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 #include "quad.h"
28
29 #ifdef __sparcv9
30 #define _Q_qtos _Qp_qtos
31 #endif
32
33 /*
34 * _Q_qtos(x) returns (float)*x.
35 */
36 float
_Q_qtos(const union longdouble * x)37 _Q_qtos(const union longdouble *x)
38 {
39 union {
40 float f;
41 unsigned int l;
42 } u;
43 unsigned int xm, round, sticky, fsr, rm;
44 int subnormal, e;
45
46 xm = x->l.msw & 0x7fffffff;
47
48 /* get the rounding mode, fudging directed rounding modes */
49 /* as though the result were positive */
50 __quad_getfsrp(&fsr);
51 rm = fsr >> 30;
52 if (x->l.msw & 0x80000000)
53 rm ^= (rm >> 1);
54
55 /* handle nan, inf, and out-of-range cases */
56 if (xm >= 0x407f0000) {
57 if (xm >= 0x7fff0000) {
58 if ((xm & 0xffff) | x->l.frac2 | x->l.frac3 |
59 x->l.frac4) {
60 /* x is nan */
61 u.l = (x->l.msw & 0x80000000) | 0x7fc00000;
62 u.l |= ((xm & 0x7fff) << 7) |
63 (x->l.frac2 >> 25);
64 if (!(xm & 0x8000)) {
65 /* snan, signal invalid */
66 if (fsr & FSR_NVM) {
67 __quad_fqtos(x, &u.f);
68 } else {
69 fsr = (fsr & ~FSR_CEXC) |
70 FSR_NVA | FSR_NVC;
71 __quad_setfsrp(&fsr);
72 }
73 }
74 return (u.f);
75 }
76 /* x is inf */
77 u.l = (x->l.msw & 0x80000000) | 0x7f800000;
78 return (u.f);
79 }
80 /* x is too big, overflow */
81 if (rm == FSR_RN || rm == FSR_RP)
82 u.l = 0x7f800000;
83 else
84 u.l = 0x7f7fffff;
85 u.l |= (x->l.msw & 0x80000000);
86 if (fsr & (FSR_OFM | FSR_NXM)) {
87 __quad_fqtos(x, &u.f);
88 } else {
89 fsr = (fsr & ~FSR_CEXC) | FSR_OFA | FSR_OFC |
90 FSR_NXA | FSR_NXC;
91 __quad_setfsrp(&fsr);
92 }
93 return (u.f);
94 }
95
96 subnormal = 0;
97 if (xm < 0x3f810000) {
98 if (xm < 0x3f690000) {
99 if (QUAD_ISZERO(*x)) {
100 u.l = (x->l.msw & 0x80000000);
101 return (u.f);
102 }
103 /* x is too small, underflow */
104 u.l = ((rm == FSR_RP)? 1 : 0);
105 u.l |= (x->l.msw & 0x80000000);
106 if (fsr & (FSR_UFM | FSR_NXM)) {
107 __quad_fqtos(x, &u.f);
108 } else {
109 fsr = (fsr & ~FSR_CEXC) | FSR_UFA | FSR_UFC |
110 FSR_NXA | FSR_NXC;
111 __quad_setfsrp(&fsr);
112 }
113 return (u.f);
114 }
115
116 /* x is in the subnormal range for single */
117 subnormal = 1;
118 u.l = 0x800000 | ((xm & 0xffff) << 7) | (x->l.frac2 >> 25);
119 e = 0x3f80 - (xm >> 16);
120 round = u.l & (1 << e);
121 sticky = (u.l & ((1 << e) - 1)) | (x->l.frac2 & 0x1ffffff) |
122 x->l.frac3 | x->l.frac4;
123 u.l >>= e + 1;
124 } else {
125 /* x is in the normal range for single */
126 u.l = ((xm - 0x3f800000) << 7) | (x->l.frac2 >> 25);
127 round = x->l.frac2 & 0x1000000;
128 sticky = (x->l.frac2 & 0xffffff) | x->l.frac3 | x->l.frac4;
129 }
130
131 /* see if we need to round */
132 fsr &= ~FSR_CEXC;
133 if (round | sticky) {
134 fsr |= FSR_NXC;
135 if (subnormal)
136 fsr |= FSR_UFC;
137
138 /* round up if necessary */
139 if (rm == FSR_RP || (rm == FSR_RN && round && (sticky ||
140 (u.l & 1)))) {
141 /* round up and check for overflow */
142 if (++u.l >= 0x7f800000)
143 fsr |= FSR_OFC;
144 }
145 }
146
147 /* if result is exact and subnormal but underflow trapping is */
148 /* enabled, signal underflow */
149 else if (subnormal && (fsr & FSR_UFM))
150 fsr |= FSR_UFC;
151
152 /* attach the sign and raise exceptions as need be */
153 u.l |= (x->l.msw & 0x80000000);
154 if ((fsr & FSR_CEXC) & (fsr >> 23)) {
155 __quad_setfsrp(&fsr);
156 __quad_fqtos(x, &u.f);
157 } else {
158 fsr |= (fsr & 0x1f) << 5;
159 __quad_setfsrp(&fsr);
160 }
161 return (u.f);
162 }
163