newlib/libc/sys/mmixware/_exit.c

   1 /* _exit for MMIXware.
   2
   3    Copyright (C) 2001, 2023 Hans-Peter Nilsson
   4
   5    Permission to use, copy, modify, and distribute this software is
   6    freely granted, provided that the above copyright notice, this notice
   7    and the following disclaimer are preserved with no changes.
   8
   9    THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
  10    IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
  11    WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  12    PURPOSE.  */
  13
  14 #include <_ansi.h>
  15 #include <sys/types.h>
  16 #include <sys/stat.h>
  17 #include "sys/syscall.h"
  18
  19 void _exit (int n)
  20 {
  21   /* The return status is passed on at exit from the simulator by all
  22      but the oldest versions of Knuth's mmixware simulator.  Beware,
  23      "TRAP 0,0,0" is the instruction corresponding to (int32_t) 0 and
  24      the value 0 in $255 is common enough that a program crash jumping
  25      to e.g. uninitialized memory will look like "exit (0)".  */
  26   __asm__ ("SET $255,%0\n\tTRAP 0,0,0"
  27            : /* No outputs.  */
  28            : "r" (n)
  29            : "memory");
  30   __unreachable ();
  31 }