diff options
author | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-16 18:20:36 -0400 |
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committer | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-16 18:20:36 -0400 |
commit | 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch) | |
tree | 0bba044c4ce775e45a88a51686b5d9f90697ea9d /arch/parisc/math-emu/dfdiv.c |
Linux-2.6.12-rc2v2.6.12-rc2
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.
Let it rip!
Diffstat (limited to 'arch/parisc/math-emu/dfdiv.c')
-rw-r--r-- | arch/parisc/math-emu/dfdiv.c | 400 |
1 files changed, 400 insertions, 0 deletions
diff --git a/arch/parisc/math-emu/dfdiv.c b/arch/parisc/math-emu/dfdiv.c new file mode 100644 index 000000000000..d7d4bec0e76f --- /dev/null +++ b/arch/parisc/math-emu/dfdiv.c | |||
@@ -0,0 +1,400 @@ | |||
1 | /* | ||
2 | * Linux/PA-RISC Project (http://www.parisc-linux.org/) | ||
3 | * | ||
4 | * Floating-point emulation code | ||
5 | * Copyright (C) 2001 Hewlett-Packard (Paul Bame) <bame@debian.org> | ||
6 | * | ||
7 | * This program is free software; you can redistribute it and/or modify | ||
8 | * it under the terms of the GNU General Public License as published by | ||
9 | * the Free Software Foundation; either version 2, or (at your option) | ||
10 | * any later version. | ||
11 | * | ||
12 | * This program is distributed in the hope that it will be useful, | ||
13 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | ||
14 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | ||
15 | * GNU General Public License for more details. | ||
16 | * | ||
17 | * You should have received a copy of the GNU General Public License | ||
18 | * along with this program; if not, write to the Free Software | ||
19 | * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA | ||
20 | */ | ||
21 | /* | ||
22 | * BEGIN_DESC | ||
23 | * | ||
24 | * File: | ||
25 | * @(#) pa/spmath/dfdiv.c $Revision: 1.1 $ | ||
26 | * | ||
27 | * Purpose: | ||
28 | * Double Precision Floating-point Divide | ||
29 | * | ||
30 | * External Interfaces: | ||
31 | * dbl_fdiv(srcptr1,srcptr2,dstptr,status) | ||
32 | * | ||
33 | * Internal Interfaces: | ||
34 | * | ||
35 | * Theory: | ||
36 | * <<please update with a overview of the operation of this file>> | ||
37 | * | ||
38 | * END_DESC | ||
39 | */ | ||
40 | |||
41 | |||
42 | #include "float.h" | ||
43 | #include "dbl_float.h" | ||
44 | |||
45 | /* | ||
46 | * Double Precision Floating-point Divide | ||
47 | */ | ||
48 | |||
49 | int | ||
50 | dbl_fdiv (dbl_floating_point * srcptr1, dbl_floating_point * srcptr2, | ||
51 | dbl_floating_point * dstptr, unsigned int *status) | ||
52 | { | ||
53 | register unsigned int opnd1p1, opnd1p2, opnd2p1, opnd2p2; | ||
54 | register unsigned int opnd3p1, opnd3p2, resultp1, resultp2; | ||
55 | register int dest_exponent, count; | ||
56 | register boolean inexact = FALSE, guardbit = FALSE, stickybit = FALSE; | ||
