unicore32 additional architecture files: low-level lib: misc
[linux-2.6.git] / arch / unicore32 / lib / delay.S
1 /*
2  * linux/arch/unicore32/lib/delay.S
3  *
4  * Code specific to PKUnity SoC and UniCore ISA
5  *
6  * Copyright (C) 2001-2010 GUAN Xue-tao
7  *
8  * This program is free software; you can redistribute it and/or modify
9  * it under the terms of the GNU General Public License version 2 as
10  * published by the Free Software Foundation.
11  */
12 #include <linux/linkage.h>
13 #include <asm/assembler.h>
14 #include <asm/param.h>
15                 .text
16
17 .LC0:           .word   loops_per_jiffy
18 .LC1:           .word   (2199023*HZ)>>11
19
20 /*
21  * r0  <= 2000
22  * lpj <= 0x01ffffff (max. 3355 bogomips)
23  * HZ  <= 1000
24  */
25
26 ENTRY(__udelay)
27                 ldw     r2, .LC1
28                 mul     r0, r2, r0
29 ENTRY(__const_udelay)                           @ 0 <= r0 <= 0x7fffff06
30                 ldw     r2, .LC0
31                 ldw     r2, [r2]                @ max = 0x01ffffff
32                 mov     r0, r0 >> #14           @ max = 0x0001ffff
33                 mov     r2, r2 >> #10           @ max = 0x00007fff
34                 mul     r0, r2, r0              @ max = 2^32-1
35                 mov.a   r0, r0 >> #6
36                 cmoveq  pc, lr
37
38 /*
39  * loops = r0 * HZ * loops_per_jiffy / 1000000
40  *
41  * Oh, if only we had a cycle counter...
42  */
43
44 @ Delay routine
45 ENTRY(__delay)
46                 sub.a   r0, r0, #2
47                 bua     __delay
48                 mov     pc, lr
49 ENDPROC(__udelay)
50 ENDPROC(__const_udelay)
51 ENDPROC(__delay)