Reorder library lessons

Signed-off-by: Konstantin Aladyshev <aladyshev22@gmail.com>

8 files changed, 246 insertions, 321 deletions

diff --git a/Lessons/Lesson_35/README.md b/Lessons/Lesson_35/README.md
index def1314..f6d64ad 100644
--- a/Lessons/Lesson_35/README.md
+++ b/Lessons/Lesson_35/README.md
@@ -1,383 +1,157 @@
-If you'll search through ShellPkg library (https://github.com/tianocore/edk2/tree/master/ShellPkg/Library) you can notice that there is a folder `UefiShellAcpiViewCommandLib` (https://github.com/tianocore/edk2/tree/master/ShellPkg/Library/UefiShellAcpiViewCommandLib).
-This folder provides a library for the support of in-shell `acpiview` command. If you check the INF file, you'll see
-https://github.com/tianocore/edk2/blob/master/ShellPkg/Library/UefiShellAcpiViewCommandLib/UefiShellAcpiViewCommandLib.inf:
-```
-# Provides Shell 'acpiview' command functions
-```
-But if you try to execute `acpiview` in our current OVMF build, you'll notice that this command is not recognized:
-```
-FS0:\> acpiview
-'acpiview' is not recognized as an internal or external command, operable program, or script file.
-```
-We have 3 ways to use this 'acpiview' command functionality:
-- compile `acpiview` as a separate app and run it as an ordinary UEFI shell application
-- compile shell with 'acpiview' command in itself and run it under OVMF
-- update OVMF image with a shell that actually includes 'acpiview' command in itself
-
-# Compile `acpiview` as a separate app
+In this lesson we will try to create the most simple library.
 
-I guess it is the most easy way.
-
-It is possible to perform such thing with a help of https://github.com/tianocore/edk2/tree/master/ShellPkg/Application/AcpiViewApp
-
-If you look at the source file, you'll see that it is pretty simple, the main function just makes a library call to `ShellCommandRunAcpiView` function:
+Usually libraries are present in these directories:
 ```
-EFI_STATUS
-EFIAPI
-AcpiViewAppMain (
-  IN EFI_HANDLE        ImageHandle,
-  IN EFI_SYSTEM_TABLE  *SystemTable
-  )
-{
-  return ShellCommandRunAcpiView (gImageHandle, SystemTable);
-}
+<Pkg Name>/Library/<Library Name>/               <---- inf and source files for the library (=library implementation)
+<Pkg Name>/Include/Library/                      <---- library headers (=library interface)
 ```
 
-To build this application issue:
+Create folders for our `SimpleLibrary`:
 ```
-build --platform=ShellPkg/ShellPkg.dsc --module=ShellPkg/Application/AcpiViewApp/AcpiViewApp.inf --arch=X64 --buildtarget=RELEASE --tagname=GCC5
+$ mkdir -p UefiLessonsPkg/Library/SimpleLibrary/
+$ mkdir -p UefiLessonsPkg/Include/Library/
 ```
 
-Copy image to the QEMU shared folder:
+First let's implement the header file, the interface for our library. Our `SimpleLibrary` would contain the only function `Plus2` that would receive a `number` and return a `number+2`.
+Therefore the content in the header file (`UefiLessonsPkg/Include/Library/SimpleLibrary.h`) would look like this:
 ```
-cp Build/Shell/RELEASE_GCC5/X64/AcpiViewApp.efi ~/UEFI_disk/
+UINTN Plus2(UINTN number);
 ```
 
