xref: /openbmc/linux/arch/mips/math-emu/ieee754.c (revision 87c2ce3b)
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 #include "ieee754sp.h"
35 #include "ieee754dp.h"
36 
37 #define DP_EBIAS	1023
38 #define DP_EMIN		(-1022)
39 #define DP_EMAX		1023
40 
41 #define SP_EBIAS	127
42 #define SP_EMIN		(-126)
43 #define SP_EMAX		127
44 
45 /* special constants
46 */
47 
48 
49 #if (defined(BYTE_ORDER) && BYTE_ORDER == LITTLE_ENDIAN) || defined(__MIPSEL__)
50 #define SPSTR(s,b,m) {m,b,s}
51 #define DPSTR(s,b,mh,ml) {ml,mh,b,s}
52 #endif
53 
54 #ifdef __MIPSEB__
55 #define SPSTR(s,b,m) {s,b,m}
56 #define DPSTR(s,b,mh,ml) {s,b,mh,ml}
57 #endif
58 
59 const struct ieee754dp_konst __ieee754dp_spcvals[] = {
60 	DPSTR(0, DP_EMIN - 1 + DP_EBIAS, 0, 0),	/* + zero   */
61 	DPSTR(1, DP_EMIN - 1 + DP_EBIAS, 0, 0),	/* - zero   */
62 	DPSTR(0, DP_EBIAS, 0, 0),	/* + 1.0   */
63 	DPSTR(1, DP_EBIAS, 0, 0),	/* - 1.0   */
64 	DPSTR(0, 3 + DP_EBIAS, 0x40000, 0),	/* + 10.0   */
65 	DPSTR(1, 3 + DP_EBIAS, 0x40000, 0),	/* - 10.0   */
66 	DPSTR(0, DP_EMAX + 1 + DP_EBIAS, 0, 0),	/* + infinity */
67 	DPSTR(1, DP_EMAX + 1 + DP_EBIAS, 0, 0),	/* - infinity */
68 	DPSTR(0,DP_EMAX+1+DP_EBIAS,0x7FFFF,0xFFFFFFFF), /* + indef quiet Nan */
69 	DPSTR(0, DP_EMAX + DP_EBIAS, 0xFFFFF, 0xFFFFFFFF),	/* + max */
70 	DPSTR(1, DP_EMAX + DP_EBIAS, 0xFFFFF, 0xFFFFFFFF),	/* - max */
71 	DPSTR(0, DP_EMIN + DP_EBIAS, 0, 0),	/* + min normal */
72 	DPSTR(1, DP_EMIN + DP_EBIAS, 0, 0),	/* - min normal */
73 	DPSTR(0, DP_EMIN - 1 + DP_EBIAS, 0, 1),	/* + min denormal */
74 	DPSTR(1, DP_EMIN - 1 + DP_EBIAS, 0, 1),	/* - min denormal */
75 	DPSTR(0, 31 + DP_EBIAS, 0, 0),	/* + 1.0e31 */
76 	DPSTR(0, 63 + DP_EBIAS, 0, 0),	/* + 1.0e63 */
77 };
78 
79 const struct ieee754sp_konst __ieee754sp_spcvals[] = {
80 	SPSTR(0, SP_EMIN - 1 + SP_EBIAS, 0),	/* + zero   */
81 	SPSTR(1, SP_EMIN - 1 + SP_EBIAS, 0),	/* - zero   */
82 	SPSTR(0, SP_EBIAS, 0),	/* + 1.0   */
83 	SPSTR(1, SP_EBIAS, 0),	/* - 1.0   */
84 	SPSTR(0, 3 + SP_EBIAS, 0x200000),	/* + 10.0   */
85 	SPSTR(1, 3 + SP_EBIAS, 0x200000),	/* - 10.0   */
86 	SPSTR(0, SP_EMAX + 1 + SP_EBIAS, 0),	/* + infinity */
87 	SPSTR(1, SP_EMAX + 1 + SP_EBIAS, 0),	/* - infinity */
88 	SPSTR(0,SP_EMAX+1+SP_EBIAS,0x3FFFFF),     /* + indef quiet Nan  */
89 	SPSTR(0, SP_EMAX + SP_EBIAS, 0x7FFFFF),	/* + max normal */
90 	SPSTR(1, SP_EMAX + SP_EBIAS, 0x7FFFFF),	/* - max normal */
91 	SPSTR(0, SP_EMIN + SP_EBIAS, 0),	/* + min normal */
92 	SPSTR(1, SP_EMIN + SP_EBIAS, 0),	/* - min normal */
93 	SPSTR(0, SP_EMIN - 1 + SP_EBIAS, 1),	/* + min denormal */
94 	SPSTR(1, SP_EMIN - 1 + SP_EBIAS, 1),	/* - min denormal */
95 	SPSTR(0, 31 + SP_EBIAS, 0),	/* + 1.0e31 */
96 	SPSTR(0, 63 + SP_EBIAS, 0),	/* + 1.0e63 */
97 };
98 
99 
100 int ieee754si_xcpt(int r, const char *op, ...)
101 {
102 	struct ieee754xctx ax;
103 
104 	if (!TSTX())
105 		return r;
106 	ax.op = op;
107 	ax.rt = IEEE754_RT_SI;
108 	ax.rv.si = r;
109 	va_start(ax.ap, op);
110 	ieee754_xcpt(&ax);
111 	return ax.rv.si;
112 }
113 
114 s64 ieee754di_xcpt(s64 r, const char *op, ...)
115 {
116 	struct ieee754xctx ax;
117 
118 	if (!TSTX())
119 		return r;
120 	ax.op = op;
121 	ax.rt = IEEE754_RT_DI;
122 	ax.rv.di = r;
123 	va_start(ax.ap, op);
124 	ieee754_xcpt(&ax);
125 	return ax.rv.di;
126 }
127