1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
|
/* $OpenBSD: fcnvff.c,v 1.3 1998/07/02 19:05:18 mickey Exp $ */
/*
* Copyright 1996 1995 by Open Software Foundation, Inc.
* All Rights Reserved
*
* Permission to use, copy, modify, and distribute this software and
* its documentation for any purpose and without fee is hereby granted,
* provided that the above copyright notice appears in all copies and
* that both the copyright notice and this permission notice appear in
* supporting documentation.
*
* OSF DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE
* INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE.
*
* IN NO EVENT SHALL OSF BE LIABLE FOR ANY SPECIAL, INDIRECT, OR
* CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
* LOSS OF USE, DATA OR PROFITS, WHETHER IN ACTION OF CONTRACT,
* NEGLIGENCE, OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION
* WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*
*/
/*
* pmk1.1
*/
/*
* (c) Copyright 1986 HEWLETT-PACKARD COMPANY
*
* To anyone who acknowledges that this file is provided "AS IS"
* without any express or implied warranty:
* permission to use, copy, modify, and distribute this file
* for any purpose is hereby granted without fee, provided that
* the above copyright notice and this notice appears in all
* copies, and that the name of Hewlett-Packard Company not be
* used in advertising or publicity pertaining to distribution
* of the software without specific, written prior permission.
* Hewlett-Packard Company makes no representations about the
* suitability of this software for any purpose.
*/
#include "../spmath/float.h"
#include "../spmath/sgl_float.h"
#include "../spmath/dbl_float.h"
#include "../spmath/cnv_float.h"
/*
* Single Floating-point to Double Floating-point
*/
/*ARGSUSED*/
int
sgl_to_dbl_fcnvff(srcptr,nullptr,dstptr,status)
sgl_floating_point *srcptr;
dbl_floating_point *dstptr;
void *nullptr;
unsigned int *status;
{
register unsigned int src, resultp1, resultp2;
register int src_exponent;
src = *srcptr;
src_exponent = Sgl_exponent(src);
Dbl_allp1(resultp1) = Sgl_all(src); /* set sign of result */
/*
* Test for NaN or infinity
*/
if (src_exponent == SGL_INFINITY_EXPONENT) {
/*
* determine if NaN or infinity
*/
if (Sgl_iszero_mantissa(src)) {
/*
* is infinity; want to return double infinity
*/
Dbl_setinfinity_exponentmantissa(resultp1,resultp2);
Dbl_copytoptr(resultp1,resultp2,dstptr);
return(NOEXCEPTION);
}
else {
/*
* is NaN; signaling or quiet?
*/
if (Sgl_isone_signaling(src)) {
/* trap if INVALIDTRAP enabled */
if (Is_invalidtrap_enabled())
return(INVALIDEXCEPTION);
/* make NaN quiet */
else {
Set_invalidflag();
Sgl_set_quiet(src);
}
}
/*
* NaN is quiet, return as double NaN
*/
Dbl_setinfinity_exponent(resultp1);
Sgl_to_dbl_mantissa(src,resultp1,resultp2);
Dbl_copytoptr(resultp1,resultp2,dstptr);
return(NOEXCEPTION);
}
}
/*
* Test for zero or denormalized
*/
if (src_exponent == 0) {
/*
* determine if zero or denormalized
*/
if (Sgl_isnotzero_mantissa(src)) {
/*
* is denormalized; want to normalize
*/
Sgl_clear_signexponent(src);
Sgl_leftshiftby1(src);
Sgl_normalize(src,src_exponent);
Sgl_to_dbl_exponent(src_exponent,resultp1);
Sgl_to_dbl_mantissa(src,resultp1,resultp2);
}
else {
Dbl_setzero_exponentmantissa(resultp1,resultp2);
}
Dbl_copytoptr(resultp1,resultp2,dstptr);
return(NOEXCEPTION);
}
/*
* No special cases, just complete the conversion
*/
Sgl_to_dbl_exponent(src_exponent, resultp1);
Sgl_to_dbl_mantissa(Sgl_mantissa(src), resultp1,resultp2);
Dbl_copytoptr(resultp1,resultp2,dstptr);
return(NOEXCEPTION);
}
/*
* Double Floating-point to Single Floating-point
*/
/*ARGSUSED*/
int
dbl_to_sgl_fcnvff(srcptr,nullptr,dstptr,status)
dbl_floating_point *srcptr;
sgl_floating_point *dstptr;
void *nullptr;
unsigned int *status;
{
register unsigned int srcp1, srcp2, result;
register int src_exponent, dest_exponent, dest_mantissa;
register boolean inexact = FALSE, guardbit = FALSE, stickybit = FALSE;
register boolean lsb_odd = FALSE;
boolean is_tiny;
Dbl_copyfromptr(srcptr,srcp1,srcp2);
src_exponent = Dbl_exponent(srcp1);
Sgl_all(result) = Dbl_allp1(srcp1); /* set sign of result */
/*
* Test for NaN or infinity
*/
if (src_exponent == DBL_INFINITY_EXPONENT) {
/*
* determine if NaN or infinity
*/
if (Dbl_iszero_mantissa(srcp1,srcp2)) {
/*
* is infinity; want to return single infinity
*/
Sgl_setinfinity_exponentmantissa(result);
*dstptr = result;
return(NOEXCEPTION);
}
/*
* is NaN; signaling or quiet?
