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