1 #ifndef _LINUX_MATH64_H 2 #define _LINUX_MATH64_H 3 4 #include <linux/types.h> 5 #include <asm/div64.h> 6 7 #if BITS_PER_LONG == 64 8 9 /** 10 * div_u64_rem - unsigned 64bit divide with 32bit divisor with remainder 11 * 12 * This is commonly provided by 32bit archs to provide an optimized 64bit 13 * divide. 14 */ 15 static inline u64 div_u64_rem(u64 dividend, u32 divisor, u32 *remainder) 16 { 17 *remainder = dividend % divisor; 18 return dividend / divisor; 19 } 20 21 /** 22 * div_s64_rem - signed 64bit divide with 32bit divisor with remainder 23 */ 24 static inline s64 div_s64_rem(s64 dividend, s32 divisor, s32 *remainder) 25 { 26 *remainder = dividend % divisor; 27 return dividend / divisor; 28 } 29 30 /** 31 * div64_u64 - unsigned 64bit divide with 64bit divisor 32 */ 33 static inline u64 div64_u64(u64 dividend, u64 divisor) 34 { 35 return dividend / divisor; 36 } 37 38 #elif BITS_PER_LONG == 32 39 40 #ifndef div_u64_rem 41 static inline u64 div_u64_rem(u64 dividend, u32 divisor, u32 *remainder) 42 { 43 *remainder = do_div(dividend, divisor); 44 return dividend; 45 } 46 #endif 47 48 #ifndef div_s64_rem 49 extern s64 div_s64_rem(s64 dividend, s32 divisor, s32 *remainder); 50 #endif 51 52 #ifndef div64_u64 53 extern u64 div64_u64(u64 dividend, u64 divisor); 54 #endif 55 56 #endif /* BITS_PER_LONG */ 57 58 /** 59 * div_u64 - unsigned 64bit divide with 32bit divisor 60 * 61 * This is the most common 64bit divide and should be used if possible, 62 * as many 32bit archs can optimize this variant better than a full 64bit 63 * divide. 64 */ 65 #ifndef div_u64 66 static inline u64 div_u64(u64 dividend, u32 divisor) 67 { 68 u32 remainder; 69 return div_u64_rem(dividend, divisor, &remainder); 70 } 71 #endif 72 73 /** 74 * div_s64 - signed 64bit divide with 32bit divisor 75 */ 76 #ifndef div_s64 77 static inline s64 div_s64(s64 dividend, s32 divisor) 78 { 79 s32 remainder; 80 return div_s64_rem(dividend, divisor, &remainder); 81 } 82 #endif 83 84 u32 iter_div_u64_rem(u64 dividend, u32 divisor, u64 *remainder); 85 86 static __always_inline u32 87 __iter_div_u64_rem(u64 dividend, u32 divisor, u64 *remainder) 88 { 89 u32 ret = 0; 90 91 while (dividend >= divisor) { 92 /* The following asm() prevents the compiler from 93 optimising this loop into a modulo operation. */ 94 asm("" : "+rm"(dividend)); 95 96 dividend -= divisor; 97 ret++; 98 } 99 100 *remainder = dividend; 101 102 return ret; 103 } 104 105 #endif /* _LINUX_MATH64_H */ 106