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