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[/] [openrisc/] [trunk/] [gnu-src/] [gcc-4.5.1/] [libgcc/] [config/] [libbid/] [bid128_next.c] - Blame information for rev 280

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1 272 jeremybenn 
/* Copyright (C) 2007, 2009  Free Software Foundation, Inc.
2 
 
3 
This file is part of GCC.
4 
 
5 
GCC is free software; you can redistribute it and/or modify it under
6 
the terms of the GNU General Public License as published by the Free
7 
Software Foundation; either version 3, or (at your option) any later
8 
version.
9 
 
10 
GCC is distributed in the hope that it will be useful, but WITHOUT ANY
11 
WARRANTY; without even the implied warranty of MERCHANTABILITY or
12 
FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
13 
for more details.
14 
 
15 
Under Section 7 of GPL version 3, you are granted additional
16 
permissions described in the GCC Runtime Library Exception, version
17 
3.1, as published by the Free Software Foundation.
18 
 
19 
You should have received a copy of the GNU General Public License and
20 
a copy of the GCC Runtime Library Exception along with this program;
21 
see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
22 
<http://www.gnu.org/licenses/>.  */
23 
 
24 
#define BID_128RES
25 
#include "bid_internal.h"
26 
 
27 
/*****************************************************************************
28 
 *  BID128 nextup
29 
 ****************************************************************************/
30 
 
31 
#if DECIMAL_CALL_BY_REFERENCE
32 
void
33 
bid128_nextup (UINT128 * pres,
34 
               UINT128 *
35 
               px _EXC_FLAGS_PARAM _EXC_MASKS_PARAM _EXC_INFO_PARAM) {
36 
  UINT128 x = *px;
37 
#else
38 
UINT128
39 
bid128_nextup (UINT128 x _EXC_FLAGS_PARAM _EXC_MASKS_PARAM
40 
               _EXC_INFO_PARAM) {
41 
#endif
42 
 
43 
  UINT128 res;
44 
  UINT64 x_sign;
45 
  UINT64 x_exp;
46 
  int exp;
47 
  BID_UI64DOUBLE tmp1;
48 
  int x_nr_bits;
49 
  int q1, ind;
50 
  UINT128 C1;                   // C1.w[1], C1.w[0] represent x_signif_hi, x_signif_lo (UINT64)
51 
 
52 
  BID_SWAP128 (x);
53 
  // unpack the argument
54 
  x_sign = x.w[1] & MASK_SIGN;  // 0 for positive, MASK_SIGN for negative
55 
  C1.w[1] = x.w[1] & MASK_COEFF;
56 
  C1.w[0] = x.w[0];
57 
 
58 
  // check for NaN or Infinity
59 
  if ((x.w[1] & MASK_SPECIAL) == MASK_SPECIAL) {
60 
    // x is special
61 
    if ((x.w[1] & MASK_NAN) == MASK_NAN) {      // x is NAN
62 
      // if x = NaN, then res = Q (x)
63 
      // check first for non-canonical NaN payload
64 
      if (((x.w[1] & 0x00003fffffffffffull) > 0x0000314dc6448d93ull) ||
65 
          (((x.w[1] & 0x00003fffffffffffull) == 0x0000314dc6448d93ull)
66 
           && (x.w[0] > 0x38c15b09ffffffffull))) {
67 
        x.w[1] = x.w[1] & 0xffffc00000000000ull;
68 
        x.w[0] = 0x0ull;
69 
      }
70 
      if ((x.w[1] & MASK_SNAN) == MASK_SNAN) {  // x is SNAN
71 
        // set invalid flag
72 
        *pfpsf |= INVALID_EXCEPTION;
73 
        // return quiet (x)
74 
        res.w[1] = x.w[1] & 0xfc003fffffffffffull;      // clear out also G[6]-G[16]
75 
        res.w[0] = x.w[0];
76 
      } else {  // x is QNaN
77 
        // return x
78 
        res.w[1] = x.w[1] & 0xfc003fffffffffffull;      // clear out G[6]-G[16]
79 
        res.w[0] = x.w[0];
80 
      }
81 
    } else {    // x is not NaN, so it must be infinity
82 
      if (!x_sign) {    // x is +inf
83 
        res.w[1] = 0x7800000000000000ull;       // +inf
84 
        res.w[0] = 0x0000000000000000ull;
85 
      } else {  // x is -inf
86 
        res.w[1] = 0xdfffed09bead87c0ull;       // -MAXFP = -999...99 * 10^emax
87 
        res.w[0] = 0x378d8e63ffffffffull;
88 
      }
89 
    }
90 
    BID_RETURN (res);
91 
  }
92 
  // check for non-canonical values (treated as zero)
93 
  if ((x.w[1] & 0x6000000000000000ull) == 0x6000000000000000ull) {      // G0_G1=11
94 
    // non-canonical
95 
    x_exp = (x.w[1] << 2) & MASK_EXP;   // biased and shifted left 49 bits
96 
    C1.w[1] = 0; // significand high
97 
    C1.w[0] = 0;  // significand low
98 
  } else {      // G0_G1 != 11
99 
    x_exp = x.w[1] & MASK_EXP;  // biased and shifted left 49 bits
100 
    if (C1.w[1] > 0x0001ed09bead87c0ull ||
101 
        (C1.w[1] == 0x0001ed09bead87c0ull
102 
         && C1.w[0] > 0x378d8e63ffffffffull)) {
103 
      // x is non-canonical if coefficient is larger than 10^34 -1
104 
      C1.w[1] = 0;
105 
      C1.w[0] = 0;
106 
    } else {    // canonical
107 
      ;
108 
    }
109 
  }
110 
 
