rdtsc.h

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/*
 * (c) 2003-2009 Adam Lackorzynski <adam@os.inf.tu-dresden.de>,
 *               Alexander Warg <warg@os.inf.tu-dresden.de>,
 *               Frank Mehnert <fm3@os.inf.tu-dresden.de>,
 *               Jork Löser <jork@os.inf.tu-dresden.de>,
 *               Martin Pohlack <mp26@os.inf.tu-dresden.de>
 *     economic rights: Technische Universität Dresden (Germany)
 * License: see LICENSE.spdx (in this directory or the directories above)
 */
 
#ifndef __l4_rdtsc_h
#define __l4_rdtsc_h
 
#include <l4/sys/compiler.h>
#include <l4/sys/l4int.h>
#include <l4/sys/kip.h>
 
__BEGIN_DECLS
 
/* interface */
extern l4_uint32_t l4_scaler_tsc_to_ns;
extern l4_uint32_t l4_scaler_tsc_to_us;
extern l4_uint32_t l4_scaler_ns_to_tsc;
extern l4_uint32_t l4_scaler_tsc_linux;
 
L4_INLINE l4_cpu_time_t
l4_rdtsc (void);
 
L4_INLINE
l4_uint32_t l4_rdtsc_32(void);
 
L4_INLINE l4_uint64_t
l4_rdpmc (int ecx);
 
L4_INLINE
l4_uint32_t l4_rdpmc_32(int ecx);
 
L4_INLINE l4_uint64_t
l4_tsc_to_ns (l4_cpu_time_t tsc);
 
L4_INLINE l4_uint64_t
l4_tsc_to_us (l4_cpu_time_t tsc);
 
L4_INLINE void
l4_tsc_to_s_and_ns (l4_cpu_time_t tsc, l4_uint32_t *s, l4_uint32_t *ns);
 
L4_INLINE l4_cpu_time_t
l4_ns_to_tsc (l4_uint64_t ns);
 
L4_INLINE void
l4_busy_wait_ns (l4_uint64_t ns);
 
L4_INLINE void
l4_busy_wait_us (l4_uint64_t us);
 
L4_INLINE l4_uint32_t
l4_calibrate_tsc(l4_kernel_info_t const *kip);
 
L4_CV l4_uint32_t
l4_tsc_init(l4_kernel_info_t const *kip);
 
L4_CV l4_uint32_t
l4_get_hz (void);
 
__END_DECLS
 
/* implementation */
 
L4_INLINE l4_uint32_t
l4_calibrate_tsc(l4_kernel_info_t const *kip)
{
  return l4_tsc_init(kip);
}
 
L4_INLINE l4_cpu_time_t
l4_rdtsc (void)
{
    l4_cpu_time_t v;
 
    __asm__ __volatile__
  ("        \n\t"
   ".byte 0x0f, 0x31    \n\t"
  /*"rdtsc\n\t"*/
  :
  "=A" (v)
  : /* no inputs */
  );
 
    return v;
}
 
/* the same, but only 32 bit. Useful for smaller differences,
   needs less cycles. */
L4_INLINE
l4_uint32_t l4_rdtsc_32(void)
{
  l4_uint32_t x;
 
  __asm__ __volatile__ (
       ".byte 0x0f, 0x31\n\t" // rdtsc
       : "=a" (x)
       :
       : "edx");
 
  return x;
}
 
L4_INLINE l4_uint64_t
l4_rdpmc (int ecx)
{
    l4_cpu_time_t v;
 
    __asm__ __volatile__ (
   "rdpmc       \n\t"
  :
  "=A" (v)
  : "c" (ecx)
  );
 
    return v;
}
 
/* the same, but only 32 bit. Useful for smaller differences,
   needs less cycles. */
L4_INLINE
l4_uint32_t l4_rdpmc_32(int ecx)
{
  l4_uint32_t x;
 
