libquadmath/math/floorq.c

   1 /* floorq.c -- __float128 version of s_floor.c.
   2  * Conversion to IEEE quad long double by Jakub Jelinek, jj@ultra.linux.cz.
   3  */
   4
   5 /*
   6  * ====================================================
   7  * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
   8  *
   9  * Developed at SunPro, a Sun Microsystems, Inc. business.
  10  * Permission to use, copy, modify, and distribute this
  11  * software is freely granted, provided that this notice
  12  * is preserved.
  13  * ====================================================
  14  */
  15
  16 #include "quadmath-imp.h"
  17
  18 __float128
  19 floorq (__float128 x)
  20 {
  21         int64_t i0,i1,j0;
  22         uint64_t i,j;
  23         GET_FLT128_WORDS64(i0,i1,x);
  24         j0 = ((i0>>48)&0x7fff)-0x3fff;
  25         if(j0<48) {
  26             if(j0<0) {
  27                 /* return 0*sign(x) if |x|<1 */
  28                 if(i0>=0) {i0=i1=0;}
  29                 else if(((i0&0x7fffffffffffffffLL)|i1)!=0)
  30                     { i0=0xbfff000000000000ULL;i1=0;}
  31             } else {
  32                 i = (0x0000ffffffffffffULL)>>j0;
  33                 if(((i0&i)|i1)==0) return x; /* x is integral */
  34                 if(i0<0) i0 += (0x0001000000000000LL)>>j0;
  35                 i0 &= (~i); i1=0;
  36             }
  37         } else if (j0>111) {
  38             if(j0==0x4000) return x+x;  /* inf or NaN */
  39             else return x;              /* x is integral */
  40         } else {
  41             i = -1ULL>>(j0-48);
  42             if((i1&i)==0) return x;     /* x is integral */
  43             if(i0<0) {
  44                 if(j0==48) i0+=1;
  45                 else {
  46                     j = i1+(1LL<<(112-j0));
  47                     if(j<i1) i0 +=1 ;   /* got a carry */
  48                     i1=j;
  49                 }
  50             }
  51             i1 &= (~i);
  52         }
  53         SET_FLT128_WORDS64(x,i0,i1);
  54         return x;
  55 }