57 | boolean is_tiny; | ||
58 | |||
59 | Dbl_copyfromptr(srcptr1,opnd1p1,opnd1p2); | ||
60 | Dbl_copyfromptr(srcptr2,opnd2p1,opnd2p2); | ||
61 | /* | ||
62 | * set sign bit of result | ||
63 | */ | ||
64 | if (Dbl_sign(opnd1p1) ^ Dbl_sign(opnd2p1)) | ||
65 | Dbl_setnegativezerop1(resultp1); | ||
66 | else Dbl_setzerop1(resultp1); | ||
67 | /* | ||
68 | * check first operand for NaN's or infinity | ||
69 | */ | ||
70 | if (Dbl_isinfinity_exponent(opnd1p1)) { | ||
71 | if (Dbl_iszero_mantissa(opnd1p1,opnd1p2)) { | ||
72 | if (Dbl_isnotnan(opnd2p1,opnd2p2)) { | ||
73 | if (Dbl_isinfinity(opnd2p1,opnd2p2)) { | ||
74 | /* | ||
75 | * invalid since both operands | ||
76 | * are infinity | ||
77 | */ | ||
78 | if (Is_invalidtrap_enabled()) | ||
79 | return(INVALIDEXCEPTION); | ||
80 | Set_invalidflag(); | ||
81 | Dbl_makequietnan(resultp1,resultp2); | ||
82 | Dbl_copytoptr(resultp1,resultp2,dstptr); | ||
83 | return(NOEXCEPTION); | ||
84 | } | ||
85 | /* | ||
86 | * return infinity | ||
87 | */ | ||
88 | Dbl_setinfinity_exponentmantissa(resultp1,resultp2); | ||
89 | Dbl_copytoptr(resultp1,resultp2,dstptr); | ||
90 | return(NOEXCEPTION); | ||
91 | } | ||
92 | } | ||
93 | else { | ||
94 | /* | ||
95 | * is NaN; signaling or quiet? | ||
96 | */ | ||
97 | if (Dbl_isone_signaling(opnd1p1)) { | ||
98 | /* trap if INVALIDTRAP enabled */ | ||
99 | if (Is_invalidtrap_enabled()) | ||
100 | return(INVALIDEXCEPTION); | ||
101 | /* make NaN quiet */ | ||
102 | Set_invalidflag(); | ||
103 | Dbl_set_quiet(opnd1p1); | ||
104 | } | ||
105 | /* | ||
106 | * is second operand a signaling NaN? | ||
107 | */ | ||
108 | else if (Dbl_is_signalingnan(opnd2p1)) { | ||
109 | /* trap if INVALIDTRAP enabled */ | ||
110 | if (Is_invalidtrap_enabled()) | ||
111 | return(INVALIDEXCEPTION); | ||
112 | /* make NaN quiet */ | ||
113 | Set_invalidflag(); | ||
114 | Dbl_set_quiet(opnd2p1); | ||
115 | Dbl_copytoptr(opnd2p1,opnd2p2,dstptr); | ||
116 | return(NOEXCEPTION); | ||
117 | } | ||
118 | /* | ||
119 | * return quiet NaN | ||
120 | */ | ||
121 | Dbl_copytoptr(opnd1p1,opnd1p2,dstptr); | ||
122 | return(NOEXCEPTION); | ||
123 | } | ||
124 | } | ||
125 | /* | ||
126 | * check second operand for NaN's or infinity | ||
127 | */ | ||
128 | if (Dbl_isinfinity_exponent(opnd2p1)) { | ||
129 | if (Dbl_iszero_mantissa(opnd2p1,opnd2p2)) { | ||
130 | /* | ||
131 | * return zero | ||
132 | */ | ||
133 | Dbl_setzero_exponentmantissa(resultp1,resultp2); | ||
134 | Dbl_copytoptr(resultp1,resultp2,dstptr); | ||
135 | return(NOEXCEPTION); | ||
136 | } | ||
137 | /* | ||
138 | * is NaN; signaling or quiet? | ||
139 | */ | ||
140 | if (Dbl_isone_signaling(opnd2p1)) { | ||
141 | /* trap if INVALIDTRAP enabled */ | ||
142 | if (Is_invalidtrap_enabled()) return(INVALIDEXCEPTION); | ||
143 | /* make NaN quiet */ | ||
144 | Set_invalidflag(); | ||
145 | Dbl_set_quiet(opnd2p1); | ||
146 | } | ||
147 | /* | ||
148 | * return quiet NaN | ||
