Iret.c

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#include <Library/BaseLib.h>
#include <Library/DebugLib.h>
 
#include "Iret.h"
 
VOID
DisableInterruptsOnIret (
  IN OUT EFI_SYSTEM_CONTEXT  SystemContext
  )
{
 #if defined (MDE_CPU_X64)
 
  IA32_EFLAGS32  Rflags;
 
  //
  // Get flags from system context.
  //
  Rflags.UintN = SystemContext.SystemContextX64->Rflags;
  ASSERT (Rflags.Bits.IF);
 
  //
  // Clear interrupts-enabled flag.
  //
  Rflags.Bits.IF                         = 0;
  SystemContext.SystemContextX64->Rflags = Rflags.UintN;
 
 #elif defined (MDE_CPU_IA32)
 
  IA32_EFLAGS32  Eflags;
 
  //
  // Get flags from system context.
  //
  Eflags.UintN = SystemContext.SystemContextIa32->Eflags;
  ASSERT (Eflags.Bits.IF);
 
  //
  // Clear interrupts-enabled flag.
  //
  Eflags.Bits.IF                          = 0;
  SystemContext.SystemContextIa32->Eflags = Eflags.UintN;
 
 #else
 
  #error "Unsupported CPU"
 
 #endif
}