48 строки
1.3 KiB
C
48 строки
1.3 KiB
C
/*
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* include/asm-v850/delay.h -- Delay routines, using a pre-computed
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* "loops_per_second" value
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*
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* Copyright (C) 2001,03 NEC Corporation
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* Copyright (C) 2001,03 Miles Bader <miles@gnu.org>
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* Copyright (C) 1994 Hamish Macdonald
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*
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* This file is subject to the terms and conditions of the GNU General
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* Public License. See the file COPYING in the main directory of this
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* archive for more details.
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*/
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#ifndef __V850_DELAY_H__
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#define __V850_DELAY_H__
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#include <asm/param.h>
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extern __inline__ void __delay(unsigned long loops)
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{
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if (loops)
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__asm__ __volatile__ ("1: add -1, %0; bnz 1b"
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: "=r" (loops) : "0" (loops));
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}
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/*
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* Use only for very small delays ( < 1 msec). Should probably use a
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* lookup table, really, as the multiplications take much too long with
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* short delays. This is a "reasonable" implementation, though (and the
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* first constant multiplications gets optimized away if the delay is
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* a constant)
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*/
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extern unsigned long loops_per_jiffy;
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extern __inline__ void udelay(unsigned long usecs)
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{
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register unsigned long full_loops, part_loops;
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full_loops = ((usecs * HZ) / 1000000) * loops_per_jiffy;
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usecs %= (1000000 / HZ);
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part_loops = (usecs * HZ * loops_per_jiffy) / 1000000;
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__delay(full_loops + part_loops);
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}
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#endif /* __V850_DELAY_H__ */
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