Update.

2001-04-21  Ulrich Drepper  <drepper@redhat.com>

	* elf/dl-support.c: Include cpuclock-init.h.  Use CPUCLOCK_VARDEF and
	CPUCLOCK_INIT if defined.
	* sysdeps/generic/dl-sysdep.c: Likewise.
	* sysdeps/generic/cpuclock-init.h: New file.
	* sysdeps/unix/i386/i586/cpuclock-init.h: New file.
	* sysdeps/unix/i386/i586/Versions: New file.
	* sysdeps/unix/i386/i586/clock_settime.c: New file.
	* sysdeps/unix/i386/i586/clock_gettime.c: Handle thread CPU clock
	separately by calling __pthread_clock_gettime if this function is
	available.  Subtract offset from tsc value before computing time value.

18 files changed, 358 insertions, 28 deletions

diff --git a/ChangeLog b/ChangeLog
index 0dde120..d5f5c5f 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,16 @@
+2001-04-21  Ulrich Drepper  <drepper@redhat.com>
+
+	* elf/dl-support.c: Include cpuclock-init.h.  Use CPUCLOCK_VARDEF and
+	CPUCLOCK_INIT if defined.
+	* sysdeps/generic/dl-sysdep.c: Likewise.
+	* sysdeps/generic/cpuclock-init.h: New file.
+	* sysdeps/unix/i386/i586/cpuclock-init.h: New file.
+	* sysdeps/unix/i386/i586/Versions: New file.
+	* sysdeps/unix/i386/i586/clock_settime.c: New file.
+	* sysdeps/unix/i386/i586/clock_gettime.c: Handle thread CPU clock
+	separately by calling __pthread_clock_gettime if this function is
+	available.  Subtract offset from tsc value before computing time value.
+
 2001-04-20  Ulrich Drepper  <drepper@redhat.com>
 
 	* iconv/iconv_prog.c (print_known_names): If printing goes not to
diff --git a/elf/dl-support.c b/elf/dl-support.c
index 8c10180..fa1b187 100644
--- a/elf/dl-support.c
+++ b/elf/dl-support.c
@@ -29,6 +29,7 @@
 #include <bits/libc-lock.h>
 #include <dl-librecon.h>
 #include <unsecvars.h>
+#include <cpuclock-init.h>
 
 extern char *__progname;
 char **_dl_argv = &__progname;	/* This is checked for some error messages.  */
@@ -92,6 +93,11 @@ struct r_scope_elem *_dl_main_searchlist = &_dl_initial_searchlist;
 /* Nonzero during startup.  */
 int _dl_starting_up = 1;
 
+/* Initial value of the CPU clock.  */
+#ifdef CPUCLOCK_VARDEF
+CPUCLOCK_VARDEF (_dl_cpuclock_offset);
+#endif
+
 /* During the program run we must not modify the global data of
    loaded shared object simultanously in two threads.  Therefore we
    protect `_dl_open' and `_dl_close' in dl-close.c.
@@ -127,6 +133,10 @@ static void non_dynamic_init (void) __attribute__ ((unused));
 static void
 non_dynamic_init (void)
 {
+#ifdef CPUCLOCK_INIT
+  CPUCLOCK_INIT (_dl_cpuclock_offset);
+#endif
+
   if (!_dl_pagesize)
     _dl_pagesize = __getpagesize ();
 
diff --git a/linuxthreads/ChangeLog b/linuxthreads/ChangeLog
index ca64e52..e74f0bf 100644
--- a/linuxthreads/ChangeLog
+++ b/linuxthreads/ChangeLog
@@ -1,3 +1,21 @@
+2001-04-21  Ulrich Drepper  <drepper@redhat.com>
+
+	* internals.h: Include <cpuclock-init.h>.
+	(struct _pthread_descr_struct): Add p_cpuclock_offset field if
+	CPUCLOCK_VARDEF is defined.
+	* pthread.c (__pthread_initialize_minimal): Initialize
+	p_cpuclock_offset field for main thread if CPUCLOCK_INIT is defined.
+	* manager.c (pthread_start_thread): Set p_cpuclock_offset field
+	for new thread to current CPU clock value.
+
+	* sysdeps/i386/useldt.h: Extend all the macros to handle 8-byte values.
+
+	* sysdeps/i386/i586/Makefile: New file.
+	* sysdeps/i386/i586/Versions: New file.
+	* sysdeps/i386/i586/ptclock_gettime.c: New file.
+	* sysdeps/i386/i586/ptclock_settime.c: New file.
+	* sysdeps/i386/i686/Implies: New file.
+
 2001-04-18  Jakub Jelinek  <jakub@redhat.com>
 
