tools/include/linux/math64.h

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 #ifndef _LINUX_MATH64_H
   3 #define _LINUX_MATH64_H
   4
   5 #include <linux/types.h>
   6
   7 #ifdef __x86_64__
   8 static inline u64 mul_u64_u64_div64(u64 a, u64 b, u64 c)
   9 {
  10         u64 q;
  11
  12         asm ("mulq %2; divq %3" : "=a" (q)
  13                                 : "a" (a), "rm" (b), "rm" (c)
  14                                 : "rdx");
  15
  16         return q;
  17 }
  18 #define mul_u64_u64_div64 mul_u64_u64_div64
  19 #endif
  20
  21 #ifdef __SIZEOF_INT128__
  22 static inline u64 mul_u64_u32_shr(u64 a, u32 b, unsigned int shift)
  23 {
  24         return (u64)(((unsigned __int128)a * b) >> shift);
  25 }
  26
  27 #else
  28
  29 #ifdef __i386__
  30 static inline u64 mul_u32_u32(u32 a, u32 b)
  31 {
  32         u32 high, low;
  33
  34         asm ("mull %[b]" : "=a" (low), "=d" (high)
  35                          : [a] "a" (a), [b] "rm" (b) );
  36
  37         return low | ((u64)high) << 32;
  38 }
  39 #else
  40 static inline u64 mul_u32_u32(u32 a, u32 b)
  41 {
  42         return (u64)a * b;
  43 }
  44 #endif
  45
  46 static inline u64 mul_u64_u32_shr(u64 a, u32 b, unsigned int shift)
  47 {
  48         u32 ah, al;
  49         u64 ret;
  50
  51         al = a;
  52         ah = a >> 32;
  53
  54         ret = mul_u32_u32(al, b) >> shift;
  55         if (ah)
  56                 ret += mul_u32_u32(ah, b) << (32 - shift);
  57
  58         return ret;
  59 }
  60
  61 #endif  /* __SIZEOF_INT128__ */
  62
  63 #ifndef mul_u64_u64_div64
  64 static inline u64 mul_u64_u64_div64(u64 a, u64 b, u64 c)
  65 {
  66         u64 quot, rem;
  67
  68         quot = a / c;
  69         rem = a % c;
  70
  71         return quot * b + (rem * b) / c;
  72 }
  73 #endif
  74
  75 #endif /* _LINUX_MATH64_H */