glibc/sysdeps/unix/sysv/linux/s390/s390-32/getcontext.S

/* Copyright (C) 2001-2017 Free Software Foundation, Inc.
   This file is part of the GNU C Library.
   Contributed by Martin Schwidefsky (schwidefsky@de.ibm.com).

   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>
#include <features.h>

#include "ucontext_i.h"

#include <shlib-compat.h>

/*  __getcontext (const ucontext_t *ucp)

  Saves the machine context in UCP such that when it is activated,
  it appears as if __getcontext() returned again.

  This implementation is intended to be used for *synchronous* context
  switches only.  Therefore, it does not have to save anything
  other than the PRESERVED state.  */

ENTRY(__getcontext)
	lr      %r1,%r2

	/* rt_sigprocmask (SIG_BLOCK, NULL, &sc->sc_mask, sigsetsize).  */
	la      %r2,SIG_BLOCK
	slr	%r3,%r3
	la	%r4,SC_MASK(%r1)
	lhi	%r5,_NSIG8
	svc	SYS_ify(rt_sigprocmask)

	/* Store fpu context.  */
	stfpc   SC_FPC(%r1)
	std     %f0,SC_FPRS(%r1)
	std     %f1,SC_FPRS+8(%r1)
	std     %f2,SC_FPRS+16(%r1)
	std     %f3,SC_FPRS+24(%r1)
	std     %f4,SC_FPRS+32(%r1)
	std     %f5,SC_FPRS+40(%r1)
	std     %f6,SC_FPRS+48(%r1)
	std     %f7,SC_FPRS+56(%r1)
	std     %f8,SC_FPRS+64(%r1)
	std     %f9,SC_FPRS+72(%r1)
	std     %f10,SC_FPRS+80(%r1)
	std     %f11,SC_FPRS+88(%r1)
	std     %f12,SC_FPRS+96(%r1)
	std     %f13,SC_FPRS+104(%r1)
	std     %f14,SC_FPRS+112(%r1)
	std     %f15,SC_FPRS+120(%r1)

	/* Set __getcontext return value to 0.  */
	slr     %r2,%r2

	/* Store access registers.  */
	stam    %a0,%a15,SC_ACRS(%r1)

	/* Store general purpose registers.  */
	stm     %r0,%r15,SC_GPRS(%r1)

	/* Return.  */
	br	%r14
END(__getcontext)

#if defined SHARED && SHLIB_COMPAT (libc, GLIBC_2_19, GLIBC_2_20)
/* In glibc release 2.19 a new version of getcontext was introduced,
   but was reverted before 2.20. Thus both versions are the same function.  */
weak_alias (__getcontext, __v1__getcontext)
weak_alias (__getcontext, __v2__getcontext)
versioned_symbol (libc, __v1__getcontext, getcontext, GLIBC_2_1)
compat_symbol (libc, __v2__getcontext, getcontext, GLIBC_2_19)

#else

weak_alias (__getcontext, getcontext)

#endif /* !(defined SHARED && SHLIB_COMPAT (libc, GLIBC_2_19, GLIBC_2_20))  */