func: void cpu_x86_update_cr4(CPUX86State *env, uint32_t new_cr4)
  
  {
  
  #if defined(DEBUG_MMU)
  
      printf("CR4 update: CR4=%08x\n", (uint32_t)env->cr[4]);
  
  #endif
  
      if ((new_cr4 & (CR4_PGE_MASK | CR4_PAE_MASK | CR4_PSE_MASK)) !=
  
          (env->cr[4] & (CR4_PGE_MASK | CR4_PAE_MASK | CR4_PSE_MASK))) {
  
          tlb_flush(env, 1);
  
      }
  
      /* SSE handling */
  
      if (!(env->cpuid_features & CPUID_SSE))
  
          new_cr4 &= ~CR4_OSFXSR_MASK;
  
      if (new_cr4 & CR4_OSFXSR_MASK)
  
          env->hflags |= HF_OSFXSR_MASK;
  
      else
  
          env->hflags &= ~HF_OSFXSR_MASK;
  
  
  
      env->cr[4] = new_cr4;
  
  }
  