111 
  if ((C1.w[1] == 0x0ull) && (C1.w[0] == 0x0ull)) {
112 
    // x is +/-0
113 
    res.w[1] = 0x0000000000000000ull;   // +1 * 10^emin
114 
    res.w[0] = 0x0000000000000001ull;
115 
  } else {      // x is not special and is not zero
116 
    if (x.w[1] == 0x5fffed09bead87c0ull
117 
        && x.w[0] == 0x378d8e63ffffffffull) {
118 
      // x = +MAXFP = 999...99 * 10^emax
119 
      res.w[1] = 0x7800000000000000ull; // +inf
120 
      res.w[0] = 0x0000000000000000ull;
121 
    } else if (x.w[1] == 0x8000000000000000ull
122 
               && x.w[0] == 0x0000000000000001ull) {
123 
      // x = -MINFP = 1...99 * 10^emin
124 
      res.w[1] = 0x8000000000000000ull; // -0
125 
      res.w[0] = 0x0000000000000000ull;
126 
    } else {    // -MAXFP <= x <= -MINFP - 1 ulp OR MINFP <= x <= MAXFP - 1 ulp
127 
      // can add/subtract 1 ulp to the significand
128 
 
129 
      // Note: we could check here if x >= 10^34 to speed up the case q1 = 34
130 
      // q1 = nr. of decimal digits in x
131 
      // determine first the nr. of bits in x
132 
      if (C1.w[1] == 0) {
133 
        if (C1.w[0] >= 0x0020000000000000ull) {  // x >= 2^53
134 
          // split the 64-bit value in two 32-bit halves to avoid rnd errors
135 
          if (C1.w[0] >= 0x0000000100000000ull) {        // x >= 2^32
136 
            tmp1.d = (double) (C1.w[0] >> 32);   // exact conversion
137 
            x_nr_bits =
138 
              33 + ((((unsigned int) (tmp1.ui64 >> 52)) & 0x7ff) -
139 
                    0x3ff);
140 
          } else {      // x < 2^32
141 
            tmp1.d = (double) (C1.w[0]); // exact conversion
142 
            x_nr_bits =
143 
              1 + ((((unsigned int) (tmp1.ui64 >> 52)) & 0x7ff) -
144 
                   0x3ff);
145 
          }
146 
        } else {        // if x < 2^53
147 
          tmp1.d = (double) C1.w[0];     // exact conversion
148 
          x_nr_bits =
149 
            1 + ((((unsigned int) (tmp1.ui64 >> 52)) & 0x7ff) - 0x3ff);
150 
        }
151 
      } else {  // C1.w[1] != 0 => nr. bits = 64 + nr_bits (C1.w[1])
152 
        tmp1.d = (double) C1.w[1];      // exact conversion
153 
        x_nr_bits =
154 
          65 + ((((unsigned int) (tmp1.ui64 >> 52)) & 0x7ff) - 0x3ff);
155 
      }
156 
      q1 = nr_digits[x_nr_bits - 1].digits;
157 
      if (q1 == 0) {
158 
        q1 = nr_digits[x_nr_bits - 1].digits1;
159 
        if (C1.w[1] > nr_digits[x_nr_bits - 1].threshold_hi
160 
            || (C1.w[1] == nr_digits[x_nr_bits - 1].threshold_hi
161 
                && C1.w[0] >= nr_digits[x_nr_bits - 1].threshold_lo))
162 
          q1++;
163 
      }
164 
      // if q1 < P34 then pad the significand with zeros
165 
      if (q1 < P34) {
166 
        exp = (x_exp >> 49) - 6176;
167 
        if (exp + 6176 > P34 - q1) {
168 
          ind = P34 - q1;       // 1 <= ind <= P34 - 1
169 
          // pad with P34 - q1 zeros, until exponent = emin
170 
          // C1 = C1 * 10^ind
171 
          if (q1 <= 19) {       // 64-bit C1
172 
            if (ind <= 19) {    // 64-bit 10^ind and 64-bit C1
173 
              __mul_64x64_to_128MACH (C1, C1.w[0], ten2k64[ind]);
174 
            } else {    // 128-bit 10^ind and 64-bit C1
175 
              __mul_128x64_to_128 (C1, C1.w[0], ten2k128[ind - 20]);
