sysdeps/alpha/__longjmp.c

   1 /* Copyright (C) 1992, 1994 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 Library General Public License as
   6 published by the Free Software Foundation; either version 2 of the
   7 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 Library General Public License for more details.
  13
  14 You should have received a copy of the GNU Library General Public
  15 License along with the GNU C Library; see the file COPYING.LIB.  If
  16 not, write to the Free Software Foundation, Inc., 675 Mass Ave,
  17 Cambridge, MA 02139, USA.  */
  18
  19 /* Global register vars must come before any function defn.  */
  20
  21 register long int
  22   r9 asm ("$9"), r10 asm ("$10"), r11 asm ("$11"), r12 asm ("$12"),
  23   r13 asm ("$13"), r14 asm ("$14");
  24
  25 register long int *fp asm ("$15"), *sp asm ("$30"), *retpc asm ("$26");
  26
  27 #if 1                           /* XXX */
  28 register double
  29   f2 asm ("$f2"), f3 asm ("$f3"), f4 asm ("$f4"), f5 asm ("$f5"),
  30   f6 asm ("$f6"), f7 asm ("$f7"), f8 asm ("$f8"), f9 asm ("$f9");
  31 #endif
  32
  33 #include <setjmp.h>
  34
  35
  36 /* Jump to the position specified by ENV, causing the
  37    setjmp call there to return VAL, or 1 if VAL is 0.  */
  38 void
  39 __longjmp (const __jmp_buf env, int val)
  40 {
  41   /* Restore the integer registers.  */
  42   r9 = env[0].__9;
  43   r10 = env[0].__10;
  44   r11 = env[0].__11;
  45   r12 = env[0].__12;
  46   r13 = env[0].__13;
  47   r14 = env[0].__14;
  48
  49 #if 1                           /* XXX */
  50   /* Restore the floating point registers.  */
  51   f2 = env[0].__f2;
  52   f3 = env[0].__f3;
  53   f4 = env[0].__f4;
  54   f5 = env[0].__f5;
  55   f6 = env[0].__f6;
  56   f7 = env[0].__f7;
  57   f8 = env[0].__f8;
  58   f9 = env[0].__f9;
  59 #endif
  60
  61   /* Set the return PC to that of setjmp's caller.  */
  62   retpc = env[0].__pc;
  63
  64   /* Restore the FP and SP of setjmp's caller.  */
  65   fp = env[0].__fp;
  66   sp = env[0].__sp;
  67
  68   /* Return VAL (or 1 if VAL is zero) to setjmp's caller.
  69
  70      We use an asm here rather than a normal C return statement
  71      just in case the compiler wanted to do some stack frobnication
  72      in the function epilogue.  Since we have already restored
  73      precisely the FP and SP the desired environment needs,
  74      we must avoid the compiler doing anything with the stack.  */
  75
  76   while (1)
  77     {
  78       /* The loop is just to avoid `volatile function does return' warnings.
  79          The instruction will only be executed once.  */
  80
  81       register long int retval asm ("$0");
  82
  83       asm volatile
  84         ("cmoveq %1, 1, %0\n\t" /* $0 = val ?: 1; */
  85          "ret $31, (%2), 1"     /* return $0 */
  86          : "=r" (retval)
  87          /* The "0" constraint should force VAL into $0.  */
  88          : "0" (val), "r" (retpc));
  89     }
  90 }