-You can see application help with a:
+No harder the library implementation file `UefiLessonsPkg/Library/SimpleLibrary/SimpleLibrary.c`:
 ```
-FS0:\> AcpiViewApp.efi -?
-Display ACPI Table information.
-
-ACPIVIEWAPP.EFI [[-?] | [[[[-l] | [-s AcpiTable [-d]]] [-q] [-h]] [-r Spec]]]
-
-
-  -l - Display list of installed ACPI Tables.
-  -s - Display only the specified AcpiTable type and only support single
-       invocation option.
-         AcpiTable    : The required ACPI Table type.
-  -d - Generate a binary file dump of the specified AcpiTable.
-  -q - Quiet. Suppress errors and warnings. Disables consistency checks.
-  -h - Enable colour highlighting.
-  -r - Validate that all required ACPI tables are installed
-         Spec  : Specification to validate against.
-                 For Arm, the possible values are:
-                   0 - Server Base Boot Requirements v1.0
-                   1 - Server Base Boot Requirements v1.1
-                   2 - Server Base Boot Requirements v1.2
-  -? - Show help.
-
+#include <Library/SimpleLibrary.h>
 
-  This program is provided to allow examination of ACPI table values from the
-  UEFI Shell.  This can help with investigations, especially at that stage
-  where the tables are not enabling an OS to boot.
-  The program is not exhaustive, and only encapsulates detailed knowledge of a
-  limited number of table types.
-
-  Default behaviour is to display the content of all tables installed.
-  'Known' table types (listed in NOTES below) will be parsed and displayed
-  with descriptions and field values.  Where appropriate a degree of
-  consistency checking is done and errors may be reported in the output.
-  Other table types will be displayed as an array of Hexadecimal bytes.
-
-  To facilitate debugging, the -s and -d options can be used to generate a
-  binary file image of a table that can be copied elsewhere for investigation
-  using tools such as those provided by acpica.org.  This is especially
-  relevant for AML type tables like DSDT and SSDT.
-
-NOTES:
-  1. The AcpiTable parameter can match any installed table type.
-     Tables without specific handling will be displayed as a raw hex dump (or
-     dumped to a file if -d is used).
-  2. -s option supports to display the specified AcpiTable type that is present
-     in the system. For normal type AcpiTable, it would display the data of the
-     AcpiTable and AcpiTable header. The following type may contain header type
-     other than AcpiTable header. The actual header can refer to the ACPI spec
-     6.3
-     Extra A. Particular types:
-       APIC  - Multiple APIC Description Table (MADT)
-       BGRT  - Boot Graphics Resource Table
-       DBG2  - Debug Port Table 2
-       DSDT  - Differentiated System Description Table
-       FACP  - Fixed ACPI Description Table (FADT)
-       GTDT  - Generic Timer Description Table
-       IORT  - IO Remapping Table
-       MCFG  - Memory Mapped Config Space Base Address Description Table
-       PPTT  - Processor Properties Topology Table
-       RSDP  - Root System Description Pointer
-       SLIT  - System Locality Information Table
-       SPCR  - Serial Port Console Redirection Table
-       SRAT  - System Resource Affinity Table
-       SSDT  - Secondary SystemDescription Table
-       XSDT  - Extended System Description Table
-
-
-
-EXAMPLES:
-  * To display a list of the installed table types:
-    fs0:\> acpiviewapp.efi -l
+UINTN Plus2(UINTN number) {
+  return number+2;
+}
+```
 
-  * To parse and display a specific table type:
-    fs0:\> acpiviewapp.efi -s GTDT
+This is really a simple library, it stands to its name!
 
-  * To save a binary dump of the contents of a table to a file
-    in the current working directory:
-    fs0:\> acpiviewapp.efi -s DSDT -d
+Now we need to create an INF file for the library `UefiLessonsPkg/Library/SimpleLibrary/SimpleLibrary.inf`:
+```
+[Defines]
+  INF_VERSION                    = 1.25
+  BASE_NAME                      = SimpleLibrary
+  FILE_GUID                      = 826c8951-5bd2-4d72-a9d9-f7ab48684117
+  MODULE_TYPE                    = UEFI_APPLICATION
+  VERSION_STRING                 = 1.0
+  LIBRARY_CLASS                  = SimpleLibrary | UEFI_APPLICATION
 
-  * To display contents of all ACPI tables:
-    fs0:\> acpiviewapp.efi
+[Sources]
+  SimpleLibrary.c
 
-  * To check if all Server Base Boot Requirements (SBBR) v1.2 mandatory
-    ACPI tables are installed (Arm only):
-    fs0:\> acpiviewapp.efi -r 2
+[Packages]
+  MdePkg/MdePkg.dec
 ```
 
