/* SPDX-License-Identifier: GPL-2.0 */
// Copyright (C) 2018 Hangzhou C-SKY Microsystems co.,ltd.

#include <linux/linkage.h>
#include "sysdep.h"

        .weak memset
ENTRY(__memset)
ENTRY(memset)
        /* Test if len less than 4 bytes.  */
        mov     r12, r0
        cmplti  r2, 8
        bt      .L_set_by_byte

        andi    r13, r0, 3
        movi    r19, 4
        /* Test if dest is not 4 bytes aligned.  */
        bnez    r13, .L_dest_not_aligned
        /* Hardware can handle unaligned access directly.  */
.L_dest_aligned:
        zextb   r3, r1
        lsli    r1, 8
        or      r1, r3
        lsli    r3, r1, 16
        or      r3, r1

        /* If dest is aligned, then copy.  */
        zext    r18, r2, 31, 4
        /* Test if len less than 16 bytes.  */
        bez     r18, .L_len_less_16bytes

        LABLE_ALIGN
.L_len_larger_16bytes:
        stw     r3, (r0, 0)
        stw     r3, (r0, 4)
        stw     r3, (r0, 8)
        stw     r3, (r0, 12)
        PRE_BNEZAD (r18)
        addi    r0, 16
        BNEZAD (r18, .L_len_larger_16bytes)

.L_len_less_16bytes:
        zext    r18, r2, 3, 2
        andi    r2, 3
        bez     r18, .L_set_by_byte
.L_len_less_16bytes_loop:
        stw     r3, (r0, 0)
        PRE_BNEZAD (r18)
        addi    r0, 4
        BNEZAD (r18, .L_len_less_16bytes_loop)

        /* Test if len less than 4 bytes.  */
.L_set_by_byte:
        zext    r18, r2, 2, 0
        bez     r18, .L_return
.L_set_by_byte_loop:
        stb     r1, (r0, 0)
        PRE_BNEZAD (r18)
        addi    r0, 1
        BNEZAD (r18, .L_set_by_byte_loop)

.L_return:
        mov     r0, r12
        rts

        /* If dest is not aligned, just set some bytes makes the dest
           align.  */

.L_dest_not_aligned:
        sub     r13, r19, r13
        sub     r2, r13
.L_dest_not_aligned_loop:
        /* Makes the dest align.  */
        stb     r1, (r0, 0)
        PRE_BNEZAD (r13)
        addi    r0, 1
        BNEZAD (r13, .L_dest_not_aligned_loop)
        cmplti  r2, 8
        bt      .L_set_by_byte
        /* Check whether the src is aligned.  */
        jbr     .L_dest_aligned
ENDPROC(memset)
ENDPROC(__memset)