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authorEric Andersen <andersen@codepoet.org>2002-02-20 09:18:50 +0000
committerEric Andersen <andersen@codepoet.org>2002-02-20 09:18:50 +0000
commite356ea321c8098cf1a83a67e27d64c44de08a298 (patch)
tree8be9273fb8f0e6acab47a9e09552cfbea5400b31 /libpthread/linuxthreads/sysdeps/i386/pt-machine.h
parent07ebf927b17572d92e785533d6e8ac1668cc57c6 (diff)
Merge in the pthread library. This is the linuxthreads library taken from
glibc 2.1.3 and ported to work with uClibc by Stefan Soucek and Erik Andersen (me). Stefan has hacked things up such that linuxthreads runs on MMU-less systems (tested only on arm-nommu). Erik cleaned things up and made it work properly as a shared library. -Erik
Diffstat (limited to 'libpthread/linuxthreads/sysdeps/i386/pt-machine.h')
-rw-r--r--libpthread/linuxthreads/sysdeps/i386/pt-machine.h99
1 files changed, 99 insertions, 0 deletions
diff --git a/libpthread/linuxthreads/sysdeps/i386/pt-machine.h b/libpthread/linuxthreads/sysdeps/i386/pt-machine.h
new file mode 100644
index 000000000..f542bb2d2
--- /dev/null
+++ b/libpthread/linuxthreads/sysdeps/i386/pt-machine.h
@@ -0,0 +1,99 @@
+/* Machine-dependent pthreads configuration and inline functions.
+ i386 version.
+ Copyright (C) 1996, 1997, 1998 Free Software Foundation, Inc.
+ This file is part of the GNU C Library.
+ Contributed by Richard Henderson <rth@tamu.edu>.
+
+ 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. */
+
+#ifndef PT_EI
+# define PT_EI extern inline
+#endif
+
+/* Get some notion of the current stack. Need not be exactly the top
+ of the stack, just something somewhere in the current frame. */
+#define CURRENT_STACK_FRAME stack_pointer
+register char * stack_pointer __asm__ ("%esp");
+
+
+/* Spinlock implementation; required. */
+PT_EI int
+testandset (int *spinlock)
+{
+ int ret;
+
+ __asm__ __volatile__(
+ "xchgl %0, %1"
+ : "=r"(ret), "=m"(*spinlock)
+ : "0"(1), "m"(*spinlock)
+ : "memory");
+
+ return ret;
+}
+
+
+/* Compare-and-swap for semaphores.
+ Available on the 486 and above, but not on the 386.
+ We test dynamically whether it's available or not. */
+
+#define HAS_COMPARE_AND_SWAP
+#define TEST_FOR_COMPARE_AND_SWAP
+
+PT_EI int
+__compare_and_swap (long int *p, long int oldval, long int newval)
+{
+ char ret;
+ long int readval;
+
+ __asm__ __volatile__ ("lock; cmpxchgl %3, %1; sete %0"
+ : "=q" (ret), "=m" (*p), "=a" (readval)
+ : "r" (newval), "m" (*p), "a" (oldval)
+ : "memory");
+ return ret;
+}
+
+
+PT_EI int
+get_eflags (void)
+{
+ int res;
+ __asm__ __volatile__ ("pushfl; popl %0" : "=r" (res) : );
+ return res;
+}
+
+
+PT_EI void
+set_eflags (int newflags)
+{
+ __asm__ __volatile__ ("pushl %0; popfl" : : "r" (newflags) : "cc");
+}
+
+
+PT_EI int
+compare_and_swap_is_available (void)
+{
+ int oldflags = get_eflags ();
+ int changed;
+ /* Flip AC bit in EFLAGS. */
+ set_eflags (oldflags ^ 0x40000);
+ /* See if bit changed. */
+ changed = (get_eflags () ^ oldflags) & 0x40000;
+ /* Restore EFLAGS. */
+ set_eflags (oldflags);
+ /* If the AC flag did not change, it's a 386 and it lacks cmpxchg.
+ Otherwise, it's a 486 or above and it has cmpxchg. */
+ return changed != 0;
+}