xref: /illumos-gate/usr/src/lib/libc/port/fp/fconvert.c (revision 7257d1b4)
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 (the "License").
6  * You may not use this file except in compliance with the License.
7  *
8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9  * or http://www.opensolaris.org/os/licensing.
10  * See the License for the specific language governing permissions
11  * and limitations under the License.
12  *
13  * When distributing Covered Code, include this CDDL HEADER in each
14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15  * If applicable, add the following below this CDDL HEADER, with the
16  * fields enclosed by brackets "[]" replaced with your own identifying
17  * information: Portions Copyright [yyyy] [name of copyright owner]
18  *
19  * CDDL HEADER END
20  */
21 
22 /*
23  * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
24  * Use is subject to license terms.
25  */
26 
27 #pragma ident	"%Z%%M%	%I%	%E% SMI"
28 
29 #include "lint.h"
30 #include "base_conversion.h"
31 #include <sys/types.h>
32 #include "libc.h"
33 
34 char *
fconvert(double arg,int ndigits,int * decpt,int * sign,char * buf)35 fconvert(double arg, int ndigits, int *decpt, int *sign, char *buf)
36 {
37 	decimal_mode    dm;
38 	decimal_record  dr;
39 	fp_exception_field_type ef;
40 	int		i;
41 
42 #if defined(__sparc)
43 	dm.rd = _QgetRD();
44 #elif defined(__i386) || defined(__amd64)
45 	dm.rd = __xgetRD();
46 #else
47 #error Unknown architecture
48 #endif
49 	dm.df = fixed_form;	/* F format. */
50 	if (ndigits <= -DECIMAL_STRING_LENGTH)
51 		ndigits = -DECIMAL_STRING_LENGTH + 1;
52 	else if (ndigits >= DECIMAL_STRING_LENGTH)
53 		ndigits = DECIMAL_STRING_LENGTH - 1;
54 	dm.ndigits = ndigits;	/* Number of digits after point. */
55 	double_to_decimal(&arg, &dm, &dr, &ef);
56 	*sign = dr.sign;
57 	switch (dr.fpclass) {
58 	case fp_normal:
59 	case fp_subnormal:
60 		*decpt = dr.exponent + dr.ndigits;
61 		for (i = 0; i < dr.ndigits; i++)
62 			buf[i] = dr.ds[i];
63 		/*
64 		 * Pad with zeroes if we didn't get all the digits
65 		 * we asked for.
66 		 */
67 		if (ndigits > 0 && dr.exponent > -ndigits) {
68 			while (i < dr.ndigits + dr.exponent + ndigits)
69 				buf[i++] = '0';
70 		}
71 		buf[i] = 0;
72 		break;
73 	case fp_zero:
74 		*decpt = 0;
75 		buf[0] = '0';
76 		for (i = 1; i < ndigits; i++)
77 			buf[i] = '0';
78 		buf[i] = 0;
79 		break;
80 	default:
81 		*decpt = 0;
82 		__infnanstring(dr.fpclass, ndigits, buf);
83 		break;
84 	}
85 	return (buf);
86 }
87 
88 char *
sfconvert(single * arg,int ndigits,int * decpt,int * sign,char * buf)89 sfconvert(single *arg, int ndigits, int *decpt, int *sign, char *buf)
90 {
91 	decimal_mode    dm;
92 	decimal_record  dr;
93 	fp_exception_field_type ef;
94 	int		i;
95 
96 #if defined(__sparc)
97 	dm.rd = _QgetRD();
98 #elif defined(__i386) || defined(__amd64)
99 	dm.rd = __xgetRD();
100 #else
101 #error Unknown architecture
102 #endif
103 	dm.df = fixed_form;	/* F format. */
104 	if (ndigits <= -DECIMAL_STRING_LENGTH)
105 		ndigits = -DECIMAL_STRING_LENGTH + 1;
106 	else if (ndigits >= DECIMAL_STRING_LENGTH)
107 		ndigits = DECIMAL_STRING_LENGTH - 1;
108 	dm.ndigits = ndigits;	/* Number of digits after point. */
109 	single_to_decimal(arg, &dm, &dr, &ef);
110 	*sign = dr.sign;
111 	switch (dr.fpclass) {
112 	case fp_normal:
113 	case fp_subnormal:
114 		*decpt = dr.exponent + dr.ndigits;
115 		for (i = 0; i < dr.ndigits; i++)
116 			buf[i] = dr.ds[i];
117 		/*
118 		 * Pad with zeroes if we didn't get all the digits
119 		 * we asked for.
