glibc/sysdeps/sparc/sparc64/cpu_relax.S

/* CPU strand yielding for busy loops.
   Copyright (C) 2012-2016 Free Software Foundation, Inc.
   Contributed by David S. Miller (davem@davemloft.net)
   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/>.  */

#include <sysdep.h>

	.text
__cpu_relax_generic:
	rd	%ccr, %g0
	rd	%ccr, %g0
	rd	%ccr, %g0
	retl
	 nop
	.size	__cpu_relax_generic,.-__cpu_relax_generic

__cpu_relax_pause:
	wr	%g0, 128, %asr27
	retl
	 nop
	.size	__cpu_relax_pause,.-__cpu_relax_pause

ENTRY(__cpu_relax)
	.type	__cpu_relax, @gnu_indirect_function
# ifdef SHARED
	SETUP_PIC_REG_LEAF(o3, o5)
# endif
	set	HWCAP_SPARC_PAUSE, %o1
	andcc	%o0, %o1, %g0
	be	1f
	 nop
# ifdef SHARED
	sethi	%gdop_hix22(__cpu_relax_pause), %o1
	xor	%o1, %gdop_lox10(__cpu_relax_pause), %o1
# else
	set	__cpu_relax_pause, %o1
# endif
	ba	10f
	 nop
1:
# ifdef SHARED
	sethi	%gdop_hix22(__cpu_relax_generic), %o1
	xor	%o1, %gdop_lox10(__cpu_relax_generic), %o1
# else
	set	__cpu_relax_generic, %o1
# endif
10:
# ifdef SHARED
	add	%o3, %o1, %o1
# endif
	retl
	 mov	%o1, %o0
END(__cpu_relax)