/* Machine-dependent pthreads configuration and inline functions.
|
/* Machine-dependent pthreads configuration and inline functions.
|
i386 version.
|
i386 version.
|
Copyright (C) 1996,1997,1998,1999,2000,2001 Free Software Foundation, Inc.
|
Copyright (C) 1996,1997,1998,1999,2000,2001 Free Software Foundation, Inc.
|
This file is part of the GNU C Library.
|
This file is part of the GNU C Library.
|
Contributed by Richard Henderson <rth@tamu.edu>.
|
Contributed by Richard Henderson <rth@tamu.edu>.
|
|
|
The GNU C Library is free software; you can redistribute it and/or
|
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
|
modify it under the terms of the GNU Library General Public License as
|
published by the Free Software Foundation; either version 2 of the
|
published by the Free Software Foundation; either version 2 of the
|
License, or (at your option) any later version.
|
License, or (at your option) any later version.
|
|
|
The GNU C Library is distributed in the hope that it will be useful,
|
The GNU C Library is distributed in the hope that it will be useful,
|
but WITHOUT ANY WARRANTY; without even the implied warranty of
|
but WITHOUT ANY WARRANTY; without even the implied warranty of
|
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
|
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
|
Library General Public License for more details.
|
Library General Public License for more details.
|
|
|
You should have received a copy of the GNU Library General Public
|
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,
|
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,
|
write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
|
Boston, MA 02111-1307, USA. */
|
Boston, MA 02111-1307, USA. */
|
|
|
#ifndef PT_EI
|
#ifndef PT_EI
|
# define PT_EI extern inline
|
# define PT_EI extern inline
|
#endif
|
#endif
|
|
|
/* Get some notion of the current stack. Need not be exactly the top
|
/* Get some notion of the current stack. Need not be exactly the top
|
of the stack, just something somewhere in the current frame. */
|
of the stack, just something somewhere in the current frame. */
|
#define CURRENT_STACK_FRAME __builtin_frame_address (0)
|
#define CURRENT_STACK_FRAME __builtin_frame_address (0)
|
|
|
|
|
/* Spinlock implementation; required. */
|
/* Spinlock implementation; required. */
|
PT_EI long int
|
PT_EI long int
|
testandset (int *spinlock)
|
testandset (int *spinlock)
|
{
|
{
|
long int ret;
|
long int ret;
|
|
|
__asm__ __volatile__(
|
__asm__ __volatile__(
|
"xchgl %0, %1"
|
"xchgl %0, %1"
|
: "=r"(ret), "=m"(*spinlock)
|
: "=r"(ret), "=m"(*spinlock)
|
: "0"(1), "m"(*spinlock)
|
: "0"(1), "m"(*spinlock)
|
: "memory");
|
: "memory");
|
|
|
return ret;
|
return ret;
|
}
|
}
|
|
|
|
|
/* Compare-and-swap for semaphores.
|
/* Compare-and-swap for semaphores.
|
Available on the 486 and above, but not on the 386.
|
Available on the 486 and above, but not on the 386.
|
We test dynamically whether it's available or not. */
|
We test dynamically whether it's available or not. */
|
|
|
#define HAS_COMPARE_AND_SWAP
|
#define HAS_COMPARE_AND_SWAP
|
#define TEST_FOR_COMPARE_AND_SWAP
|
#define TEST_FOR_COMPARE_AND_SWAP
|
|
|
PT_EI int
|
PT_EI int
|
__compare_and_swap (long int *p, long int oldval, long int newval)
|
__compare_and_swap (long int *p, long int oldval, long int newval)
|
{
|
{
|
char ret;
|
char ret;
|
long int readval;
|
long int readval;
|
|
|
__asm__ __volatile__ ("lock; cmpxchgl %3, %1; sete %0"
|
__asm__ __volatile__ ("lock; cmpxchgl %3, %1; sete %0"
|
: "=q" (ret), "=m" (*p), "=a" (readval)
|
: "=q" (ret), "=m" (*p), "=a" (readval)
|
: "r" (newval), "m" (*p), "a" (oldval)
|
: "r" (newval), "m" (*p), "a" (oldval)
|
: "memory");
|
: "memory");
|
return ret;
|
return ret;
|
}
|
}
|
|
|
|
|
PT_EI int
|
PT_EI int
|
get_eflags (void)
|
get_eflags (void)
|
{
|
{
|
int res;
|
int res;
|
__asm__ __volatile__ ("pushfl; popl %0" : "=r" (res) : );
|
__asm__ __volatile__ ("pushfl; popl %0" : "=r" (res) : );
|
return res;
|
return res;
|
}
|
}
|
|
|
|
|
PT_EI void
|
PT_EI void
|
set_eflags (int newflags)
|
set_eflags (int newflags)
|
{
|
{
|
__asm__ __volatile__ ("pushl %0; popfl" : : "r" (newflags) : "cc");
|
__asm__ __volatile__ ("pushl %0; popfl" : : "r" (newflags) : "cc");
|
}
|
}
|
|
|
|
|
PT_EI int
|
PT_EI int
|
compare_and_swap_is_available (void)
|
compare_and_swap_is_available (void)
|
{
|
{
|
int oldflags = get_eflags ();
|
int oldflags = get_eflags ();
|
int changed;
|
int changed;
|
/* Flip AC bit in EFLAGS. */
|
/* Flip AC bit in EFLAGS. */
|
set_eflags (oldflags ^ 0x40000);
|
set_eflags (oldflags ^ 0x40000);
|
/* See if bit changed. */
|
/* See if bit changed. */
|
changed = (get_eflags () ^ oldflags) & 0x40000;
|
changed = (get_eflags () ^ oldflags) & 0x40000;
|
/* Restore EFLAGS. */
|
/* Restore EFLAGS. */
|
set_eflags (oldflags);
|
set_eflags (oldflags);
|
/* If the AC flag did not change, it's a 386 and it lacks cmpxchg.
|
/* 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. */
|
Otherwise, it's a 486 or above and it has cmpxchg. */
|
return changed != 0;
|
return changed != 0;
|
}
|
}
|
|
|