176 
            }
177 
          } else {      // C1 is (most likely) 128-bit
178 
            if (ind <= 14) {    // 64-bit 10^ind and 128-bit C1 (most likely)
179 
              __mul_128x64_to_128 (C1, ten2k64[ind], C1);
180 
            } else if (ind <= 19) {     // 64-bit 10^ind and 64-bit C1 (q1 <= 19)
181 
              __mul_64x64_to_128MACH (C1, C1.w[0], ten2k64[ind]);
182 
            } else {    // 128-bit 10^ind and 64-bit C1 (C1 must be 64-bit)
183 
              __mul_128x64_to_128 (C1, C1.w[0], ten2k128[ind - 20]);
184 
            }
185 
          }
186 
          x_exp = x_exp - ((UINT64) ind << 49);
187 
        } else {        // pad with zeros until the exponent reaches emin
188 
          ind = exp + 6176;
189 
          // C1 = C1 * 10^ind
190 
          if (ind <= 19) {      // 1 <= P34 - q1 <= 19 <=> 15 <= q1 <= 33
191 
            if (q1 <= 19) {     // 64-bit C1, 64-bit 10^ind
192 
              __mul_64x64_to_128MACH (C1, C1.w[0], ten2k64[ind]);
193 
            } else {    // 20 <= q1 <= 33 => 128-bit C1, 64-bit 10^ind
194 
              __mul_128x64_to_128 (C1, ten2k64[ind], C1);
195 
            }
196 
          } else {      // if 20 <= P34 - q1 <= 33 <=> 1 <= q1 <= 14 =>
197 
            // 64-bit C1, 128-bit 10^ind
198 
            __mul_128x64_to_128 (C1, C1.w[0], ten2k128[ind - 20]);
199 
          }
200 
          x_exp = EXP_MIN;
201 
        }
202 
      }
203 
      if (!x_sign) {    // x > 0
204 
        // add 1 ulp (add 1 to the significand)
205 
        C1.w[0]++;
206 
        if (C1.w[0] == 0)
207 
          C1.w[1]++;
208 
        if (C1.w[1] == 0x0001ed09bead87c0ull && C1.w[0] == 0x378d8e6400000000ull) {      // if  C1 = 10^34
209 
          C1.w[1] = 0x0000314dc6448d93ull;      // C1 = 10^33
210 
          C1.w[0] = 0x38c15b0a00000000ull;
211 
          x_exp = x_exp + EXP_P1;
212 
        }
213 
      } else {  // x < 0
214 
        // subtract 1 ulp (subtract 1 from the significand)
215 
        C1.w[0]--;
216 
        if (C1.w[0] == 0xffffffffffffffffull)
217 
          C1.w[1]--;
218 
        if (x_exp != 0 && C1.w[1] == 0x0000314dc6448d93ull && C1.w[0] == 0x38c15b09ffffffffull) { // if  C1 = 10^33 - 1
219 
          C1.w[1] = 0x0001ed09bead87c0ull;      // C1 = 10^34 - 1
220 
          C1.w[0] = 0x378d8e63ffffffffull;
221 
          x_exp = x_exp - EXP_P1;
222 
        }
223 
      }
224 
      // assemble the result
225 
      res.w[1] = x_sign | x_exp | C1.w[1];
226 
      res.w[0] = C1.w[0];
227 
    }   // end -MAXFP <= x <= -MINFP - 1 ulp OR MINFP <= x <= MAXFP - 1 ulp
228 
  }     // end x is not special and is not zero
229 
  BID_RETURN (res);
230 
}
231 
 
232 
/*****************************************************************************
233 
 *  BID128 nextdown
234 
 ****************************************************************************/
235 
 
236 
#if DECIMAL_CALL_BY_REFERENCE
237 
void
238 
bid128_nextdown (UINT128 * pres,
239 
                 UINT128 *
240 
                 px _EXC_FLAGS_PARAM _EXC_MASKS_PARAM _EXC_INFO_PARAM) {
241 
  UINT128 x = *px;
242 
#else
243 
UINT128
244 
bid128_nextdown (UINT128 x _EXC_FLAGS_PARAM _EXC_MASKS_PARAM
245 
                 _EXC_INFO_PARAM) {
246 
#endif
247 
 
