7 * Copyright (C) 1994 Hamish Macdonald
9 * Delay routines, using a pre-computed "loops_per_jiffy" value.
12 static inline void __delay(unsigned long loops
)
14 __asm__
__volatile__ ("1: subql #1,%0; jcc 1b"
15 : "=d" (loops
) : "0" (loops
));
18 extern void __bad_udelay(void);
21 * Use only for very small delays ( < 1 msec). Should probably use a
22 * lookup table, really, as the multiplications take much too long with
23 * short delays. This is a "reasonable" implementation, though (and the
24 * first constant multiplications gets optimized away if the delay is
27 static inline void __const_udelay(unsigned long xloops
)
31 __asm__ ("mulul %2,%0:%1"
32 : "=d" (xloops
), "=d" (tmp
)
33 : "d" (xloops
), "1" (loops_per_jiffy
));
37 static inline void __udelay(unsigned long usecs
)
39 __const_udelay(usecs
* 4295); /* 2**32 / 1000000 */
42 #define udelay(n) (__builtin_constant_p(n) ? \
43 ((n) > 20000 ? __bad_udelay() : __const_udelay((n) * 4295)) : \
46 static inline unsigned long muldiv(unsigned long a
, unsigned long b
,
51 __asm__ ("mulul %2,%0:%1; divul %3,%0:%1"
52 : "=d" (tmp
), "=d" (a
)
53 : "d" (b
), "d" (c
), "1" (a
));
57 #endif /* defined(_M68K_DELAY_H) */
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