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/ieee754dp.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/ieee754dp.c')
-rw-r--r-- | arch/mips/math-emu/ieee754dp.c | 243 |
1 files changed, 243 insertions, 0 deletions
diff --git a/arch/mips/math-emu/ieee754dp.c b/arch/mips/math-emu/ieee754dp.c new file mode 100644 index 000000000000..3e214aac4b12 --- /dev/null +++ b/arch/mips/math-emu/ieee754dp.c | |||
@@ -0,0 +1,243 @@ | |||
1 | /* IEEE754 floating point arithmetic | ||
2 | * double precision: common utilities | ||
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 "ieee754dp.h" | ||
29 | |||
30 | int ieee754dp_class(ieee754dp x) | ||
31 | { | ||
32 | COMPXDP; | ||
33 | EXPLODEXDP; | ||
34 | return xc; | ||
35 | } | ||
36 | |||
37 | int ieee754dp_isnan(ieee754dp x) | ||
38 | { | ||
39 | return ieee754dp_class(x) >= IEEE754_CLASS_SNAN; | ||
40 | } | ||
41 | |||
42 | int ieee754dp_issnan(ieee754dp x) | ||
43 | { | ||
44 | assert(ieee754dp_isnan(x)); | ||
45 | return ((DPMANT(x) & DP_MBIT(DP_MBITS-1)) == DP_MBIT(DP_MBITS-1)); | ||
46 | } | ||
47 | |||
48 | |||
49 | ieee754dp ieee754dp_xcpt(ieee754dp r, const char *op, ...) | ||
50 | { | ||
51 | struct ieee754xctx ax; | ||
52 | if (!TSTX()) | ||
53 | return r; | ||
54 | |||
55 | ax.op = op; | ||
56 | ax.rt = IEEE754_RT_DP; | ||
57 | ax.rv.dp = r; | ||
58 | va_start(ax.ap, op); | ||
59 | ieee754_xcpt(&ax); | ||
60 | return ax.rv.dp; | ||
61 | } | ||
62 | |||
63 | ieee754dp ieee754dp_nanxcpt(ieee754dp r, const char *op, ...) | ||
64 | { | ||
65 | struct ieee754xctx ax; | ||
66 | |||
67 | assert(ieee754dp_isnan(r)); | ||
68 | |||
69 | if (!ieee754dp_issnan(r)) /* QNAN does not cause invalid op !! */ | ||
70 | return r; | ||
71 | |||
72 | if (!SETANDTESTCX(IEEE754_INVALID_OPERATION)) { | ||
73 | /* not enabled convert to a quiet NaN */ | ||
74 | DPMANT(r) &= (~DP_MBIT(DP_MBITS-1)); | ||
75 | if (ieee754dp_isnan(r)) | ||
76 | return r; | ||
77 | else | ||
78 | return ieee754dp_indef(); | ||
79 | } | ||
80 | |||
81 | ax.op = op; | ||
82 | ax.rt = 0; | ||
83 | ax.rv.dp = r; | ||
84 | va_start(ax.ap, op); | ||
85 | ieee754_xcpt(&ax); | ||
86 | return ax.rv.dp; | ||
87 | } | ||
88 | |||
89 | ieee754dp ieee754dp_bestnan(ieee754dp x, ieee754dp y) | ||
90 | { | ||
91 | assert(ieee754dp_isnan(x)); | ||
92 | assert(ieee754dp_isnan(y)); | ||
93 | |||
94 | if (DPMANT(x) > DPMANT(y)) | ||
95 | return x; | ||
96 | else | ||
97 | return y; | ||
98 | } | ||
99 | |||
100 | |||
101 | static u64 get_rounding(int sn, u64 xm) | ||
102 | { | ||
103 | /* inexact must round of 3 bits | ||
104 | */ | ||
105 | if (xm & (DP_MBIT(3) - 1)) { | ||
106 | switch (ieee754_csr.rm) { | ||
107 | case IEEE754_RZ: | ||
108 | break; | ||
109 | case IEEE754_RN: | ||
110 | xm += 0x3 + ((xm >> 3) & 1); | ||
111 | /* xm += (xm&0x8)?0x4:0x3 */ | ||
112 | break; | ||
113 | case IEEE754_RU: /* toward +Infinity */ | ||
114 | if (!sn) /* ?? */ | ||
115 | xm += 0x8; | ||
116 | break; | ||
117 | case IEEE754_RD: /* toward -Infinity */ | ||
118 | if (sn) /* ?? */ | ||
119 | xm += 0x8; | ||
120 | break; | ||
121 | } | ||
122 | } | ||
123 | return xm; | ||
124 | } | ||
125 | |||
126 | |||
127 | /* generate a normal/denormal number with over,under handling | ||
128 | * sn is sign | ||
