diff options
author | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-16 18:20:36 -0400 |
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committer | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-16 18:20:36 -0400 |
commit | 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch) | |
tree | 0bba044c4ce775e45a88a51686b5d9f90697ea9d /arch/mips/math-emu/ieee754sp.c |
Linux-2.6.12-rc2v2.6.12-rc2
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.
Let it rip!
Diffstat (limited to 'arch/mips/math-emu/ieee754sp.c')
-rw-r--r-- | arch/mips/math-emu/ieee754sp.c | 243 |
1 files changed, 243 insertions, 0 deletions
diff --git a/arch/mips/math-emu/ieee754sp.c b/arch/mips/math-emu/ieee754sp.c new file mode 100644 index 000000000000..adda851cd04f --- /dev/null +++ b/arch/mips/math-emu/ieee754sp.c | |||
@@ -0,0 +1,243 @@ | |||
1 | /* IEEE754 floating point arithmetic | ||
2 | * single precision | ||
3 | */ | ||
4 | /* | ||
5 | * MIPS floating point support | ||
6 | * Copyright (C) 1994-2000 Algorithmics Ltd. | ||
7 | * http://www.algor.co.uk | ||
8 | * | ||
9 | * ######################################################################## | ||
10 | * | ||
11 | * This program is free software; you can distribute it and/or modify it | ||
12 | * under the terms of the GNU General Public License (Version 2) as | ||
13 | * published by the Free Software Foundation. | ||
14 | * | ||
15 | * This program is distributed in the hope it will be useful, but WITHOUT | ||
16 | * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or | ||
17 | * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License | ||
18 | * for more details. | ||
19 | * | ||
20 | * You should have received a copy of the GNU General Public License along | ||
21 | * with this program; if not, write to the Free Software Foundation, Inc., | ||
22 | * 59 Temple Place - Suite 330, Boston MA 02111-1307, USA. | ||
23 | * | ||
24 | * ######################################################################## | ||
25 | */ | ||
26 | |||
27 | |||
28 | #include "ieee754sp.h" | ||
29 | |||
30 | int ieee754sp_class(ieee754sp x) | ||
31 | { | ||
32 | COMPXSP; | ||
33 | EXPLODEXSP; | ||
34 | return xc; | ||
35 | } | ||
36 | |||
37 | int ieee754sp_isnan(ieee754sp x) | ||
38 | { | ||
39 | return ieee754sp_class(x) >= IEEE754_CLASS_SNAN; | ||
40 | } | ||
41 | |||
42 | int ieee754sp_issnan(ieee754sp x) | ||
43 | { | ||
44 | assert(ieee754sp_isnan(x)); | ||
45 | return (SPMANT(x) & SP_MBIT(SP_MBITS-1)); | ||
46 | } | ||
47 | |||
48 | |||
49 | ieee754sp ieee754sp_xcpt(ieee754sp r, const char *op, ...) | ||
50 | { | ||
51 | struct ieee754xctx ax; | ||
52 | |||
53 | if (!TSTX()) | ||
54 | return r; | ||
55 | |||
56 | ax.op = op; | ||
57 | ax.rt = IEEE754_RT_SP; | ||
58 | ax.rv.sp = r; | ||
59 | va_start(ax.ap, op); | ||
60 | ieee754_xcpt(&ax); | ||
61 | return ax.rv.sp; | ||
62 | } | ||
63 | |||
64 | ieee754sp ieee754sp_nanxcpt(ieee754sp r, const char *op, ...) | ||
65 | { | ||
66 | struct ieee754xctx ax; | ||
67 | |||
68 | assert(ieee754sp_isnan(r)); | ||
69 | |||
70 | if (!ieee754sp_issnan(r)) /* QNAN does not cause invalid op !! */ | ||
71 | return r; | ||
72 | |||
73 | if (!SETANDTESTCX(IEEE754_INVALID_OPERATION)) { | ||
74 | /* not enabled convert to a quiet NaN */ | ||
75 | SPMANT(r) &= (~SP_MBIT(SP_MBITS-1)); | ||
76 | if (ieee754sp_isnan(r)) | ||
77 | return r; | ||
78 | else | ||
79 | return ieee754sp_indef(); | ||
80 | } | ||
81 | |||
82 | ax.op = op; | ||
83 | ax.rt = 0; | ||
84 | ax.rv.sp = r; | ||
85 | va_start(ax.ap, op); | ||
86 | ieee754_xcpt(&ax); | ||
87 | return ax.rv.sp; | ||
88 | } | ||
89 | |||
90 | ieee754sp ieee754sp_bestnan(ieee754sp x, ieee754sp y) | ||
91 | { | ||
92 | assert(ieee754sp_isnan(x)); | ||
93 | assert(ieee754sp_isnan(y)); | ||
94 | |||
95 | if (SPMANT(x) > SPMANT(y)) | ||
96 | return x; | ||
97 | else | ||
98 | return y; | ||
99 | } | ||
100 | |||
101 | |||
102 | static unsigned get_rounding(int sn, unsigned xm) | ||
103 | { | ||
104 | /* inexact must round of 3 bits | ||
105 | */ | ||
106 | if (xm & (SP_MBIT(3) - 1)) { | ||
107 | switch (ieee754_csr.rm) { | ||
108 | case IEEE754_RZ: | ||
