cpu.h

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/*
 * (c) 2004-2009 Author(s)
 *     economic rights: Technische Universität Dresden (Germany)
 * License: see LICENSE.spdx (in this directory or the directories above)
 */
 
#ifndef __L4_UTIL_CPU_H
#define __L4_UTIL_CPU_H
 
#include <l4/sys/compiler.h>
 
__BEGIN_DECLS
 
L4_INLINE int          l4util_cpu_has_cpuid(void);
 
L4_INLINE unsigned int l4util_cpu_capabilities(void);
 
L4_INLINE unsigned int l4util_cpu_capabilities_nocheck(void);
 
L4_INLINE void
l4util_cpu_cpuid(unsigned long mode,
                 unsigned long *eax, unsigned long *ebx,
                 unsigned long *ecx, unsigned long *edx);
 
static inline void
l4util_cpu_pause(void)
{
  __asm__ __volatile__ ("rep; nop");
}
 
L4_INLINE int
l4util_cpu_has_cpuid(void)
{
  return 1;
}
l4util_cpu_has_cpuid(void) {…}
 
L4_INLINE void
l4util_cpu_cpuid(unsigned long mode,
                 unsigned long *eax, unsigned long *ebx,
                 unsigned long *ecx, unsigned long *edx)
{
  asm volatile("cpuid"
               : "=a" (*eax),
                 "=b" (*ebx),
                 "=c" (*ecx),
                 "=d" (*edx)
               : "a"  (mode)
               );
}
l4util_cpu_cpuid(unsigned long mode, {…}
 
L4_INLINE unsigned int
l4util_cpu_capabilities_nocheck(void)
{
  unsigned long dummy, capability;
 
  /* get CPU capabilities */
  l4util_cpu_cpuid(1, &dummy, &dummy, &dummy, &capability);
 
  return capability;
}
l4util_cpu_capabilities_nocheck(void) {…}
 
L4_INLINE unsigned int
l4util_cpu_capabilities(void)
{
  if (!l4util_cpu_has_cpuid())
    return 0; /* CPU has not cpuid instruction */
 
  return l4util_cpu_capabilities_nocheck();
}
l4util_cpu_capabilities(void) {…}
 
__END_DECLS
 
#endif