149 | */ | ||
150 | Dbl_copytoptr(opnd2p1,opnd2p2,dstptr); | ||
151 | return(NOEXCEPTION); | ||
152 | } | ||
153 | /* | ||
154 | * check for division by zero | ||
155 | */ | ||
156 | if (Dbl_iszero_exponentmantissa(opnd2p1,opnd2p2)) { | ||
157 | if (Dbl_iszero_exponentmantissa(opnd1p1,opnd1p2)) { | ||
158 | /* invalid since both operands are zero */ | ||
159 | if (Is_invalidtrap_enabled()) return(INVALIDEXCEPTION); | ||
160 | Set_invalidflag(); | ||
161 | Dbl_makequietnan(resultp1,resultp2); | ||
162 | Dbl_copytoptr(resultp1,resultp2,dstptr); | ||
163 | return(NOEXCEPTION); | ||
164 | } | ||
165 | if (Is_divisionbyzerotrap_enabled()) | ||
166 | return(DIVISIONBYZEROEXCEPTION); | ||
167 | Set_divisionbyzeroflag(); | ||
168 | Dbl_setinfinity_exponentmantissa(resultp1,resultp2); | ||
169 | Dbl_copytoptr(resultp1,resultp2,dstptr); | ||
170 | return(NOEXCEPTION); | ||
171 | } | ||
172 | /* | ||
173 | * Generate exponent | ||
174 | */ | ||
175 | dest_exponent = Dbl_exponent(opnd1p1) - Dbl_exponent(opnd2p1) + DBL_BIAS; | ||
176 | |||
177 | /* | ||
178 | * Generate mantissa | ||
179 | */ | ||
180 | if (Dbl_isnotzero_exponent(opnd1p1)) { | ||
181 | /* set hidden bit */ | ||
182 | Dbl_clear_signexponent_set_hidden(opnd1p1); | ||
183 | } | ||
184 | else { | ||
185 | /* check for zero */ | ||
186 | if (Dbl_iszero_mantissa(opnd1p1,opnd1p2)) { | ||
187 | Dbl_setzero_exponentmantissa(resultp1,resultp2); | ||
188 | Dbl_copytoptr(resultp1,resultp2,dstptr); | ||
189 | return(NOEXCEPTION); | ||
190 | } | ||
191 | /* is denormalized, want to normalize */ | ||
192 | Dbl_clear_signexponent(opnd1p1); | ||
193 | Dbl_leftshiftby1(opnd1p1,opnd1p2); | ||
194 | Dbl_normalize(opnd1p1,opnd1p2,dest_exponent); | ||
195 | } | ||
196 | /* opnd2 needs to have hidden bit set with msb in hidden bit */ | ||
197 | if (Dbl_isnotzero_exponent(opnd2p1)) { | ||
198 | Dbl_clear_signexponent_set_hidden(opnd2p1); | ||
199 | } | ||
200 | else { | ||
201 | /* is denormalized; want to normalize */ | ||
202 | Dbl_clear_signexponent(opnd2p1); | ||
203 | Dbl_leftshiftby1(opnd2p1,opnd2p2); | ||
204 | while (Dbl_iszero_hiddenhigh7mantissa(opnd2p1)) { | ||
205 | dest_exponent+=8; | ||
206 | Dbl_leftshiftby8(opnd2p1,opnd2p2); | ||
207 | } | ||
208 | if (Dbl_iszero_hiddenhigh3mantissa(opnd2p1)) { | ||
209 | dest_exponent+=4; | ||
210 | Dbl_leftshiftby4(opnd2p1,opnd2p2); | ||
211 | } | ||
212 | while (Dbl_iszero_hidden(opnd2p1)) { | ||
213 | dest_exponent++; | ||
214 | Dbl_leftshiftby1(opnd2p1,opnd2p2); | ||
215 | } | ||
216 | } | ||
217 | |||
218 | /* Divide the source mantissas */ | ||
219 | |||
220 | /* | ||
221 | * A non-restoring divide algorithm is used. | ||
222 | */ | ||
223 | Twoword_subtract(opnd1p1,opnd1p2,opnd2p1,opnd2p2); | ||
224 | Dbl_setzero(opnd3p1,opnd3p2); | ||
225 | for (count=1; count <= DBL_P && (opnd1p1 || opnd1p2); count++) { | ||
226 | Dbl_leftshiftby1(opnd1p1,opnd1p2); | ||
