Book a Demo!
CoCalc Logo Icon
StoreFeaturesDocsShareSupportNewsAboutPoliciesSign UpSign In
awilliam
GitHub Repository: awilliam/linux-vfio
 Path: blob/master/arch/arm/lib/delay.S
10817 views
1
/*

2
 *  linux/arch/arm/lib/delay.S

3
 *

4
 *  Copyright (C) 1995, 1996 Russell King

5
 *

6
 * This program is free software; you can redistribute it and/or modify

7
 * it under the terms of the GNU General Public License version 2 as

8
 * published by the Free Software Foundation.

9
 */

10
#include <linux/linkage.h>

11
#include <asm/assembler.h>

12
#include <asm/param.h>

13
		.text

14


15
.LC0:		.word	loops_per_jiffy

16
.LC1:		.word	(2199023*HZ)>>11

17


18
/*

19
 * r0  <= 2000

20
 * lpj <= 0x01ffffff (max. 3355 bogomips)

21
 * HZ  <= 1000

22
 */

23


24
ENTRY(__udelay)

25
		ldr	r2, .LC1

26
		mul	r0, r2, r0

27
ENTRY(__const_udelay)				@ 0 <= r0 <= 0x7fffff06

28
		mov	r1, #-1

29
		ldr	r2, .LC0

30
		ldr	r2, [r2]		@ max = 0x01ffffff

31
		add	r0, r0, r1, lsr #32-14

32
		mov	r0, r0, lsr #14		@ max = 0x0001ffff

33
		add	r2, r2, r1, lsr #32-10

34
		mov	r2, r2, lsr #10		@ max = 0x00007fff

35
		mul	r0, r2, r0		@ max = 2^32-1

36
		add	r0, r0, r1, lsr #32-6

37
		movs	r0, r0, lsr #6

38
		moveq	pc, lr

39


40
/*

41
 * loops = r0 * HZ * loops_per_jiffy / 1000000

42
 *

43
 * Oh, if only we had a cycle counter...

44
 */

45


46
@ Delay routine

47
ENTRY(__delay)

48
		subs	r0, r0, #1

49
#if 0

50
		movls	pc, lr

51
		subs	r0, r0, #1

52
		movls	pc, lr

53
		subs	r0, r0, #1

54
		movls	pc, lr

55
		subs	r0, r0, #1

56
		movls	pc, lr

57
		subs	r0, r0, #1

58
		movls	pc, lr

59
		subs	r0, r0, #1

60
		movls	pc, lr

61
		subs	r0, r0, #1

62
		movls	pc, lr

63
		subs	r0, r0, #1

64
#endif

65
		bhi	__delay

66
		mov	pc, lr

67
ENDPROC(__udelay)

68
ENDPROC(__const_udelay)

69
ENDPROC(__delay)

70


71