1
2 /*
3 ===============================================================================
4
5 This C source fragment is part of the SoftFloat IEC/IEEE Floating-point
6 Arithmetic Package, Release 2.
7
8 Written by John R. Hauser. This work was made possible in part by the
9 International Computer Science Institute, located at Suite 600, 1947 Center
10 Street, Berkeley, California 94704. Funding was partially provided by the
11 National Science Foundation under grant MIP-9311980. The original version
12 of this code was written as part of a project to build a fixed-point vector
13 processor in collaboration with the University of California at Berkeley,
14 overseen by Profs. Nelson Morgan and John Wawrzynek. More information
15 is available through the Web page
16 http://www.jhauser.us/arithmetic/SoftFloat-2b/SoftFloat-source.txt
17
18 THIS SOFTWARE IS DISTRIBUTED AS IS, FOR FREE. Although reasonable effort
19 has been made to avoid it, THIS SOFTWARE MAY CONTAIN FAULTS THAT WILL AT
20 TIMES RESULT IN INCORRECT BEHAVIOR. USE OF THIS SOFTWARE IS RESTRICTED TO
21 PERSONS AND ORGANIZATIONS WHO CAN AND WILL TAKE FULL RESPONSIBILITY FOR ANY
22 AND ALL LOSSES, COSTS, OR OTHER PROBLEMS ARISING FROM ITS USE.
23
24 Derivative works are acceptable, even for commercial purposes, so long as
25 (1) they include prominent notice that the work is derivative, and (2) they
26 include prominent notice akin to these three paragraphs for those parts of
27 this code that are retained.
28
29 ===============================================================================
30 */
31
32 /*
33 -------------------------------------------------------------------------------
34 Underflow tininess-detection mode, statically initialized to default value.
35 (The declaration in `softfloat.h' must match the `int8' type here.)
36 -------------------------------------------------------------------------------
37 */
38 int8 float_detect_tininess = float_tininess_after_rounding;
39
40 /*
41 -------------------------------------------------------------------------------
42 Raises the exceptions specified by `flags'. Floating-point traps can be
43 defined here if desired. It is currently not possible for such a trap to
44 substitute a result value. If traps are not implemented, this routine
45 should be simply `float_exception_flags |= flags;'.
46
47 ScottB: November 4, 1998
48 Moved this function out of softfloat-specialize into fpmodule.c.
49 This effectively isolates all the changes required for integrating with the
50 Linux kernel into fpmodule.c. Porting to NetBSD should only require modifying
51 fpmodule.c to integrate with the NetBSD kernel (I hope!).
52 -------------------------------------------------------------------------------
53 void float_raise( int8 flags )
54 {
55 float_exception_flags |= flags;
56 }
57 */
58
59 /*
60 -------------------------------------------------------------------------------
61 Internal canonical NaN format.
62 -------------------------------------------------------------------------------
63 */
64 typedef struct {
65 flag sign;
66 bits64 high, low;
67 } commonNaNT;
68
69 /*
70 -------------------------------------------------------------------------------
71 The pattern for a default generated single-precision NaN.
72 -------------------------------------------------------------------------------
73 */
74 #define float32_default_nan 0xFFFFFFFF
75
76 /*
77 -------------------------------------------------------------------------------
78 Returns 1 if the single-precision floating-point value `a' is a NaN;
79 otherwise returns 0.
80 -------------------------------------------------------------------------------
81 */
82 flag float32_is_nan( float32 a )
83 {
84
85 return ( 0xFF000000 < (bits32) ( a<<1 ) );
86
87 }
88
89 /*
90 -------------------------------------------------------------------------------
91 Returns 1 if the single-precision floating-point value `a' is a signaling
92 NaN; otherwise returns 0.
93 -------------------------------------------------------------------------------
94 */
95 flag float32_is_signaling_nan( float32 a )
96 {
97
98 return ( ( ( a>>22 ) & 0x1FF ) == 0x1FE ) && ( a & 0x003FFFFF );
99
100 }
101
102 /*
103 -------------------------------------------------------------------------------
104 Returns the result of converting the single-precision floating-point NaN
105 `a' to the canonical NaN format. If `a' is a signaling NaN, the invalid
106 exception is raised.
