From bdfc472751caad9843b6527141264550df80bb6d Mon Sep 17 00:00:00 2001
From: Sintendo <bram.speeckaert@gmail.com>
Date: Mon, 13 Jan 2020 00:10:46 +0100
Subject: [PATCH] x64Emitter: Refactor OpArg::WriteRest

Shorter, displacement is now handled in one location.
---
 Source/Core/Common/x64Emitter.cpp | 82 +++++++++++--------------------
 1 file changed, 28 insertions(+), 54 deletions(-)

diff --git a/Source/Core/Common/x64Emitter.cpp b/Source/Core/Common/x64Emitter.cpp
index 169ffdc519..a90af4c288 100644
--- a/Source/Core/Common/x64Emitter.cpp
+++ b/Source/Core/Common/x64Emitter.cpp
@@ -270,71 +270,45 @@ void OpArg::WriteRest(XEmitter* emit, int extraBytes, X64Reg _operandReg,
     return;
   }
 
-  if (scale == 0)
+  if (scale == SCALE_NONE)
   {
     // Oh, no memory, Just a reg.
     mod = 3;  // 11
   }
+  else if (scale >= SCALE_NOBASE_2 && scale <= SCALE_NOBASE_8)
+  {
+    SIB = true;
+    mod = 0;
+    _offsetOrBaseReg = 5;
+    // Always has 32-bit displacement
+  }
   else
   {
-    // Ah good, no scaling.
-    if (scale == SCALE_ATREG && !((_offsetOrBaseReg & 7) == 4 || (_offsetOrBaseReg & 7) == 5))
-    {
-      // Okay, we're good. No SIB necessary.
-      int ioff = (int)offset;
-      if (ioff == 0)
-      {
-        mod = 0;
-      }
-      else if (ioff < -128 || ioff > 127)
-      {
-        mod = 2;  // 32-bit displacement
-      }
-      else
-      {
-        mod = 1;  // 8-bit displacement
-      }
-    }
-    else if (scale >= SCALE_NOBASE_2 && scale <= SCALE_NOBASE_8)
+    if (scale != SCALE_ATREG)
     {
       SIB = true;
-      mod = 0;
-      _offsetOrBaseReg = 5;
+    }
+    else if ((_offsetOrBaseReg & 7) == 4)
+    {
+      // Special case for which SCALE_ATREG needs SIB
+      SIB = true;
+      ireg = _offsetOrBaseReg;
+    }
+
+    // Okay, we're fine. Just disp encoding.
+    // We need displacement. Which size?
+    int ioff = (int)(s64)offset;
+    if (ioff == 0 && (_offsetOrBaseReg & 7) != 5)
+    {
+      mod = 0;  // No displacement
+    }
+    else if (ioff >= -128 && ioff <= 127)
+    {
+      mod = 1;  // 8-bit displacement
     }
     else
     {
-      if ((_offsetOrBaseReg & 7) == 4)  // this would occupy the SIB encoding :(
-      {
-        // So we have to fake it with SIB encoding :(
-        SIB = true;
-      }
-
-      if (scale >= SCALE_1 && scale < SCALE_ATREG)
-      {
-        SIB = true;
-      }
-
-      if (scale == SCALE_ATREG && ((_offsetOrBaseReg & 7) == 4))
-      {
-        SIB = true;
-        ireg = _offsetOrBaseReg;
-      }
-
-      // Okay, we're fine. Just disp encoding.
-      // We need displacement. Which size?
-      int ioff = (int)(s64)offset;
-      if (ioff == 0 && (_offsetOrBaseReg & 7) != 5)
-      {
-        mod = 0;
-      }
-      else if (ioff < -128 || ioff > 127)
-      {
-        mod = 2;  // 32-bit displacement
-      }
-      else
-      {
-        mod = 1;  // 8-bit displacement
-      }
+      mod = 2;  // 32-bit displacement
     }
   }