248 
  UINT128 res;
249 
  UINT64 x_sign;
250 
  UINT64 x_exp;
251 
  int exp;
252 
  BID_UI64DOUBLE tmp1;
253 
  int x_nr_bits;
254 
  int q1, ind;
255 
  UINT128 C1;                   // C1.w[1], C1.w[0] represent x_signif_hi, x_signif_lo (UINT64)
256 
 
257 
  BID_SWAP128 (x);
258 
  // unpack the argument
259 
  x_sign = x.w[1] & MASK_SIGN;  // 0 for positive, MASK_SIGN for negative
260 
  C1.w[1] = x.w[1] & MASK_COEFF;
261 
  C1.w[0] = x.w[0];
262 
 
263 
  // check for NaN or Infinity
264 
  if ((x.w[1] & MASK_SPECIAL) == MASK_SPECIAL) {
265 
    // x is special
266 
    if ((x.w[1] & MASK_NAN) == MASK_NAN) {      // x is NAN
267 
      // if x = NaN, then res = Q (x)
268 
      // check first for non-canonical NaN payload
269 
      if (((x.w[1] & 0x00003fffffffffffull) > 0x0000314dc6448d93ull) ||
270 
          (((x.w[1] & 0x00003fffffffffffull) == 0x0000314dc6448d93ull)
271 
           && (x.w[0] > 0x38c15b09ffffffffull))) {
272 
        x.w[1] = x.w[1] & 0xffffc00000000000ull;
273 
        x.w[0] = 0x0ull;
274 
      }
275 
      if ((x.w[1] & MASK_SNAN) == MASK_SNAN) {  // x is SNAN
276 
        // set invalid flag
277 
        *pfpsf |= INVALID_EXCEPTION;
278 
        // return quiet (x)
279 
        res.w[1] = x.w[1] & 0xfc003fffffffffffull;      // clear out also G[6]-G[16]
280 
        res.w[0] = x.w[0];
281 
      } else {  // x is QNaN
282 
        // return x
283 
        res.w[1] = x.w[1] & 0xfc003fffffffffffull;      // clear out G[6]-G[16]
284 
        res.w[0] = x.w[0];
285 
      }
286 
    } else {    // x is not NaN, so it must be infinity
287 
      if (!x_sign) {    // x is +inf
288 
        res.w[1] = 0x5fffed09bead87c0ull;       // +MAXFP = +999...99 * 10^emax
289 
        res.w[0] = 0x378d8e63ffffffffull;
290 
      } else {  // x is -inf
291 
        res.w[1] = 0xf800000000000000ull;       // -inf
292 
        res.w[0] = 0x0000000000000000ull;
293 
      }
294 
    }
295 
    BID_RETURN (res);
296 
  }
297 
  // check for non-canonical values (treated as zero)
298 
  if ((x.w[1] & 0x6000000000000000ull) == 0x6000000000000000ull) {      // G0_G1=11
299 
    // non-canonical
300 
    x_exp = (x.w[1] << 2) & MASK_EXP;   // biased and shifted left 49 bits
301 
    C1.w[1] = 0; // significand high
302 
    C1.w[0] = 0;  // significand low
303 
  } else {      // G0_G1 != 11
304 
    x_exp = x.w[1] & MASK_EXP;  // biased and shifted left 49 bits
305 
    if (C1.w[1] > 0x0001ed09bead87c0ull ||
306 
        (C1.w[1] == 0x0001ed09bead87c0ull
307 
         && C1.w[0] > 0x378d8e63ffffffffull)) {
308 
      // x is non-canonical if coefficient is larger than 10^34 -1
309 
      C1.w[1] = 0;
310 
      C1.w[0] = 0;
311 
    } else {    // canonical
312 
      ;
313 
    }
314 
  }
315 
 
316 
  if ((C1.w[1] == 0x0ull) && (C1.w[0] == 0x0ull)) {
317 
    // x is +/-0
318 
    res.w[1] = 0x8000000000000000ull;   // -1 * 10^emin
319 
    res.w[0] = 0x0000000000000001ull;
320 
  } else {      // x is not special and is not zero
321 
    if (x.w[1] == 0xdfffed09bead87c0ull
322 
        && x.w[0] == 0x378d8e63ffffffffull) {
323 
      // x = -MAXFP = -999...99 * 10^emax
324 
      res.w[1] = 0xf800000000000000ull; // -inf
325 
      res.w[0] = 0x0000000000000000ull;
326 
    } else if (x.w[1] == 0x0ull && x.w[0] == 0x0000000000000001ull) {    // +MINFP
327 
      res.w[1] = 0x0000000000000000ull; // +0
328 
      res.w[0] = 0x0000000000000000ull;
329 
    } else {    // -MAXFP <= x <= -MINFP - 1 ulp OR MINFP <= x <= MAXFP - 1 ulp
330 
      // can add/subtract 1 ulp to the significand
331 
 
