82 lines
1.9 KiB
C
82 lines
1.9 KiB
C
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/*
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* Copyright (C) 2011 Tobias Klauser <tklauser@distanz.ch>
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* Copyright (C) 2004 Microtronix Datacom Ltd
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*
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* This file is subject to the terms and conditions of the GNU General Public
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* License. See the file "COPYING" in the main directory of this archive
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* for more details.
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*/
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#include <linux/types.h>
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#include <linux/string.h>
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#ifdef __HAVE_ARCH_MEMSET
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void *memset(void *s, int c, size_t count)
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{
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int destptr, charcnt, dwordcnt, fill8reg, wrkrega;
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if (!count)
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return s;
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c &= 0xFF;
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if (count <= 8) {
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char *xs = (char *) s;
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while (count--)
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*xs++ = c;
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return s;
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}
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__asm__ __volatile__ (
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/* fill8 %3, %5 (c & 0xff) */
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" slli %4, %5, 8\n"
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" or %4, %4, %5\n"
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" slli %3, %4, 16\n"
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" or %3, %3, %4\n"
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/* Word-align %0 (s) if necessary */
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" andi %4, %0, 0x01\n"
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" beq %4, zero, 1f\n"
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" addi %1, %1, -1\n"
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" stb %3, 0(%0)\n"
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" addi %0, %0, 1\n"
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"1: mov %2, %1\n"
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/* Dword-align %0 (s) if necessary */
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" andi %4, %0, 0x02\n"
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" beq %4, zero, 2f\n"
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" addi %1, %1, -2\n"
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" sth %3, 0(%0)\n"
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" addi %0, %0, 2\n"
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" mov %2, %1\n"
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/* %1 and %2 are how many more bytes to set */
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"2: srli %2, %2, 2\n"
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/* %2 is how many dwords to set */
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"3: stw %3, 0(%0)\n"
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" addi %0, %0, 4\n"
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" addi %2, %2, -1\n"
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" bne %2, zero, 3b\n"
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/* store residual word and/or byte if necessary */
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" andi %4, %1, 0x02\n"
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" beq %4, zero, 4f\n"
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" sth %3, 0(%0)\n"
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" addi %0, %0, 2\n"
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/* store residual byte if necessary */
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"4: andi %4, %1, 0x01\n"
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" beq %4, zero, 5f\n"
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" stb %3, 0(%0)\n"
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"5:\n"
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: "=r" (destptr), /* %0 Output */
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"=r" (charcnt), /* %1 Output */
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"=r" (dwordcnt), /* %2 Output */
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"=r" (fill8reg), /* %3 Output */
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"=r" (wrkrega) /* %4 Output */
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: "r" (c), /* %5 Input */
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"0" (s), /* %0 Input/Output */
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"1" (count) /* %1 Input/Output */
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: "memory" /* clobbered */
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);
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return s;
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}
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#endif /* __HAVE_ARCH_MEMSET */
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