/* SPDX-License-Identifier: GPL-2.0 */
/*
 * Copyright (C) 2020-2022 Loongson Technology Corporation Limited
 */

#include <linux/export.h>
#include <asm/alternative-asm.h>
#include <asm/asm.h>
#include <asm/asmmacro.h>
#include <asm/cpu.h>
#include <asm/regdef.h>

.section .noinstr.text, "ax"

SYM_FUNC_START(memmove)
        blt     a0, a1, __memcpy        /* dst < src, memcpy */
        blt     a1, a0, __rmemcpy       /* src < dst, rmemcpy */
        jr      ra                      /* dst == src, return */
SYM_FUNC_END(memmove)
SYM_FUNC_ALIAS(__memmove, memmove)

EXPORT_SYMBOL(memmove)
EXPORT_SYMBOL(__memmove)

_ASM_NOKPROBE(memmove)
_ASM_NOKPROBE(__memmove)

SYM_FUNC_START(__rmemcpy)
        /*
         * Some CPUs support hardware unaligned access
         */
        ALTERNATIVE     "b __rmemcpy_generic", \
                        "b __rmemcpy_fast", CPU_FEATURE_UAL
SYM_FUNC_END(__rmemcpy)
_ASM_NOKPROBE(__rmemcpy)

/*
 * void *__rmemcpy_generic(void *dst, const void *src, size_t n)
 *
 * a0: dst
 * a1: src
 * a2: n
 */
SYM_FUNC_START(__rmemcpy_generic)
        move    a3, a0
        beqz    a2, 2f

        add.d   a0, a0, a2
        add.d   a1, a1, a2

1:      ld.b    t0, a1, -1
        st.b    t0, a0, -1
        addi.d  a0, a0, -1
        addi.d  a1, a1, -1
        addi.d  a2, a2, -1
        bgt     a2, zero, 1b

2:      move    a0, a3
        jr      ra
SYM_FUNC_END(__rmemcpy_generic)
_ASM_NOKPROBE(__rmemcpy_generic)

/*
 * void *__rmemcpy_fast(void *dst, const void *src, size_t n)
 *
 * a0: dst
 * a1: src
 * a2: n
 */
SYM_FUNC_START(__rmemcpy_fast)
        sltui   t0, a2, 9
        bnez    t0, __memcpy_small

        add.d   a3, a1, a2
        add.d   a2, a0, a2
        ld.d    a6, a1, 0
        ld.d    a7, a3, -8

        /* align up destination address */
        andi    t1, a2, 7
        sub.d   a3, a3, t1
        sub.d   a5, a2, t1

        addi.d  a4, a1, 64
        bgeu    a4, a3, .Llt64

        /* copy 64 bytes at a time */
.Lloop64:
        ld.d    t0, a3, -8
        ld.d    t1, a3, -16
        ld.d    t2, a3, -24
        ld.d    t3, a3, -32
        ld.d    t4, a3, -40
        ld.d    t5, a3, -48
        ld.d    t6, a3, -56
        ld.d    t7, a3, -64
        addi.d  a3, a3, -64
        st.d    t0, a5, -8
        st.d    t1, a5, -16
        st.d    t2, a5, -24
        st.d    t3, a5, -32
        st.d    t4, a5, -40
        st.d    t5, a5, -48
        st.d    t6, a5, -56
        st.d    t7, a5, -64
        addi.d  a5, a5, -64
        bltu    a4, a3, .Lloop64

        /* copy the remaining bytes */
.Llt64:
        addi.d  a4, a1, 32
        bgeu    a4, a3, .Llt32
        ld.d    t0, a3, -8
        ld.d    t1, a3, -16
        ld.d    t2, a3, -24
        ld.d    t3, a3, -32
        addi.d  a3, a3, -32
        st.d    t0, a5, -8
        st.d    t1, a5, -16
        st.d    t2, a5, -24
        st.d    t3, a5, -32
        addi.d  a5, a5, -32

.Llt32:
        addi.d  a4, a1, 16
        bgeu    a4, a3, .Llt16
        ld.d    t0, a3, -8
        ld.d    t1, a3, -16
        addi.d  a3, a3, -16
        st.d    t0, a5, -8
        st.d    t1, a5, -16
        addi.d  a5, a5, -16

.Llt16:
        addi.d  a4, a1, 8
        bgeu    a4, a3, .Llt8
        ld.d    t0, a3, -8
        st.d    t0, a5, -8

.Llt8:
        st.d    a6, a0, 0
        st.d    a7, a2, -8

        /* return */
        jr      ra
SYM_FUNC_END(__rmemcpy_fast)
_ASM_NOKPROBE(__rmemcpy_fast)