332 
      // Note: we could check here if x >= 10^34 to speed up the case q1 = 34
333 
      // q1 = nr. of decimal digits in x
334 
      // determine first the nr. of bits in x
335 
      if (C1.w[1] == 0) {
336 
        if (C1.w[0] >= 0x0020000000000000ull) {  // x >= 2^53
337 
          // split the 64-bit value in two 32-bit halves to avoid rnd errors
338 
          if (C1.w[0] >= 0x0000000100000000ull) {        // x >= 2^32
339 
            tmp1.d = (double) (C1.w[0] >> 32);   // exact conversion
340 
            x_nr_bits =
341 
              33 + ((((unsigned int) (tmp1.ui64 >> 52)) & 0x7ff) -
342 
                    0x3ff);
343 
          } else {      // x < 2^32
344 
            tmp1.d = (double) (C1.w[0]); // exact conversion
345 
            x_nr_bits =
346 
              1 + ((((unsigned int) (tmp1.ui64 >> 52)) & 0x7ff) -
347 
                   0x3ff);
348 
          }
349 
        } else {        // if x < 2^53
350 
          tmp1.d = (double) C1.w[0];     // exact conversion
351 
          x_nr_bits =
352 
            1 + ((((unsigned int) (tmp1.ui64 >> 52)) & 0x7ff) - 0x3ff);
353 
        }
354 
      } else {  // C1.w[1] != 0 => nr. bits = 64 + nr_bits (C1.w[1])
355 
        tmp1.d = (double) C1.w[1];      // exact conversion
356 
        x_nr_bits =
357 
          65 + ((((unsigned int) (tmp1.ui64 >> 52)) & 0x7ff) - 0x3ff);
358 
      }
359 
      q1 = nr_digits[x_nr_bits - 1].digits;
360 
      if (q1 == 0) {
361 
        q1 = nr_digits[x_nr_bits - 1].digits1;
362 
        if (C1.w[1] > nr_digits[x_nr_bits - 1].threshold_hi
363 
            || (C1.w[1] == nr_digits[x_nr_bits - 1].threshold_hi
364 
                && C1.w[0] >= nr_digits[x_nr_bits - 1].threshold_lo))
365 
          q1++;
366 
      }
367 
      // if q1 < P then pad the significand with zeros
368 
      if (q1 < P34) {
369 
        exp = (x_exp >> 49) - 6176;
370 
        if (exp + 6176 > P34 - q1) {
371 
          ind = P34 - q1;       // 1 <= ind <= P34 - 1
372 
          // pad with P34 - q1 zeros, until exponent = emin
373 
          // C1 = C1 * 10^ind
374 
          if (q1 <= 19) {       // 64-bit C1
375 
            if (ind <= 19) {    // 64-bit 10^ind and 64-bit C1
376 
              __mul_64x64_to_128MACH (C1, C1.w[0], ten2k64[ind]);
377 
            } else {    // 128-bit 10^ind and 64-bit C1
378 
              __mul_128x64_to_128 (C1, C1.w[0], ten2k128[ind - 20]);
379 
            }
380 
          } else {      // C1 is (most likely) 128-bit
381 
            if (ind <= 14) {    // 64-bit 10^ind and 128-bit C1 (most likely)
