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/*
* Copyright (C) 2013 Regents of the University of California
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation, version 2.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*/
#include <linux/linkage.h>
#include <asm/asm.h>
/* void *memset(void *, int, size_t) */
ENTRY(memset)
move t0, a0 /* Preserve return value */
/* Defer to byte-oriented fill for small sizes */
sltiu a3, a2, 16
bnez a3, 4f
/*
* Round to nearest XLEN-aligned address
* greater than or equal to start address
*/
addi a3, t0, SZREG-1
andi a3, a3, ~(SZREG-1)
beq a3, t0, 2f /* Skip if already aligned */
/* Handle initial misalignment */
sub a4, a3, t0
1:
sb a1, 0(t0)
addi t0, t0, 1
bltu t0, a3, 1b
sub a2, a2, a4 /* Update count */
2: /* Duff's device with 32 XLEN stores per iteration */
/* Broadcast value into all bytes */
andi a1, a1, 0xff
slli a3, a1, 8
or a1, a3, a1
slli a3, a1, 16
or a1, a3, a1
#ifdef CONFIG_64BIT
slli a3, a1, 32
or a1, a3, a1
#endif
/* Calculate end address */
andi a4, a2, ~(SZREG-1)
add a3, t0, a4
andi a4, a4, 31*SZREG /* Calculate remainder */
beqz a4, 3f /* Shortcut if no remainder */
neg a4, a4
addi a4, a4, 32*SZREG /* Calculate initial offset */
/* Adjust start address with offset */
sub t0, t0, a4
/* Jump into loop body */
/* Assumes 32-bit instruction lengths */
la a5, 3f
#ifdef CONFIG_64BIT
srli a4, a4, 1
#endif
add a5, a5, a4
jr a5
3:
REG_S a1, 0(t0)
REG_S a1, SZREG(t0)
REG_S a1, 2*SZREG(t0)
REG_S a1, 3*SZREG(t0)
REG_S a1, 4*SZREG(t0)
REG_S a1, 5*SZREG(t0)
REG_S a1, 6*SZREG(t0)
REG_S a1, 7*SZREG(t0)
REG_S a1, 8*SZREG(t0)
REG_S a1, 9*SZREG(t0)
REG_S a1, 10*SZREG(t0)
REG_S a1, 11*SZREG(t0)
REG_S a1, 12*SZREG(t0)
REG_S a1, 13*SZREG(t0)
REG_S a1, 14*SZREG(t0)
REG_S a1, 15*SZREG(t0)
REG_S a1, 16*SZREG(t0)
REG_S a1, 17*SZREG(t0)
REG_S a1, 18*SZREG(t0)
REG_S a1, 19*SZREG(t0)
REG_S a1, 20*SZREG(t0)
REG_S a1, 21*SZREG(t0)
REG_S a1, 22*SZREG(t0)
REG_S a1, 23*SZREG(t0)
REG_S a1, 24*SZREG(t0)
REG_S a1, 25*SZREG(t0)
REG_S a1, 26*SZREG(t0)
REG_S a1, 27*SZREG(t0)
REG_S a1, 28*SZREG(t0)
REG_S a1, 29*SZREG(t0)
REG_S a1, 30*SZREG(t0)
REG_S a1, 31*SZREG(t0)
addi t0, t0, 32*SZREG
bltu t0, a3, 3b
andi a2, a2, SZREG-1 /* Update count */
4:
/* Handle trailing misalignment */
beqz a2, 6f
add a3, t0, a2
5:
sb a1, 0(t0)
addi t0, t0, 1
bltu t0, a3, 5b
6:
ret
END(memset)
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