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authorUlrich Drepper <drepper@redhat.com>2005-11-01 02:13:41 +0000
committerUlrich Drepper <drepper@redhat.com>2005-11-01 02:13:41 +0000
commit7006f757e6d6f110b88f6a5a7759d1e118870489 (patch)
tree7630af90063c8630ff668bcfb06972db2f5ecdef /sysdeps/unix/sysv/linux/powerpc/get_clockfreq.c
parentcb07f6f67db0ef4ccbf3bedfb7c9c4f140773d2c (diff)
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* sysdeps/powerpc/powerpc64/Makefile
	(sysdep_routines, elide-routines.os): Add hp-timing.
	* sysdeps/powerpc/powerpc64/hp-timing.c: New file.
	* sysdeps/powerpc/powerpc64/hp-timing.h: New file.
	* sysdeps/unix/sysv/linux/powerpc/get_clockfreq.c: New file.
Diffstat (limited to 'sysdeps/unix/sysv/linux/powerpc/get_clockfreq.c')
-rw-r--r--sysdeps/unix/sysv/linux/powerpc/get_clockfreq.c105
1 files changed, 105 insertions, 0 deletions
diff --git a/sysdeps/unix/sysv/linux/powerpc/get_clockfreq.c b/sysdeps/unix/sysv/linux/powerpc/get_clockfreq.c
new file mode 100644
index 0000000000..ddaff303c5
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/powerpc/get_clockfreq.c
@@ -0,0 +1,105 @@
+/* Get frequency of the system processor.  powerpc/Linux version.
+   Copyright (C) 2000, 2001, 2005 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 Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 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
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, write to the Free
+   Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
+   02111-1307 USA.  */
+
+#include <ctype.h>
+#include <fcntl.h>
+#include <string.h>
+#include <unistd.h>
+#include <libc-internal.h>
+
+
+hp_timing_t
+__get_clockfreq (void)
+{
+  /* We read the information from the /proc filesystem.  /proc/cpuinfo
+     contains at least one line like:
+        timebase        : 33333333
+     We search for this line and convert the number into an integer.  */
+  static hp_timing_t timebase_freq;
+  hp_timing_t result = 0L;
+
+  /* If this function was called before, we know the result.  */
+  if (timebase_freq != 0)
+    return timebase_freq;
+
+  int fd = open ("/proc/cpuinfo", O_RDONLY);
+  if (__builtin_expect (fd != -1, 1))
+    {
+      /* The timebase will be in the 1st 1024 bytes for systems with up
+         to 8 processors.  If the first read returns less then 1024
+	 bytes read,  we have the whole cpuinfo and can start the scan.
+	 Otherwise we will have to read more to insure we have the
+	 timebase value in the scan.  */
+      char buf[1024];
+      ssize_t n;
+
+      n = read (fd, buf, sizeof (buf));
+      if (n == sizeof (buf))
+	{
+	  /* We are here because the 1st read returned exactly sizeof
+	     (buf) bytes.  This implies that we are not at EOF and may
+	     not have read the timebase value yet.  So we need to read
+	     more bytes until we know we have EOF.  We copy the lower
+	     half of buf to the upper half and read sizeof (buf)/2
+	     bytes into the lower half of buf and repeat until we
+	     reach EOF.  We can assume that the timebase will be in
+	     the last 512 bytes of cpuinfo, so two 512 byte half_bufs
+	     will be sufficient to contain the timebase and will
+	     handle the case where the timebase spans the half_buf
+	     boundry.  */
+	  const ssize_t half_buf = sizeof (buf) / 2;
+	  while (n >= half_buf)
+	    {
+	      memcpy (buf, buf + half_buf, half_buf);
+	      n = read (fd, buf + half_buf, half_buf);
+	    }
+	  if (n >= 0)
+	    n += half_buf;
+	}
+
+      if (__builtin_expect (n, 1) > 0)
+	{
+	  char *mhz = memmem (buf, n, "timebase", 7);
+
+	  if (__builtin_expect (mhz != NULL, 1))
+	    {
+	      char *endp = buf + n;
+
+	      /* Search for the beginning of the string.  */
+	      while (mhz < endp && (*mhz < '0' || *mhz > '9') && *mhz != '\n')
+		++mhz;
+
+	      while (mhz < endp && *mhz != '\n')
+		{
+		  if (*mhz >= '0' && *mhz <= '9')
+		    {
+		      result *= 10;
+		      result += *mhz - '0';
+		    }
+
+		  ++mhz;
+		}
+	    }
+	  timebase_freq = result;
+	}
+      close (fd);
+    }
+
+  return timebase_freq;
+}