382 
              __mul_128x64_to_128 (C1, ten2k64[ind], C1);
383 
            } else if (ind <= 19) {     // 64-bit 10^ind and 64-bit C1 (q1 <= 19)
384 
              __mul_64x64_to_128MACH (C1, C1.w[0], ten2k64[ind]);
385 
            } else {    // 128-bit 10^ind and 64-bit C1 (C1 must be 64-bit)
386 
              __mul_128x64_to_128 (C1, C1.w[0], ten2k128[ind - 20]);
387 
            }
388 
          }
389 
          x_exp = x_exp - ((UINT64) ind << 49);
390 
        } else {        // pad with zeros until the exponent reaches emin
391 
          ind = exp + 6176;
392 
          // C1 = C1 * 10^ind
393 
          if (ind <= 19) {      // 1 <= P34 - q1 <= 19 <=> 15 <= q1 <= 33
394 
            if (q1 <= 19) {     // 64-bit C1, 64-bit 10^ind
395 
              __mul_64x64_to_128MACH (C1, C1.w[0], ten2k64[ind]);
396 
            } else {    // 20 <= q1 <= 33 => 128-bit C1, 64-bit 10^ind
397 
              __mul_128x64_to_128 (C1, ten2k64[ind], C1);
398 
            }
399 
          } else {      // if 20 <= P34 - q1 <= 33 <=> 1 <= q1 <= 14 =>
400 
            // 64-bit C1, 128-bit 10^ind
401 
            __mul_128x64_to_128 (C1, C1.w[0], ten2k128[ind - 20]);
402 
          }
403 
          x_exp = EXP_MIN;
404 
        }
405 
      }
406 
      if (x_sign) {     // x < 0
407 
        // add 1 ulp (add 1 to the significand)
408 
        C1.w[0]++;
409 
        if (C1.w[0] == 0)
410 
          C1.w[1]++;
411 
        if (C1.w[1] == 0x0001ed09bead87c0ull && C1.w[0] == 0x378d8e6400000000ull) {      // if  C1 = 10^34
412 
          C1.w[1] = 0x0000314dc6448d93ull;      // C1 = 10^33
413 
          C1.w[0] = 0x38c15b0a00000000ull;
414 
          x_exp = x_exp + EXP_P1;
415 
        }
416 
      } else {  // x > 0
417 
        // subtract 1 ulp (subtract 1 from the significand)
418 
        C1.w[0]--;
419 
        if (C1.w[0] == 0xffffffffffffffffull)
420 
          C1.w[1]--;
421 
        if (x_exp != 0 && C1.w[1] == 0x0000314dc6448d93ull && C1.w[0] == 0x38c15b09ffffffffull) { // if  C1 = 10^33 - 1
422 
          C1.w[1] = 0x0001ed09bead87c0ull;      // C1 = 10^34 - 1
423 
          C1.w[0] = 0x378d8e63ffffffffull;
424 
          x_exp = x_exp - EXP_P1;
425 
        }
426 
      }
427 
      // assemble the result
428 
      res.w[1] = x_sign | x_exp | C1.w[1];
429 
      res.w[0] = C1.w[0];
430 
    }   // end -MAXFP <= x <= -MINFP - 1 ulp OR MINFP <= x <= MAXFP - 1 ulp
431 
  }     // end x is not special and is not zero
432 
  BID_RETURN (res);
433 
}
434 
 