 	* sysdeps/unix/sysv/linux/sparc/sparc64/Makefile: Put specs into
diff --git a/linuxthreads/internals.h b/linuxthreads/internals.h
index 998f778..fbe0ea3 100644
--- a/linuxthreads/internals.h
+++ b/linuxthreads/internals.h
@@ -33,6 +33,7 @@ extern int __compare_and_swap (long int *p, long int oldval, long int newval);
 #include "pt-machine.h"
 #include "semaphore.h"
 #include "../linuxthreads_db/thread_dbP.h"
+#include <cpuclock-init.h>
 
 #ifndef THREAD_GETMEM
 # define THREAD_GETMEM(descr, member) descr->member
@@ -179,6 +180,9 @@ struct _pthread_descr_struct {
   struct __res_state *p_resp;	/* Pointer to resolver state */
   struct __res_state p_res;	/* per-thread resolver state */
   int p_inheritsched;           /* copied from the thread attribute */
+#ifdef CPUCLOCK_VARDEF
+  CPUCLOCK_VARDEF (p_cpuclock_offset); /* Initial CPU clock for thread.  */
+#endif
   /* New elements must be added at the end.  */
 } __attribute__ ((aligned(32))); /* We need to align the structure so that
 				    doubles are aligned properly.  This is 8
diff --git a/linuxthreads/manager.c b/linuxthreads/manager.c
index 431e149..dbe2aa2 100644
--- a/linuxthreads/manager.c
+++ b/linuxthreads/manager.c
@@ -225,10 +225,17 @@ static int pthread_start_thread(void *arg)
   pthread_descr self = (pthread_descr) arg;
   struct pthread_request request;
   void * outcome;
+#ifdef CPUCLOCK_VARDEF
+  CPUCLOCK_VARDEF (tmpclock);
+#endif
   /* Initialize special thread_self processing, if any.  */
 #ifdef INIT_THREAD_SELF
   INIT_THREAD_SELF(self, self->p_nr);
 #endif
+#ifdef CPUCLOCK_INIT
+  CPUCLOCK_INIT (tmpclock);
+  THREAD_SETMEM (self, p_cpuclock_offset, tmpclock);
+#endif
   /* Make sure our pid field is initialized, just in case we get there
      before our father has initialized it. */
   THREAD_SETMEM(self, p_pid, __getpid());
diff --git a/linuxthreads/pthread.c b/linuxthreads/pthread.c
index ff9c083..73a7acb 100644
--- a/linuxthreads/pthread.c
+++ b/linuxthreads/pthread.c
@@ -225,6 +225,11 @@ static void pthread_handle_sigcancel(int sig);
 static void pthread_handle_sigrestart(int sig);
 static void pthread_handle_sigdebug(int sig);
 
+/* CPU clock handling.  */
+#ifdef CPUCLOCK_VARDECL
+CPUCLOCK_VARDECL (_dl_cpuclock_offset);
+#endif
+
 /* Signal numbers used for the communication.
    In these variables we keep track of the used variables.  If the
    platform does not support any real-time signals we will define the
@@ -390,6 +395,9 @@ __pthread_initialize_minimal(void)
 #ifdef INIT_THREAD_SELF
   INIT_THREAD_SELF(&__pthread_initial_thread, 0);
 #endif
+#ifdef CPUCLOCK_INIT
+  __pthread_initial_thread.p_cpuclock_offset = _dl_cpuclock_offset;
+#endif
 }
 
