tests/stack-alignment-offset.c

   1 /* Compiled and run by foreign-stack-alignment.lisp
   2  *
   3  * stack_alignment_offset(int) returns the offset of the first argument from a
   4  * given alignment. run (1) from main, to obtain the good value with no
   5  * lisp involved (2) from lisp both with and without callbacks to see that
   6  * we have not messed the alignment.
   7  *
   8  * trampoline(int(*)()) is here so that we can get callbacks on the
   9  * stack too.
  10  */
  11
  12 /* This software is part of the SBCL system. See the README file for
  13  * more information.
  14  *
  15  * While most of SBCL is derived from the CMU CL system, the test
  16  * files (like this one) were written from scratch after the fork
  17  * from CMU CL.
  18  *
  19  * This software is in the public domain and is provided with
  20  * absolutely no warranty. See the COPYING and CREDITS files for
  21  * more information.
  22  */
  23
  24 #include <stdio.h>
  25 #include <stdlib.h>
  26
  27 /* <nikodemus> bwahahahaaa!
  28  * <Xophe> oh dear.  He's finally flipped
  29  * <lisppaste> nikodemus pasted "stack_alignment_offset" at
  30  *             http://paste.lisp.org/display/13231
  31  * <Xophe> heh
  32  * <Xophe> along with a big / * This code is really twisted * / comment :-)
  33  * <antifuchs> gods.
  34  */
  35 extern int
  36 stack_alignment_offset (int alignment)
  37 {
  38     return ((unsigned int)&alignment) % alignment;
  39 }
  40
  41 extern int
  42 trampoline (int(*callback)(void))
  43 {
  44     return callback();
  45 }
  46
  47 int main (int argc, char** argv)
  48 {
  49     if (argc != 2) {
  50         printf("wrong number of arguments: %d\n", argc-1);
  51         return 1;
  52     }
  53
  54     printf("%d\n", stack_alignment_offset(atoi(argv[1])));
  55     return 0;
  56 }