-With this program you can list ACPI tables in system:
+The interesting string here is the:
 ```
-FS0:\> AcpiViewApp.efi -l
-
-Installed Table(s):
-           1. RSDP
-           2. XSDT
-           3. FACP
-           4. FACS
-           5. DSDT
-           6. APIC
-           7. HPET
-           8. BGRT
+LIBRARY_CLASS = SimpleLibrary | UEFI_APPLICATION
 ```
-
-Show the content of any table:
+It says that this library can only be used in modules with a type `UEFI_APPLICATION`. If you would say here `DXE_DRIVER` and try to link it to some of you UEFI applications, build process would fail. The error message would look like this:
+```
+build.py...
+/home/kostr/tiano/edk2/UefiLessonsPkg/UefiLessonsPkg.dsc(...): error 1001: Module type [UEFI_APPLICATION] is not supported by library instance [/home/kostr/tiano/edk2/UefiLessonsPkg/Library/SimpleLibrary/SimpleLibrary.inf]
+        consumed by [/home/kostr/tiano/edk2/UefiLessonsPkg/<path to your app inf file>]
 ```
-FS0:\> AcpiViewApp.efi -s BGRT
-
-
- --------------- BGRT Table ---------------
-
-Address  : 0x7B77000
-Length   : 56
-
-00000000 : 42 47 52 54 38 00 00 00 - 01 C5 49 4E 54 45 4C 20   BGRT8.....INTEL
-00000010 : 45 44 4B 32 20 20 20 20 - 02 00 00 00 20 20 20 20   EDK2    ....
-00000020 : 13 00 00 01 01 00 01 00 - 18 30 8B 06 00 00 00 00   .........0......
-00000030 : 2F 01 00 00 0F 01 00 00                             /.......
-
-Table Checksum : OK
-
-BGRT                                 :
-  Signature                          : BGRT
-  Length                             : 56
-  Revision                           : 1
-  Checksum                           : 0xC5
-  Oem ID                             : INTEL
-  Oem Table ID                       : EDK2
-  Oem Revision                       : 0x2
-  Creator ID                         :
-  Creator Revision                   : 0x1000013
-  Version                            : 0x1
-  Status                             : 0x1
-  Image Type                         : 0x0
-  Image Address                      : 0x68B3018
-  Image Offset X                     : 303
-  Image Offset Y                     : 271
 
-Table Statistics:
-        0 Error(s)
-        0 Warning(s)
+Now we need to include our library to our package DSC file `UefiLessonsPkg/UefiLessonsPkg.dsc`, so it would get build on a package build:
+```
+[Components]
+  ...
+  UefiLessonsPkg/Library/SimpleLibrary/SimpleLibrary.inf
 ```
 
-Or dump any ACPI table:
+But if you try to build our package now build would fail with a message:
 ```
-FS0:\> acpiview -s APIC -d
-Dumping ACPI table to : .\APIC0000.bin ... DONE.
+/home/kostr/tiano/edk2/UefiLessonsPkg/Library/SimpleLibrary/SimpleLibrary.c:1:10: fatal error: Library/SimpleLibrary.h: No such file or directory
+    1 | #include <Library/SimpleLibrary.h>
+      |          ^~~~~~~~~~~~~~~~~~~~~~~~~
+compilation terminated.
 ```
-You can disassemble this image with `iasl -d <file>` like we did earlier.
+The reason of that is a fact that our `UefiLessonsPkg/Include/Library/` folder is not recognized by a build system as a place where headers might be.
 
+To fix it we need to add to our `UefiLessonsPkg/UefiLessonsPkg.dec` file `[Includes]` section:
+```
+[Includes]
+  Include
+```
 
-# Compile shell with 'acpiview' command in itself and run it under OVMF
+And include this `UefiLessonsPkg/UefiLessonsPkg.dec` file to the library module INF file section `[Packages]`:
+```
+[Packages]
+  MdePkg/MdePkg.dec
+  UefiLessonsPkg/UefiLessonsPkg.dec
+```
 
-This case is a little bit crazy, we would be running a shell applicaion inside the shell application.
+Now we are good, build would succeed.
 
-I guess this is not the usual case, but it will help you to know how to compile the shell image that you can actually use in your projects.
+# SimpleLibraryUser
 
-If you'll look at the https://github.com/tianocore/edk2/blob/master/ShellPkg/ShellPkg.dsc you'll see that if you build `ShellPkg`, you'll actually build two versions of the `Shell.inf`:
-- one would have general commands
-- another one would have all the commands
-```
-ShellPkg/Application/Shell/Shell.inf {
-  <PcdsFixedAtBuild>
-    gEfiShellPkgTokenSpaceGuid.PcdShellLibAutoInitialize|FALSE
-  <LibraryClasses>
-    NULL|ShellPkg/Library/UefiShellLevel2CommandsLib/UefiShellLevel2CommandsLib.inf
-    NULL|ShellPkg/Library/UefiShellLevel1CommandsLib/UefiShellLevel1CommandsLib.inf
-    NULL|ShellPkg/Library/UefiShellLevel3CommandsLib/UefiShellLevel3CommandsLib.inf
-fndef $(NO_SHELL_PROFILES)
-    NULL|ShellPkg/Library/UefiShellDriver1CommandsLib/UefiShellDriver1CommandsLib.inf
-    NULL|ShellPkg/Library/UefiShellInstall1CommandsLib/UefiShellInstall1CommandsLib.inf
-    NULL|ShellPkg/Library/UefiShellDebug1CommandsLib/UefiShellDebug1CommandsLib.inf
-    NULL|ShellPkg/Library/UefiShellNetwork1CommandsLib/UefiShellNetwork1CommandsLib.inf
-    NULL|ShellPkg/Library/UefiShellNetwork2CommandsLib/UefiShellNetwork2CommandsLib.inf
-ndif #$(NO_SHELL_PROFILES)
-}
+Now let's create an application that would use our library.
 
