aboutsummaryrefslogtreecommitdiffstats
path: root/arch/x86/lib/memmove_64.c
diff options
context:
space:
mode:
Diffstat (limited to 'arch/x86/lib/memmove_64.c')
-rw-r--r--arch/x86/lib/memmove_64.c225
1 files changed, 180 insertions, 45 deletions
diff --git a/arch/x86/lib/memmove_64.c b/arch/x86/lib/memmove_64.c
index ecacc4b3d9e5..6d0f0ec41b34 100644
--- a/arch/x86/lib/memmove_64.c
+++ b/arch/x86/lib/memmove_64.c
@@ -8,50 +8,185 @@
8#undef memmove 8#undef memmove
9void *memmove(void *dest, const void *src, size_t count) 9void *memmove(void *dest, const void *src, size_t count)
10{ 10{
11 unsigned long d0, d1, d2, d3; 11 unsigned long d0,d1,d2,d3,d4,d5,d6,d7;
12 if (dest < src) { 12 char *ret;
13 if ((dest + count) < src) 13
14 return memcpy(dest, src, count); 14 __asm__ __volatile__(
15 else 15 /* Handle more 32bytes in loop */
16 __asm__ __volatile__( 16 "mov %2, %3\n\t"
17 "movq %0, %3\n\t" 17 "cmp $0x20, %0\n\t"
18 "shr $3, %0\n\t" 18 "jb 1f\n\t"
19 "andq $7, %3\n\t" 19
20 "rep\n\t" 20 /* Decide forward/backward copy mode */
21 "movsq\n\t" 21 "cmp %2, %1\n\t"
22 "movq %3, %0\n\t" 22 "jb 2f\n\t"
23 "rep\n\t" 23
24 "movsb" 24 /*
25 : "=&c" (d0), "=&S" (d1), "=&D" (d2), "=r" (d3) 25 * movsq instruction have many startup latency
26 :"0" (count), 26 * so we handle small size by general register.
27 "1" (src), 27 */
28 "2" (dest) 28 "cmp $680, %0\n\t"
29 :"memory"); 29 "jb 3f\n\t"
30 } else { 30 /*
31 if((src + count) < dest) 31 * movsq instruction is only good for aligned case.
32 return memcpy(dest, src, count); 32 */
33 else 33 "cmpb %%dil, %%sil\n\t"
34 __asm__ __volatile__( 34 "je 4f\n\t"
35 "movq %0, %3\n\t" 35 "3:\n\t"
36 "lea -8(%1, %0), %1\n\t" 36 "sub $0x20, %0\n\t"
37 "lea -8(%2, %0), %2\n\t" 37 /*
38 "shr $3, %0\n\t" 38 * We gobble 32byts forward in each loop.
39 "andq $7, %3\n\t" 39 */
40 "std\n\t" 40 "5:\n\t"
41 "rep\n\t" 41 "sub $0x20, %0\n\t"
42 "movsq\n\t" 42 "movq 0*8(%1), %4\n\t"
43 "lea 7(%1), %1\n\t" 43 "movq 1*8(%1), %5\n\t"
44 "lea 7(%2), %2\n\t" 44 "movq 2*8(%1), %6\n\t"
45 "movq %3, %0\n\t" 45 "movq 3*8(%1), %7\n\t"
46 "rep\n\t" 46 "leaq 4*8(%1), %1\n\t"
47 "movsb\n\t" 47
48 "cld" 48 "movq %4, 0*8(%2)\n\t"
49 : "=&c" (d0), "=&S" (d1), "=&D" (d2), "=r" (d3) 49 "movq %5, 1*8(%2)\n\t"
50 :"0" (count), 50 "movq %6, 2*8(%2)\n\t"
51 "1" (src), 51 "movq %7, 3*8(%2)\n\t"
52 "2" (dest) 52 "leaq 4*8(%2), %2\n\t"
53 :"memory"); 53 "jae 5b\n\t"
54 } 54 "addq $0x20, %0\n\t"
55 return dest; 55 "jmp 1f\n\t"
56 /*
57 * Handle data forward by movsq.
58 */
59 ".p2align 4\n\t"
60 "4:\n\t"
61 "movq %0, %8\n\t"
62 "movq -8(%1, %0), %4\n\t"
63 "lea -8(%2, %0), %5\n\t"
64 "shrq $3, %8\n\t"
65 "rep movsq\n\t"
66 "movq %4, (%5)\n\t"
67 "jmp 13f\n\t"
68 /*
69 * Handle data backward by movsq.
