arch/parisc/lib/libgcc/__umulsidi3.c

   1 #include "libgcc.h"
   2
   3 #define __ll_B ((u32) 1 << (32 / 2))
   4 #define __ll_lowpart(t) ((u32) (t) & (__ll_B - 1))
   5 #define __ll_highpart(t) ((u32) (t) >> 16)
   6
   7 #define umul_ppmm(w1, w0, u, v)                                         \
   8   do {                                                                  \
   9     u32 __x0, __x1, __x2, __x3;                                         \
  10     u16 __ul, __vl, __uh, __vh;                                         \
  11                                                                         \
  12     __ul = __ll_lowpart (u);                                            \
  13     __uh = __ll_highpart (u);                                           \
  14     __vl = __ll_lowpart (v);                                            \
  15     __vh = __ll_highpart (v);                                           \
  16                                                                         \
  17     __x0 = (u32) __ul * __vl;                                           \
  18     __x1 = (u32) __ul * __vh;                                           \
  19     __x2 = (u32) __uh * __vl;                                           \
  20     __x3 = (u32) __uh * __vh;                                           \
  21                                                                         \
  22     __x1 += __ll_highpart (__x0);/* this can't give carry */            \
  23     __x1 += __x2;                /* but this indeed can */              \
  24     if (__x1 < __x2)             /* did we get it? */                   \
  25       __x3 += __ll_B;            /* yes, add it in the proper pos.  */  \
  26                                                                         \
  27     (w1) = __x3 + __ll_highpart (__x1);                                 \
  28     (w0) = __ll_lowpart (__x1) * __ll_B + __ll_lowpart (__x0);          \
  29   } while (0)
  30
  31 union DWunion {
  32         struct {
  33                 s32 high;
  34                 s32 low;
  35         } s;
  36         s64 ll;
  37 };
  38
  39 u64 __umulsidi3(u32 u, u32 v)
  40 {
  41         union DWunion __w;
  42
  43         umul_ppmm(__w.s.high, __w.s.low, u, v);
  44
  45         return __w.ll;
  46 }