 
diff --git a/linuxthreads/sysdeps/i386/i586/Makefile b/linuxthreads/sysdeps/i386/i586/Makefile
new file mode 100644
index 0000000..96c195f
--- /dev/null
+++ b/linuxthreads/sysdeps/i386/i586/Makefile
@@ -0,0 +1,3 @@
+ifeq ($(subdir),linuxthreads)
+libpthread-sysdep_routines += ptclock_gettime ptclock_settime
+endif
diff --git a/linuxthreads/sysdeps/i386/i586/Versions b/linuxthreads/sysdeps/i386/i586/Versions
new file mode 100644
index 0000000..f9921af
--- /dev/null
+++ b/linuxthreads/sysdeps/i386/i586/Versions
@@ -0,0 +1,5 @@
+libpthread {
+  GLIBC_2.2.3 {
+    __pthread_clock_gettime; __pthread_clock_settime;
+  }
+}
diff --git a/linuxthreads/sysdeps/i386/i586/ptclock_gettime.c b/linuxthreads/sysdeps/i386/i586/ptclock_gettime.c
new file mode 100644
index 0000000..8182510
--- /dev/null
+++ b/linuxthreads/sysdeps/i386/i586/ptclock_gettime.c
@@ -0,0 +1,45 @@
+/* Copyright (C) 2001 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Library General Public License as
+   published by the Free Software Foundation; either version 2 of the
+   License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Library General Public License for more details.
+
+   You should have received a copy of the GNU Library General Public
+   License along with the GNU C Library; see the file COPYING.LIB.  If not,
+   write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+   Boston, MA 02111-1307, USA.  */
+
+#include <time.h>
+#include <libc-internal.h>
+
+#include "../../../internals.h"
+
+
+int
+__pthread_clock_gettime (unsigned long long int freq, struct timespec *tp)
+{
+  unsigned long long int tsc;
+  pthread_descr self = thread_self ();
+
+  /* Get the current counter.  */
+  asm volatile ("rdtsc" : "=A" (tsc));
+
+  /* Compute the offset since the start time of the process.  */
+  tsc -= THREAD_GETMEM (self, p_cpuclock_offset);
+
+  /* Compute the seconds.  */
+  tp->tv_sec = tsc / freq;
+
+  /* And the nanoseconds.  This computation should be stable until
+     we get machines with about 16GHz frequency.  */
+  tp->tv_nsec = ((tsc % freq) * 1000000000ull) / freq;
+
+  return 0;
+}
diff --git a/linuxthreads/sysdeps/i386/i586/ptclock_settime.c b/linuxthreads/sysdeps/i386/i586/ptclock_settime.c
new file mode 100644
index 0000000..3026528
--- /dev/null
+++ b/linuxthreads/sysdeps/i386/i586/ptclock_settime.c
@@ -0,0 +1,32 @@
+/* Copyright (C) 2001 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Library General Public License as
+   published by the Free Software Foundation; either version 2 of the
+   License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Library General Public License for more details.
+
+   You should have received a copy of the GNU Library General Public
+   License along with the GNU C Library; see the file COPYING.LIB.  If not,
+   write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+   Boston, MA 02111-1307, USA.  */
+
+#include <time.h>
+#include <libc-internal.h>
+
+#include "../../../internals.h"
+
+
+void
+__pthread_clock_settime (unsigned long long int offset)
+{
+  pthread_descr self = thread_self ();
+
+  /* Compute the offset since the start time of the process.  */
+  THREAD_SETMEM (self, p_cpuclock_offset, offset);
+}
diff --git a/linuxthreads/sysdeps/i386/i686/Implies b/linuxthreads/sysdeps/i386/i686/Implies
new file mode 100644
index 0000000..0df509e
--- /dev/null
+++ b/linuxthreads/sysdeps/i386/i686/Implies
@@ -0,0 +1 @@
+i386/i586
diff --git a/linuxthreads/sysdeps/i386/useldt.h b/linuxthreads/sysdeps/i386/useldt.h
index ebf520c..b9566ac 100644
--- a/linuxthreads/sysdeps/i386/useldt.h
+++ b/linuxthreads/sysdeps/i386/useldt.h
@@ -1,6 +1,6 @@
 /* Special definitions for ix86 machine using segment register based
    thread descriptor.
-   Copyright (C) 1998, 2000 Free Software Foundation, Inc.
+   Copyright (C) 1998, 2000, 2001 Free Software Foundation, Inc.
    This file is part of the GNU C Library.
    Contributed by Ulrich Drepper <drepper@cygnus.com>.
 
