1 /*
2 * CDDL HEADER START
3 *
4 * The contents of this file are subject to the terms of the
5 * Common Development and Distribution License, Version 1.0 only
6 * (the "License"). You may not use this file except in compliance
7 * with the License.
8 *
9 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
10 * or http://www.opensolaris.org/os/licensing.
11 * See the License for the specific language governing permissions
12 * and limitations under the License.
13 *
14 * When distributing Covered Code, include this CDDL HEADER in each
15 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
16 * If applicable, add the following below this CDDL HEADER, with the
17 * fields enclosed by brackets "[]" replaced with your own identifying
18 * information: Portions Copyright [yyyy] [name of copyright owner]
19 *
20 * CDDL HEADER END
21 */
22 /*
23 * Copyright (c) 1994-1997, by Sun Microsystems, Inc.
24 * All rights reserved.
25 */
26
27 #pragma ident "%Z%%M% %I% %E% SMI"
28
29 #include "quad.h"
30
31 #ifdef __sparcv9
32 #define _Q_qtos _Qp_qtos
33 #endif
34
35 /*
36 * _Q_qtos(x) returns (float)*x.
37 */
38 float
_Q_qtos(const union longdouble * x)39 _Q_qtos(const union longdouble *x)
40 {
41 union {
42 float f;
43 unsigned int l;
44 } u;
45 unsigned int xm, round, sticky, fsr, rm;
46 int subnormal, e;
47
48 xm = x->l.msw & 0x7fffffff;
49
50 /* get the rounding mode, fudging directed rounding modes */
51 /* as though the result were positive */
52 __quad_getfsrp(&fsr);
53 rm = fsr >> 30;
54 if (x->l.msw & 0x80000000)
55 rm ^= (rm >> 1);
56
57 /* handle nan, inf, and out-of-range cases */
58 if (xm >= 0x407f0000) {
59 if (xm >= 0x7fff0000) {
60 if ((xm & 0xffff) | x->l.frac2 | x->l.frac3 |
61 x->l.frac4) {
62 /* x is nan */
63 u.l = (x->l.msw & 0x80000000) | 0x7fc00000;
64 u.l |= ((xm & 0x7fff) << 7) |
65 (x->l.frac2 >> 25);
66 if (!(xm & 0x8000)) {
67 /* snan, signal invalid */
68 if (fsr & FSR_NVM) {
69 __quad_fqtos(x, &u.f);
70 } else {
71 fsr = (fsr & ~FSR_CEXC) |
72 FSR_NVA | FSR_NVC;
73 __quad_setfsrp(&fsr);
74 }
75 }
76 return (u.f);
77 }
78 /* x is inf */
79 u.l = (x->l.msw & 0x80000000) | 0x7f800000;
80 return (u.f);
81 }
82 /* x is too big, overflow */
83 if (rm == FSR_RN || rm == FSR_RP)
84 u.l = 0x7f800000;
85 else
86 u.l = 0x7f7fffff;
87 u.l |= (x->l.msw & 0x80000000);
88 if (fsr & (FSR_OFM | FSR_NXM)) {
89 __quad_fqtos(x, &u.f);
90 } else {
91 fsr = (fsr & ~FSR_CEXC) | FSR_OFA | FSR_OFC |
92 FSR_NXA | FSR_NXC;
93 __quad_setfsrp(&fsr);
94 }
95 return (u.f);
96 }
97
98 subnormal = 0;
99 if (xm < 0x3f810000) {
100 if (xm < 0x3f690000) {
101 if (QUAD_ISZERO(*x)) {
102 u.l = (x->l.msw & 0x80000000);
103 return (u.f);
104 }
105 /* x is too small, underflow */
106 u.l = ((rm == FSR_RP)? 1 : 0);
107 u.l |= (x->l.msw & 0x80000000);
108 if (fsr & (FSR_UFM | FSR_NXM)) {
109 __quad_fqtos(x, &u.f);
110 } else {
111 fsr = (fsr & ~FSR_CEXC) | FSR_UFA | FSR_UFC |
112 FSR_NXA | FSR_NXC;
113 __quad_setfsrp(&fsr);
114 }
115 return (u.f);
116 }
117
118 /* x is in the subnormal range for single */
119 subnormal = 1;
120 u.l = 0x800000 | ((xm & 0xffff) << 7) | (x->l.frac2 >> 25);
121 e = 0x3f80 - (xm >> 16);
122 round = u.l & (1 << e);
123 sticky = (u.l & ((1 << e) - 1)) | (x->l.frac2 & 0x1ffffff) |
124 x->l.frac3 | x->l.frac4;
125 u.l >>= e + 1;
126 } else {
127 /* x is in the normal range for single */
128 u.l = ((xm - 0x3f800000) << 7) | (x->l.frac2 >> 25);
129 round = x->l.frac2 & 0x1000000;
130 sticky = (x->l.frac2 & 0xffffff) | x->l.frac3 | x->l.frac4;
131 }
132
133 /* see if we need to round */
134 fsr &= ~FSR_CEXC;
135 if (round | sticky) {
136 fsr |= FSR_NXC;
137 if (subnormal)
138 fsr |= FSR_UFC;
139
140 /* round up if necessary */
141 if (rm == FSR_RP || (rm == FSR_RN && round && (sticky ||
142 (u.l & 1)))) {
143 /* round up and check for overflow */
144 if (++u.l >= 0x7f800000)
145 fsr |= FSR_OFC;
146 }
147 }
148
149 /* if result is exact and subnormal but underflow trapping is */
150 /* enabled, signal underflow */
151 else if (subnormal && (fsr & FSR_UFM))
152 fsr |= FSR_UFC;
153
154 /* attach the sign and raise exceptions as need be */
155 u.l |= (x->l.msw & 0x80000000);
156 if ((fsr & FSR_CEXC) & (fsr >> 23)) {
157 __quad_setfsrp(&fsr);
158 __quad_fqtos(x, &u.f);
159 } else {
160 fsr |= (fsr & 0x1f) << 5;
161 __quad_setfsrp(&fsr);
162 }
163 return (u.f);
164 }
165