[aandrejevic] 60586: [SOFT386] Fix more prefix handling code. Implement the XLAT instruction.

Author: aandrejevic
Date: Wed Oct  9 00:36:37 2013
New Revision: 60586

URL: http://svn.reactos.org/svn/reactos?rev=60586&view=rev
Log:
[SOFT386]
Fix more prefix handling code.
Implement the XLAT instruction.


Modified:
    branches/ntvdm/lib/soft386/opcodes.c

Modified: branches/ntvdm/lib/soft386/opcodes.c
URL:
http://svn.reactos.org/svn/reactos/branches/ntvdm/lib/soft386/opcodes.c?rev…
==============================================================================
--- branches/ntvdm/lib/soft386/opcodes.c	[iso-8859-1] (original)
+++ branches/ntvdm/lib/soft386/opcodes.c	[iso-8859-1] Wed Oct  9 00:36:37 2013
@@ -549,8 +549,7 @@
 
 SOFT386_OPCODE_HANDLER(Soft386OpcodePushReg)
 {
-    if ((State->PrefixFlags != SOFT386_PREFIX_OPSIZE)
-        && (State->PrefixFlags != 0))
+    if (State->PrefixFlags & SOFT386_PREFIX_LOCK)
     {
         /* Invalid prefix */
         Soft386Exception(State, SOFT386_EXCEPTION_UD);
@@ -569,12 +568,13 @@
     ULONG Value;
     BOOLEAN Size = State->SegmentRegs[SOFT386_REG_SS].Size;
 
-    if (State->PrefixFlags == SOFT386_PREFIX_OPSIZE)
+    if (State->PrefixFlags & SOFT386_PREFIX_OPSIZE)
     {
         /* The OPSIZE prefix toggles the size */
         Size = !Size;
     }
-    else if (State->PrefixFlags != 0)
+
+    if (State->PrefixFlags & SOFT386_PREFIX_LOCK)
     {
         /* Invalid prefix */
         Soft386Exception(State, SOFT386_EXCEPTION_UD);
@@ -3880,12 +3880,13 @@
     /* Make sure this is the right instruction */
     ASSERT(Opcode == 0x60);
 
-    if (State->PrefixFlags == SOFT386_PREFIX_OPSIZE)
+    if (State->PrefixFlags & SOFT386_PREFIX_OPSIZE)
     {
         /* The OPSIZE prefix toggles the size */
         Size = !Size;
     }
-    else
+
+    if (State->PrefixFlags & SOFT386_PREFIX_LOCK)
     {
         /* Invalid prefix */
         Soft386Exception(State, SOFT386_EXCEPTION_UD);
@@ -3928,12 +3929,13 @@
     /* Make sure this is the right instruction */
     ASSERT(Opcode == 0x61);
 
-    if (State->PrefixFlags == SOFT386_PREFIX_OPSIZE)
+    if (State->PrefixFlags & SOFT386_PREFIX_OPSIZE)
     {
         /* The OPSIZE prefix toggles the size */
         Size = !Size;
     }
-    else
+
+    if (State->PrefixFlags & SOFT386_PREFIX_LOCK)
     {
         /* Invalid prefix */
         Soft386Exception(State, SOFT386_EXCEPTION_UD);
@@ -5437,10 +5439,34 @@
 
 SOFT386_OPCODE_HANDLER(Soft386OpcodeXlat)
 {
-    // TODO: NOT IMPLEMENTED
-    UNIMPLEMENTED;
-
-    return FALSE;
+    UCHAR Value;
+    BOOLEAN AddressSize = State->SegmentRegs[SOFT386_REG_CS].Size;
+
+    if (State->PrefixFlags & SOFT386_PREFIX_ADSIZE)
+    {
+        /* The ADSIZE prefix toggles the size */
+        AddressSize = !AddressSize;
+    }
+
+    /* Read a byte from DS:[(E)BX + AL] */
+    if (!Soft386ReadMemory(State,
+                           SOFT386_REG_DS,
+                           AddressSize ? State->GeneralRegs[SOFT386_REG_EBX].Long
+                                       : State->GeneralRegs[SOFT386_REG_EBX].LowWord
+                           + State->GeneralRegs[SOFT386_REG_EAX].LowByte,
+                           FALSE,
+                           &Value,
+                           sizeof(UCHAR)))
+    {
+        /* Exception occurred */
+        return FALSE;
+    }
+
+    /* Set AL to the result */
+    State->GeneralRegs[SOFT386_REG_EAX].LowByte = Value;
+
+    /* Return success */
+    return TRUE;
 }
 
 SOFT386_OPCODE_HANDLER(Soft386OpcodeLoop)