109 | break; | ||
110 | case IEEE754_RN: | ||
111 | xm += 0x3 + ((xm >> 3) & 1); | ||
112 | /* xm += (xm&0x8)?0x4:0x3 */ | ||
113 | break; | ||
114 | case IEEE754_RU: /* toward +Infinity */ | ||
115 | if (!sn) /* ?? */ | ||
116 | xm += 0x8; | ||
117 | break; | ||
118 | case IEEE754_RD: /* toward -Infinity */ | ||
119 | if (sn) /* ?? */ | ||
120 | xm += 0x8; | ||
121 | break; | ||
122 | } | ||
123 | } | ||
124 | return xm; | ||
125 | } | ||
126 | |||
127 | |||
128 | /* generate a normal/denormal number with over,under handling | ||
129 | * sn is sign | ||
130 | * xe is an unbiased exponent | ||
131 | * xm is 3bit extended precision value. | ||
132 | */ | ||
133 | ieee754sp ieee754sp_format(int sn, int xe, unsigned xm) | ||
134 | { | ||
135 | assert(xm); /* we don't gen exact zeros (probably should) */ | ||
136 | |||
137 | assert((xm >> (SP_MBITS + 1 + 3)) == 0); /* no execess */ | ||
138 | assert(xm & (SP_HIDDEN_BIT << 3)); | ||
139 | |||
140 | if (xe < SP_EMIN) { | ||
141 | /* strip lower bits */ | ||
142 | int es = SP_EMIN - xe; | ||
143 | |||
144 | if (ieee754_csr.nod) { | ||
145 | SETCX(IEEE754_UNDERFLOW); | ||
146 | SETCX(IEEE754_INEXACT); | ||
147 | |||
148 | switch(ieee754_csr.rm) { | ||
149 | case IEEE754_RN: | ||
150 | return ieee754sp_zero(sn); | ||
151 | case IEEE754_RZ: | ||
152 | return ieee754sp_zero(sn); | ||
153 | case IEEE754_RU: /* toward +Infinity */ | ||
154 | if(sn == 0) | ||
155 | return ieee754sp_min(0); | ||
156 | else | ||
157 | return ieee754sp_zero(1); | ||
158 | case IEEE754_RD: /* toward -Infinity */ | ||
159 | if(sn == 0) | ||
160 | return ieee754sp_zero(0); | ||
161 | else | ||
162 | return ieee754sp_min(1); | ||
163 | } | ||
164 | } | ||
165 | |||
166 | if (xe == SP_EMIN - 1 | ||
167 | && get_rounding(sn, xm) >> (SP_MBITS + 1 + 3)) | ||
168 | { | ||
169 | /* Not tiny after rounding */ | ||
170 | SETCX(IEEE754_INEXACT); | ||
171 | xm = get_rounding(sn, xm); | ||
172 | xm >>= 1; | ||
173 | /* Clear grs bits */ | ||
174 | xm &= ~(SP_MBIT(3) - 1); | ||
175 | xe++; | ||
176 | } | ||
177 | else { | ||
178 | /* sticky right shift es bits | ||
179 | */ | ||
180 | SPXSRSXn(es); | ||
181 | assert((xm & (SP_HIDDEN_BIT << 3)) == 0); | ||
182 | assert(xe == SP_EMIN); | ||
183 | } | ||
184 | } | ||
185 | if (xm & (SP_MBIT(3) - 1)) { | ||
186 | SETCX(IEEE754_INEXACT); | ||
187 | if ((xm & (SP_HIDDEN_BIT << 3)) == 0) { | ||
188 | SETCX(IEEE754_UNDERFLOW); | ||
189 | } | ||
190 | |||
191 | /* inexact must round of 3 bits | ||
192 | */ | ||
193 | xm = get_rounding(sn, xm); | ||
194 | /* adjust exponent for rounding add overflowing | ||
195 | */ | ||
196 | if (xm >> (SP_MBITS + 1 + 3)) { | ||
197 | /* add causes mantissa overflow */ | ||
198 | xm >>= 1; | ||
199 | xe++; | ||
200 | } | ||
201 | } | ||
202 | /* strip grs bits */ | ||
203 | xm >>= 3; | ||
204 | |||
205 | assert((xm >> (SP_MBITS + 1)) == 0); /* no execess */ | ||
206 | assert(xe >= SP_EMIN); | ||
207 | |||
208 | if (xe > SP_EMAX) { | ||
209 | SETCX(IEEE754_OVERFLOW); | ||
210 | SETCX(IEEE754_INEXACT); | ||
211 | /* -O can be table indexed by (rm,sn) */ | ||
212 | switch (ieee754_csr.rm) { | ||
213 | case IEEE754_RN: | ||
214 | return ieee754sp_inf(sn); | ||
215 | case IEEE754_RZ: | ||
216 | return ieee754sp_max(sn); | ||
217 | case IEEE754_RU: /* toward +Infinity */ | ||
218 | if (sn == 0) | ||
219 | return ieee754sp_inf(0); | ||
220 | else | ||
221 | return ieee754sp_max(1); | ||
222 | case IEEE754_RD: /* toward -Infinity */ | ||
223 | if (sn == 0) | ||
224 | return ieee754sp_max(0); | ||
225 | else | ||
226 | return ieee754sp_inf(1); | ||
227 | } | ||
228 | } | ||
229 | /* gen norm/denorm/zero */ | ||
230 | |||
231 | if ((xm & SP_HIDDEN_BIT) == 0) { | ||
232 | /* we underflow (tiny/zero) */ | ||
233 | assert(xe == SP_EMIN); | ||
234 | if (ieee754_csr.mx & IEEE754_UNDERFLOW) | ||
235 | SETCX(IEEE754_UNDERFLOW); | ||
236 | return buildsp(sn, SP_EMIN - 1 + SP_EBIAS, xm); | ||
237 | } else { | ||
238 | assert((xm >> (SP_MBITS + 1)) == 0); /* no execess */ | ||
239 | assert(xm & SP_HIDDEN_BIT); | ||
240 | |||
241 | return buildsp(sn, xe + SP_EBIAS, xm & ~SP_HIDDEN_BIT); | ||
242 | } | ||
243 | } | ||