-#
-# Build a second version of the shell with all commands integrated
-#
-ShellPkg/Application/Shell/Shell.inf {
- <Defines>
-    FILE_GUID = EA4BB293-2D7F-4456-A681-1F22F42CD0BC
-  <PcdsFixedAtBuild>
-    gEfiShellPkgTokenSpaceGuid.PcdShellLibAutoInitialize|FALSE
-  <LibraryClasses>
-    NULL|ShellPkg/Library/UefiShellLevel2CommandsLib/UefiShellLevel2CommandsLib.inf
-    NULL|ShellPkg/Library/UefiShellLevel1CommandsLib/UefiShellLevel1CommandsLib.inf
-    NULL|ShellPkg/Library/UefiShellLevel3CommandsLib/UefiShellLevel3CommandsLib.inf
-    NULL|ShellPkg/Library/UefiShellDriver1CommandsLib/UefiShellDriver1CommandsLib.inf
-    NULL|ShellPkg/Library/UefiShellInstall1CommandsLib/UefiShellInstall1CommandsLib.inf
-    NULL|ShellPkg/Library/UefiShellDebug1CommandsLib/UefiShellDebug1CommandsLib.inf
-    NULL|ShellPkg/Library/UefiShellNetwork1CommandsLib/UefiShellNetwork1CommandsLib.inf
-    NULL|ShellPkg/Library/UefiShellNetwork2CommandsLib/UefiShellNetwork2CommandsLib.inf
-    NULL|ShellPkg/Library/UefiShellAcpiViewCommandLib/UefiShellAcpiViewCommandLib.inf         <------- acpiview is present in this Shell version
-}
+UefiLessonsPkg/SimpleLibraryUser/SimpleLibraryUser.c:
 ```
+#include <Library/UefiBootServicesTableLib.h>
+#include <Library/UefiLib.h>
 
-In case you wonder how `UefiShellAcpiViewCommandLib.inf` registers new command take a look at its sources:
-
-https://github.com/tianocore/edk2/blob/master/ShellPkg/Library/UefiShellAcpiViewCommandLib/UefiShellAcpiViewCommandLib.inf
-```
-[Defines]
-  INF_VERSION                    = 0x00010019
-  BASE_NAME                      = UefiShellAcpiViewCommandLib
-  FILE_GUID                      = FB5B305E-84F5-461F-940D-82D345757AFA
-  MODULE_TYPE                    = UEFI_APPLICATION
-  VERSION_STRING                 = 1.0
-  LIBRARY_CLASS                  = AcpiViewCommandLib|UEFI_APPLICATION UEFI_DRIVER
-  CONSTRUCTOR                    = UefiShellAcpiViewCommandLibConstructor
-  DESTRUCTOR                     = UefiShellAcpiViewCommandLibDestructor
+#include <Library/SimpleLibrary.h>
 
-  ...
-```
-https://github.com/tianocore/edk2/blob/master/ShellPkg/Library/UefiShellAcpiViewCommandLib/UefiShellAcpiViewCommandLib.c
-```
 EFI_STATUS
 EFIAPI
-UefiShellAcpiViewCommandLibConstructor (
+UefiMain (
   IN EFI_HANDLE        ImageHandle,
   IN EFI_SYSTEM_TABLE  *SystemTable
   )
 {
- ...
-  // Install our Shell command handler
-  ShellCommandRegisterCommandName (
-    L"acpiview",
-    ShellCommandRunAcpiView,
-    ShellCommandGetManFileNameAcpiView,
-    0,
-    L"acpiview",
-    TRUE,
-    gShellAcpiViewHiiHandle,
-    STRING_TOKEN (STR_GET_HELP_ACPIVIEW)
-    );
+  Print(L"%d\n", Plus2(3));
 
   return EFI_SUCCESS;
 }
 ```
-It doesn't look too scary, so you can even try to add your command to the shell. Maybe will try that in later lessons.
 
