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eea9507a LFT |
1 | /* |
2 | * Copyright (C) 2011 Tobias Klauser <tklauser@distanz.ch> | |
3 | * Copyright (C) 2004 Microtronix Datacom Ltd | |
4 | * | |
5 | * This file is subject to the terms and conditions of the GNU General Public | |
6 | * License. See the file "COPYING" in the main directory of this archive | |
7 | * for more details. | |
8 | */ | |
9 | ||
10 | #include <linux/types.h> | |
11 | #include <linux/string.h> | |
12 | ||
13 | #ifdef __HAVE_ARCH_MEMSET | |
14 | void *memset(void *s, int c, size_t count) | |
15 | { | |
16 | int destptr, charcnt, dwordcnt, fill8reg, wrkrega; | |
17 | ||
18 | if (!count) | |
19 | return s; | |
20 | ||
21 | c &= 0xFF; | |
22 | ||
23 | if (count <= 8) { | |
24 | char *xs = (char *) s; | |
25 | ||
26 | while (count--) | |
27 | *xs++ = c; | |
28 | return s; | |
29 | } | |
30 | ||
31 | __asm__ __volatile__ ( | |
32 | /* fill8 %3, %5 (c & 0xff) */ | |
33 | " slli %4, %5, 8\n" | |
34 | " or %4, %4, %5\n" | |
35 | " slli %3, %4, 16\n" | |
36 | " or %3, %3, %4\n" | |
37 | /* Word-align %0 (s) if necessary */ | |
38 | " andi %4, %0, 0x01\n" | |
39 | " beq %4, zero, 1f\n" | |
40 | " addi %1, %1, -1\n" | |
41 | " stb %3, 0(%0)\n" | |
42 | " addi %0, %0, 1\n" | |
43 | "1: mov %2, %1\n" | |
44 | /* Dword-align %0 (s) if necessary */ | |
45 | " andi %4, %0, 0x02\n" | |
46 | " beq %4, zero, 2f\n" | |
47 | " addi %1, %1, -2\n" | |
48 | " sth %3, 0(%0)\n" | |
49 | " addi %0, %0, 2\n" | |
50 | " mov %2, %1\n" | |
51 | /* %1 and %2 are how many more bytes to set */ | |
52 | "2: srli %2, %2, 2\n" | |
53 | /* %2 is how many dwords to set */ | |
54 | "3: stw %3, 0(%0)\n" | |
55 | " addi %0, %0, 4\n" | |
56 | " addi %2, %2, -1\n" | |
57 | " bne %2, zero, 3b\n" | |
58 | /* store residual word and/or byte if necessary */ | |
59 | " andi %4, %1, 0x02\n" | |
60 | " beq %4, zero, 4f\n" | |
61 | " sth %3, 0(%0)\n" | |
62 | " addi %0, %0, 2\n" | |
63 | /* store residual byte if necessary */ | |
64 | "4: andi %4, %1, 0x01\n" | |
65 | " beq %4, zero, 5f\n" | |
66 | " stb %3, 0(%0)\n" | |
67 | "5:\n" | |
68 | : "=r" (destptr), /* %0 Output */ | |
69 | "=r" (charcnt), /* %1 Output */ | |
70 | "=r" (dwordcnt), /* %2 Output */ | |
71 | "=r" (fill8reg), /* %3 Output */ | |
72 | "=r" (wrkrega) /* %4 Output */ | |
73 | : "r" (c), /* %5 Input */ | |
74 | "0" (s), /* %0 Input/Output */ | |
75 | "1" (count) /* %1 Input/Output */ | |
76 | : "memory" /* clobbered */ | |
77 | ); | |
78 | ||
79 | return s; | |
80 | } | |
81 | #endif /* __HAVE_ARCH_MEMSET */ |