1 /* $NetBSD: fcnvff.c,v 1.6 2012/02/04 17:03:09 skrll Exp $ */
2
3 /* $OpenBSD: fcnvff.c,v 1.5 2001/03/29 03:58:18 mickey Exp $ */
4
5 /*
6 * Copyright 1996 1995 by Open Software Foundation, Inc.
7 * All Rights Reserved
8 *
9 * Permission to use, copy, modify, and distribute this software and
10 * its documentation for any purpose and without fee is hereby granted,
11 * provided that the above copyright notice appears in all copies and
12 * that both the copyright notice and this permission notice appear in
13 * supporting documentation.
14 *
15 * OSF DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE
16 * INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
17 * FOR A PARTICULAR PURPOSE.
18 *
19 * IN NO EVENT SHALL OSF BE LIABLE FOR ANY SPECIAL, INDIRECT, OR
20 * CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
21 * LOSS OF USE, DATA OR PROFITS, WHETHER IN ACTION OF CONTRACT,
22 * NEGLIGENCE, OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION
23 * WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
24 *
25 */
26 /*
27 * pmk1.1
28 */
29 /*
30 * (c) Copyright 1986 HEWLETT-PACKARD COMPANY
31 *
32 * To anyone who acknowledges that this file is provided "AS IS"
33 * without any express or implied warranty:
34 * permission to use, copy, modify, and distribute this file
35 * for any purpose is hereby granted without fee, provided that
36 * the above copyright notice and this notice appears in all
37 * copies, and that the name of Hewlett-Packard Company not be
38 * used in advertising or publicity pertaining to distribution
39 * of the software without specific, written prior permission.
40 * Hewlett-Packard Company makes no representations about the
41 * suitability of this software for any purpose.
42 */
43
44 #include <sys/cdefs.h>
45 __KERNEL_RCSID(0, "$NetBSD: fcnvff.c,v 1.6 2012/02/04 17:03:09 skrll Exp $");
46
47 #include "../spmath/float.h"
48 #include "../spmath/sgl_float.h"
49 #include "../spmath/dbl_float.h"
50 #include "../spmath/cnv_float.h"
51
52 /*
53 * Single Floating-point to Double Floating-point
54 */
55 /*ARGSUSED*/
56 int
sgl_to_dbl_fcnvff(sgl_floating_point * srcptr,dbl_floating_point * dstptr,unsigned int * status)57 sgl_to_dbl_fcnvff(sgl_floating_point *srcptr, dbl_floating_point *dstptr,
58 unsigned int *status)
59 {
60 register unsigned int src, resultp1, resultp2;
61 register int src_exponent;
62
63 src = *srcptr;
64 src_exponent = Sgl_exponent(src);
65 Dbl_allp1(resultp1) = Sgl_all(src); /* set sign of result */
66 /*
67 * Test for NaN or infinity
68 */
69 if (src_exponent == SGL_INFINITY_EXPONENT) {
70 /*
71 * determine if NaN or infinity
72 */
73 if (Sgl_iszero_mantissa(src)) {
74 /*
75 * is infinity; want to return double infinity
76 */
77 Dbl_setinfinity_exponentmantissa(resultp1,resultp2);
78 Dbl_copytoptr(resultp1,resultp2,dstptr);
79 return(NOEXCEPTION);
80 }
81 else {
82 /*
83 * is NaN; signaling or quiet?
