contrib/gdtoa/dmisc.c

   1 /****************************************************************
   2
   3 The author of this software is David M. Gay.
   4
   5 Copyright (C) 1998 by Lucent Technologies
   6 All Rights Reserved
   7
   8 Permission to use, copy, modify, and distribute this software and
   9 its documentation for any purpose and without fee is hereby
  10 granted, provided that the above copyright notice appear in all
  11 copies and that both that the copyright notice and this
  12 permission notice and warranty disclaimer appear in supporting
  13 documentation, and that the name of Lucent or any of its entities
  14 not be used in advertising or publicity pertaining to
  15 distribution of the software without specific, written prior
  16 permission.
  17
  18 LUCENT DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
  19 INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS.
  20 IN NO EVENT SHALL LUCENT OR ANY OF ITS ENTITIES BE LIABLE FOR ANY
  21 SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
  22 WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER
  23 IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION,
  24 ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF
  25 THIS SOFTWARE.
  26
  27 ****************************************************************/
  28
  29 /* Please send bug reports to David M. Gay (dmg at acm dot org,
  30  * with " at " changed at "@" and " dot " changed to ".").      */
  31
  32 #include "gdtoaimp.h"
  33
  34 #ifndef MULTIPLE_THREADS
  35  char *dtoa_result;
  36 #endif
  37
  38  char *
  39 #ifdef KR_headers
  40 rv_alloc(i) int i;
  41 #else
  42 rv_alloc(int i)
  43 #endif
  44 {
  45         int j, k, *r;
  46
  47         j = sizeof(ULong);
  48         for(k = 0;
  49                 sizeof(Bigint) - sizeof(ULong) - sizeof(int) + j <= i;
  50                 j <<= 1)
  51                         k++;
  52         r = (int*)Balloc(k);
  53         *r = k;
  54         return
  55 #ifndef MULTIPLE_THREADS
  56         dtoa_result =
  57 #endif
  58                 (char *)(r+1);
  59         }
  60
  61  char *
  62 #ifdef KR_headers
  63 nrv_alloc(s, rve, n) char *s, **rve; int n;
  64 #else
  65 nrv_alloc(char *s, char **rve, int n)
  66 #endif
  67 {
  68         char *rv, *t;
  69
  70         t = rv = rv_alloc(n);
  71         while((*t = *s++) !=0)
  72                 t++;
  73         if (rve)
  74                 *rve = t;
  75         return rv;
  76         }
  77
  78 /* freedtoa(s) must be used to free values s returned by dtoa
  79  * when MULTIPLE_THREADS is #defined.  It should be used in all cases,
  80  * but for consistency with earlier versions of dtoa, it is optional
  81  * when MULTIPLE_THREADS is not defined.
  82  */
  83
  84  void
  85 #ifdef KR_headers
  86 freedtoa(s) char *s;
  87 #else
  88 freedtoa(char *s)
  89 #endif
  90 {
  91         Bigint *b = (Bigint *)((int *)s - 1);
  92         b->maxwds = 1 << (b->k = *(int*)b);
  93         Bfree(b);
  94 #ifndef MULTIPLE_THREADS
  95         if (s == dtoa_result)
  96                 dtoa_result = 0;
  97 #endif
  98         }
  99
 100  int
 101 quorem
 102 #ifdef KR_headers
 103         (b, S) Bigint *b, *S;
 104 #else
 105         (Bigint *b, Bigint *S)
 106 #endif
 107 {
 108         int n;
 109         ULong *bx, *bxe, q, *sx, *sxe;
 110 #ifdef ULLong
 111         ULLong borrow, carry, y, ys;
 112 #else
 113         ULong borrow, carry, y, ys;
 114 #ifdef Pack_32
 115         ULong si, z, zs;
 116 #endif
 117 #endif
 118
 119         n = S->wds;
 120 #ifdef DEBUG
 121         /*debug*/ if (b->wds > n)
 122         /*debug*/       Bug("oversize b in quorem");
 123 #endif
 124         if (b->wds < n)
 125                 return 0;
 126         sx = S->x;
 127         sxe = sx + --n;
 128         bx = b->x;
 129         bxe = bx + n;
 130         q = *bxe / (*sxe + 1);  /* ensure q <= true quotient */
 131 #ifdef DEBUG
 132         /*debug*/ if (q > 9)
 133         /*debug*/       Bug("oversized quotient in quorem");
 134 #endif
 135         if (q) {
 136                 borrow = 0;
 137                 carry = 0;
 138                 do {
 139 #ifdef ULLong
 140                         ys = *sx++ * (ULLong)q + carry;
 141                         carry = ys >> 32;
 142                         y = *bx - (ys & 0xffffffffUL) - borrow;
 143                         borrow = y >> 32 & 1UL;
 144                         *bx++ = y & 0xffffffffUL;
 145 #else
 146 #ifdef Pack_32
 147                         si = *sx++;
 148                         ys = (si & 0xffff) * q + carry;
 149                         zs = (si >> 16) * q + (ys >> 16);
 150                         carry = zs >> 16;
 151                         y = (*bx & 0xffff) - (ys & 0xffff) - borrow;
 152                         borrow = (y & 0x10000) >> 16;
 153                         z = (*bx >> 16) - (zs & 0xffff) - borrow;
 154                         borrow = (z & 0x10000) >> 16;
 155                         Storeinc(bx, z, y);
 156 #else
 157                         ys = *sx++ * q + carry;
 158                         carry = ys >> 16;
 159                         y = *bx - (ys & 0xffff) - borrow;
 160                         borrow = (y & 0x10000) >> 16;
 161                         *bx++ = y & 0xffff;
 162 #endif
 163 #endif
 164                         }
 165                         while(sx <= sxe);
 166                 if (!*bxe) {
 167                         bx = b->x;
 168                         while(--bxe > bx && !*bxe)
 169                                 --n;
 170                         b->wds = n;
 171                         }
 172                 }
 173         if (cmp(b, S) >= 0) {
 174                 q++;
 175                 borrow = 0;
 176                 carry = 0;
 177                 bx = b->x;
 178                 sx = S->x;
 179                 do {
 180 #ifdef ULLong
 181                         ys = *sx++ + carry;
 182                         carry = ys >> 32;
 183                         y = *bx - (ys & 0xffffffffUL) - borrow;
 184                         borrow = y >> 32 & 1UL;
 185                         *bx++ = y & 0xffffffffUL;
 186 #else
 187 #ifdef Pack_32
 188                         si = *sx++;
 189                         ys = (si & 0xffff) + carry;
 190                         zs = (si >> 16) + (ys >> 16);
 191                         carry = zs >> 16;
 192                         y = (*bx & 0xffff) - (ys & 0xffff) - borrow;
 193                         borrow = (y & 0x10000) >> 16;
 194                         z = (*bx >> 16) - (zs & 0xffff) - borrow;
 195                         borrow = (z & 0x10000) >> 16;
 196                         Storeinc(bx, z, y);
 197 #else
 198                         ys = *sx++ + carry;
 199                         carry = ys >> 16;
 200                         y = *bx - (ys & 0xffff) - borrow;
 201                         borrow = (y & 0x10000) >> 16;
 202                         *bx++ = y & 0xffff;
 203 #endif
 204 #endif
 205                         }
 206                         while(sx <= sxe);
 207                 bx = b->x;
 208                 bxe = bx + n;
 209                 if (!*bxe) {
 210                         while(--bxe > bx && !*bxe)
 211                                 --n;
 212                         b->wds = n;
 213                         }
 214                 }
 215         return q;
 216         }