamp = -1;
+        if ((ConsoleType == 1) && cpu && (IE2 & IF2) && (curtime < arm.IRQTimestamp))
+            arm.IRQTimestamp = curtime;
     }
     else
     {
-        arm.IRQ = 0;
+         arm.IRQTimestamp = -1;
     }
 }