From be0b8cf2f52840db3189955fd19648dedd4cd078 Mon Sep 17 00:00:00 2001
From: Gregory Hainaut <gregory.hainaut@gmail.com>
Date: Sat, 16 Jan 2016 20:47:13 +0100
Subject: [PATCH] x86emitter: implement some function to emit the REX prefix

Same fashion as EmitSibMagic
---
 common/include/x86emitter/internal.h |  6 ++++
 common/src/x86emitter/x86emitter.cpp | 50 +++++++++++++++++++++++++++-
 2 files changed, 55 insertions(+), 1 deletion(-)

diff --git a/common/include/x86emitter/internal.h b/common/include/x86emitter/internal.h
index c8e555ae27..6bf573ead8 100644
--- a/common/include/x86emitter/internal.h
+++ b/common/include/x86emitter/internal.h
@@ -31,6 +31,12 @@ namespace x86Emitter {
 	extern void EmitSibMagic( const xRegisterBase& reg1, const void* src );
 	extern void EmitSibMagic( const xRegisterBase& reg1, const xIndirectVoid& sib );
 
+	void EmitRex( const xRegisterBase& reg1, const xRegisterBase& reg2 );
+	void EmitRex( const xRegisterBase& reg1, const void* src );
+	void EmitRex( const xRegisterBase& reg1, const xIndirectVoid& sib );
+	void EmitRex( const xRegisterBase& reg1 );
+	void EmitRex( const xIndirectVoid& sib );
+
 	extern void _xMovRtoR( const xRegisterInt& to, const xRegisterInt& from );
 
 	template< typename T > inline
diff --git a/common/src/x86emitter/x86emitter.cpp b/common/src/x86emitter/x86emitter.cpp
index fc2f906c1b..2717c04e40 100644
--- a/common/src/x86emitter/x86emitter.cpp
+++ b/common/src/x86emitter/x86emitter.cpp
@@ -321,8 +321,9 @@ static __fi bool NeedsSibMagic( const xIndirectVoid& info )
 //
 void EmitSibMagic( uint regfield, const xIndirectVoid& info )
 {
+	// 3 bits also on x86_64 (so max is 8)
+	// We might need to mask it on x86_64
 	pxAssertDev( regfield < 8, "Invalid x86 register identifier." );
-
 	int displacement_size = (info.Displacement == 0) ? 0 :
 		( ( info.IsByteSizeDisp() ) ? 1 : 2 );
 
@@ -404,6 +405,53 @@ void EmitSibMagic( const xRegisterBase& reg1, const xIndirectVoid& sib )
 	EmitSibMagic( reg1.Id, sib );
 }
 
+//////////////////////////////////////////////////////////////////////////////////////////
+void EmitRex( const xRegisterBase& reg1, const xRegisterBase& reg2 )
+{
+	u8 w = reg1.IsWide() << 3;
+	u8 r = reg1.IsExtended() << 2;
+	u8 x = 0;
+	u8 b = reg2.IsExtended();
+	xWrite8( 0x40 | w | r | x | b );
+}
+
+void EmitRex( const xRegisterBase& reg1, const void* src )
+{
+	pxAssert(0); //see fixme
+	u8 w = reg1.IsWide() << 3;
+	u8 r = reg1.IsExtended() << 2;
+	u8 x = 0;
+	u8 b = 0; // FIXME src.IsExtended();
+	xWrite8( 0x40 | w | r | x | b );
+}
+
+void EmitRex( const xRegisterBase& reg1, const xIndirectVoid& sib )
+{
+	u8 w = reg1.IsWide() << 3;
+	u8 r = reg1.IsExtended() << 2;
+	u8 x = sib.Index.IsExtended() << 1;
+	u8 b = sib.Base.IsExtended();
+	xWrite8( 0x40 | w | r | x | b );
+}
+
+void EmitRex( const xRegisterBase& reg1)
+{
+	u8 w = reg1.IsWide() << 3;
+	u8 r = 0;
+	u8 x = 0;
+	u8 b = reg1.IsExtended();
+	xWrite8( 0x40 | w | r | x | b );
+}
+
+void EmitRex( const xIndirectVoid& sib)
+{
+	u8 w = sib.Base.IsWide() << 3;
+	u8 r = 0;
+	u8 x = 0;
+	u8 b = sib.IsExtended();
+	xWrite8( 0x40 | w | r | x | b );
+}
+
 // --------------------------------------------------------------------------------------
 //  xSetPtr / xAlignPtr / xGetPtr / xAdvancePtr
 // --------------------------------------------------------------------------------------