1 /* Software floating-point emulation.
2    Definitions for IEEE Extended Precision.
3    Copyright (C) 1999,2006,2007,2012 Free Software Foundation, Inc.
4    This file is part of the GNU C Library.
5    Contributed by Jakub Jelinek (jj@ultra.linux.cz).
6 
7    The GNU C Library is free software; you can redistribute it and/or
8    modify it under the terms of the GNU Lesser General Public
9    License as published by the Free Software Foundation; either
10    version 2.1 of the License, or (at your option) any later version.
11 
12    In addition to the permissions in the GNU Lesser General Public
13    License, the Free Software Foundation gives you unlimited
14    permission to link the compiled version of this file into
15    combinations with other programs, and to distribute those
16    combinations without any restriction coming from the use of this
17    file.  (The Lesser General Public License restrictions do apply in
18    other respects; for example, they cover modification of the file,
19    and distribution when not linked into a combine executable.)
20 
21    The GNU C Library is distributed in the hope that it will be useful,
22    but WITHOUT ANY WARRANTY; without even the implied warranty of
23    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
24    Lesser General Public License for more details.
25 
26    You should have received a copy of the GNU Lesser General Public
27    License along with the GNU C Library; if not, see
28    <http://www.gnu.org/licenses/>.  */
29 
30 #if _FP_W_TYPE_SIZE < 32
31 #error "Here's a nickel, kid. Go buy yourself a real computer."
32 #endif
33 
34 #if _FP_W_TYPE_SIZE < 64
35 #define _FP_FRACTBITS_E         (4*_FP_W_TYPE_SIZE)
36 #else
37 #define _FP_FRACTBITS_E		(2*_FP_W_TYPE_SIZE)
38 #endif
39 
40 #define _FP_FRACBITS_E		64
41 #define _FP_FRACXBITS_E		(_FP_FRACTBITS_E - _FP_FRACBITS_E)
42 #define _FP_WFRACBITS_E		(_FP_WORKBITS + _FP_FRACBITS_E)
43 #define _FP_WFRACXBITS_E	(_FP_FRACTBITS_E - _FP_WFRACBITS_E)
44 #define _FP_EXPBITS_E		15
45 #define _FP_EXPBIAS_E		16383
46 #define _FP_EXPMAX_E		32767
47 
48 #define _FP_QNANBIT_E		\
49 	((_FP_W_TYPE)1 << (_FP_FRACBITS_E-2) % _FP_W_TYPE_SIZE)
50 #define _FP_QNANBIT_SH_E		\
51 	((_FP_W_TYPE)1 << (_FP_FRACBITS_E-2+_FP_WORKBITS) % _FP_W_TYPE_SIZE)
52 #define _FP_IMPLBIT_E		\
53 	((_FP_W_TYPE)1 << (_FP_FRACBITS_E-1) % _FP_W_TYPE_SIZE)
54 #define _FP_IMPLBIT_SH_E		\
55 	((_FP_W_TYPE)1 << (_FP_FRACBITS_E-1+_FP_WORKBITS) % _FP_W_TYPE_SIZE)
56 #define _FP_OVERFLOW_E		\
57 	((_FP_W_TYPE)1 << (_FP_WFRACBITS_E % _FP_W_TYPE_SIZE))
58 
59 typedef float XFtype __attribute__((mode(XF)));
60 
61 #if _FP_W_TYPE_SIZE < 64
62 
63 union _FP_UNION_E
64 {
65    XFtype flt;
66    struct _FP_STRUCT_LAYOUT
67    {
68 #if __BYTE_ORDER == __BIG_ENDIAN