-Now execute this command to build the Shell application:
-```
-build --platform=ShellPkg/ShellPkg.dsc --module=ShellPkg/Application/Shell/Shell.inf --arch=X64 --buildtarget=RELEASE --tagname=GCC5
+UefiLessonsPkg/SimpleLibraryUser/SimpleLibraryUser.inf
 ```
+[Defines]
+  INF_VERSION                    = 1.25
+  BASE_NAME                      = SimpleLibraryUser
+  FILE_GUID                      = 22a1f57c-21ca-4011-9133-e3df0d01dace
+  MODULE_TYPE                    = UEFI_APPLICATION
+  VERSION_STRING                 = 1.0
+  ENTRY_POINT                    = UefiMain
 
-After the build there would be two files in the build folder:
-```
-$ ls Build/Shell/RELEASE_GCC5/X64/Shell*.efi
-Build/Shell/RELEASE_GCC5/X64/Shell_7C04A583-9E3E-4f1c-AD65-E05268D0B4D1.efi
-Build/Shell/RELEASE_GCC5/X64/Shell_EA4BB293-2D7F-4456-A681-1F22F42CD0BC.efi
-```
+[Sources]
+  SimpleLibraryUser.c
 
-If you look closely to the code from the `ShellPkg/ShellPkg.dsc` that I've pasted earlier, you can notice that the image that we need is an image with a `EA4BB293-2D7F-4456-A681-1F22F42CD0BC` guid.
+[Packages]
+  MdePkg/MdePkg.dec
+  UefiLessonsPkg/UefiLessonsPkg.dec                  <--- we need to include this for the same reason as in library INF file (for the header search)
 
-Copy it to the QEMU shared folder:
+[LibraryClasses]
+  UefiApplicationEntryPoint
+  UefiLib
+  SimpleLibrary                                      <--- library is included as usual
 ```
-$ cp Build/Shell/RELEASE_GCC5/X64/Shell_EA4BB293-2D7F-4456-A681-1F22F42CD0BC.efi ~/UEFI_disk/
-```
-In your default shell there wouldn't be any `acpiview` command, but when as you'll move to the `Shell_EA4BB293-2D7F-4456-A681-1F22F42CD0BC.efi` this `acpiview` command would became present in the shell.
-```
-FS0:\> acpiview -l
-'acpiview' is not recognized as an internal or external command, operable program, or script file.
-FS0:\> Shell_EA4BB293-2D7F-4456-A681-1F22F42CD0BC.efi
-UEFI Interactive Shell v2.2
-EDK II
-UEFI v2.70 (EDK II, 0x00010000)
-Mapping table
-      FS0: Alias(s):HD0a1:;BLK1:
-          PciRoot(0x0)/Pci(0x1,0x1)/Ata(0x0)/HD(1,MBR,0xBE1AFDFA,0x3F,0xFBFC1)
-     BLK0: Alias(s):
-          PciRoot(0x0)/Pci(0x1,0x1)/Ata(0x0)
-     BLK2: Alias(s):
-          PciRoot(0x0)/Pci(0x1,0x1)/Ata(0x0)
-Press ESC in 4 seconds to skip startup.nsh or any other key to continue.
-FS0:\> acpiview -l
 
-Installed Table(s):
-           1. RSDP
-           2. XSDT
-           3. FACP
-           4. FACS
-           5. DSDT
-           6. APIC
-           7. HPET
-           8. BGRT
+Now add modifications to the `UefiLessonsPkg/UefiLessonsPkg.dsc`:
 ```
+[LibraryClasses]
+  ...
+  SimpleLibrary|UefiLessonsPkg/Library/SimpleLibrary/SimpleLibrary.inf
 
-# Update OVMF image with a shell that actually includes 'acpiview' command in itself
-
-Correct `OvmfPkg/OvmfPkgX64.dsc`. You'll need to add `UefiShellAcpiViewCommandLib.inf` to the `Shell.inf` library classes:
-```
 [Components]
   ...
-  ShellPkg/Application/Shell/Shell.inf {
-    <LibraryClasses>
-      ShellCommandLib|ShellPkg/Library/UefiShellCommandLib/UefiShellCommandLib.inf
-      NULL|ShellPkg/Library/UefiShellLevel2CommandsLib/UefiShellLevel2CommandsLib.inf
-      NULL|ShellPkg/Library/UefiShellLevel1CommandsLib/UefiShellLevel1CommandsLib.inf
-      NULL|ShellPkg/Library/UefiShellLevel3CommandsLib/UefiShellLevel3CommandsLib.inf
-      NULL|ShellPkg/Library/UefiShellDriver1CommandsLib/UefiShellDriver1CommandsLib.inf
-      NULL|ShellPkg/Library/UefiShellDebug1CommandsLib/UefiShellDebug1CommandsLib.inf
-      NULL|ShellPkg/Library/UefiShellInstall1CommandsLib/UefiShellInstall1CommandsLib.inf
-      NULL|ShellPkg/Library/UefiShellNetwork1CommandsLib/UefiShellNetwork1CommandsLib.inf
-      NULL|ShellPkg/Library/UefiShellAcpiViewCommandLib/UefiShellAcpiViewCommandLib.inf          <-----------
-!if $(NETWORK_IP6_ENABLE) == TRUE
-      NULL|ShellPkg/Library/UefiShellNetwork2CommandsLib/UefiShellNetwork2CommandsLib.inf
-!endif
-      HandleParsingLib|ShellPkg/Library/UefiHandleParsingLib/UefiHandleParsingLib.inf
-      PrintLib|MdePkg/Library/BasePrintLib/BasePrintLib.inf
-      BcfgCommandLib|ShellPkg/Library/UefiShellBcfgCommandLib/UefiShellBcfgCommandLib.inf
-
-    <PcdsFixedAtBuild>
-      gEfiMdePkgTokenSpaceGuid.PcdDebugPropertyMask|0xFF
-      gEfiShellPkgTokenSpaceGuid.PcdShellLibAutoInitialize|FALSE
-      gEfiMdePkgTokenSpaceGuid.PcdUefiLibMaxPrintBufferSize|8000
-  }
+  UefiLessonsPkg/SimpleLibraryUser/SimpleLibraryUser.inf
 ```
+Here we've added implementation for our library class and added our new module to the package components.
 
