OvmfPkg: Add QemuFwCfgLib library class and implementation

QEMU's Firmware Configuration interface gives the firmware
access to various types of information.

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Jordan Justen <jordan.l.justen@intel.com>
Reviewed-by: Laszlo Ersek <lersek@redhat.com>

git-svn-id: https://edk2.svn.sourceforge.net/svnroot/edk2/trunk/edk2@13383 6f19259b-4bc3-4df7-8a09-765794883524

OvmfPkg/Library/QemuFwCfgLib/Ia32/IoLibExAsm.asm

@@ -0,0 +1,40 @@
+;------------------------------------------------------------------------------
+;
+; Copyright (c) 2006 - 2012, Intel Corporation. All rights reserved.<BR>
+; This program and the accompanying materials
+; are licensed and made available under the terms and conditions of the BSD License
+; which accompanies this distribution.  The full text of the license may be found at
+; http://opensource.org/licenses/bsd-license.php.
+;
+; THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
+; WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
+;
+;------------------------------------------------------------------------------
+
+    .586P
+    .model  flat,C
+    .code
+
+;------------------------------------------------------------------------------
+;  VOID
+;  EFIAPI
+;  IoReadFifo8 (
+;    IN UINTN                  Port,
+;    IN UINTN                  Size,
+;    IN VOID                   *Buffer
+;    );
+;------------------------------------------------------------------------------
+IoReadFifo8 PROC
+
+    mov     dx, [esp + 4]
+    mov     ecx, [esp + 8]
+    push    edi
+    mov     edx, [esp + 16]
+rep insb
+    pop     edi
+    ret
+
+IoReadFifo8 ENDP
+
+    END
+