Merge pull request #2680 from degasus/idle

Interpreter: Idle skipping support

Source/Core/Core/PowerPC/Interpreter/Interpreter_Branch.cpp

@@ -23,6 +23,11 @@ void Interpreter::bx(UGeckoInstruction _inst)
 #endif*/
 
 	m_EndBlock = true;
+
+	if (NPC == PC && SConfig::GetInstance().bSkipIdle)
+	{
+		CoreTiming::Idle();
+	}
 }
 
 // bcx - ugly, straight from PPC manual equations :)
@@ -50,6 +55,23 @@ void Interpreter::bcx(UGeckoInstruction _inst)
 	}
 
 	m_EndBlock = true;
+
+	// this code trys to detect the most common idle loop:
+	// lwz r0, XXXX(r13)
+	// cmpXwi r0,0
+	// beq -8
+	if (NPC == PC - 8 && _inst.hex == 0x4182fff8 /* beq */ && SConfig::GetInstance().bSkipIdle)
+	{
+		if (PowerPC::HostRead_U32(PC - 8) >> 16 == 0x800D /* lwz */ )
+		{
+			u32 last_inst = PowerPC::HostRead_U32(PC - 4);
+
+			if (last_inst == 0x28000000 /* cmplwi */ || (last_inst == 0x2C000000 /* cmpwi */ && SConfig::GetInstance().bWii))
+			{
+				CoreTiming::Idle();
+			}
+		}
+	}
 }
 
 void Interpreter::bcctrx(UGeckoInstruction _inst)