1/* SPDX-License-Identifier: GPL-2.0 */
2/* Copyright (C) 2023 Rivos Inc. */
3
4#include <linux/linkage.h>
5#include <asm/asm.h>
6
7 .text
8
9/* void __riscv_copy_words_unaligned(void *, const void *, size_t) */
10/* Performs a memcpy without aligning buffers, using word loads and stores. */
11/* Note: The size is truncated to a multiple of 8 * SZREG */
12SYM_FUNC_START(__riscv_copy_words_unaligned)
13 andi a4, a2, ~((8*SZREG)-1)
14 beqz a4, 2f
15 add a3, a1, a4
161:
17 REG_L a4, 0(a1)
18 REG_L a5, SZREG(a1)
19 REG_L a6, 2*SZREG(a1)
20 REG_L a7, 3*SZREG(a1)
21 REG_L t0, 4*SZREG(a1)
22 REG_L t1, 5*SZREG(a1)
23 REG_L t2, 6*SZREG(a1)
24 REG_L t3, 7*SZREG(a1)
25 REG_S a4, 0(a0)
26 REG_S a5, SZREG(a0)
27 REG_S a6, 2*SZREG(a0)
28 REG_S a7, 3*SZREG(a0)
29 REG_S t0, 4*SZREG(a0)
30 REG_S t1, 5*SZREG(a0)
31 REG_S t2, 6*SZREG(a0)
32 REG_S t3, 7*SZREG(a0)
33 addi a0, a0, 8*SZREG
34 addi a1, a1, 8*SZREG
35 bltu a1, a3, 1b
36
372:
38 ret
39SYM_FUNC_END(__riscv_copy_words_unaligned)
40
41/* void __riscv_copy_bytes_unaligned(void *, const void *, size_t) */
42/* Performs a memcpy without aligning buffers, using only byte accesses. */
43/* Note: The size is truncated to a multiple of 8 */
44SYM_FUNC_START(__riscv_copy_bytes_unaligned)
45 andi a4, a2, ~(8-1)
46 beqz a4, 2f
47 add a3, a1, a4
481:
49 lb a4, 0(a1)
50 lb a5, 1(a1)
51 lb a6, 2(a1)
52 lb a7, 3(a1)
53 lb t0, 4(a1)
54 lb t1, 5(a1)
55 lb t2, 6(a1)
56 lb t3, 7(a1)
57 sb a4, 0(a0)
58 sb a5, 1(a0)
59 sb a6, 2(a0)
60 sb a7, 3(a0)
61 sb t0, 4(a0)
62 sb t1, 5(a0)
63 sb t2, 6(a0)
64 sb t3, 7(a0)
65 addi a0, a0, 8
66 addi a1, a1, 8
67 bltu a1, a3, 1b
68
692:
70 ret
71SYM_FUNC_END(__riscv_copy_bytes_unaligned)
72

source code of linux/arch/riscv/kernel/copy-unaligned.S