69       unsigned long pad1 : _FP_W_TYPE_SIZE;
70       unsigned long pad2 : (_FP_W_TYPE_SIZE - 1 - _FP_EXPBITS_E);
71       unsigned long sign : 1;
72       unsigned long exp : _FP_EXPBITS_E;
73       unsigned long frac1 : _FP_W_TYPE_SIZE;
74       unsigned long frac0 : _FP_W_TYPE_SIZE;
75 #else
76       unsigned long frac0 : _FP_W_TYPE_SIZE;
77       unsigned long frac1 : _FP_W_TYPE_SIZE;
78       unsigned exp : _FP_EXPBITS_E;
79       unsigned sign : 1;
80 #endif /* not bigendian */
81    } bits __attribute__((packed));
82 };
83 
84 
85 #define FP_DECL_E(X)		_FP_DECL(4,X)
86 
87 #define FP_UNPACK_RAW_E(X, val)				\
88   do {							\
89     union _FP_UNION_E _flo; _flo.flt = (val);		\
90 							\
91     X##_f[2] = 0; X##_f[3] = 0;				\
92     X##_f[0] = _flo.bits.frac0;				\
93     X##_f[1] = _flo.bits.frac1;				\
94     X##_e  = _flo.bits.exp;				\
95     X##_s  = _flo.bits.sign;				\
96   } while (0)
97 
98 #define FP_UNPACK_RAW_EP(X, val)			\
99   do {							\
100     union _FP_UNION_E *_flo =				\
101     (union _FP_UNION_E *)(val);				\
102 							\
103     X##_f[2] = 0; X##_f[3] = 0;				\
104     X##_f[0] = _flo->bits.frac0;			\
105     X##_f[1] = _flo->bits.frac1;			\
106     X##_e  = _flo->bits.exp;				\
107     X##_s  = _flo->bits.sign;				\
108   } while (0)
109 
110 #define FP_PACK_RAW_E(val, X)				\
111   do {							\
112     union _FP_UNION_E _flo;				\
113 							\
114     if (X##_e) X##_f[1] |= _FP_IMPLBIT_E;		\
115     else X##_f[1] &= ~(_FP_IMPLBIT_E);			\
116     _flo.bits.frac0 = X##_f[0];				\
117     _flo.bits.frac1 = X##_f[1];				\
118     _flo.bits.exp   = X##_e;				\
119     _flo.bits.sign  = X##_s;				\
120 							\
121     (val) = _flo.flt;					\
122   } while (0)
123 
124 #define FP_PACK_RAW_EP(val, X)				\
125   do {							\
126     if (!FP_INHIBIT_RESULTS)				\
127       {							\
128 	union _FP_UNION_E *_flo =			\
129 	  (union _FP_UNION_E *)(val);			\
130 							\
131 	if (X##_e) X##_f[1] |= _FP_IMPLBIT_E;		\
132 	else X##_f[1] &= ~(_FP_IMPLBIT_E);		\
133 	_flo->bits.frac0 = X##_f[0];			\
134 	_flo->bits.frac1 = X##_f[1];			\
135 	_flo->bits.exp   = X##_e;			\
136 	_flo->bits.sign  = X##_s;			\
137       }							\
138   } while (0)
139 
140 #define FP_UNPACK_E(X,val)		\
141   do {					\
142     FP_UNPACK_RAW_E(X,val);		\
143     _FP_UNPACK_CANONICAL(E,4,X);	\
144   } while (0)
145 
146 #define FP_UNPACK_EP(X,val)		\
147   do {					\
148     FP_UNPACK_RAW_EP(X,val);		\
149     _FP_UNPACK_CANONICAL(E,4,X);	\
150   } while (0)
151 
152 #define FP_UNPACK_SEMIRAW_E(X,val)	\
153   do {					\
154     FP_UNPACK_RAW_E(X,val);		\
155     _FP_UNPACK_SEMIRAW(E,4,X);		\
156   } while (0)
157 
158 #define FP_UNPACK_SEMIRAW_EP(X,val)	\
159   do {					\
160     FP_UNPACK_RAW_EP(X,val);		\
