59 lines
1.3 KiB
C
59 lines
1.3 KiB
C
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#ifndef _ASM_GENERIC_DIV64_H
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#define _ASM_GENERIC_DIV64_H
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/*
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* Copyright (C) 2003 Bernardo Innocenti <bernie@develer.com>
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* Based on former asm-ppc/div64.h and asm-m68knommu/div64.h
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*
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* The semantics of do_div() are:
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*
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* uint32_t do_div(uint64_t *n, uint32_t base)
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* {
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* uint32_t remainder = *n % base;
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* *n = *n / base;
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* return remainder;
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* }
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*
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* NOTE: macro parameter n is evaluated multiple times,
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* beware of side effects!
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*/
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#include <linux/types.h>
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#include <linux/compiler.h>
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#if BITS_PER_LONG == 64
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# define do_div(n,base) ({ \
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uint32_t __base = (base); \
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uint32_t __rem; \
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__rem = ((uint64_t)(n)) % __base; \
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(n) = ((uint64_t)(n)) / __base; \
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__rem; \
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})
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#elif BITS_PER_LONG == 32
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extern uint32_t __div64_32(uint64_t *dividend, uint32_t divisor);
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/* The unnecessary pointer compare is there
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* to check for type safety (n must be 64bit)
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*/
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# define do_div(n,base) ({ \
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uint32_t __base = (base); \
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uint32_t __rem; \
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(void)(((typeof((n)) *)0) == ((uint64_t *)0)); \
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if (likely(((n) >> 32) == 0)) { \
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__rem = (uint32_t)(n) % __base; \
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(n) = (uint32_t)(n) / __base; \
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} else \
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__rem = __div64_32(&(n), __base); \
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__rem; \
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})
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#else /* BITS_PER_LONG == ?? */
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# error do_div() does not yet support the C64
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#endif /* BITS_PER_LONG */
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#endif /* _ASM_GENERIC_DIV64_H */
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