From 1d21bb125fd6c18fa5edbdda5882424a3c3a08fe Mon Sep 17 00:00:00 2001
From: Aleksandar Andrejevic <aandrejevic@reactos.org>
Date: Mon, 11 Nov 2013 17:24:22 +0000
Subject: [PATCH] [FAST486] Fix the Mod-Reg-R/M parser. EBP cannot be used as a
 SIB byte base, instead it's used to mark that the base is an immediate
 operand.

svn path=/branches/ntvdm/; revision=60944
---
 lib/fast486/common.inl | 16 +++++++++++++++-
 1 file changed, 15 insertions(+), 1 deletion(-)

diff --git a/lib/fast486/common.inl b/lib/fast486/common.inl
index 38dadbf00c3..524d3d90867 100644
--- a/lib/fast486/common.inl
+++ b/lib/fast486/common.inl
@@ -719,7 +719,21 @@ Fast486ParseModRegRm(PFAST486_STATE State,
             Index = (SibByte >> 3) & 0x07;
             if (Index != FAST486_REG_ESP) Index = State->GeneralRegs[Index].Long;
             else Index = 0;
-            Base = State->GeneralRegs[SibByte & 0x07].Long;
+
+            if ((SibByte & 0x07) != FAST486_REG_EBP)
+            {
+                /* Use the register a base */
+                Base = State->GeneralRegs[SibByte & 0x07].Long;
+            }
+            else
+            {
+                /* Fetch the base */
+                if (!Fast486FetchDword(State, &Base))
+                {
+                    /* Exception occurred */
+                    return FALSE;
+                }
+            }
 
             /* Calculate the address */
             ModRegRm->MemoryAddress = Base + Index * Scale;
-- 
2.17.1