161     _FP_UNPACK_SEMIRAW(E,4,X);		\
162   } while (0)
163 
164 #define FP_PACK_E(val,X)		\
165   do {					\
166     _FP_PACK_CANONICAL(E,4,X);		\
167     FP_PACK_RAW_E(val,X);		\
168   } while (0)
169 
170 #define FP_PACK_EP(val,X)		\
171   do {					\
172     _FP_PACK_CANONICAL(E,4,X);		\
173     FP_PACK_RAW_EP(val,X);		\
174   } while (0)
175 
176 #define FP_PACK_SEMIRAW_E(val,X)	\
177   do {					\
178     _FP_PACK_SEMIRAW(E,4,X);		\
179     FP_PACK_RAW_E(val,X);		\
180   } while (0)
181 
182 #define FP_PACK_SEMIRAW_EP(val,X)	\
183   do {					\
184     _FP_PACK_SEMIRAW(E,4,X);		\
185     FP_PACK_RAW_EP(val,X);		\
186   } while (0)
187 
188 #define FP_ISSIGNAN_E(X)	_FP_ISSIGNAN(E,4,X)
189 #define FP_NEG_E(R,X)		_FP_NEG(E,4,R,X)
190 #define FP_ADD_E(R,X,Y)		_FP_ADD(E,4,R,X,Y)
191 #define FP_SUB_E(R,X,Y)		_FP_SUB(E,4,R,X,Y)
192 #define FP_MUL_E(R,X,Y)		_FP_MUL(E,4,R,X,Y)
193 #define FP_DIV_E(R,X,Y)		_FP_DIV(E,4,R,X,Y)
194 #define FP_SQRT_E(R,X)		_FP_SQRT(E,4,R,X)
195 
196 /*
197  * Square root algorithms:
198  * We have just one right now, maybe Newton approximation
199  * should be added for those machines where division is fast.
200  * This has special _E version because standard _4 square
201  * root would not work (it has to start normally with the
202  * second word and not the first), but as we have to do it
203  * anyway, we optimize it by doing most of the calculations
204  * in two UWtype registers instead of four.
205  */
206 
207 #define _FP_SQRT_MEAT_E(R, S, T, X, q)			\
208   do {							\
209     q = (_FP_W_TYPE)1 << (_FP_W_TYPE_SIZE - 1);		\
210     _FP_FRAC_SRL_4(X, (_FP_WORKBITS));			\
211     while (q)						\
212       {							\
213 	T##_f[1] = S##_f[1] + q;			\
214 	if (T##_f[1] <= X##_f[1])			\
215 	  {						\
216 	    S##_f[1] = T##_f[1] + q;			\
217 	    X##_f[1] -= T##_f[1];			\
218 	    R##_f[1] += q;				\
219 	  }						\
220 	_FP_FRAC_SLL_2(X, 1);				\
221 	q >>= 1;					\
222       }							\
223     q = (_FP_W_TYPE)1 << (_FP_W_TYPE_SIZE - 1);		\
224     while (q)						\
225       {							\
226 	T##_f[0] = S##_f[0] + q;			\
227 	T##_f[1] = S##_f[1];				\
228 	if (T##_f[1] < X##_f[1] || 			\
229 	    (T##_f[1] == X##_f[1] &&			\
230 	     T##_f[0] <= X##_f[0]))			\
231 	  {						\
232 	    S##_f[0] = T##_f[0] + q;			\
233 	    S##_f[1] += (T##_f[0] > S##_f[0]);		\
234 	    _FP_FRAC_DEC_2(X, T);			\
235 	    R##_f[0] += q;				\
236 	  }						\
237 	_FP_FRAC_SLL_2(X, 1);				\
238 	q >>= 1;					\
239       }							\
240     _FP_FRAC_SLL_4(R, (_FP_WORKBITS));			\
241     if (X##_f[0] | X##_f[1])				\
242       {							\
243 	if (S##_f[1] < X##_f[1] || 			\
244 	    (S##_f[1] == X##_f[1] &&			\
245 	     S##_f[0] < X##_f[0]))			\
246 	  R##_f[0] |= _FP_WORK_ROUND;			\
247 	R##_f[0] |= _FP_WORK_STICKY;			\
