GNU Linux-libre 4.19.264-gnu1
[releases.git] / arch / arm / lib / delay-loop.S
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/delay.h>
13
14                 .text
15
16 .LC0:           .word   loops_per_jiffy
17 .LC1:           .word   UDELAY_MULT
18
19 /*
20  * loops = r0 * HZ * loops_per_jiffy / 1000000
21  *
22  * r0  <= 2000
23  * HZ  <= 1000
24  */
25
26 ENTRY(__loop_udelay)
27                 ldr     r2, .LC1
28                 mul     r0, r2, r0              @ r0 = delay_us * UDELAY_MULT
29 ENTRY(__loop_const_udelay)                      @ 0 <= r0 <= 0xfffffaf0
30                 ldr     r2, .LC0
31                 ldr     r2, [r2]
32                 umull   r1, r0, r2, r0          @ r0-r1 = r0 * loops_per_jiffy
33                 adds    r1, r1, #0xffffffff     @ rounding up ...
34                 adcs    r0, r0, r0              @ and right shift by 31
35                 reteq   lr
36
37                 .align 3
38
39 @ Delay routine
40 ENTRY(__loop_delay)
41                 subs    r0, r0, #1
42 #if 0
43                 retls   lr
44                 subs    r0, r0, #1
45                 retls   lr
46                 subs    r0, r0, #1
47                 retls   lr
48                 subs    r0, r0, #1
49                 retls   lr
50                 subs    r0, r0, #1
51                 retls   lr
52                 subs    r0, r0, #1
53                 retls   lr
54                 subs    r0, r0, #1
55                 retls   lr
56                 subs    r0, r0, #1
57 #endif
58                 bhi     __loop_delay
59                 ret     lr
60 ENDPROC(__loop_udelay)
61 ENDPROC(__loop_const_udelay)
62 ENDPROC(__loop_delay)