@@ -88,16 +88,24 @@ extern int __modify_ldt (int, struct modify_ldt_ldt_s *, size_t);
 			  : "0" (0),					      \
 			    "i" (offsetof (struct _pthread_descr_struct,      \
 					   member)));			      \
+  else if (sizeof (__value) == 4)					      \
+    __asm__ __volatile__ ("movl %%gs:%P1,%0"				      \
+			  : "=r" (__value)				      \
+			  : "i" (offsetof (struct _pthread_descr_struct,      \
+					   member)));			      \
   else									      \
     {									      \
-      if (sizeof (__value) != 4)					      \
-	/* There should not be any value with a size other than 1 or 4.  */   \
+      if (sizeof (__value) != 8)					      \
+	/* There should not be any value with a size other than 1, 4 or 8.  */\
 	abort ();							      \
 									      \
-      __asm__ __volatile__ ("movl %%gs:%P1,%0"				      \
-			    : "=r" (__value)				      \
+      __asm__ __volatile__ ("movl %%gs:%P1,%%eax\n\t"			      \
+			    "movl %%gs:%P2,%%edx"			      \
+			    : "=A" (__value)				      \
 			    : "i" (offsetof (struct _pthread_descr_struct,    \
-					     member)));			      \
+					     member)),			      \
+			      "i" (offsetof (struct _pthread_descr_struct,    \
+					     member) + 4));		      \
     }									      \
   __value;								      \
 })
@@ -112,14 +120,20 @@ extern int __modify_ldt (int, struct modify_ldt_ldt_s *, size_t);
 			  : "0" (0),					      \
 			    "r" (offsetof (struct _pthread_descr_struct,      \
 					   member)));			      \
+  else if (sizeof (__value) == 4)					      \
+    __asm__ __volatile__ ("movl %%gs:(%1),%0"				      \
+			  : "=r" (__value)				      \
+			  : "r" (offsetof (struct _pthread_descr_struct,      \
+					   member)));			      \
   else									      \
     {									      \
-      if (sizeof (__value) != 4)					      \
-	/* There should not be any value with a size other than 1 or 4.  */   \
+      if (sizeof (__value) != 8)					      \
+	/* There should not be any value with a size other than 1, 4 or 8.  */\
 	abort ();							      \
 									      \
-      __asm__ __volatile__ ("movl %%gs:(%1),%0"				      \
-			    : "=r" (__value)				      \
+      __asm__ __volatile__ ("movl %%gs:(%1),%%eax\n\t"			      \
+			    "movl %%gs:4(%1),%%edx"			      \
+			    : "=&A" (__value)				      \
 			    : "r" (offsetof (struct _pthread_descr_struct,    \
 					     member)));			      \
     }									      \
@@ -135,16 +149,24 @@ extern int __modify_ldt (int, struct modify_ldt_ldt_s *, size_t);
 			  : "q" (__value),				      \
 			    "i" (offsetof (struct _pthread_descr_struct,      \
 					   member)));			      \
+  else if (sizeof (__value) == 4)					      \
+    __asm__ __volatile__ ("movl %0,%%gs:%P1" :				      \
+			  : "r" (__value),				      \
+			    "i" (offsetof (struct _pthread_descr_struct,      \
+					   member)));			      \
   else									      \
     {									      \
-      if (sizeof (__value) != 4)					      \
-	/* There should not be any value with a size other than 1 or 4.  */   \
+      if (sizeof (__value) != 8)					      \
+	/* There should not be any value with a size other than 1, 4 or 8.  */\
 	abort ();							      \
 									      \
-      __asm__ __volatile__ ("movl %0,%%gs:%P1" :			      \
-			    : "r" (__value),				      \
+      __asm__ __volatile__ ("movl %%eax,%%gs:%P1\n\n"			      \
+			    "movl %%edx,%%gs:%P2" :			      \
+			    : "A" (__value),				      \
 			      "i" (offsetof (struct _pthread_descr_struct,    \
-					     member)));			      \
+					     member)),			      \
+			      "i" (offsetof (struct _pthread_descr_struct,    \
+					     member) + 4));		      \
     }									      \
 })
 