227 | Dbl_leftshiftby1(opnd3p1,opnd3p2); | ||
228 | if (Dbl_iszero_sign(opnd1p1)) { | ||
229 | Dbl_setone_lowmantissap2(opnd3p2); | ||
230 | Twoword_subtract(opnd1p1,opnd1p2,opnd2p1,opnd2p2); | ||
231 | } | ||
232 | else { | ||
233 | Twoword_add(opnd1p1, opnd1p2, opnd2p1, opnd2p2); | ||
234 | } | ||
235 | } | ||
236 | if (count <= DBL_P) { | ||
237 | Dbl_leftshiftby1(opnd3p1,opnd3p2); | ||
238 | Dbl_setone_lowmantissap2(opnd3p2); | ||
239 | Dbl_leftshift(opnd3p1,opnd3p2,(DBL_P-count)); | ||
240 | if (Dbl_iszero_hidden(opnd3p1)) { | ||
241 | Dbl_leftshiftby1(opnd3p1,opnd3p2); | ||
242 | dest_exponent--; | ||
243 | } | ||
244 | } | ||
245 | else { | ||
246 | if (Dbl_iszero_hidden(opnd3p1)) { | ||
247 | /* need to get one more bit of result */ | ||
248 | Dbl_leftshiftby1(opnd1p1,opnd1p2); | ||
249 | Dbl_leftshiftby1(opnd3p1,opnd3p2); | ||
250 | if (Dbl_iszero_sign(opnd1p1)) { | ||
251 | Dbl_setone_lowmantissap2(opnd3p2); | ||
252 | Twoword_subtract(opnd1p1,opnd1p2,opnd2p1,opnd2p2); | ||
253 | } | ||
254 | else { | ||
255 | Twoword_add(opnd1p1,opnd1p2,opnd2p1,opnd2p2); | ||
256 | } | ||
257 | dest_exponent--; | ||
258 | } | ||
259 | if (Dbl_iszero_sign(opnd1p1)) guardbit = TRUE; | ||
260 | stickybit = Dbl_allp1(opnd1p1) || Dbl_allp2(opnd1p2); | ||
261 | } | ||
262 | inexact = guardbit | stickybit; | ||
263 | |||
264 | /* | ||
265 | * round result | ||
266 | */ | ||
267 | if (inexact && (dest_exponent > 0 || Is_underflowtrap_enabled())) { | ||
268 | Dbl_clear_signexponent(opnd3p1); | ||
269 | switch (Rounding_mode()) { | ||
270 | case ROUNDPLUS: | ||
271 | if (Dbl_iszero_sign(resultp1)) | ||
272 | Dbl_increment(opnd3p1,opnd3p2); | ||
273 | break; | ||
274 | case ROUNDMINUS: | ||
275 | if (Dbl_isone_sign(resultp1)) | ||
276 | Dbl_increment(opnd3p1,opnd3p2); | ||
277 | break; | ||
278 | case ROUNDNEAREST: | ||
279 | if (guardbit && (stickybit || | ||
280 | Dbl_isone_lowmantissap2(opnd3p2))) { | ||
281 | Dbl_increment(opnd3p1,opnd3p2); | ||
282 | } | ||
283 | } | ||
284 | if (Dbl_isone_hidden(opnd3p1)) dest_exponent++; | ||
285 | } | ||
286 | Dbl_set_mantissa(resultp1,resultp2,opnd3p1,opnd3p2); | ||
287 | |||
288 | /* | ||
289 | * Test for overflow | ||
290 | */ | ||
291 | if (dest_exponent >= DBL_INFINITY_EXPONENT) { | ||
292 | /* trap if OVERFLOWTRAP enabled */ | ||
293 | if (Is_overflowtrap_enabled()) { | ||
294 | /* | ||
295 | * Adjust bias of result | ||
296 | */ | ||
297 | Dbl_setwrapped_exponent(resultp1,dest_exponent,ovfl); | ||
298 | Dbl_copytoptr(resultp1,resultp2,dstptr); | ||
299 | if (inexact) | ||
300 | if (Is_inexacttrap_enabled()) | ||
301 | return(OVERFLOWEXCEPTION | INEXACTEXCEPTION); | ||
302 | else Set_inexactflag(); | ||
303 | return(OVERFLOWEXCEPTION); | ||
304 | } | ||
305 | Set_overflowflag(); | ||
306 | /* set result to infinity or largest number */ | ||
307 | Dbl_setoverflow(resultp1,resultp2); | ||
308 | inexact = TRUE; | ||
309 | } | ||
310 | /* | ||