-Rebuild OVMF:
-```
-build --platform=OvmfPkg/OvmfPkgX64.dsc --arch=X64 --buildtarget=RELEASE --tagname=GCC5
+If you build everything now and execute it under OVMF, you would get:
 ```
-
-You can test that this OVMF image has a shell that includes `acpiview` command in itself:
+FS0:\> SimpleLibraryUser.efi
+5
 ```
-FS0:\> acpiview -l
 
-Installed Table(s):
-           1. RSDP
-           2. XSDT
-           3. FACP
-           4. FACS
-           5. DSDT
-           6. APIC
-           7. HPET
-           8. BGRT
-```
+`3+2` is indeed `5`, so our library works correctly!
 
diff --git a/Lessons/Lesson_35/UefiLessonsPkg/Include/Library/SimpleLibrary.h b/Lessons/Lesson_35/UefiLessonsPkg/Include/Library/SimpleLibrary.h
new file mode 100644
index 0000000..105bc87
--- /dev/null
+++ b/Lessons/Lesson_35/UefiLessonsPkg/Include/Library/SimpleLibrary.h
@@ -0,0 +1,2 @@
+UINTN Plus2(UINTN number);
+
diff --git a/Lessons/Lesson_35/UefiLessonsPkg/Library/SimpleLibrary/SimpleLibrary.c b/Lessons/Lesson_35/UefiLessonsPkg/Library/SimpleLibrary/SimpleLibrary.c
new file mode 100644
index 0000000..acffba4
--- /dev/null
+++ b/Lessons/Lesson_35/UefiLessonsPkg/Library/SimpleLibrary/SimpleLibrary.c
@@ -0,0 +1,5 @@
+#include <Library/SimpleLibrary.h>
+
+UINTN Plus2(UINTN number) {
+  return number+2;
+}
diff --git a/Lessons/Lesson_35/UefiLessonsPkg/Library/SimpleLibrary/SimpleLibrary.inf b/Lessons/Lesson_35/UefiLessonsPkg/Library/SimpleLibrary/SimpleLibrary.inf
new file mode 100644
index 0000000..92027a4
--- /dev/null
+++ b/Lessons/Lesson_35/UefiLessonsPkg/Library/SimpleLibrary/SimpleLibrary.inf
@@ -0,0 +1,15 @@
+[Defines]
+  INF_VERSION                    = 1.25
+  BASE_NAME                      = SimpleLibrary
+  FILE_GUID                      = 826c8951-5bd2-4d72-a9d9-f7ab48684117
+  MODULE_TYPE                    = UEFI_APPLICATION
+  VERSION_STRING                 = 1.0
+  LIBRARY_CLASS                  = SimpleLibrary | UEFI_APPLICATION
+
+[Sources]
+  SimpleLibrary.c
+
+[Packages]
+  MdePkg/MdePkg.dec
+  UefiLessonsPkg/UefiLessonsPkg.dec
+
diff --git a/Lessons/Lesson_35/UefiLessonsPkg/SimpleLibraryUser/SimpleLibraryUser.c b/Lessons/Lesson_35/UefiLessonsPkg/SimpleLibraryUser/SimpleLibraryUser.c
new file mode 100644
index 0000000..9747b97
--- /dev/null
+++ b/Lessons/Lesson_35/UefiLessonsPkg/SimpleLibraryUser/SimpleLibraryUser.c
@@ -0,0 +1,16 @@
+#include <Library/UefiBootServicesTableLib.h>
+#include <Library/UefiLib.h>
+
+#include <Library/SimpleLibrary.h>
+
+EFI_STATUS
+EFIAPI
+UefiMain (
+  IN EFI_HANDLE        ImageHandle,
+  IN EFI_SYSTEM_TABLE  *SystemTable
+  )
+{
+  Print(L"%d\n", Plus2(3));
+
+  return EFI_SUCCESS;
+}
diff --git a/Lessons/Lesson_35/UefiLessonsPkg/SimpleLibraryUser/SimpleLibraryUser.inf b/Lessons/Lesson_35/UefiLessonsPkg/SimpleLibraryUser/SimpleLibraryUser.inf
new file mode 100644
index 0000000..d7e5be8
--- /dev/null
+++ b/Lessons/Lesson_35/UefiLessonsPkg/SimpleLibraryUser/SimpleLibraryUser.inf
@@ -0,0 +1,20 @@
+[Defines]
+  INF_VERSION                    = 1.25
+  BASE_NAME                      = SimpleLibraryUser
+  FILE_GUID                      = 22a1f57c-21ca-4011-9133-e3df0d01dace
+  MODULE_TYPE                    = UEFI_APPLICATION
+  VERSION_STRING                 = 1.0
+  ENTRY_POINT                    = UefiMain
+
+[Sources]
+  SimpleLibraryUser.c
+
+[Packages]
+  MdePkg/MdePkg.dec
+  UefiLessonsPkg/UefiLessonsPkg.dec
+
+[LibraryClasses]
+  UefiApplicationEntryPoint
+  UefiLib
+  SimpleLibrary
+
diff --git a/Lessons/Lesson_35/UefiLessonsPkg/UefiLessonsPkg.dec b/Lessons/Lesson_35/UefiLessonsPkg/UefiLessonsPkg.dec
new file mode 100644
index 0000000..cc355aa
--- /dev/null
+++ b/Lessons/Lesson_35/UefiLessonsPkg/UefiLessonsPkg.dec
@@ -0,0 +1,34 @@
+[Defines]

