1 #ifndef _ASM_GENERIC_DIV64_H 2 #define _ASM_GENERIC_DIV64_H 3 /* 4 * Copyright (C) 2003 Bernardo Innocenti <bernie@develer.com> 5 * Based on former asm-ppc/div64.h and asm-m68knommu/div64.h 6 * 7 * The semantics of do_div() are: 8 * 9 * uint32_t do_div(uint64_t *n, uint32_t base) 10 * { 11 * uint32_t remainder = *n % base; 12 * *n = *n / base; 13 * return remainder; 14 * } 15 * 16 * NOTE: macro parameter n is evaluated multiple times, 17 * beware of side effects! 18 */ 19 20 #include <linux/types.h> 21 #include <linux/compiler.h> 22 23 #if BITS_PER_LONG == 64 24 25 # define do_div(n,base) ({ \ 26 uint32_t __base = (base); \ 27 uint32_t __rem; \ 28 __rem = ((uint64_t)(n)) % __base; \ 29 (n) = ((uint64_t)(n)) / __base; \ 30 __rem; \ 31 }) 32 33 #elif BITS_PER_LONG == 32 34 35 extern uint32_t __div64_32(uint64_t *dividend, uint32_t divisor); 36 37 /* The unnecessary pointer compare is there 38 * to check for type safety (n must be 64bit) 39 */ 40 # define do_div(n,base) ({ \ 41 uint32_t __base = (base); \ 42 uint32_t __rem; \ 43 (void)(((typeof((n)) *)0) == ((uint64_t *)0)); \ 44 if (likely(((n) >> 32) == 0)) { \ 45 __rem = (uint32_t)(n) % __base; \ 46 (n) = (uint32_t)(n) / __base; \ 47 } else \ 48 __rem = __div64_32(&(n), __base); \ 49 __rem; \ 50 }) 51 52 #else /* BITS_PER_LONG == ?? */ 53 54 # error do_div() does not yet support the C64 55 56 #endif /* BITS_PER_LONG */ 57 58 #endif /* _ASM_GENERIC_DIV64_H */ 59