311 | * Test for underflow | ||
312 | */ | ||
313 | else if (dest_exponent <= 0) { | ||
314 | /* trap if UNDERFLOWTRAP enabled */ | ||
315 | if (Is_underflowtrap_enabled()) { | ||
316 | /* | ||
317 | * Adjust bias of result | ||
318 | */ | ||
319 | Dbl_setwrapped_exponent(resultp1,dest_exponent,unfl); | ||
320 | Dbl_copytoptr(resultp1,resultp2,dstptr); | ||
321 | if (inexact) | ||
322 | if (Is_inexacttrap_enabled()) | ||
323 | return(UNDERFLOWEXCEPTION | INEXACTEXCEPTION); | ||
324 | else Set_inexactflag(); | ||
325 | return(UNDERFLOWEXCEPTION); | ||
326 | } | ||
327 | |||
328 | /* Determine if should set underflow flag */ | ||
329 | is_tiny = TRUE; | ||
330 | if (dest_exponent == 0 && inexact) { | ||
331 | switch (Rounding_mode()) { | ||
332 | case ROUNDPLUS: | ||
333 | if (Dbl_iszero_sign(resultp1)) { | ||
334 | Dbl_increment(opnd3p1,opnd3p2); | ||
335 | if (Dbl_isone_hiddenoverflow(opnd3p1)) | ||
336 | is_tiny = FALSE; | ||
337 | Dbl_decrement(opnd3p1,opnd3p2); | ||
338 | } | ||
339 | break; | ||
340 | case ROUNDMINUS: | ||
341 | if (Dbl_isone_sign(resultp1)) { | ||
342 | Dbl_increment(opnd3p1,opnd3p2); | ||
343 | if (Dbl_isone_hiddenoverflow(opnd3p1)) | ||
344 | is_tiny = FALSE; | ||
345 | Dbl_decrement(opnd3p1,opnd3p2); | ||
346 | } | ||
347 | break; | ||
348 | case ROUNDNEAREST: | ||
349 | if (guardbit && (stickybit || | ||
350 | Dbl_isone_lowmantissap2(opnd3p2))) { | ||
351 | Dbl_increment(opnd3p1,opnd3p2); | ||
352 | if (Dbl_isone_hiddenoverflow(opnd3p1)) | ||
353 | is_tiny = FALSE; | ||
354 | Dbl_decrement(opnd3p1,opnd3p2); | ||
355 | } | ||
356 | break; | ||
357 | } | ||
358 | } | ||
359 | |||
360 | /* | ||
361 | * denormalize result or set to signed zero | ||
362 | */ | ||
363 | stickybit = inexact; | ||
364 | Dbl_denormalize(opnd3p1,opnd3p2,dest_exponent,guardbit, | ||
365 | stickybit,inexact); | ||
366 | |||
367 | /* return rounded number */ | ||
368 | if (inexact) { | ||
369 | switch (Rounding_mode()) { | ||
370 | case ROUNDPLUS: | ||
371 | if (Dbl_iszero_sign(resultp1)) { | ||
372 | Dbl_increment(opnd3p1,opnd3p2); | ||
373 | } | ||
374 | break; | ||
375 | case ROUNDMINUS: | ||
376 | if (Dbl_isone_sign(resultp1)) { | ||
377 | Dbl_increment(opnd3p1,opnd3p2); | ||
378 | } | ||
379 | break; | ||
380 | case ROUNDNEAREST: | ||
381 | if (guardbit && (stickybit || | ||
382 | Dbl_isone_lowmantissap2(opnd3p2))) { | ||
383 | Dbl_increment(opnd3p1,opnd3p2); | ||
384 | } | ||
385 | break; | ||
386 | } | ||
387 | if (is_tiny) Set_underflowflag(); | ||
388 | } | ||
389 | Dbl_set_exponentmantissa(resultp1,resultp2,opnd3p1,opnd3p2); | ||
390 | } | ||
391 | else Dbl_set_exponent(resultp1,dest_exponent); | ||
392 | Dbl_copytoptr(resultp1,resultp2,dstptr); | ||
393 | |||
394 | /* check for inexact */ | ||
395 | if (inexact) { | ||
396 | if (Is_inexacttrap_enabled()) return(INEXACTEXCEPTION); | ||
397 | else Set_inexactflag(); | ||
398 | } | ||
399 | return(NOEXCEPTION); | ||
400 | } | ||