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awilliam
GitHub Repository: awilliam/linux-vfio
 Path: blob/master/arch/unicore32/lib/delay.S
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/*

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 * linux/arch/unicore32/lib/delay.S

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 *

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 * Code specific to PKUnity SoC and UniCore ISA

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 *

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 * Copyright (C) 2001-2010 GUAN Xue-tao

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 *

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 * This program is free software; you can redistribute it and/or modify

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 * it under the terms of the GNU General Public License version 2 as

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 * published by the Free Software Foundation.

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 */

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#include <linux/linkage.h>

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#include <asm/assembler.h>

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#include <asm/param.h>

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		.text

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.LC0:		.word	loops_per_jiffy

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.LC1:		.word	(2199023*HZ)>>11

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/*

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 * r0  <= 2000

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 * lpj <= 0x01ffffff (max. 3355 bogomips)

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 * HZ  <= 1000

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 */

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ENTRY(__udelay)

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		ldw	r2, .LC1

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		mul	r0, r2, r0

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ENTRY(__const_udelay)				@ 0 <= r0 <= 0x7fffff06

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		ldw	r2, .LC0

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		ldw	r2, [r2]		@ max = 0x01ffffff

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		mov	r0, r0 >> #14		@ max = 0x0001ffff

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		mov	r2, r2 >> #10		@ max = 0x00007fff

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		mul	r0, r2, r0		@ max = 2^32-1

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		mov.a	r0, r0 >> #6

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		cmoveq	pc, lr

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/*

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 * loops = r0 * HZ * loops_per_jiffy / 1000000

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 *

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 * Oh, if only we had a cycle counter...

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 */

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@ Delay routine

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ENTRY(__delay)

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		sub.a	r0, r0, #2

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		bua	__delay

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		mov	pc, lr

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ENDPROC(__udelay)

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ENDPROC(__const_udelay)

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ENDPROC(__delay)

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