+  DEC_SPECIFICATION              = 0x00010005

+  PACKAGE_NAME                   = UefiLessonsPkg

+  PACKAGE_GUID                   = 7e7edbba-ca2c-4177-a3f0-d3371358773a

+  PACKAGE_VERSION                = 1.01

+

+[Includes]

+  Include

+

+[Guids]

+  # FILE_GUID as defined in UefiLessonsPkg/HelloWorld/HelloWorld.inf

+  gHelloWorldFileGuid            = {0x2e55fa38, 0xf148, 0x42d3, {0xaf, 0x90, 0x1b, 0xe2, 0x47, 0x32, 0x3e, 0x30}}

+  gUefiLessonsPkgTokenSpaceGuid = {0x150cab53, 0xad47, 0x4385, {0xb5, 0xdd, 0xbc, 0xfc, 0x76, 0xba, 0xca, 0xf0}}

+

+[Protocols]

+

+[PcdsFixedAtBuild]

+  gUefiLessonsPkgTokenSpaceGuid.PcdMyVar32|42|UINT32|0x00000001

+  gUefiLessonsPkgTokenSpaceGuid.PcdMyVar32_1|42|UINT32|0x00000002

+  gUefiLessonsPkgTokenSpaceGuid.PcdMyVar32_2|42|UINT32|0x00000003

+  gUefiLessonsPkgTokenSpaceGuid.PcdMyVarBool|FALSE|BOOLEAN|0x00000004

+

+[PcdsPatchableInModule]

+  gUefiLessonsPkgTokenSpaceGuid.PcdMyPatchableVar32|0x31313131|UINT32|0x10000001

+

+[PcdsFeatureFlag]

+  gUefiLessonsPkgTokenSpaceGuid.PcdMyFeatureFlagVar|FALSE|BOOLEAN|0x20000001

+

+[PcdsDynamic]

+  gUefiLessonsPkgTokenSpaceGuid.PcdMyDynamicVar32|0x38323232|UINT32|0x30000001

+  gUefiLessonsPkgTokenSpaceGuid.PcdMyDynamicVar32_1|42|UINT32|0x30000002

+

+[PcdsDynamicEx]