@@ -157,14 +179,20 @@ extern int __modify_ldt (int, struct modify_ldt_ldt_s *, size_t);
 			  : "q" (__value),				      \
 			    "r" (offsetof (struct _pthread_descr_struct,      \
 					   member)));			      \
+  else if (sizeof (__value) == 4)					      \
+    __asm__ __volatile__ ("movl %0,%%gs:(%1)" :				      \
+			  : "r" (__value),				      \
+			    "r" (offsetof (struct _pthread_descr_struct,      \
+					   member)));			      \
   else									      \
     {									      \
-      if (sizeof (__value) != 4)					      \
-	/* There should not be any value with a size other than 1 or 4.  */   \
+      if (sizeof (__value) != 8)					      \
+	/* There should not be any value with a size other than 1, 4 or 8.  */\
 	abort ();							      \
 									      \
-      __asm__ __volatile__ ("movl %0,%%gs:(%1)" :			      \
-			    : "r" (__value),				      \
+      __asm__ __volatile__ ("movl %%eax,%%gs:(%1)\n\t"			      \
+			    "movl %%edx,%%gs:4(%1)" :			      \
+			    : "A" (__value),				      \
 			      "r" (offsetof (struct _pthread_descr_struct,    \
 					     member)));			      \
     }									      \
diff --git a/sysdeps/generic/cpuclock-init.h b/sysdeps/generic/cpuclock-init.h
new file mode 100644
index 0000000..085cf17
--- /dev/null
+++ b/sysdeps/generic/cpuclock-init.h
@@ -0,0 +1 @@
+/* In general there is no CPU clock.  */
diff --git a/sysdeps/generic/dl-sysdep.c b/sysdeps/generic/dl-sysdep.c
index eb70d3d..024864f 100644
--- a/sysdeps/generic/dl-sysdep.c
+++ b/sysdeps/generic/dl-sysdep.c
@@ -35,6 +35,7 @@
 #include <dl-machine.h>
 #include <dl-procinfo.h>
 #include <dl-osinfo.h>
+#include <cpuclock-init.h>
 
 extern int _dl_argc;
 extern char **_dl_argv;
@@ -60,7 +61,9 @@ int __libc_multiple_libcs = 0;	/* Defining this here avoids the inclusion
 void *__libc_stack_end;
 static ElfW(auxv_t) *_dl_auxv;
 unsigned long int _dl_hwcap_mask = HWCAP_IMPORTANT;
-
+#ifdef CPUCLOCK_VARDEF
+CPUCLOCK_VARDEF (_dl_cpuclock_offset);
+#endif
 
 #ifndef DL_FIND_ARG_COMPONENTS
 # define DL_FIND_ARG_COMPONENTS(cookie, argc, argv, envp, auxp)	\
@@ -97,6 +100,10 @@ _dl_sysdep_start (void **start_argptr,
 # define set_seen(tag) seen |= M ((tag)->a_type)
 #endif
 
