Manual for platform-specific features and new __ppc_get_timebase inline.

[BZ #13743]
A new class of installed headers has been documented for low-level
platform-specific functionality.  PowerPC added the first instance with a
function to provide time base register access (__ppc_get_timebase).  This
is required for applications that measure time at high frequencies with
high precision that can't afford a syscall.

1 files changed, 46 insertions, 0 deletions

diff --git a/sysdeps/powerpc/test-gettimebase.c b/sysdeps/powerpc/test-gettimebase.c
new file mode 100644
index 0000000..0e828ff
--- /dev/null
+++ b/sysdeps/powerpc/test-gettimebase.c
@@ -0,0 +1,46 @@
+/* Check __ppc_get_timebase() for architecture changes
+   Copyright (C) 2012 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, see
+   <http://www.gnu.org/licenses/>.  */
+
+/* Test if __ppc_get_timebase() is compatible with the current processor and if
+   it's changing between reads.  A read failure might indicate a Power ISA or
+   binutils change.  */
+
+#include <inttypes.h>
+#include <stdio.h>
+
+#include <sys/platform/ppc.h>
+
+static int
+do_test (void)
+{
+  uint64_t t1, t2, t3;
+  t1 = __ppc_get_timebase ();
+  printf ("Time Base = %"PRIu64"\n", t1);
+  t2 = __ppc_get_timebase ();
+  printf ("Time Base = %"PRIu64"\n", t2);
+  t3 = __ppc_get_timebase ();
+  printf ("Time Base = %"PRIu64"\n", t3);
+  if (t1 != t2 && t1 != t3 && t2 != t3)
+    return 0;
+
+  printf ("Fail: timebase reads should always be different.");
+  return 1;
+}
+
+#define TEST_FUNCTION do_test ()
+#include "../test-skeleton.c"