glibc/sysdeps/mips/__longjmp.c

/* Copyright (C) 1992-2020 Free Software Foundation, Inc.
   This file is part of the GNU C Library.
   Contributed by Brendan Kehoe (brendan@zen.org).

   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
   <https://www.gnu.org/licenses/>.  */

#include <setjmp.h>
#include <stdlib.h>

#ifndef	__GNUC__
  #error This file uses GNU C extensions; you must compile with GCC.
#endif

static void __attribute__ ((nomips16))
____longjmp (__jmp_buf env_arg, int val_arg)
{
  /* gcc 1.39.19 miscompiled the longjmp routine (as it did setjmp before
     the hack around it); force it to use $a1 for the longjmp value.
     Without this it saves $a1 in a register which gets clobbered
     along the way.  */
  register struct __jmp_buf_internal_tag *env asm ("a0");
  register int val asm ("a1");
#ifdef CHECK_SP
  register long sp asm ("$29");
  CHECK_SP (env[0].__sp, sp, long);
#endif

#ifdef __mips_hard_float
  /* Pull back the floating point callee-saved registers.  */
  asm volatile ("l.d $f20, %0" : : "m" (env[0].__fpregs[0]));
  asm volatile ("l.d $f22, %0" : : "m" (env[0].__fpregs[1]));
  asm volatile ("l.d $f24, %0" : : "m" (env[0].__fpregs[2]));
  asm volatile ("l.d $f26, %0" : : "m" (env[0].__fpregs[3]));
  asm volatile ("l.d $f28, %0" : : "m" (env[0].__fpregs[4]));
  asm volatile ("l.d $f30, %0" : : "m" (env[0].__fpregs[5]));
#endif

  /* Get the GP. */
  asm volatile ("lw $gp, %0" : : "m" (env[0].__gp));

  /* Get the callee-saved registers.  */
  asm volatile ("lw $16, %0" : : "m" (env[0].__regs[0]));
  asm volatile ("lw $17, %0" : : "m" (env[0].__regs[1]));
  asm volatile ("lw $18, %0" : : "m" (env[0].__regs[2]));
  asm volatile ("lw $19, %0" : : "m" (env[0].__regs[3]));
  asm volatile ("lw $20, %0" : : "m" (env[0].__regs[4]));
  asm volatile ("lw $21, %0" : : "m" (env[0].__regs[5]));
  asm volatile ("lw $22, %0" : : "m" (env[0].__regs[6]));
  asm volatile ("lw $23, %0" : : "m" (env[0].__regs[7]));

  /* Get the PC.  */
  asm volatile ("lw $25, %0" : : "m" (env[0].__pc));

  /* Restore the stack pointer and the FP.  They have to be restored
     last and in a single asm as gcc, depending on options used, may
     use either of them to access env.  */
  asm volatile ("lw $29, %0\n\t"
		"lw $30, %1\n\t" : : "m" (env[0].__sp), "m" (env[0].__fp));

/* Give setjmp 1 if given a 0, or what they gave us if non-zero.  */
  if (val == 0)
    asm volatile ("li $2, 1");
  else
    asm volatile ("move $2, %0" : : "r" (val));

  asm volatile ("jr $25");

  /* Avoid `volatile function does return' warnings.  */
  for (;;);
}

/* Not using strong_alias because the nomips16 attribute cannot be
   copied from ____longjmp to __longjmp, because of the
   architecture-independent declaration of __longjmp without the
   attribute and compiler errors for such attributes not being the
   same on all declarations.  */
extern __typeof (____longjmp) __longjmp __attribute__ ((alias ("____longjmp")));