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		moveq	pc, 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		movls	pc, lr
50		subs	r0, r0, #1
51		movls	pc, lr
52		subs	r0, r0, #1
53		movls	pc, lr
54		subs	r0, r0, #1
55		movls	pc, lr
56		subs	r0, r0, #1
57		movls	pc, lr
58		subs	r0, r0, #1
59		movls	pc, lr
60		subs	r0, r0, #1
61		movls	pc, lr
62		subs	r0, r0, #1
63#endif
64		bhi	__loop_delay
65		mov	pc, lr
66ENDPROC(__loop_udelay)
67ENDPROC(__loop_const_udelay)
68ENDPROC(__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
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
26ENTRY(__loop_udelay)
27		ldr	r2, .LC1
28		mul	r0, r2, r0		@ r0 = delay_us * UDELAY_MULT
29ENTRY(__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
40ENTRY(__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
60ENDPROC(__loop_udelay)
61ENDPROC(__loop_const_udelay)
62ENDPROC(__loop_delay)