120 		 */
121 		if (ndigits > 0 && dr.exponent > -ndigits) {
122 			while (i < dr.ndigits + dr.exponent + ndigits)
123 				buf[i++] = '0';
124 		}
125 		buf[i] = 0;
126 		break;
127 	case fp_zero:
128 		*decpt = 0;
129 		buf[0] = '0';
130 		for (i = 1; i < ndigits; i++)
131 			buf[i] = '0';
132 		buf[i] = 0;
133 		break;
134 	default:
135 		*decpt = 0;
136 		__infnanstring(dr.fpclass, ndigits, buf);
137 		break;
138 	}
139 	return (buf);
140 }
141 
142 char *
qfconvert(quadruple * arg,int ndigits,int * decpt,int * sign,char * buf)143 qfconvert(quadruple *arg, int ndigits, int *decpt, int *sign, char *buf)
144 {
145 	decimal_mode    dm;
146 	decimal_record  dr;
147 	fp_exception_field_type ef;
148 	int		i;
149 
150 #if defined(__sparc)
151 	dm.rd = _QgetRD();
152 #elif defined(__i386) || defined(__amd64)
153 	dm.rd = __xgetRD();
154 #else
155 #error Unknown architecture
156 #endif
157 	dm.df = fixed_form;	/* F format. */
158 	if (ndigits <= -DECIMAL_STRING_LENGTH)
159 		ndigits = -DECIMAL_STRING_LENGTH + 1;
160 	else if (ndigits >= DECIMAL_STRING_LENGTH)
161 		ndigits = DECIMAL_STRING_LENGTH - 1;
162 	dm.ndigits = ndigits;	/* Number of digits after point. */
163 #if defined(__sparc)
164 	quadruple_to_decimal(arg, &dm, &dr, &ef);
165 #elif defined(__i386) || defined(__amd64)
166 	extended_to_decimal((extended *)arg, &dm, &dr, &ef);
167 #else
168 #error Unknown architecture
169 #endif
170 	*sign = dr.sign;
171 	if (ef & (1 << fp_overflow)) {
172 		/*
173 		 * *_to_decimal raises overflow whenever dr.ds isn't large
174 		 * enough to hold all the digits requested.  For float and
175 		 * double, this can only happen when the requested format
176 		 * would require trailing zeroes, in which case fconvert
177 		 * and sfconvert just add them.  For long double, the arg-
178 		 * ument might be large enough that even the nonzero digits
179 		 * would overflow dr.ds, so we punt instead.  (We could
180 		 * distinguish these two cases, but it doesn't seem worth
181 		 * changing things now, particularly since no real appli-
182 		 * cation prints floating point numbers to 500 digits.)
183 		 */
184 		*decpt = 0;
185 		buf[0] = 0;
186 		return (buf);
187 	}
188 	switch (dr.fpclass) {
189 	case fp_normal:
190 	case fp_subnormal:
191 		*decpt = dr.exponent + dr.ndigits;
192 		for (i = 0; i < dr.ndigits; i++)
193 			buf[i] = dr.ds[i];
194 		buf[i] = 0;
195 		break;
196 	case fp_zero:
197 		*decpt = 0;
198 		buf[0] = '0';
199 		for (i = 1; i < ndigits; i++)
200 			buf[i] = '0';
201 		buf[i] = 0;
202 		break;
203 	default:
204 		*decpt = 0;
205 		__infnanstring(dr.fpclass, ndigits, buf);
206 		break;
207 	}
208 	return (buf);
209 }
210