248       }							\
249   } while (0)
250 
251 #define FP_CMP_E(r,X,Y,un)	_FP_CMP(E,4,r,X,Y,un)
252 #define FP_CMP_EQ_E(r,X,Y)	_FP_CMP_EQ(E,4,r,X,Y)
253 #define FP_CMP_UNORD_E(r,X,Y)	_FP_CMP_UNORD(E,4,r,X,Y)
254 
255 #define FP_TO_INT_E(r,X,rsz,rsg)	_FP_TO_INT(E,4,r,X,rsz,rsg)
256 #define FP_FROM_INT_E(X,r,rs,rt)	_FP_FROM_INT(E,4,X,r,rs,rt)
257 
258 #define _FP_FRAC_HIGH_E(X)	(X##_f[2])
259 #define _FP_FRAC_HIGH_RAW_E(X)	(X##_f[1])
260 
261 #else   /* not _FP_W_TYPE_SIZE < 64 */
262 union _FP_UNION_E
263 {
264   XFtype flt;
265   struct _FP_STRUCT_LAYOUT {
266 #if __BYTE_ORDER == __BIG_ENDIAN
267     _FP_W_TYPE pad  : (_FP_W_TYPE_SIZE - 1 - _FP_EXPBITS_E);
268     unsigned sign   : 1;
269     unsigned exp    : _FP_EXPBITS_E;
270     _FP_W_TYPE frac : _FP_W_TYPE_SIZE;
271 #else
272     _FP_W_TYPE frac : _FP_W_TYPE_SIZE;
273     unsigned exp    : _FP_EXPBITS_E;
274     unsigned sign   : 1;
275 #endif
276   } bits;
277 };
278 
279 #define FP_DECL_E(X)		_FP_DECL(2,X)
280 
281 #define FP_UNPACK_RAW_E(X, val)					\
282   do {								\
283     union _FP_UNION_E _flo; _flo.flt = (val);			\
284 								\
285     X##_f0 = _flo.bits.frac;					\
286     X##_f1 = 0;							\
287     X##_e = _flo.bits.exp;					\
288     X##_s = _flo.bits.sign;					\
289   } while (0)
290 
291 #define FP_UNPACK_RAW_EP(X, val)				\
292   do {								\
293     union _FP_UNION_E *_flo =					\
294       (union _FP_UNION_E *)(val);				\
295 								\
296     X##_f0 = _flo->bits.frac;					\
297     X##_f1 = 0;							\
298     X##_e = _flo->bits.exp;					\
299     X##_s = _flo->bits.sign;					\
300   } while (0)
301 
302 #define FP_PACK_RAW_E(val, X)					\
303   do {								\
304     union _FP_UNION_E _flo;					\
305 								\
306     if (X##_e) X##_f0 |= _FP_IMPLBIT_E;				\
307     else X##_f0 &= ~(_FP_IMPLBIT_E);				\
308     _flo.bits.frac = X##_f0;					\
309     _flo.bits.exp  = X##_e;					\
310     _flo.bits.sign = X##_s;					\
311 								\
312     (val) = _flo.flt;						\
313   } while (0)
314 
315 #define FP_PACK_RAW_EP(fs, val, X)				\
316   do {								\
317     if (!FP_INHIBIT_RESULTS)					\
318       {								\
319 	union _FP_UNION_E *_flo =				\
320 	  (union _FP_UNION_E *)(val);				\
321 								\
322 	if (X##_e) X##_f0 |= _FP_IMPLBIT_E;			\
323 	else X##_f0 &= ~(_FP_IMPLBIT_E);			\
324 	_flo->bits.frac = X##_f0;				\
325 	_flo->bits.exp  = X##_e;				\
326 	_flo->bits.sign = X##_s;				\
327       }								\
328   } while (0)
329 
330 
331 #define FP_UNPACK_E(X,val)		\
332   do {					\
333     FP_UNPACK_RAW_E(X,val);		\
334     _FP_UNPACK_CANONICAL(E,2,X);	\
335   } while (0)
336 
337 #define FP_UNPACK_EP(X,val)		\
338   do {					\
339     FP_UNPACK_RAW_EP(X,val);		\
340     _FP_UNPACK_CANONICAL(E,2,X);	\
341   } while (0)