84 */
85 if (Sgl_isone_signaling(src)) {
86 /* trap if INVALIDTRAP enabled */
87 if (Is_invalidtrap_enabled())
88 return(INVALIDEXCEPTION);
89 /* make NaN quiet */
90 else {
91 Set_invalidflag();
92 Sgl_set_quiet(src);
93 }
94 }
95 /*
96 * NaN is quiet, return as double NaN
97 */
98 Dbl_setinfinity_exponent(resultp1);
99 Sgl_to_dbl_mantissa(src,resultp1,resultp2);
100 Dbl_copytoptr(resultp1,resultp2,dstptr);
101 return(NOEXCEPTION);
102 }
103 }
104 /*
105 * Test for zero or denormalized
106 */
107 if (src_exponent == 0) {
108 /*
109 * determine if zero or denormalized
110 */
111 if (Sgl_isnotzero_mantissa(src)) {
112 /*
113 * is denormalized; want to normalize
114 */
115 Sgl_clear_signexponent(src);
116 Sgl_leftshiftby1(src);
117 Sgl_normalize(src,src_exponent);
118 Sgl_to_dbl_exponent(src_exponent,resultp1);
119 Sgl_to_dbl_mantissa(src,resultp1,resultp2);
120 }
121 else {
122 Dbl_setzero_exponentmantissa(resultp1,resultp2);
123 }
124 Dbl_copytoptr(resultp1,resultp2,dstptr);
125 return(NOEXCEPTION);
126 }
127 /*
128 * No special cases, just complete the conversion
129 */
130 Sgl_to_dbl_exponent(src_exponent, resultp1);
131 Sgl_to_dbl_mantissa(Sgl_mantissa(src), resultp1,resultp2);
132 Dbl_copytoptr(resultp1,resultp2,dstptr);
133 return(NOEXCEPTION);
134 }
135
136 /*
137 * Double Floating-point to Single Floating-point
138 */
139 /*ARGSUSED*/
140 int
dbl_to_sgl_fcnvff(dbl_floating_point * srcptr,sgl_floating_point * dstptr,unsigned int * status)141 dbl_to_sgl_fcnvff(dbl_floating_point *srcptr, sgl_floating_point *dstptr,
142 unsigned int *status)
143 {
144 register unsigned int srcp1, srcp2, result;
145 register int src_exponent, dest_exponent, dest_mantissa;
146 register int inexact = false, guardbit = false, stickybit = false;
147 register int lsb_odd = false;
148 int is_tiny = false;
149
150 Dbl_copyfromptr(srcptr,srcp1,srcp2);
151 src_exponent = Dbl_exponent(srcp1);
152 Sgl_all(result) = Dbl_allp1(srcp1); /* set sign of result */
153 /*
154 * Test for NaN or infinity
155 */
156 if (src_exponent == DBL_INFINITY_EXPONENT) {
157 /*
158 * determine if NaN or infinity
159 */
160 if (Dbl_iszero_mantissa(srcp1,srcp2)) {
161 /*
162 * is infinity; want to return single infinity
163 */
164 Sgl_setinfinity_exponentmantissa(result);
165 *dstptr = result;
166 return(NOEXCEPTION);
167 }
168 /*
169 * is NaN; signaling or quiet?
