LXR linux/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__
   8static 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__
  22static 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__
  30static 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
  40static inline u64 mul_u32_u32(u32 a, u32 b)
  41{
  42        return (u64)a * b;
  43}
  44#endif
  45
  46static 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
  64static 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 */
  76