435 
/*****************************************************************************
436 
 *  BID128 nextafter
437 
 ****************************************************************************/
438 
 
439 
#if DECIMAL_CALL_BY_REFERENCE
440 
void
441 
bid128_nextafter (UINT128 * pres, UINT128 * px,
442 
                  UINT128 *
443 
                  py _EXC_FLAGS_PARAM _EXC_MASKS_PARAM _EXC_INFO_PARAM)
444 
{
445 
  UINT128 x = *px;
446 
  UINT128 y = *py;
447 
  UINT128 xnswp = *px;
448 
  UINT128 ynswp = *py;
449 
#else
450 
UINT128
451 
bid128_nextafter (UINT128 x,
452 
                  UINT128 y _EXC_FLAGS_PARAM _EXC_MASKS_PARAM
453 
                  _EXC_INFO_PARAM) {
454 
  UINT128 xnswp = x;
455 
  UINT128 ynswp = y;
456 
#endif
457 
 
458 
  UINT128 res;
459 
  UINT128 tmp1, tmp2, tmp3;
460 
  FPSC tmp_fpsf = 0;             // dummy fpsf for calls to comparison functions
461 
  int res1, res2;
462 
  UINT64 x_exp;
463 
 
464 
 
465 
  BID_SWAP128 (x);
466 
  BID_SWAP128 (y);
467 
  // check for NaNs
468 
  if (((x.w[1] & MASK_SPECIAL) == MASK_SPECIAL)
469 
      || ((y.w[1] & MASK_SPECIAL) == MASK_SPECIAL)) {
470 
    // x is special or y is special
471 
    if ((x.w[1] & MASK_NAN) == MASK_NAN) {      // x is NAN
472 
      // if x = NaN, then res = Q (x)
473 
      // check first for non-canonical NaN payload
474 
      if (((x.w[1] & 0x00003fffffffffffull) > 0x0000314dc6448d93ull) ||
475 
          (((x.w[1] & 0x00003fffffffffffull) == 0x0000314dc6448d93ull)
476 
           && (x.w[0] > 0x38c15b09ffffffffull))) {
477 
        x.w[1] = x.w[1] & 0xffffc00000000000ull;
478 
        x.w[0] = 0x0ull;
479 
      }
480 
      if ((x.w[1] & MASK_SNAN) == MASK_SNAN) {  // x is SNAN
481 
        // set invalid flag
482 
        *pfpsf |= INVALID_EXCEPTION;
483 
        // return quiet (x)
484 
        res.w[1] = x.w[1] & 0xfc003fffffffffffull;      // clear out also G[6]-G[16]
485 
        res.w[0] = x.w[0];
486 
      } else {  // x is QNaN
487 
        // return x
488 
        res.w[1] = x.w[1] & 0xfc003fffffffffffull;      // clear out G[6]-G[16]
489 
        res.w[0] = x.w[0];
490 
        if ((y.w[1] & MASK_SNAN) == MASK_SNAN) {        // y is SNAN
491 
          // set invalid flag
492 
          *pfpsf |= INVALID_EXCEPTION;
493 
        }
494 
      }
495 
      BID_RETURN (res)
496 
    } else if ((y.w[1] & MASK_NAN) == MASK_NAN) {       // y is NAN
497 
      // if x = NaN, then res = Q (x)
498 
      // check first for non-canonical NaN payload
499 
      if (((y.w[1] & 0x00003fffffffffffull) > 0x0000314dc6448d93ull) ||
500 
          (((y.w[1] & 0x00003fffffffffffull) == 0x0000314dc6448d93ull)
501 
           && (y.w[0] > 0x38c15b09ffffffffull))) {
502 
        y.w[1] = y.w[1] & 0xffffc00000000000ull;
503 
        y.w[0] = 0x0ull;
504 
      }
505 
      if ((y.w[1] & MASK_SNAN) == MASK_SNAN) {  // y is SNAN
506 
        // set invalid flag
507 
        *pfpsf |= INVALID_EXCEPTION;
508 
        // return quiet (x)
509 
        res.w[1] = y.w[1] & 0xfc003fffffffffffull;      // clear out also G[6]-G[16]
510 
        res.w[0] = y.w[0];
511 
      } else {  // x is QNaN
512 
        // return x
513 
        res.w[1] = y.w[1] & 0xfc003fffffffffffull;      // clear out G[6]-G[16]
514 
        res.w[0] = y.w[0];
515 
      }
516 
      BID_RETURN (res)
517 
    } else {    // at least one is infinity
518 
      if ((x.w[1] & MASK_ANY_INF) == MASK_INF) {        // x = inf
519 
        x.w[1] = x.w[1] & (MASK_SIGN | MASK_INF);
520 
        x.w[0] = 0x0ull;
521 
      }
522 
      if ((y.w[1] & MASK_ANY_INF) == MASK_INF) {        // y = inf
523 
        y.w[1] = y.w[1] & (MASK_SIGN | MASK_INF);
524 
        y.w[0] = 0x0ull;
525 
      }
526 
    }
527 
  }
528 
  // neither x nor y is NaN
529 
 
530 
  // if not infinity, check for non-canonical values x (treated as zero)
531 
  if ((x.w[1] & MASK_ANY_INF) != MASK_INF) {    // x != inf
532 
    if ((x.w[1] & 0x6000000000000000ull) == 0x6000000000000000ull) {    // G0_G1=11
533 
      // non-canonical
534 
      x_exp = (x.w[1] << 2) & MASK_EXP; // biased and shifted left 49 bits
535 
      x.w[1] = (x.w[1] & MASK_SIGN) | x_exp;
536 
      x.w[0] = 0x0ull;
537 
    } else {    // G0_G1 != 11
538 
      x_exp = x.w[1] & MASK_EXP;        // biased and shifted left 49 bits
539 
      if ((x.w[1] & MASK_COEFF) > 0x0001ed09bead87c0ull ||
540 
          ((x.w[1] & MASK_COEFF) == 0x0001ed09bead87c0ull
541 
           && x.w[0] > 0x378d8e63ffffffffull)) {
542 
        // x is non-canonical if coefficient is larger than 10^34 -1
543 
        x.w[1] = (x.w[1] & MASK_SIGN) | x_exp;
544 
        x.w[0] = 0x0ull;
545 
      } else {  // canonical
546 
        ;
547 
      }
548 
    }
549 
  }
550 
  // no need to check for non-canonical y
551 
 
