1 /*
2 * (c) 2009 Adam Lackorzynski <adam@os.inf.tu-dresden.de>
3 * economic rights: Technische Universität Dresden (Germany)
4 *
5 * This file is part of TUD:OS and distributed under the terms of the
6 * GNU General Public License 2.
7 * Please see the COPYING-GPL-2 file for details.
8 *
9 * As a special exception, you may use this file as part of a free software
10 * library without restriction. Specifically, if other files instantiate
11 * templates or use macros or inline functions from this file, or you compile
12 * this file and link it with other files to produce an executable, this
13 * file does not by itself cause the resulting executable to be covered by
14 * the GNU General Public License. This exception does not however
15 * invalidate any other reasons why the executable file might be covered by
16 * the GNU General Public License.
17 */
18 #include <l4/sys/kdebug.h>
19
20 long int
l4_atomic_add(volatile long int * mem,long int offset)21 l4_atomic_add(volatile long int* mem, long int offset)
22 {
23 long int ret = 0;
24 asm volatile ( " 1: \n"
25 " lwarx %%r12, 0, %[ptr] \n" //reserve
26 " add %[ret], %%r12, %[val] \n" //add
27 " stwcx. %[ret], 0, %[ptr] \n" //store if still reserved
28 " bne- 1b \n" //repeat if store failed
29 : [ret]"=r" (ret),
30 [ptr]"=r" (mem),
31 [val]"=r" (offset)
32 : "0" (ret),
33 "1" (mem),
34 "2" (offset)
35 : "r12", "memory"
36 );
37 return ret;
38 }
39
40 long int
l4_atomic_cmpxchg(volatile long int * mem,long int oldval,long int newval)41 l4_atomic_cmpxchg(volatile long int* mem, long int oldval, long int newval)
42 {
43 long int ret = 0;
44 asm volatile ( " 1: \n"
45 " lwarx %%r12, 0, %[ptr] \n"
46 " cmpw %[oldval], %%r12 \n"
47 " bne- 2f \n"
48 " stwcx. %[newval], 0,%[ptr] \n"
49 " bne- 1b \n"
50 " 2: \n"
51 " mr %[ret], %%r12 \n"
52 : [ret] "=r"(ret),
53 [ptr] "=r"(mem),
54 [oldval] "=r"(oldval),
55 [newval] "=r"(newval)
56 : "0" (ret),
57 "1" (mem),
58 "2" (oldval),
59 "3" (newval)
60 : "memory", "r12"
61 );
62 return (oldval == ret);
63 }
64
65 long int
l4_atomic_xchg(volatile long int * mem,long int newval)66 l4_atomic_xchg(volatile long int* mem, long int newval)
67 {
68 // someone not speaking ppc has added this...
69 unsigned long r = *mem;
70 outstring("l4_atomic_xchg is not atomic!\n");
71 *mem = newval;
72 return r;
73 }
74