sysdeps/mips/__longjmp.c

   1 /* Copyright (C) 1992-2023 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3
   4    The GNU C Library is free software; you can redistribute it and/or
   5    modify it under the terms of the GNU Lesser General Public
   6    License as published by the Free Software Foundation; either
   7    version 2.1 of the License, or (at your option) any later version.
   8
   9    The GNU C Library is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12    Lesser General Public License for more details.
  13
  14    You should have received a copy of the GNU Lesser General Public
  15    License along with the GNU C Library.  If not, see
  16    <https://www.gnu.org/licenses/>.  */
  17
  18 #include <setjmp.h>
  19 #include <stdlib.h>
  20
  21 #ifndef __GNUC__
  22   #error This file uses GNU C extensions; you must compile with GCC.
  23 #endif
  24
  25 static void __attribute__ ((nomips16))
  26 ____longjmp (__jmp_buf env_arg, int val_arg)
  27 {
  28   /* gcc 1.39.19 miscompiled the longjmp routine (as it did setjmp before
  29      the hack around it); force it to use $a1 for the longjmp value.
  30      Without this it saves $a1 in a register which gets clobbered
  31      along the way.  */
  32   register struct __jmp_buf_internal_tag *env asm ("a0");
  33   register int val asm ("a1");
  34 #ifdef CHECK_SP
  35   register long sp asm ("$29");
  36   CHECK_SP (env[0].__sp, sp, long);
  37 #endif
  38
  39 #ifdef __mips_hard_float
  40   /* Pull back the floating point callee-saved registers.  */
  41   asm volatile ("l.d $f20, %0" : : "m" (env[0].__fpregs[0]));
  42   asm volatile ("l.d $f22, %0" : : "m" (env[0].__fpregs[1]));
  43   asm volatile ("l.d $f24, %0" : : "m" (env[0].__fpregs[2]));
  44   asm volatile ("l.d $f26, %0" : : "m" (env[0].__fpregs[3]));
  45   asm volatile ("l.d $f28, %0" : : "m" (env[0].__fpregs[4]));
  46   asm volatile ("l.d $f30, %0" : : "m" (env[0].__fpregs[5]));
  47 #endif
  48
  49   /* Get the GP. */
  50   asm volatile ("lw $gp, %0" : : "m" (env[0].__gp));
  51
  52   /* Get the callee-saved registers.  */
  53   asm volatile ("lw $16, %0" : : "m" (env[0].__regs[0]));
  54   asm volatile ("lw $17, %0" : : "m" (env[0].__regs[1]));
  55   asm volatile ("lw $18, %0" : : "m" (env[0].__regs[2]));
  56   asm volatile ("lw $19, %0" : : "m" (env[0].__regs[3]));
  57   asm volatile ("lw $20, %0" : : "m" (env[0].__regs[4]));
  58   asm volatile ("lw $21, %0" : : "m" (env[0].__regs[5]));
  59   asm volatile ("lw $22, %0" : : "m" (env[0].__regs[6]));
  60   asm volatile ("lw $23, %0" : : "m" (env[0].__regs[7]));
  61
  62   /* Get the PC.  */
  63   asm volatile ("lw $25, %0" : : "m" (env[0].__pc));
  64
  65   /* Restore the stack pointer and the FP.  They have to be restored
  66      last and in a single asm as gcc, depending on options used, may
  67      use either of them to access env.  */
  68   asm volatile ("lw $29, %0\n\t"
  69                 "lw $30, %1\n\t" : : "m" (env[0].__sp), "m" (env[0].__fp));
  70
  71 /* Give setjmp 1 if given a 0, or what they gave us if non-zero.  */
  72   if (val == 0)
  73     asm volatile ("li $2, 1");
  74   else
  75     asm volatile ("move $2, %0" : : "r" (val));
  76
  77   asm volatile ("jr $25");
  78
  79   /* Avoid `volatile function does return' warnings.  */
  80   for (;;);
  81 }
  82
  83 /* Not using strong_alias because the nomips16 attribute cannot be
  84    copied from ____longjmp to __longjmp, because of the
  85    architecture-independent declaration of __longjmp without the
  86    attribute and compiler errors for such attributes not being the
  87    same on all declarations.  */
  88 extern __typeof (____longjmp) __longjmp __attribute__ ((alias ("____longjmp")));