129 | * xe is an unbiased exponent | ||
130 | * xm is 3bit extended precision value. | ||
131 | */ | ||
132 | ieee754dp ieee754dp_format(int sn, int xe, u64 xm) | ||
133 | { | ||
134 | assert(xm); /* we don't gen exact zeros (probably should) */ | ||
135 | |||
136 | assert((xm >> (DP_MBITS + 1 + 3)) == 0); /* no execess */ | ||
137 | assert(xm & (DP_HIDDEN_BIT << 3)); | ||
138 | |||
139 | if (xe < DP_EMIN) { | ||
140 | /* strip lower bits */ | ||
141 | int es = DP_EMIN - xe; | ||
142 | |||
143 | if (ieee754_csr.nod) { | ||
144 | SETCX(IEEE754_UNDERFLOW); | ||
145 | SETCX(IEEE754_INEXACT); | ||
146 | |||
147 | switch(ieee754_csr.rm) { | ||
148 | case IEEE754_RN: | ||
149 | return ieee754dp_zero(sn); | ||
150 | case IEEE754_RZ: | ||
151 | return ieee754dp_zero(sn); | ||
152 | case IEEE754_RU: /* toward +Infinity */ | ||
153 | if(sn == 0) | ||
154 | return ieee754dp_min(0); | ||
155 | else | ||
156 | return ieee754dp_zero(1); | ||
157 | case IEEE754_RD: /* toward -Infinity */ | ||
158 | if(sn == 0) | ||
159 | return ieee754dp_zero(0); | ||
160 | else | ||
161 | return ieee754dp_min(1); | ||
162 | } | ||
163 | } | ||
164 | |||
165 | if (xe == DP_EMIN - 1 | ||
166 | && get_rounding(sn, xm) >> (DP_MBITS + 1 + 3)) | ||
167 | { | ||
168 | /* Not tiny after rounding */ | ||
169 | SETCX(IEEE754_INEXACT); | ||
170 | xm = get_rounding(sn, xm); | ||
171 | xm >>= 1; | ||
172 | /* Clear grs bits */ | ||
173 | xm &= ~(DP_MBIT(3) - 1); | ||
174 | xe++; | ||
175 | } | ||
176 | else { | ||
177 | /* sticky right shift es bits | ||
178 | */ | ||
179 | xm = XDPSRS(xm, es); | ||
180 | xe += es; | ||
181 | assert((xm & (DP_HIDDEN_BIT << 3)) == 0); | ||
182 | assert(xe == DP_EMIN); | ||
183 | } | ||
184 | } | ||
185 | if (xm & (DP_MBIT(3) - 1)) { | ||
186 | SETCX(IEEE754_INEXACT); | ||
187 | if ((xm & (DP_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 >> (DP_MBITS + 3 + 1)) { | ||
197 | /* add causes mantissa overflow */ | ||
198 | xm >>= 1; | ||
199 | xe++; | ||
200 | } | ||
201 | } | ||
202 | /* strip grs bits */ | ||
203 | xm >>= 3; | ||
204 | |||
205 | assert((xm >> (DP_MBITS + 1)) == 0); /* no execess */ | ||
206 | assert(xe >= DP_EMIN); | ||
207 | |||
208 | if (xe > DP_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 ieee754dp_inf(sn); | ||
215 | case IEEE754_RZ: | ||
216 | return ieee754dp_max(sn); | ||
217 | case IEEE754_RU: /* toward +Infinity */ | ||
218 | if (sn == 0) | ||
219 | return ieee754dp_inf(0); | ||
220 | else | ||
221 | return ieee754dp_max(1); | ||
222 | case IEEE754_RD: /* toward -Infinity */ | ||
223 | if (sn == 0) | ||
224 | return ieee754dp_max(0); | ||
225 | else | ||
226 | return ieee754dp_inf(1); | ||
227 | } | ||
228 | } | ||
229 | /* gen norm/denorm/zero */ | ||
230 | |||
231 | if ((xm & DP_HIDDEN_BIT) == 0) { | ||
232 | /* we underflow (tiny/zero) */ | ||
233 | assert(xe == DP_EMIN); | ||
234 | if (ieee754_csr.mx & IEEE754_UNDERFLOW) | ||
235 | SETCX(IEEE754_UNDERFLOW); | ||
236 | return builddp(sn, DP_EMIN - 1 + DP_EBIAS, xm); | ||
237 | } else { | ||
238 | assert((xm >> (DP_MBITS + 1)) == 0); /* no execess */ | ||
239 | assert(xm & DP_HIDDEN_BIT); | ||
240 | |||
241 | return builddp(sn, xe + DP_EBIAS, xm & ~DP_HIDDEN_BIT); | ||
242 | } | ||
243 | } | ||