+#ifdef CPUCLOCK_INIT
+  CPUCLOCK_INIT (_dl_cpuclock_offset);
+#endif
+
   DL_FIND_ARG_COMPONENTS (start_argptr, _dl_argc, _dl_argv, _environ,
 			  _dl_auxv);
 
diff --git a/sysdeps/unix/i386/i586/Versions b/sysdeps/unix/i386/i586/Versions
new file mode 100644
index 0000000..4242ca4
--- /dev/null
+++ b/sysdeps/unix/i386/i586/Versions
@@ -0,0 +1,5 @@
+ld {
+  GLIBC_2.2.3 {
+    _dl_cpuclock_offset;
+  }
+}
diff --git a/sysdeps/unix/i386/i586/clock_gettime.c b/sysdeps/unix/i386/i586/clock_gettime.c
index 85dcdcf..5e28370 100644
--- a/sysdeps/unix/i386/i586/clock_gettime.c
+++ b/sysdeps/unix/i386/i586/clock_gettime.c
@@ -19,6 +19,9 @@
 #include <time.h>
 #include <libc-internal.h>
 
+#include "cpuclock-init.h"
+
+
 /* This implementation uses the TSC register in modern (i586 and up) IA-32
    processors (most modern clones also provide it).  Since we need the
    resolution of the clock and since determining this is not cheap, we
@@ -33,17 +36,42 @@
 static unsigned long long int freq;
 
 
-/* We add an limitation here: we assume that the machine is not up as
-   long as it takes to wrap-around the 64-bit timestamp counter.  On a
-   4GHz machine it would take 136 years of uptime to wrap around so
-   this "limitation" is not severe.
+/* We need the starting time for the process.  */
+CPUCLOCK_VARDECL (_dl_cpuclock_offset);
+
+
+/* This function is defined in the thread library.  */
+extern int __pthread_clock_gettime (unsigned long long int freq,
+				    struct timespec *tp)
+     __attribute__ ((__weak__));
+
 