342 
343 #define FP_UNPACK_SEMIRAW_E(X,val)	\
344   do {					\
345     FP_UNPACK_RAW_E(X,val);		\
346     _FP_UNPACK_SEMIRAW(E,2,X);		\
347   } while (0)
348 
349 #define FP_UNPACK_SEMIRAW_EP(X,val)	\
350   do {					\
351     FP_UNPACK_RAW_EP(X,val);		\
352     _FP_UNPACK_SEMIRAW(E,2,X);		\
353   } while (0)
354 
355 #define FP_PACK_E(val,X)		\
356   do {					\
357     _FP_PACK_CANONICAL(E,2,X);		\
358     FP_PACK_RAW_E(val,X);		\
359   } while (0)
360 
361 #define FP_PACK_EP(val,X)		\
362   do {					\
363     _FP_PACK_CANONICAL(E,2,X);		\
364     FP_PACK_RAW_EP(val,X);		\
365   } while (0)
366 
367 #define FP_PACK_SEMIRAW_E(val,X)	\
368   do {					\
369     _FP_PACK_SEMIRAW(E,2,X);		\
370     FP_PACK_RAW_E(val,X);		\
371   } while (0)
372 
373 #define FP_PACK_SEMIRAW_EP(val,X)	\
374   do {					\
375     _FP_PACK_SEMIRAW(E,2,X);		\
376     FP_PACK_RAW_EP(val,X);		\
377   } while (0)
378 
379 #define FP_ISSIGNAN_E(X)	_FP_ISSIGNAN(E,2,X)
380 #define FP_NEG_E(R,X)		_FP_NEG(E,2,R,X)
381 #define FP_ADD_E(R,X,Y)		_FP_ADD(E,2,R,X,Y)
382 #define FP_SUB_E(R,X,Y)		_FP_SUB(E,2,R,X,Y)
383 #define FP_MUL_E(R,X,Y)		_FP_MUL(E,2,R,X,Y)
384 #define FP_DIV_E(R,X,Y)		_FP_DIV(E,2,R,X,Y)
385 #define FP_SQRT_E(R,X)		_FP_SQRT(E,2,R,X)
386 
387 /*
388  * Square root algorithms:
389  * We have just one right now, maybe Newton approximation
390  * should be added for those machines where division is fast.
391  * We optimize it by doing most of the calculations
392  * in one UWtype registers instead of two, although we don't
393  * have to.
394  */
395 #define _FP_SQRT_MEAT_E(R, S, T, X, q)			\
396   do {							\
397     q = (_FP_W_TYPE)1 << (_FP_W_TYPE_SIZE - 1);		\
398     _FP_FRAC_SRL_2(X, (_FP_WORKBITS));			\
399     while (q)						\
400       {							\
401         T##_f0 = S##_f0 + q;				\
402         if (T##_f0 <= X##_f0)				\
403           {						\
404             S##_f0 = T##_f0 + q;			\
405             X##_f0 -= T##_f0;				\
406             R##_f0 += q;				\
407           }						\
408         _FP_FRAC_SLL_1(X, 1);				\
409         q >>= 1;					\
410       }							\
411     _FP_FRAC_SLL_2(R, (_FP_WORKBITS));			\
412     if (X##_f0)						\
413       {							\
414 	if (S##_f0 < X##_f0)				\
415 	  R##_f0 |= _FP_WORK_ROUND;			\
416 	R##_f0 |= _FP_WORK_STICKY;			\
417       }							\
418   } while (0)
419 
420 #define FP_CMP_E(r,X,Y,un)	_FP_CMP(E,2,r,X,Y,un)
421 #define FP_CMP_EQ_E(r,X,Y)	_FP_CMP_EQ(E,2,r,X,Y)
422 #define FP_CMP_UNORD_E(r,X,Y)	_FP_CMP_UNORD(E,2,r,X,Y)
423 
424 #define FP_TO_INT_E(r,X,rsz,rsg)	_FP_TO_INT(E,2,r,X,rsz,rsg)
425 #define FP_FROM_INT_E(X,r,rs,rt)	_FP_FROM_INT(E,2,X,r,rs,rt)
426 
427 #define _FP_FRAC_HIGH_E(X)	(X##_f1)
428 #define _FP_FRAC_HIGH_RAW_E(X)	(X##_f0)
429 
430 #endif /* not _FP_W_TYPE_SIZE < 64 */
431