Book a Demo!
CoCalc Logo Icon
StoreFeaturesDocsShareSupportNewsAboutPoliciesSign UpSign In
torvalds
GitHub Repository: torvalds/linux
 Path: blob/master/arch/riscv/lib/memcpy.S
26424 views
1
/* SPDX-License-Identifier: GPL-2.0-only */

2
/*

3
 * Copyright (C) 2013 Regents of the University of California

4
 */

5


6
#include <linux/linkage.h>

7
#include <asm/asm.h>

8


9
/* void *memcpy(void *, const void *, size_t) */

10
SYM_FUNC_START(__memcpy)

11
	move t6, a0  /* Preserve return value */

12


13
	/* Defer to byte-oriented copy for small sizes */

14
	sltiu a3, a2, 128

15
	bnez a3, 4f

16
	/* Use word-oriented copy only if low-order bits match */

17
	andi a3, t6, SZREG-1

18
	andi a4, a1, SZREG-1

19
	bne a3, a4, 4f

20


21
	beqz a3, 2f  /* Skip if already aligned */

22
	/*

23
	 * Round to nearest double word-aligned address

24
	 * greater than or equal to start address

25
	 */

26
	andi a3, a1, ~(SZREG-1)

27
	addi a3, a3, SZREG

28
	/* Handle initial misalignment */

29
	sub a4, a3, a1

30
1:

31
	lb a5, 0(a1)

32
	addi a1, a1, 1

33
	sb a5, 0(t6)

34
	addi t6, t6, 1

35
	bltu a1, a3, 1b

36
	sub a2, a2, a4  /* Update count */

37


38
2:

39
	andi a4, a2, ~((16*SZREG)-1)

40
	beqz a4, 4f

41
	add a3, a1, a4

42
3:

43
	REG_L a4,       0(a1)

44
	REG_L a5,   SZREG(a1)

45
	REG_L a6, 2*SZREG(a1)

46
	REG_L a7, 3*SZREG(a1)

47
	REG_L t0, 4*SZREG(a1)

48
	REG_L t1, 5*SZREG(a1)

49
	REG_L t2, 6*SZREG(a1)

50
	REG_L t3, 7*SZREG(a1)

51
	REG_L t4, 8*SZREG(a1)

52
	REG_L t5, 9*SZREG(a1)

53
	REG_S a4,       0(t6)

54
	REG_S a5,   SZREG(t6)

55
	REG_S a6, 2*SZREG(t6)

56
	REG_S a7, 3*SZREG(t6)

57
	REG_S t0, 4*SZREG(t6)

58
	REG_S t1, 5*SZREG(t6)

59
	REG_S t2, 6*SZREG(t6)

60
	REG_S t3, 7*SZREG(t6)

61
	REG_S t4, 8*SZREG(t6)

62
	REG_S t5, 9*SZREG(t6)

63
	REG_L a4, 10*SZREG(a1)

64
	REG_L a5, 11*SZREG(a1)

65
	REG_L a6, 12*SZREG(a1)

66
	REG_L a7, 13*SZREG(a1)

67
	REG_L t0, 14*SZREG(a1)

68
	REG_L t1, 15*SZREG(a1)

69
	addi a1, a1, 16*SZREG

70
	REG_S a4, 10*SZREG(t6)

71
	REG_S a5, 11*SZREG(t6)

72
	REG_S a6, 12*SZREG(t6)

73
	REG_S a7, 13*SZREG(t6)

74
	REG_S t0, 14*SZREG(t6)

75
	REG_S t1, 15*SZREG(t6)

76
	addi t6, t6, 16*SZREG

77
	bltu a1, a3, 3b

78
	andi a2, a2, (16*SZREG)-1  /* Update count */

79


80
4:

81
	/* Handle trailing misalignment */

82
	beqz a2, 6f

83
	add a3, a1, a2

84


85
	/* Use word-oriented copy if co-aligned to word boundary */

86
	or a5, a1, t6

87
	or a5, a5, a3

88
	andi a5, a5, 3

89
	bnez a5, 5f

90
7:

91
	lw a4, 0(a1)

92
	addi a1, a1, 4

93
	sw a4, 0(t6)

94
	addi t6, t6, 4

95
	bltu a1, a3, 7b

96


97
	ret

98


99
5:

100
	lb a4, 0(a1)

101
	addi a1, a1, 1

102
	sb a4, 0(t6)

103
	addi t6, t6, 1

104
	bltu a1, a3, 5b

105
6:

106
	ret

107
SYM_FUNC_END(__memcpy)

108
SYM_FUNC_ALIAS_WEAK(memcpy, __memcpy)

109
SYM_FUNC_ALIAS(__pi_memcpy, __memcpy)

110
SYM_FUNC_ALIAS(__pi___memcpy, __memcpy)

111


112