From b51b5facfd67620c71a7557a6bbf4f00192cf9a5 Mon Sep 17 00:00:00 2001
From: jpd002 <jpd002@b36208d7-6611-0410-8bec-b1987f11c4a2>
Date: Wed, 13 May 2009 00:03:11 +0000
Subject: [PATCH] Added immediate constant stuff in ARM CodeGen.

git-svn-id: http://svn.purei.org/purei/trunk@522 b36208d7-6611-0410-8bec-b1987f11c4a2
---
 Source/ArmAssembler.cpp |  5 +++
 Source/ArmAssembler.h   |  1 +
 Source/CodeGenARM.cpp   | 72 ++++++++++++++++++++++++++++++-----------
 Source/CodeGenARM.h     |  3 ++
 4 files changed, 63 insertions(+), 18 deletions(-)

diff --git a/Source/ArmAssembler.cpp b/Source/ArmAssembler.cpp
index fc7977913..b14004cf4 100644
--- a/Source/ArmAssembler.cpp
+++ b/Source/ArmAssembler.cpp
@@ -218,6 +218,11 @@ void CArmAssembler::Mov(REGISTER rd, const RegisterAluOperand& operand)
 	WriteWord(opcode);
 }
 
+void CArmAssembler::Mov(REGISTER rd, const ImmediateAluOperand& operand)
+{
+	MovCc(CONDITION_AL, rd, operand);
+}
+
 void CArmAssembler::MovCc(CONDITION condition, REGISTER rd, const ImmediateAluOperand& operand)
 {
 	InstructionAlu instruction;
diff --git a/Source/ArmAssembler.h b/Source/ArmAssembler.h
index 2558e7daf..0d881cf36 100644
--- a/Source/ArmAssembler.h
+++ b/Source/ArmAssembler.h
@@ -177,6 +177,7 @@ public:
 	void									Ldr(REGISTER, REGISTER, const LdrAddress&);
 	void									Mov(REGISTER, REGISTER);
 	void									Mov(REGISTER, const RegisterAluOperand&);
+	void									Mov(REGISTER, const ImmediateAluOperand&);
 	void									MovCc(CONDITION, REGISTER, const ImmediateAluOperand&);
 	void									Mvn(REGISTER, REGISTER);
 	void									Or(REGISTER, REGISTER, REGISTER);
diff --git a/Source/CodeGenARM.cpp b/Source/CodeGenARM.cpp
index 8671f15c5..46ce8ea44 100644
--- a/Source/CodeGenARM.cpp
+++ b/Source/CodeGenARM.cpp
@@ -964,33 +964,69 @@ void CCodeGen::LoadRelativeInRegister(CArmAssembler::REGISTER registerId, uint32
 	m_assembler.Ldr(registerId, g_baseRegister, CArmAssembler::MakeImmediateLdrAddress(relative));
 }
 
+uint32 CCodeGen::RotateRight(uint32 value)
+{
+	uint32 carry = value & 1;
+	value >>= 1;
+	value |= carry << 31;
+	return value;
+}
+
+uint32 CCodeGen::RotateLeft(uint32 value)
+{
+	uint32 carry = value >> 31;
+	value <<= 1;
+	value |= carry;
+	return value;
+}
+
 void CCodeGen::LoadConstantInRegister(CArmAssembler::REGISTER registerId, uint32 constant)
 {
-	//Search for an existing literal
-	unsigned int literalPtr = -1;
-	for(unsigned int i = 0; i < m_lastLiteralPtr; i++)
+	uint32 shadowConstant = constant;
+	int shiftAmount = -1;
+	for(unsigned int i = 0; i < 16; i++)
 	{
-		if(m_literalPool[i] == constant) 
+		if((shadowConstant & 0xFF) == shadowConstant)
 		{
-			literalPtr = i;
+			shiftAmount = i;
 			break;
 		}
+		shadowConstant = RotateLeft(shadowConstant);
+		shadowConstant = RotateLeft(shadowConstant);
 	}
-	if(literalPtr == -1)
+	
+	if(shiftAmount != -1)
 	{
-		assert(m_lastLiteralPtr != LITERAL_POOL_SIZE);
-		literalPtr = m_lastLiteralPtr++;
-		m_literalPool[literalPtr] = constant;
+		m_assembler.Mov(registerId, CArmAssembler::MakeImmediateAluOperand(shadowConstant, shiftAmount));
+	}
+	else
+	{
+		//Search for an existing literal
+		unsigned int literalPtr = -1;
+		for(unsigned int i = 0; i < m_lastLiteralPtr; i++)
+		{
+			if(m_literalPool[i] == constant) 
+			{
+				literalPtr = i;
+				break;
+			}
+		}
+		if(literalPtr == -1)
+		{
+			assert(m_lastLiteralPtr != LITERAL_POOL_SIZE);
+			literalPtr = m_lastLiteralPtr++;
+			m_literalPool[literalPtr] = constant;
+		}
+		
+		LITERAL_POOL_REF reference;
+		reference.poolPtr = literalPtr;
+		reference.dstRegister = registerId;
+		reference.offset = m_stream->Tell();
+		m_literalPoolRefs.push_back(reference);
+		
+		//Write a blank instruction
+		m_stream->Write32(0);
 	}
-	
-	LITERAL_POOL_REF reference;
-	reference.poolPtr = literalPtr;
-	reference.dstRegister = registerId;
-	reference.offset = m_stream->Tell();
-	m_literalPoolRefs.push_back(reference);
-	
-	//Write a blank instruction
-	m_stream->Write32(0);
 }
 
 void CCodeGen::DumpLiteralPool()
diff --git a/Source/CodeGenARM.h b/Source/CodeGenARM.h
index cc1f410b1..81727c967 100644
--- a/Source/CodeGenARM.h
+++ b/Source/CodeGenARM.h
@@ -161,6 +161,9 @@ private:
 	
 	void							PushReg(CArmAssembler::REGISTER);
 	
+	uint32							RotateRight(uint32);
+	uint32							RotateLeft(uint32);
+	
 	void							LoadRelativeInRegister(CArmAssembler::REGISTER, uint32);
 	void							LoadConstantInRegister(CArmAssembler::REGISTER, uint32);