blob: c6d553e85ab1112e3a6dffd2a0c0f0aa870b6620 [file] [log] [blame]
Heiko Carstens535c6112012-08-14 13:20:20 +02001/*
2 * String handling functions.
3 *
4 * Copyright IBM Corp. 2012
5 */
6
7#include <linux/linkage.h>
8
9/*
10 * memset implementation
11 *
12 * This code corresponds to the C construct below. We do distinguish
13 * between clearing (c == 0) and setting a memory array (c != 0) simply
14 * because nearly all memset invocations in the kernel clear memory and
15 * the xc instruction is preferred in such cases.
16 *
17 * void *memset(void *s, int c, size_t n)
18 * {
19 * if (likely(c == 0))
20 * return __builtin_memset(s, 0, n);
21 * return __builtin_memset(s, c, n);
22 * }
23 */
24ENTRY(memset)
25 ltgr %r4,%r4
26 bzr %r14
27 ltgr %r3,%r3
28 jnz .Lmemset_fill
29 aghi %r4,-1
30 srlg %r3,%r4,8
31 ltgr %r3,%r3
32 lgr %r1,%r2
33 jz .Lmemset_clear_rest
34.Lmemset_clear_loop:
35 xc 0(256,%r1),0(%r1)
36 la %r1,256(%r1)
37 brctg %r3,.Lmemset_clear_loop
38.Lmemset_clear_rest:
39 larl %r3,.Lmemset_xc
40 ex %r4,0(%r3)
41 br %r14
42.Lmemset_fill:
43 stc %r3,0(%r2)
44 cghi %r4,1
45 lgr %r1,%r2
46 ber %r14
47 aghi %r4,-2
48 srlg %r3,%r4,8
49 ltgr %r3,%r3
50 jz .Lmemset_fill_rest
51.Lmemset_fill_loop:
52 mvc 1(256,%r1),0(%r1)
53 la %r1,256(%r1)
54 brctg %r3,.Lmemset_fill_loop
55.Lmemset_fill_rest:
56 larl %r3,.Lmemset_mvc
57 ex %r4,0(%r3)
58 br %r14
59.Lmemset_xc:
60 xc 0(1,%r1),0(%r1)
61.Lmemset_mvc:
62 mvc 1(1,%r1),0(%r1)
63
64/*
65 * memcpy implementation
66 *
67 * void *memcpy(void *dest, const void *src, size_t n)
68 */
69ENTRY(memcpy)
70 ltgr %r4,%r4
71 bzr %r14
72 aghi %r4,-1
73 srlg %r5,%r4,8
74 ltgr %r5,%r5
75 lgr %r1,%r2
76 jnz .Lmemcpy_loop
77.Lmemcpy_rest:
78 larl %r5,.Lmemcpy_mvc
79 ex %r4,0(%r5)
80 br %r14
81.Lmemcpy_loop:
82 mvc 0(256,%r1),0(%r3)
83 la %r1,256(%r1)
84 la %r3,256(%r3)
85 brctg %r5,.Lmemcpy_loop
86 j .Lmemcpy_rest
87.Lmemcpy_mvc:
88 mvc 0(1,%r1),0(%r3)