*/
if (Dbl_isone_signaling(srcp1)) {
/* trap if INVALIDTRAP enabled */
if (Is_invalidtrap_enabled()) return(INVALIDEXCEPTION);
else {
Set_invalidflag();
/* make NaN quiet */
Dbl_set_quiet(srcp1);
}
}
/*
* NaN is quiet, return as single NaN
*/
Sgl_setinfinity_exponent(result);
Sgl_set_mantissa(result,Dallp1(srcp1)<<3 | Dallp2(srcp2)>>29);
if (Sgl_iszero_mantissa(result)) Sgl_set_quiet(result);
*dstptr = result;
return(NOEXCEPTION);
}
/*
* Generate result
*/
Dbl_to_sgl_exponent(src_exponent,dest_exponent);
if (dest_exponent > 0) {
Dbl_to_sgl_mantissa(srcp1,srcp2,dest_mantissa,inexact,guardbit,
stickybit,lsb_odd);
}
else {
if (Dbl_iszero_exponentmantissa(srcp1,srcp2)){
Sgl_setzero_exponentmantissa(result);
*dstptr = result;
return(NOEXCEPTION);
}
if (Is_underflowtrap_enabled()) {
Dbl_to_sgl_mantissa(srcp1,srcp2,dest_mantissa,inexact,
guardbit,stickybit,lsb_odd);
}
else {
/* compute result, determine inexact info,
* and set Underflowflag if appropriate
*/
Dbl_to_sgl_denormalized(srcp1,srcp2,dest_exponent,
dest_mantissa,inexact,guardbit,stickybit,lsb_odd,
is_tiny);
}
}
/*
* Now round result if not exact
*/
if (inexact) {
switch (Rounding_mode()) {
case ROUNDPLUS:
if (Sgl_iszero_sign(result)) dest_mantissa++;
break;
case ROUNDMINUS:
if (Sgl_isone_sign(result)) dest_mantissa++;
break;
case ROUNDNEAREST:
if (guardbit) {
if (stickybit || lsb_odd) dest_mantissa++;
}
}
}
Sgl_set_exponentmantissa(result,dest_mantissa);
/*
* check for mantissa overflow after rounding
*/
if ((dest_exponent>0 || Is_underflowtrap_enabled()) &&
Sgl_isone_hidden(result)) dest_exponent++;
/*
* Test for overflow
*/
if (dest_exponent >= SGL_INFINITY_EXPONENT) {
/* trap if OVERFLOWTRAP enabled */
if (Is_overflowtrap_enabled()) {
/*
* Check for gross overflow
*/
if (dest_exponent >= SGL_INFINITY_EXPONENT+SGL_WRAP)
return(UNIMPLEMENTEDEXCEPTION);
/*
* Adjust bias of result
*/
Sgl_setwrapped_exponent(result,dest_exponent,ovfl);
*dstptr = result;
if (inexact) {
if (Is_inexacttrap_enabled())
return(OVERFLOWEXCEPTION|INEXACTEXCEPTION);
else
Set_inexactflag();
}
return(OVERFLOWEXCEPTION);
}
Set_overflowflag();
inexact = TRUE;
/* set result to infinity or largest number */
Sgl_setoverflow(result);
}
/*
* Test for underflow
*/
else if (dest_exponent <= 0) {
/* trap if UNDERFLOWTRAP enabled */
if (Is_underflowtrap_enabled()) {
/*
* Check for gross underflow
*/
if (dest_exponent <= -(SGL_WRAP))
return(UNIMPLEMENTEDEXCEPTION);
/*
* Adjust bias of result
*/
Sgl_setwrapped_exponent(result,dest_exponent,unfl);
*dstptr = result;
if (inexact) {
if (Is_inexacttrap_enabled())
return(UNDERFLOWEXCEPTION|INEXACTEXCEPTION);
else
Set_inexactflag();
}
return(UNDERFLOWEXCEPTION);
}
/*
* result is denormalized or signed zero
*/
if (inexact && is_tiny) Set_underflowflag();
}
else Sgl_set_exponent(result,dest_exponent);
*dstptr = result;
/*
* Trap if inexact trap is enabled
*/
if (inexact) {
if (Is_inexacttrap_enabled()) return(INEXACTEXCEPTION);
else Set_inexactflag();
}
return(NOEXCEPTION);
}
|