170 */
171 if (Dbl_isone_signaling(srcp1)) {
172 /* trap if INVALIDTRAP enabled */
173 if (Is_invalidtrap_enabled()) return(INVALIDEXCEPTION);
174 else {
175 Set_invalidflag();
176 /* make NaN quiet */
177 Dbl_set_quiet(srcp1);
178 }
179 }
180 /*
181 * NaN is quiet, return as single NaN
182 */
183 Sgl_setinfinity_exponent(result);
184 Sgl_set_mantissa(result,Dallp1(srcp1)<<3 | Dallp2(srcp2)>>29);
185 if (Sgl_iszero_mantissa(result)) Sgl_set_quiet(result);
186 *dstptr = result;
187 return(NOEXCEPTION);
188 }
189 /*
190 * Generate result
191 */
192 Dbl_to_sgl_exponent(src_exponent,dest_exponent);
193 if (dest_exponent > 0) {
194 Dbl_to_sgl_mantissa(srcp1,srcp2,dest_mantissa,inexact,guardbit,
195 stickybit,lsb_odd);
196 }
197 else {
198 if (Dbl_iszero_exponentmantissa(srcp1,srcp2)){
199 Sgl_setzero_exponentmantissa(result);
200 *dstptr = result;
201 return(NOEXCEPTION);
202 }
203 if (Is_underflowtrap_enabled()) {
204 Dbl_to_sgl_mantissa(srcp1,srcp2,dest_mantissa,inexact,
205 guardbit,stickybit,lsb_odd);
206 }
207 else {
208 /* compute result, determine inexact info,
209 * and set Underflowflag if appropriate
210 */
211 Dbl_to_sgl_denormalized(srcp1,srcp2,dest_exponent,
212 dest_mantissa,inexact,guardbit,stickybit,lsb_odd,
213 is_tiny);
214 }
215 }
216 /*
217 * Now round result if not exact
218 */
219 if (inexact) {
220 switch (Rounding_mode()) {
221 case ROUNDPLUS:
222 if (Sgl_iszero_sign(result)) dest_mantissa++;
223 break;
224 case ROUNDMINUS:
225 if (Sgl_isone_sign(result)) dest_mantissa++;
226 break;
227 case ROUNDNEAREST:
228 if (guardbit) {
229 if (stickybit || lsb_odd) dest_mantissa++;
230 }
231 }
232 }
233 Sgl_set_exponentmantissa(result,dest_mantissa);
234
235 /*
236 * check for mantissa overflow after rounding
237 */
238 if ((dest_exponent>0 || Is_underflowtrap_enabled()) &&
239 Sgl_isone_hidden(result)) dest_exponent++;
240
241 /*
242 * Test for overflow
243 */
244 if (dest_exponent >= SGL_INFINITY_EXPONENT) {
245 /* trap if OVERFLOWTRAP enabled */
246 if (Is_overflowtrap_enabled()) {
247 /*
248 * Check for gross overflow
249 */
250 if (dest_exponent >= SGL_INFINITY_EXPONENT+SGL_WRAP)
251 return(UNIMPLEMENTEDEXCEPTION);
252
253 /*
254 * Adjust bias of result
255 */
256 Sgl_setwrapped_exponent(result,dest_exponent,ovfl);
257 *dstptr = result;
258 if (inexact) {
259 if (Is_inexacttrap_enabled())
260 return(OVERFLOWEXCEPTION|INEXACTEXCEPTION);
261 else
262 Set_inexactflag();
263 }
264 return(OVERFLOWEXCEPTION);
265 }
266 Set_overflowflag();
267 inexact = true;
268 /* set result to infinity or largest number */
269 Sgl_setoverflow(result);
270 }
271 /*
272 * Test for underflow
273 */
274 else if (dest_exponent <= 0) {
275 /* trap if UNDERFLOWTRAP enabled */
276 if (Is_underflowtrap_enabled()) {
277 /*
278 * Check for gross underflow
279 */
280 if (dest_exponent <= -(SGL_WRAP))
281 return(UNIMPLEMENTEDEXCEPTION);
282 /*
283 * Adjust bias of result
284 */
285 Sgl_setwrapped_exponent(result,dest_exponent,unfl);
286 *dstptr = result;
287 if (inexact) {
288 if (Is_inexacttrap_enabled())
289 return(UNDERFLOWEXCEPTION|INEXACTEXCEPTION);
290 else
291 Set_inexactflag();
292 }
293 return(UNDERFLOWEXCEPTION);
294 }
295 /*
296 * result is denormalized or signed zero
297 */
298 if (inexact && is_tiny) Set_underflowflag();
299
300 }
301 else Sgl_set_exponent(result,dest_exponent);
302 *dstptr = result;
303 /*
304 * Trap if inexact trap is enabled
305 */
306 if (inexact) {
307 if (Is_inexacttrap_enabled())
308 return(INEXACTEXCEPTION);
309 else
310 Set_inexactflag();
311 }
312 return(NOEXCEPTION);
313 }
314