StrucutrePcd Usage

1. Define C Structure in C Header file. This structure has bit field, union and flexible array. It defines MACROs. C structure and MACROs can be referred in DEC/DSC for structure PCD.

   Example in Guid/Test.h:
   #define MACRO_A 0xA
   #define MACRO_B 0xB
   typedef struct {
     BOOLEAN  Bool;
     UINT8    A:4;
     UINT8    B:4;
     UINT16   C;
     UINT8    E[10];
     union {
       UINT8   Foo[8];
       UINT64  Bar;
     } Array[0x8];
     UINT8    Guid[16];
     UINT8    FlexibleArray[];
   } TEST;

2. Define PCD with C structure in DEC. Structure name, header file and the dependency package dec files are required.

   Example in TestPkg.dec:
   [PcdsFixedAtBuild, PcdsPatchableInModule, PcdsDynamic, PcdsDynamicEx]
     gStructuredPcdPkgTokenSpaceGuid.PcdTest|{0x0}|TEST|0x00010080 {
       <HeaderFiles>
         Guid/Test.h
       <Packages>
         MdePkg/MdePkg.dec
         TestPkg/TestPkg.dec
     }

3. Assign PCD field value in DEC/DSC

   Example in TestPkg.dec or TestPkg.dsc:
   gStructuredPcdPkgTokenSpaceGuid.PcdTest.Bool|TRUE
   gStructuredPcdPkgTokenSpaceGuid.PcdTest.A|MACRO_A
   gStructuredPcdPkgTokenSpaceGuid.PcdTest.C|0xFEDC
   gStructuredPcdPkgTokenSpaceGuid.PcdTest.E|{'&','*'}
   gStructuredPcdPkgTokenSpaceGuid.PcdTest.Guid|{GUID("6F08F62E-5C19-498E-9157-B59CE6F362F1")}
   gStructuredPcdPkgTokenSpaceGuid.PcdTest.Array[1].Foo|"ABC"
   gStructuredPcdPkgTokenSpaceGuid.PcdTest.FlexibleArray|"PcdTest"

4. Access PCD in module source files

   Module.inf
   [Pcd]
   gStructuredPcdPkgTokenSpaceGuid.PcdTest

   Module.c
   #include <Guid/Test.h>
   VOID Test () {
     TEST *TestBuffer;
     TestBuffer = (TEST *) PcdGetPtr (PcdTest);
     TestBuffer->A = 5;
     TestBuffer->Array[0].Bar = 0xE0000000;
     ZeroMem (TestBuffer->E, sizeof (TestBuffer->E));
     AsciiStrnCpyS (TestBuffer->E, sizeof (TestBuffer->E), “Test”, 5);
     PcdSetPtrS (PcdTest, PcdGetSize (PcdTest), TestBuffer);
   }