ArmPlatformPkg/ArmPlatformLib: Added support for ArmPlatformIsPrimaryCore()

Checking if a core if the primary/boot core used to be done with the macro
IS_PRIMARY_CORE().
Some platforms exposes configuration registers to change the primary core.
Replacing the macro IS_PRIMARY_CORE() by ArmPlatformIsPrimaryCore() allows
some flexibility in the way to check the primary core.

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Olivier Martin <olivier.martin@arm.com>
Reviewed-by: Leif Lindholm <leif.lindholm@linaro.org>
Acked-by: Ryan Harkin <ryan.harkin@linaro.org>


git-svn-id: https://edk2.svn.sourceforge.net/svnroot/edk2/trunk/edk2@14344 6f19259b-4bc3-4df7-8a09-765794883524

ArmPlatformPkg/Library/ArmPlatformLibNull/Arm/ArmPlatformHelper.asm

@@ -17,7 +17,11 @@
   INCLUDE AsmMacroIoLib.inc
 
   EXPORT  ArmPlatformGetCorePosition
+  EXPORT  ArmPlatformIsPrimaryCore
 
+  IMPORT  _gPcd_FixedAtBuild_PcdArmPrimaryCore
+  IMPORT  _gPcd_FixedAtBuild_PcdArmPrimaryCoreMask
+  
   PRESERVE8
   AREA    ArmPlatformNullHelper, CODE, READONLY
 
@@ -32,5 +36,21 @@ ArmPlatformGetCorePosition FUNCTION
   bx 	lr
   ENDFUNC
 
+//UINTN
+//ArmPlatformIsPrimaryCore (
+//  IN UINTN MpId
+//  );
+ArmPlatformIsPrimaryCore FUNCTION
+  LoadConstantToReg (_gPcd_FixedAtBuild_PcdArmPrimaryCoreMask, r1)
+  ldr   r1, [r1]
+  and   r0, r0, r1
+  LoadConstantToReg (_gPcd_FixedAtBuild_PcdArmPrimaryCore, r1)
+  ldr   r1, [r1]
+  cmp   r0, r1
+  moveq r0, #1
+  movne r0, #0
+  bx    lr
+  ENDFUNC
+
   END