1/* Legacy sub-word atomics for RISC-V.
2
3   Copyright (C) 2016-2020 Free Software Foundation, Inc.
4
5This file is part of GCC.
6
7GCC is free software; you can redistribute it and/or modify it under
8the terms of the GNU General Public License as published by the Free
9Software Foundation; either version 3, or (at your option) any later
10version.
11
12GCC is distributed in the hope that it will be useful, but WITHOUT ANY
13WARRANTY; without even the implied warranty of MERCHANTABILITY or
14FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
15for more details.
16
17Under Section 7 of GPL version 3, you are granted additional
18permissions described in the GCC Runtime Library Exception, version
193.1, as published by the Free Software Foundation.
20
21You should have received a copy of the GNU General Public License and
22a copy of the GCC Runtime Library Exception along with this program;
23see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
24<http://www.gnu.org/licenses/>.  */
25
26#ifdef __riscv_atomic
27
28#include <stdbool.h>
29
30#define INVERT		"not %[tmp1], %[tmp1]\n\t"
31#define DONT_INVERT	""
32
33#define GENERATE_FETCH_AND_OP(type, size, opname, insn, invert, cop)	\
34  type __sync_fetch_and_ ## opname ## _ ## size (type *p, type v)	\
35  {									\
36    unsigned long aligned_addr = ((unsigned long) p) & ~3UL;		\
37    int shift = (((unsigned long) p) & 3) * 8;				\
38    unsigned mask = ((1U << ((sizeof v) * 8)) - 1) << shift;		\
39    unsigned old, tmp1, tmp2;						\
40									\
41    asm volatile ("1:\n\t"						\
42		  "lr.w.aq %[old], %[mem]\n\t"				\
43		  #insn " %[tmp1], %[old], %[value]\n\t"		\
44		  invert						\
45		  "and %[tmp1], %[tmp1], %[mask]\n\t"			\
46		  "and %[tmp2], %[old], %[not_mask]\n\t"		\
47		  "or %[tmp2], %[tmp2], %[tmp1]\n\t"			\
48		  "sc.w.rl %[tmp1], %[tmp2], %[mem]\n\t"		\
49		  "bnez %[tmp1], 1b"					\
50		  : [old] "=&r" (old),					\
51		    [mem] "+A" (*(volatile unsigned*) aligned_addr),	\
52		    [tmp1] "=&r" (tmp1),				\
53		    [tmp2] "=&r" (tmp2)					\
54		  : [value] "r" (((unsigned) v) << shift),		\
55		    [mask] "r" (mask),					\
56		    [not_mask] "r" (~mask));				\
57									\
58    return (type) (old >> shift);					\
59  }									\
60									\
61  type __sync_ ## opname ## _and_fetch_ ## size (type *p, type v)	\
62  {									\
63    type o = __sync_fetch_and_ ## opname ## _ ## size (p, v);		\
64    return cop;								\
65  }
66
67#define GENERATE_COMPARE_AND_SWAP(type, size)				\
68  type __sync_val_compare_and_swap_ ## size (type *p, type o, type n)	\
69  {									\
70    unsigned long aligned_addr = ((unsigned long) p) & ~3UL;		\
71    int shift = (((unsigned long) p) & 3) * 8;				\
72    unsigned mask = ((1U << ((sizeof o) * 8)) - 1) << shift;		\
73    unsigned old, tmp1;							\
74									\
75    asm volatile ("1:\n\t"						\
76		  "lr.w.aq %[old], %[mem]\n\t"				\
77		  "and %[tmp1], %[old], %[mask]\n\t"			\
78		  "bne %[tmp1], %[o], 1f\n\t"				\
79		  "and %[tmp1], %[old], %[not_mask]\n\t"		\
80		  "or %[tmp1], %[tmp1], %[n]\n\t"			\
81		  "sc.w.rl %[tmp1], %[tmp1], %[mem]\n\t"		\
82		  "bnez %[tmp1], 1b\n\t"				\
83		  "1:"							\
84		  : [old] "=&r" (old),					\
85		    [mem] "+A" (*(volatile unsigned*) aligned_addr),	\
86		    [tmp1] "=&r" (tmp1)					\
87		  : [o] "r" ((((unsigned) o) << shift) & mask),		\
88		    [n] "r" ((((unsigned) n) << shift) & mask),		\
89		    [mask] "r" (mask),					\
90		    [not_mask] "r" (~mask));				\
91									\
92    return (type) (old >> shift);					\
93  }									\
94  bool __sync_bool_compare_and_swap_ ## size (type *p, type o, type n)	\
95  {									\
96    return __sync_val_compare_and_swap(p, o, n) == o;			\
97  }
98
99#define GENERATE_ALL(type, size)					\
100  GENERATE_FETCH_AND_OP(type, size, add, add, DONT_INVERT, o + v)	\
101  GENERATE_FETCH_AND_OP(type, size, sub, sub, DONT_INVERT, o - v)	\
102  GENERATE_FETCH_AND_OP(type, size, and, and, DONT_INVERT, o & v)	\
103  GENERATE_FETCH_AND_OP(type, size, xor, xor, DONT_INVERT, o ^ v)	\
104  GENERATE_FETCH_AND_OP(type, size, or, or, DONT_INVERT, o | v)		\
105  GENERATE_FETCH_AND_OP(type, size, nand, and, INVERT, ~(o & v))	\
106  GENERATE_COMPARE_AND_SWAP(type, size)
107
108GENERATE_ALL(unsigned char, 1)
109GENERATE_ALL(unsigned short, 2)
110
111#endif
112