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96cf5185 G |
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) |