xref: /openbmc/linux/arch/mips/math-emu/ieee754.c (revision 1da177e4)
1 /* ieee754 floating point arithmetic
2  * single and double precision
3  *
4  * BUGS
5  * not much dp done
6  * doesn't generate IEEE754_INEXACT
7  *
8  */
9 /*
10  * MIPS floating point support
11  * Copyright (C) 1994-2000 Algorithmics Ltd.
12  * http://www.algor.co.uk
13  *
14  * ########################################################################
15  *
16  *  This program is free software; you can distribute it and/or modify it
17  *  under the terms of the GNU General Public License (Version 2) as
18  *  published by the Free Software Foundation.
19  *
20  *  This program is distributed in the hope it will be useful, but WITHOUT
21  *  ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
22  *  FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
23  *  for more details.
24  *
25  *  You should have received a copy of the GNU General Public License along
26  *  with this program; if not, write to the Free Software Foundation, Inc.,
27  *  59 Temple Place - Suite 330, Boston MA 02111-1307, USA.
28  *
29  * ########################################################################
30  */
31 
32 
33 #include "ieee754int.h"
34 
35 #define DP_EBIAS	1023
36 #define DP_EMIN		(-1022)
37 #define DP_EMAX		1023
38 
39 #define SP_EBIAS	127
40 #define SP_EMIN		(-126)
41 #define SP_EMAX		127
42 
43 /* indexed by class */
44 const char *const ieee754_cname[] = {
45 	"Normal",
46 	"Zero",
47 	"Denormal",
48 	"Infinity",
49 	"QNaN",
50 	"SNaN",
51 };
52 
53 /* the control status register
54 */
55 struct ieee754_csr ieee754_csr;
56 
57 /* special constants
58 */
59 
60 
61 #if (defined(BYTE_ORDER) && BYTE_ORDER == LITTLE_ENDIAN) || defined(__MIPSEL__)
62 #define SPSTR(s,b,m) {m,b,s}
63 #define DPSTR(s,b,mh,ml) {ml,mh,b,s}
64 #endif
65 
66 #ifdef __MIPSEB__
67 #define SPSTR(s,b,m) {s,b,m}
68 #define DPSTR(s,b,mh,ml) {s,b,mh,ml}
69 #endif
70 
71 const struct ieee754dp_konst __ieee754dp_spcvals[] = {
72 	DPSTR(0, DP_EMIN - 1 + DP_EBIAS, 0, 0),	/* + zero   */
73 	DPSTR(1, DP_EMIN - 1 + DP_EBIAS, 0, 0),	/* - zero   */
74 	DPSTR(0, DP_EBIAS, 0, 0),	/* + 1.0   */
75 	DPSTR(1, DP_EBIAS, 0, 0),	/* - 1.0   */
76 	DPSTR(0, 3 + DP_EBIAS, 0x40000, 0),	/* + 10.0   */
77 	DPSTR(1, 3 + DP_EBIAS, 0x40000, 0),	/* - 10.0   */
78 	DPSTR(0, DP_EMAX + 1 + DP_EBIAS, 0, 0),	/* + infinity */
79 	DPSTR(1, DP_EMAX + 1 + DP_EBIAS, 0, 0),	/* - infinity */
80 	DPSTR(0,DP_EMAX+1+DP_EBIAS,0x7FFFF,0xFFFFFFFF), /* + indef quiet Nan */
81 	DPSTR(0, DP_EMAX + DP_EBIAS, 0xFFFFF, 0xFFFFFFFF),	/* + max */
82 	DPSTR(1, DP_EMAX + DP_EBIAS, 0xFFFFF, 0xFFFFFFFF),	/* - max */
83 	DPSTR(0, DP_EMIN + DP_EBIAS, 0, 0),	/* + min normal */
84 	DPSTR(1, DP_EMIN + DP_EBIAS, 0, 0),	/* - min normal */
85 	DPSTR(0, DP_EMIN - 1 + DP_EBIAS, 0, 1),	/* + min denormal */
86 	DPSTR(1, DP_EMIN - 1 + DP_EBIAS, 0, 1),	/* - min denormal */
87 	DPSTR(0, 31 + DP_EBIAS, 0, 0),	/* + 1.0e31 */
88 	DPSTR(0, 63 + DP_EBIAS, 0, 0),	/* + 1.0e63 */
89 };
90 
91 const struct ieee754sp_konst __ieee754sp_spcvals[] = {
92 	SPSTR(0, SP_EMIN - 1 + SP_EBIAS, 0),	/* + zero   */
93 	SPSTR(1, SP_EMIN - 1 + SP_EBIAS, 0),	/* - zero   */
94 	SPSTR(0, SP_EBIAS, 0),	/* + 1.0   */
95 	SPSTR(1, SP_EBIAS, 0),	/* - 1.0   */
96 	SPSTR(0, 3 + SP_EBIAS, 0x200000),	/* + 10.0   */
97 	SPSTR(1, 3 + SP_EBIAS, 0x200000),	/* - 10.0   */
98 	SPSTR(0, SP_EMAX + 1 + SP_EBIAS, 0),	/* + infinity */
99 	SPSTR(1, SP_EMAX + 1 + SP_EBIAS, 0),	/* - infinity */
100 	SPSTR(0,SP_EMAX+1+SP_EBIAS,0x3FFFFF),     /* + indef quiet Nan  */
101 	SPSTR(0, SP_EMAX + SP_EBIAS, 0x7FFFFF),	/* + max normal */
102 	SPSTR(1, SP_EMAX + SP_EBIAS, 0x7FFFFF),	/* - max normal */
103 	SPSTR(0, SP_EMIN + SP_EBIAS, 0),	/* + min normal */
104 	SPSTR(1, SP_EMIN + SP_EBIAS, 0),	/* - min normal */
105 	SPSTR(0, SP_EMIN - 1 + SP_EBIAS, 1),	/* + min denormal */
106 	SPSTR(1, SP_EMIN - 1 + SP_EBIAS, 1),	/* - min denormal */
107 	SPSTR(0, 31 + SP_EBIAS, 0),	/* + 1.0e31 */
108 	SPSTR(0, 63 + SP_EBIAS, 0),	/* + 1.0e63 */
109 };
110 
111 
112 int ieee754si_xcpt(int r, const char *op, ...)
113 {
114 	struct ieee754xctx ax;
115 
116 	if (!TSTX())
117 		return r;
118 	ax.op = op;
119 	ax.rt = IEEE754_RT_SI;
120 	ax.rv.si = r;
121 	va_start(ax.ap, op);
122 	ieee754_xcpt(&ax);
123 	return ax.rv.si;
124 }
125 
126 s64 ieee754di_xcpt(s64 r, const char *op, ...)
127 {
128 	struct ieee754xctx ax;
129 
130 	if (!TSTX())
131 		return r;
132 	ax.op = op;
133 	ax.rt = IEEE754_RT_DI;
134 	ax.rv.di = r;
135 	va_start(ax.ap, op);
136 	ieee754_xcpt(&ax);
137 	return ax.rv.di;
138 }
139