  __asm__ __volatile__ (
       "rdpmc       \n\t"
       : "=a" (x)
       : "c" (ecx)
       : "edx");
 
  return x;
}
 
L4_INLINE l4_uint64_t
l4_tsc_to_ns (l4_cpu_time_t tsc)
{
    l4_uint32_t dummy;
    l4_uint64_t ns;
    __asm__
  ("        \n\t"
   "movl  %%edx, %%ecx    \n\t"
   "mull  %3      \n\t"
   "movl  %%ecx, %%eax    \n\t"
   "movl  %%edx, %%ecx    \n\t"
   "mull  %3      \n\t"
   "addl  %%ecx, %%eax    \n\t"
   "adcl  $0, %%edx   \n\t"
   "shld  $5, %%eax, %%edx  \n\t"
   "shll  $5, %%eax   \n\t"
  :"=A" (ns),
   "=&c" (dummy)
  :"0" (tsc),
   "g" (l4_scaler_tsc_to_ns)
  );
    return ns;
}
 
L4_INLINE l4_uint64_t
l4_tsc_to_us (l4_cpu_time_t tsc)
{
    l4_uint32_t dummy;
    l4_uint64_t us;
    __asm__
  ("        \n\t"
   "movl  %%edx, %%ecx    \n\t"
   "mull  %3      \n\t"
   "movl  %%ecx, %%eax    \n\t"
   "movl  %%edx, %%ecx    \n\t"
   "mull  %3      \n\t"
   "addl  %%ecx, %%eax    \n\t"
   "adcl  $0, %%edx   \n\t"
  :"=A" (us),
   "=&c" (dummy)
  :"0" (tsc),
   "g" (l4_scaler_tsc_to_us)
  );
    return us;
}
 
L4_INLINE void
l4_tsc_to_s_and_ns (l4_cpu_time_t tsc, l4_uint32_t *s, l4_uint32_t *ns)
{
    l4_uint32_t dummy;
    __asm__
  ("        \n\t"
   "movl  %%edx, %%ecx    \n\t"
   "mull  %4      \n\t"
   "movl  %%ecx, %%eax    \n\t"
   "movl  %%edx, %%ecx    \n\t"
   "mull  %4      \n\t"
   "addl  %%ecx, %%eax    \n\t"
   "adcl  $0, %%edx   \n\t"
   "movl  $1000000000, %%ecx  \n\t"
   "shld  $5, %%eax, %%edx  \n\t"
   "shll  $5, %%eax   \n\t"
   "divl  %%ecx     \n\t"
  :"=a" (*s), "=d" (*ns), "=&c" (dummy)
  : "A" (tsc), "g" (l4_scaler_tsc_to_ns)
  );
}
 
L4_INLINE l4_cpu_time_t
l4_ns_to_tsc (l4_uint64_t ns)
{
    l4_uint32_t dummy;
    l4_cpu_time_t tsc;
    __asm__
  ("        \n\t"
   "movl  %%edx, %%ecx    \n\t"
   "mull  %3      \n\t"
   "movl  %%ecx, %%eax    \n\t"
   "movl  %%edx, %%ecx    \n\t"
   "mull  %3      \n\t"
   "addl  %%ecx, %%eax    \n\t"
   "adcl  $0, %%edx   \n\t"
   "shld  $5, %%eax, %%edx  \n\t"
   "shll  $5, %%eax   \n\t"
  :"=A" (tsc),
   "=&c" (dummy)
  :"0" (ns),
   "g" (l4_scaler_ns_to_tsc)
  );
    return tsc;
}
 
L4_INLINE void
l4_busy_wait_ns (l4_uint64_t ns)
{
  l4_cpu_time_t stop = l4_rdtsc();
  stop += l4_ns_to_tsc(ns);
 
  while (l4_rdtsc() < stop)
    ;
}
 
L4_INLINE void
l4_busy_wait_us (l4_uint64_t us)
{
  l4_cpu_time_t stop = l4_rdtsc ();
  stop += l4_ns_to_tsc(us*1000ULL);
 
  while (l4_rdtsc() < stop)
    ;
}
 
#endif /* __l4_rdtsc_h */