OcCpuLib: Initial import of OcAtomicPreIncUint8

Include/Acidanthera/Library/OcCpuLib.h

@@ -234,4 +234,17 @@ OcGetTSCFrequency (
   VOID
   );
 
+/**
+  Atomically pre-increment 8-bit integer.
+
+  @param[in]  Value  Pointer to 8-bit integer to increment.
+
+  @retval value before incrementing.
+**/
+UINT8
+EFIAPI
+OcAtomicPreIncUint8 (
+  IN OUT volatile UINT8  *Value
+  );
+
 #endif // OC_CPU_LIB_H_

Library/OcCpuLib/Ia32/Atomic.nasm

@@ -18,6 +18,20 @@ DEFAULT  REL
 
 SECTION  .text
 
+;------------------------------------------------------------------------------
+; UINT8
+; EFIAPI
+; OcAtomicPreIncUint8 (
+;   IN OUT volatile UINT8  *Value
+;   );
+;------------------------------------------------------------------------------
+global ASM_PFX(OcAtomicPreIncUint8)
+ASM_PFX(OcAtomicPreIncUint8):
+  mov       ecx, [esp + 4]
+  mov       eax, 1
+  lock xadd byte [ecx], al
+  ret
+
 ;------------------------------------------------------------------------------
 ; UINT32
 ; EFIAPI

Library/OcCpuLib/X64/Atomic.nasm

@@ -18,6 +18,19 @@ DEFAULT  REL
 
 SECTION  .text
 
+;------------------------------------------------------------------------------
+; UINT8
+; EFIAPI
+; OcAtomicPreIncUint8 (
+;   IN OUT volatile UINT8  *Value
+;   );
+;------------------------------------------------------------------------------
+global ASM_PFX(OcAtomicPreIncUint8)
+ASM_PFX(OcAtomicPreIncUint8):
+  mov       eax, 1
+  lock xadd byte [rcx], al
+  ret
+
 ;------------------------------------------------------------------------------
 ; UINT32
 ; EFIAPI

User/Library/UserMisc.c

@@ -161,6 +161,17 @@ AsmCpuidEx (
   #endif
 }
 
+UINT8
+EFIAPI
+OcAtomicPreIncUint8 (
+  IN OUT volatile UINT8  *Value
+  )
+{
+  ASSERT (FALSE);
+
+  return 0;
+}
+
 UINT32
 EFIAPI
 AsmIncrementUint32 (