552 
  // neither x nor y is NaN
553 
  tmp_fpsf = *pfpsf;    // save fpsf
554 
#if DECIMAL_CALL_BY_REFERENCE
555 
  bid128_quiet_equal (&res1, &xnswp,
556 
                      &ynswp _EXC_FLAGS_ARG _EXC_MASKS_ARG
557 
                      _EXC_INFO_ARG);
558 
  bid128_quiet_greater (&res2, &xnswp,
559 
                        &ynswp _EXC_FLAGS_ARG _EXC_MASKS_ARG
560 
                        _EXC_INFO_ARG);
561 
#else
562 
  res1 =
563 
    bid128_quiet_equal (xnswp,
564 
                        ynswp _EXC_FLAGS_ARG _EXC_MASKS_ARG
565 
                        _EXC_INFO_ARG);
566 
  res2 =
567 
    bid128_quiet_greater (xnswp,
568 
                          ynswp _EXC_FLAGS_ARG _EXC_MASKS_ARG
569 
                          _EXC_INFO_ARG);
570 
#endif
571 
  *pfpsf = tmp_fpsf;    // restore fpsf
572 
 
573 
  if (res1) {   // x = y
574 
    // return x with the sign of y
575 
    res.w[1] =
576 
      (x.w[1] & 0x7fffffffffffffffull) | (y.
577 
                                          w[1] & 0x8000000000000000ull);
578 
    res.w[0] = x.w[0];
579 
  } else if (res2) {    // x > y
580 
#if DECIMAL_CALL_BY_REFERENCE
581 
    bid128_nextdown (&res,
582 
                     &xnswp _EXC_FLAGS_ARG _EXC_MASKS_ARG
583 
                     _EXC_INFO_ARG);
584 
#else
585 
    res =
586 
      bid128_nextdown (xnswp _EXC_FLAGS_ARG _EXC_MASKS_ARG
587 
                       _EXC_INFO_ARG);
588 
#endif
589 
    BID_SWAP128 (res);
590 
  } else {      // x < y
591 
#if DECIMAL_CALL_BY_REFERENCE
592 
    bid128_nextup (&res,
593 
                   &xnswp _EXC_FLAGS_ARG _EXC_MASKS_ARG _EXC_INFO_ARG);
594 
#else
595 
    res =
596 
      bid128_nextup (xnswp _EXC_FLAGS_ARG _EXC_MASKS_ARG _EXC_INFO_ARG);
597 
#endif
598 
    BID_SWAP128 (res);
599 
  }
600 
  // if the operand x is finite but the result is infinite, signal
601 
  // overflow and inexact
602 
  if (((x.w[1] & MASK_SPECIAL) != MASK_SPECIAL)
603 
      && ((res.w[1] & MASK_SPECIAL) == MASK_SPECIAL)) {
604 
    // set the inexact flag
605 
    *pfpsf |= INEXACT_EXCEPTION;
606 
    // set the overflow flag
607 
    *pfpsf |= OVERFLOW_EXCEPTION;
608 
  }
609 
  // if the result is in (-10^emin, 10^emin), and is different from the
610 
  // operand x, signal underflow and inexact
611 
  tmp1.w[HIGH_128W] = 0x0000314dc6448d93ull;
612 
  tmp1.w[LOW_128W] = 0x38c15b0a00000000ull;     // +100...0[34] * 10^emin
613 
  tmp2.w[HIGH_128W] = res.w[1] & 0x7fffffffffffffffull;
614 
  tmp2.w[LOW_128W] = res.w[0];
615 
  tmp3.w[HIGH_128W] = res.w[1];
616 
  tmp3.w[LOW_128W] = res.w[0];
617 
  tmp_fpsf = *pfpsf;    // save fpsf
618 
#if DECIMAL_CALL_BY_REFERENCE
619 
  bid128_quiet_greater (&res1, &tmp1,
620 
                        &tmp2 _EXC_FLAGS_ARG _EXC_MASKS_ARG
621 
                        _EXC_INFO_ARG);
622 
  bid128_quiet_not_equal (&res2, &xnswp,
623 
                          &tmp3 _EXC_FLAGS_ARG _EXC_MASKS_ARG
624 
                          _EXC_INFO_ARG);
625 
#else
626 
  res1 =
627 
    bid128_quiet_greater (tmp1,
628 
                          tmp2 _EXC_FLAGS_ARG _EXC_MASKS_ARG
629 
                          _EXC_INFO_ARG);
630 
  res2 =
631 
    bid128_quiet_not_equal (xnswp,
632 
                            tmp3 _EXC_FLAGS_ARG _EXC_MASKS_ARG
633 
                            _EXC_INFO_ARG);
634 
#endif
635 
  *pfpsf = tmp_fpsf;    // restore fpsf
636 
  if (res1 && res2) {
637 
    // set the inexact flag
638 
    *pfpsf |= INEXACT_EXCEPTION;
639 
    // set the underflow flag
640 
    *pfpsf |= UNDERFLOW_EXCEPTION;
641 
  }
642 
  BID_RETURN (res);
643 
}

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