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[edk2,2/3] MdePkg/BaseMemoryLibStm: implement new IsZeroGuid() API function

Message ID 20160902142912.17297-3-leif.lindholm@linaro.org
State Accepted
Commit a548a5421f98f0890e3ab9703a5209d3ef8a9183
Headers show

Commit Message

Leif Lindholm Sept. 2, 2016, 2:29 p.m. UTC 
From: Ard Biesheuvel <ard.biesheuvel@linaro.org>


BaseMemoryLib has recently been extended with an API function
IsZeroGuid(), so copy the default implementation into BaseMemoryLibStm
as well.

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>

Reviewed-by: Leif Lindholm <leif.lindholm@linaro.org>

---
 MdePkg/Library/BaseMemoryLibStm/MemLibGuid.c | 29 ++++++++++++++++++++++++++++
 1 file changed, 29 insertions(+)

-- 
2.9.3

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diff mbox

Patch

diff --git a/MdePkg/Library/BaseMemoryLibStm/MemLibGuid.c b/MdePkg/Library/BaseMemoryLibStm/MemLibGuid.c
index 2b4ed57..36d42d7 100644
--- a/MdePkg/Library/BaseMemoryLibStm/MemLibGuid.c
+++ b/MdePkg/Library/BaseMemoryLibStm/MemLibGuid.c
@@ -130,3 +130,32 @@  ScanGuid (
   }
   return NULL;
 }
+
+/**
+  Checks if the given GUID is a zero GUID.
+
+  This function checks whether the given GUID is a zero GUID. If the GUID is
+  identical to a zero GUID then TRUE is returned. Otherwise, FALSE is returned.
+
+  If Guid is NULL, then ASSERT().
+
+  @param  Guid        The pointer to a 128 bit GUID.
+
+  @retval TRUE        Guid is a zero GUID.
+  @retval FALSE       Guid is not a zero GUID.
+
+**/
+BOOLEAN
+EFIAPI
+IsZeroGuid (
+  IN CONST GUID  *Guid
+  )
+{
+  UINT64  LowPartOfGuid;
+  UINT64  HighPartOfGuid;
+
+  LowPartOfGuid  = ReadUnaligned64 ((CONST UINT64*) Guid);
+  HighPartOfGuid = ReadUnaligned64 ((CONST UINT64*) Guid + 1);
+
+  return (BOOLEAN) (LowPartOfGuid == 0 && HighPartOfGuid == 0);
+}