/usr/include/atomic_ops/sysdeps/gcc/s390.h is in libatomic-ops-dev 7.4-0ubuntu3.
This file is owned by root:root, with mode 0o644.
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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 | /*
* Copyright (c) 1991-1994 by Xerox Corporation. All rights reserved.
* Copyright (c) 1996-1999 by Silicon Graphics. All rights reserved.
* Copyright (c) 1999-2003 by Hewlett-Packard Company. All rights reserved.
*
*
* THIS MATERIAL IS PROVIDED AS IS, WITH ABSOLUTELY NO WARRANTY EXPRESSED
* OR IMPLIED. ANY USE IS AT YOUR OWN RISK.
*
* Permission is hereby granted to use or copy this program
* for any purpose, provided the above notices are retained on all copies.
* Permission to modify the code and to distribute modified code is granted,
* provided the above notices are retained, and a notice that the code was
* modified is included with the above copyright notice.
*
*/
/* FIXME: untested. */
/* The relevant documentation appears to be at */
/* http://publibz.boulder.ibm.com/epubs/pdf/dz9zr003.pdf */
/* around page 5-96. Apparently: */
/* - Memory references in general are atomic only for a single */
/* byte. But it appears that the most common load/store */
/* instructions also guarantee atomicity for aligned */
/* operands of standard types. WE FOOLISHLY ASSUME that */
/* compilers only generate those. If that turns out to be */
/* wrong, we need inline assembly code for AO_load and */
/* AO_store. */
/* - A store followed by a load is unordered since the store */
/* may be delayed. Otherwise everything is ordered. */
/* - There is a hardware compare-and-swap (CS) instruction. */
#include "../all_aligned_atomic_load_store.h"
#include "../ordered_except_wr.h"
#include "../test_and_set_t_is_ao_t.h"
/* FIXME: Is there a way to do byte-sized test-and-set? */
/* TODO: AO_nop_full should probably be implemented directly. */
/* It appears that certain BCR instructions have that effect. */
/* Presumably they're cheaper than CS? */
AO_INLINE int AO_compare_and_swap_full(volatile AO_t *addr,
AO_t old, AO_t new_val)
{
int retval;
__asm__ __volatile__ (
# ifndef __s390x__
" cs %1,%2,0(%3)\n"
# else
" csg %1,%2,0(%3)\n"
# endif
" ipm %0\n"
" srl %0,28\n"
: "=&d" (retval), "+d" (old)
: "d" (new_val), "a" (addr)
: "cc", "memory");
return retval == 0;
}
#define AO_HAVE_compare_and_swap_full
/* TODO: implement AO_fetch_compare_and_swap. */
/* TODO: Add double-wide operations for 32-bit executables. */
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