+  gUefiLessonsPkgTokenSpaceGuid.PcdMyDynamicExVar32|0x38333333|UINT32|0x40000001

diff --git a/Lessons/Lesson_35/UefiLessonsPkg/UefiLessonsPkg.dsc b/Lessons/Lesson_35/UefiLessonsPkg/UefiLessonsPkg.dsc
new file mode 100644
index 0000000..c42b57d
--- /dev/null
+++ b/Lessons/Lesson_35/UefiLessonsPkg/UefiLessonsPkg.dsc
@@ -0,0 +1,59 @@
+[Defines]
+  DSC_SPECIFICATION              = 0x0001001C
+  PLATFORM_GUID                  = 3db7270f-ffac-4139-90a4-0ae68f3f8167
+  PLATFORM_VERSION               = 0.01
+  PLATFORM_NAME                  = UefiLessonsPkg
+  SKUID_IDENTIFIER               = DEFAULT
+  SUPPORTED_ARCHITECTURES        = X64
+  BUILD_TARGETS                  = RELEASE
+
+
+[LibraryClasses]
+  UefiApplicationEntryPoint|MdePkg/Library/UefiApplicationEntryPoint/UefiApplicationEntryPoint.inf
+  UefiBootServicesTableLib|MdePkg/Library/UefiBootServicesTableLib/UefiBootServicesTableLib.inf
+  DebugLib|MdePkg/Library/UefiDebugLibConOut/UefiDebugLibConOut.inf
+  BaseLib|MdePkg/Library/BaseLib/BaseLib.inf
+  #PcdLib|MdePkg/Library/BasePcdLibNull/BasePcdLibNull.inf
+  PcdLib|MdePkg/Library/DxePcdLib/DxePcdLib.inf
+  BaseMemoryLib|MdePkg/Library/BaseMemoryLib/BaseMemoryLib.inf
+  RegisterFilterLib|MdePkg/Library/RegisterFilterLibNull/RegisterFilterLibNull.inf
+  PrintLib|MdePkg/Library/BasePrintLib/BasePrintLib.inf
+  DebugPrintErrorLevelLib|MdePkg/Library/BaseDebugPrintErrorLevelLib/BaseDebugPrintErrorLevelLib.inf
+  UefiLib|MdePkg/Library/UefiLib/UefiLib.inf
+  MemoryAllocationLib|MdePkg/Library/UefiMemoryAllocationLib/UefiMemoryAllocationLib.inf
+  DevicePathLib|MdePkg/Library/UefiDevicePathLib/UefiDevicePathLib.inf
+  UefiRuntimeServicesTableLib|MdePkg/Library/UefiRuntimeServicesTableLib/UefiRuntimeServicesTableLib.inf
+  ShellCEntryLib|ShellPkg/Library/UefiShellCEntryLib/UefiShellCEntryLib.inf
+  ShellLib|ShellPkg/Library/UefiShellLib/UefiShellLib.inf
+  FileHandleLib|MdePkg/Library/UefiFileHandleLib/UefiFileHandleLib.inf  
+  HiiLib|MdeModulePkg/Library/UefiHiiLib/UefiHiiLib.inf
+  SortLib|MdeModulePkg/Library/UefiSortLib/UefiSortLib.inf
+  UefiHiiServicesLib|MdeModulePkg/Library/UefiHiiServicesLib/UefiHiiServicesLib.inf
+  SimpleLibrary|UefiLessonsPkg/Library/SimpleLibrary/SimpleLibrary.inf
+
+[Components]
+  UefiLessonsPkg/SimplestApp/SimplestApp.inf
+  UefiLessonsPkg/HelloWorld/HelloWorld.inf
+  UefiLessonsPkg/ImageHandle/ImageHandle.inf
+  UefiLessonsPkg/ImageInfo/ImageInfo.inf
+  UefiLessonsPkg/MemoryInfo/MemoryInfo.inf
+  UefiLessonsPkg/SimpleShellApp/SimpleShellApp.inf
+  UefiLessonsPkg/ListVariables/ListVariables.inf
+  UefiLessonsPkg/ShowBootVariables/ShowBootVariables.inf
+  UefiLessonsPkg/InteractiveApp/InteractiveApp.inf
+  #UefiLessonsPkg/GOPInfo/GOPInfo.inf
+  #UefiLessonsPkg/HiiMenu/HiiMenu.inf
+  #UefiLessonsPkg/TestGlyphs/TestGlyphs.inf
+  #UefiLessonsPkg/ShowHii/ShowHii.inf
+  UefiLessonsPkg/PCDLesson/PCDLesson.inf
+  UefiLessonsPkg/ShowTables/ShowTables.inf
+  UefiLessonsPkg/AcpiInfo/AcpiInfo.inf
+  UefiLessonsPkg/SaveBGRT/SaveBGRT.inf
+  UefiLessonsPkg/ListPCI/ListPCI.inf
+  UefiLessonsPkg/PCIRomInfo/PCIRomInfo.inf
+  UefiLessonsPkg/Library/SimpleLibrary/SimpleLibrary.inf
+  UefiLessonsPkg/SimpleLibraryUser/SimpleLibraryUser.inf
+
+[PcdsFixedAtBuild]
+  gUefiLessonsPkgTokenSpaceGuid.PcdMyVar32_2|44
+