1/* SPDX-License-Identifier: GPL-2.0-only */
 2/*
 3 *  linux/arch/arm/lib/delay.S
 4 *
 5 *  Copyright (C) 1995, 1996 Russell King
 
 
 
 
 6 */
 7#include <linux/linkage.h>
 8#include <asm/assembler.h>
 9#include <asm/delay.h>
10
11		.text
12
13.LC0:		.word	loops_per_jiffy
14.LC1:		.word	UDELAY_MULT
15
16/*
17 * loops = r0 * HZ * loops_per_jiffy / 1000000
18 *
19 * r0  <= 2000
 
20 * HZ  <= 1000
21 */
22
23ENTRY(__loop_udelay)
24		ldr	r2, .LC1
25		mul	r0, r2, r0		@ r0 = delay_us * UDELAY_MULT
26ENTRY(__loop_const_udelay)			@ 0 <= r0 <= 0xfffffaf0
 
27		ldr	r2, .LC0
28		ldr	r2, [r2]
29		umull	r1, r0, r2, r0		@ r0-r1 = r0 * loops_per_jiffy
30		adds	r1, r1, #0xffffffff	@ rounding up ...
31		adcs	r0, r0, r0		@ and right shift by 31
 
 
 
 
32		reteq	lr
33
 
 
 
34		.align 3
35
36@ Delay routine
37ENTRY(__loop_delay)
38		subs	r0, r0, #1
39#if 0
40		retls	lr
41		subs	r0, r0, #1
42		retls	lr
43		subs	r0, r0, #1
44		retls	lr
45		subs	r0, r0, #1
46		retls	lr
47		subs	r0, r0, #1
48		retls	lr
49		subs	r0, r0, #1
50		retls	lr
51		subs	r0, r0, #1
52		retls	lr
53		subs	r0, r0, #1
54#endif
55		bhi	__loop_delay
56		ret	lr
57ENDPROC(__loop_udelay)
58ENDPROC(__loop_const_udelay)
59ENDPROC(__loop_delay)

 
 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		.text
14
15.LC0:		.word	loops_per_jiffy
16.LC1:		.word	UDELAY_MULT
17
18/*
 
 
19 * r0  <= 2000
20 * lpj <= 0x01ffffff (max. 3355 bogomips)
21 * HZ  <= 1000
22 */
23
24ENTRY(__loop_udelay)
25		ldr	r2, .LC1
26		mul	r0, r2, r0
27ENTRY(__loop_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		reteq	lr
39
40/*
41 * loops = r0 * HZ * loops_per_jiffy / 1000000
42 */
43		.align 3
44
45@ Delay routine
46ENTRY(__loop_delay)
47		subs	r0, r0, #1
48#if 0
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		retls	lr
58		subs	r0, r0, #1
59		retls	lr
60		subs	r0, r0, #1
61		retls	lr
62		subs	r0, r0, #1
63#endif
64		bhi	__loop_delay
65		ret	lr
66ENDPROC(__loop_udelay)
67ENDPROC(__loop_const_udelay)
68ENDPROC(__loop_delay)