-   We use this clock also as the monotonic clock since we don't allow
-   setting the CPU-time clock.  If this should ever change we will have
-   to separate the two.  */
+/* We add an limitation here: we assume that the process is not
+   running as long as it takes to wrap-around the 64-bit timestamp
+   counter.  On a 4GHz machine it would take 136 years of uptime to
+   wrap around so this "limitation" is not severe.  */
 #define EXTRA_CLOCK_CASES \
-  case CLOCK_PROCESS_CPUTIME_ID:					      \
   case CLOCK_THREAD_CPUTIME_ID:						      \
+    if (__pthread_clock_gettime != NULL)				      \
+      {									      \
+	if (__builtin_expect (freq == 0, 0))				      \
+	  {								      \
+	    /* This can only happen if we haven't initialized the `freq'      \
+	       variable yet.  Do this now. We don't have to protect this      \
+	       code against multiple execution since all of them should	      \
+	       lead to the same result.  */				      \
+	    freq = __get_clockfreq ();					      \
+	    if (__builtin_expect (freq == 0, 0))			      \
+	      /* Something went wrong.  */				      \
+	      break;							      \
+	  }								      \
+									      \
+	retval = __pthread_clock_gettime (freq, tp);			      \
+	break;								      \
+      }									      \
+    /* FALLTHROUGH */							      \
+									      \
+  case CLOCK_PROCESS_CPUTIME_ID:					      \
     {									      \
       unsigned long long int tsc;					      \
 									      \
@@ -62,6 +90,9 @@ static unsigned long long int freq;
       /* Get the current counter.  */					      \
       asm volatile ("rdtsc" : "=A" (tsc));				      \
 									      \
+      /* Compute the offset since the start time of the process.  */	      \
+      tsc -= _dl_cpuclock_offset;					      \
+									      \
       /* Compute the seconds.  */					      \
       tp->tv_sec = tsc / freq;						      \
 									      \
diff --git a/sysdeps/unix/i386/i586/clock_settime.c b/sysdeps/unix/i386/i586/clock_settime.c
new file mode 100644
index 0000000..465a68f
--- /dev/null
+++ b/sysdeps/unix/i386/i586/clock_settime.c
@@ -0,0 +1,85 @@
+/* Copyright (C) 2001 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Library General Public License as
+   published by the Free Software Foundation; either version 2 of the
+   License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Library General Public License for more details.
+
+   You should have received a copy of the GNU Library General Public
+   License along with the GNU C Library; see the file COPYING.LIB.  If not,
+   write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+   Boston, MA 02111-1307, USA.  */
+
+#include <time.h>
+
+#include "cpuclock-init.h"
+
+
+/* This implementation uses the TSC register in modern (i586 and up) IA-32
+   processors (most modern clones also provide it).  Since we need the
+   resolution of the clock and since determining this is not cheap, we
+   cache the value.  But this means that systems with processors running
+   at different speeds or process migration to machines with slower or
+   faster processors will not work without changes.  */
+
+
+/* Clock frequency of the processor.  We make it a 64-bit variable
+   because some jokers are already playing with processors with more
+   than 4GHz.  */
+static unsigned long long int freq;
+
+
+/* We need the starting time for the process.  */
+CPUCLOCK_VARDECL (_dl_cpuclock_offset);
+
+
+/* This function is defined in the thread library.  */
+extern void __pthread_clock_settime (unsigned long long int offset)
+     __attribute__ ((__weak__));
+
+
+/* We add an limitation here: we assume that the process is not
+   running as long as it takes to wrap-around the 64-bit timestamp
+   counter.  On a 4GHz machine it would take 136 years of uptime to
+   wrap around so this "limitation" is not severe.  */
+#define EXTRA_CLOCK_CASES \
+  case CLOCK_PROCESS_CPUTIME_ID:					      \
+  case CLOCK_THREAD_CPUTIME_ID:						      \
+    {									      \
+      unsigned long long int tsc;					      \
+      unsigned long long int usertime;					      \
+									      \
+      /* First thing is to get the current time.  */			      \
+      asm volatile ("rdtsc" : "=A" (tsc));				      \
+									      \
+      if (__builtin_expect (freq == 0, 0))				      \
+	{								      \
+	  /* This can only happen if we haven't initialized the `freq'	      \
+	     variable yet.  Do this now. We don't have to protect this	      \
+	     code against multiple execution since all of them should	      \
+	     lead to the same result.  */				      \
+	  freq = __get_clockfreq ();					      \
+	  if (__builtin_expect (freq == 0, 0))				      \
+	    /* Something went wrong.  */				      \
+	    break;							      \
+	}								      \
+									      \
+      /* Convert the user-provided time into CPU ticks.  */		      \
+      usertime = tp->tv_sec * freq + (tp->tv_nsec * freq) / 1000000000ull;    \
+									      \
+      /* Determine the offset and use it as the new base value.  */	      \
+      if (clock_id != CLOCK_THREAD_CPUTIME_ID				      \
+	  || __pthread_clock_settime == NULL)				      \
+	_dl_cpuclock_offset = tsc - usertime;				      \
+      else								      \
+	__pthread_clock_settime (tsc - usertime);			      \
+    }									      \
+  break;
+
+#include <sysdeps/unix/clock_settime.c>
diff --git a/sysdeps/unix/i386/i586/cpuclock-init.h b/sysdeps/unix/i386/i586/cpuclock-init.h
new file mode 100644
index 0000000..ff1ff97
--- /dev/null
+++ b/sysdeps/unix/i386/i586/cpuclock-init.h
@@ -0,0 +1,27 @@
+/* x86 TSC based CPU clock initialization code.
+   Copyright (C) 2001 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Library General Public License as
+   published by the Free Software Foundation; either version 2 of the
+   License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Library General Public License for more details.
+
+   You should have received a copy of the GNU Library General Public
+   License along with the GNU C Library; see the file COPYING.LIB.  If not,
+   write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+   Boston, MA 02111-1307, USA.  */
+
+/* The TSC value has 64 bits.  */
+#define CPUCLOCK_VARDEF(name) unsigned long long int name
+
+/* A declaration.  */
+#define CPUCLOCK_VARDECL(name) extern unsigned long long int name
+
+/* Reading the TSC value is a simple instruction.  */
+#define CPUCLOCK_INIT(name) asm volatile ("rdtsc" : "=A" (name))