70 */
71 ".p2align 4\n\t"
72 "7:\n\t"
73 "movq %0, %8\n\t"
74 "movq (%1), %4\n\t"
75 "movq %2, %5\n\t"
76 "leaq -8(%1, %0), %1\n\t"
77 "leaq -8(%2, %0), %2\n\t"
78 "shrq $3, %8\n\t"
79 "std\n\t"
80 "rep movsq\n\t"
81 "cld\n\t"
82 "movq %4, (%5)\n\t"
83 "jmp 13f\n\t"
84
85 /*
86 * Start to prepare for backward copy.
87 */
88 ".p2align 4\n\t"
89 "2:\n\t"
90 "cmp $680, %0\n\t"
91 "jb 6f \n\t"
92 "cmp %%dil, %%sil\n\t"
93 "je 7b \n\t"
94 "6:\n\t"
95 /*
96 * Calculate copy position to tail.
97 */
98 "addq %0, %1\n\t"
99 "addq %0, %2\n\t"
100 "subq $0x20, %0\n\t"
101 /*
102 * We gobble 32byts backward in each loop.
103 */
104 "8:\n\t"
105 "subq $0x20, %0\n\t"
106 "movq -1*8(%1), %4\n\t"
107 "movq -2*8(%1), %5\n\t"
108 "movq -3*8(%1), %6\n\t"
109 "movq -4*8(%1), %7\n\t"
110 "leaq -4*8(%1), %1\n\t"
111
112 "movq %4, -1*8(%2)\n\t"
113 "movq %5, -2*8(%2)\n\t"
114 "movq %6, -3*8(%2)\n\t"
115 "movq %7, -4*8(%2)\n\t"
116 "leaq -4*8(%2), %2\n\t"
117 "jae 8b\n\t"
118 /*
119 * Calculate copy position to head.
120 */
121 "addq $0x20, %0\n\t"
122 "subq %0, %1\n\t"
123 "subq %0, %2\n\t"
124 "1:\n\t"
125 "cmpq $16, %0\n\t"
126 "jb 9f\n\t"
127 /*
128 * Move data from 16 bytes to 31 bytes.
129 */
130 "movq 0*8(%1), %4\n\t"
131 "movq 1*8(%1), %5\n\t"
132 "movq -2*8(%1, %0), %6\n\t"
133 "movq -1*8(%1, %0), %7\n\t"
134 "movq %4, 0*8(%2)\n\t"
135 "movq %5, 1*8(%2)\n\t"
136 "movq %6, -2*8(%2, %0)\n\t"
137 "movq %7, -1*8(%2, %0)\n\t"
138 "jmp 13f\n\t"
139 ".p2align 4\n\t"
140 "9:\n\t"
141 "cmpq $8, %0\n\t"
142 "jb 10f\n\t"
143 /*
144 * Move data from 8 bytes to 15 bytes.
145 */
146 "movq 0*8(%1), %4\n\t"
147 "movq -1*8(%1, %0), %5\n\t"
148 "movq %4, 0*8(%2)\n\t"
149 "movq %5, -1*8(%2, %0)\n\t"
150 "jmp 13f\n\t"
151 "10:\n\t"
152 "cmpq $4, %0\n\t"
153 "jb 11f\n\t"
154 /*
155 * Move data from 4 bytes to 7 bytes.
156 */
157 "movl (%1), %4d\n\t"
158 "movl -4(%1, %0), %5d\n\t"
159 "movl %4d, (%2)\n\t"
160 "movl %5d, -4(%2, %0)\n\t"
161 "jmp 13f\n\t"
162 "11:\n\t"
163 "cmp $2, %0\n\t"
164 "jb 12f\n\t"
165 /*
166 * Move data from 2 bytes to 3 bytes.
167 */
168 "movw (%1), %4w\n\t"
169 "movw -2(%1, %0), %5w\n\t"
170 "movw %4w, (%2)\n\t"
171 "movw %5w, -2(%2, %0)\n\t"
172 "jmp 13f\n\t"
173 "12:\n\t"
174 "cmp $1, %0\n\t"
175 "jb 13f\n\t"
176 /*
177 * Move data for 1 byte.
178 */
179 "movb (%1), %4b\n\t"
180 "movb %4b, (%2)\n\t"
181 "13:\n\t"
182 : "=&d" (d0), "=&S" (d1), "=&D" (d2), "=&a" (ret) ,
183 "=r"(d3), "=r"(d4), "=r"(d5), "=r"(d6), "=&c" (d7)
184 :"0" (count),
185 "1" (src),
186 "2" (dest)
187 :"memory");
188
189 return ret;
190
56} 191}
57EXPORT_SYMBOL(memmove); 192EXPORT_SYMBOL(memmove);
generated by cgit v1.2.2 (git 2.25.0) at 2025-09-11 18:08:03 -0400