107 -------------------------------------------------------------------------------
108 */
109 static commonNaNT float32ToCommonNaN( float32 a )
110 {
111 commonNaNT z;
112
113 if ( float32_is_signaling_nan( a ) ) float_raise( float_flag_invalid );
114 z.sign = a>>31;
115 z.low = 0;
116 z.high = ( (bits64) a )<<41;
117 return z;
118
119 }
120
121 /*
122 -------------------------------------------------------------------------------
123 Returns the result of converting the canonical NaN `a' to the single-
124 precision floating-point format.
125 -------------------------------------------------------------------------------
126 */
127 static float32 commonNaNToFloat32( commonNaNT a )
128 {
129
130 return ( ( (bits32) a.sign )<<31 ) | 0x7FC00000 | ( a.high>>41 );
131
132 }
133
134 /*
135 -------------------------------------------------------------------------------
136 Takes two single-precision floating-point values `a' and `b', one of which
137 is a NaN, and returns the appropriate NaN result. If either `a' or `b' is a
138 signaling NaN, the invalid exception is raised.
139 -------------------------------------------------------------------------------
140 */
141 static float32 propagateFloat32NaN( float32 a, float32 b )
142 {
143 flag aIsNaN, aIsSignalingNaN, bIsNaN, bIsSignalingNaN;
144
145 aIsNaN = float32_is_nan( a );
146 aIsSignalingNaN = float32_is_signaling_nan( a );
147 bIsNaN = float32_is_nan( b );
148 bIsSignalingNaN = float32_is_signaling_nan( b );
149 a |= 0x00400000;
150 b |= 0x00400000;
151 if ( aIsSignalingNaN | bIsSignalingNaN ) float_raise( float_flag_invalid );
152 if ( aIsNaN ) {
153 return ( aIsSignalingNaN & bIsNaN ) ? b : a;
154 }
155 else {
156 return b;
157 }
158
159 }
160
161 /*
162 -------------------------------------------------------------------------------
163 The pattern for a default generated double-precision NaN.
164 -------------------------------------------------------------------------------
165 */
166 #define float64_default_nan LIT64( 0xFFFFFFFFFFFFFFFF )
167
168 /*
169 -------------------------------------------------------------------------------
170 Returns 1 if the double-precision floating-point value `a' is a NaN;
171 otherwise returns 0.
172 -------------------------------------------------------------------------------
173 */
174 flag float64_is_nan( float64 a )
175 {
176
177 return ( LIT64( 0xFFE0000000000000 ) < (bits64) ( a<<1 ) );
178
179 }
180
181 /*
182 -------------------------------------------------------------------------------
183 Returns 1 if the double-precision floating-point value `a' is a signaling
184 NaN; otherwise returns 0.
185 -------------------------------------------------------------------------------
186 */
187 flag float64_is_signaling_nan( float64 a )
188 {
189
190 return
191 ( ( ( a>>51 ) & 0xFFF ) == 0xFFE )
192 && ( a & LIT64( 0x0007FFFFFFFFFFFF ) );
193
194 }
195
196 /*
197 -------------------------------------------------------------------------------
198 Returns the result of converting the double-precision floating-point NaN
199 `a' to the canonical NaN format. If `a' is a signaling NaN, the invalid
200 exception is raised.
201 -------------------------------------------------------------------------------
202 */
203 static commonNaNT float64ToCommonNaN( float64 a )
204 {
205 commonNaNT z;
206
207 if ( float64_is_signaling_nan( a ) ) float_raise( float_flag_invalid );
208 z.sign = a>>63;
209 z.low = 0;
210 z.high = a<<12;
211 return z;
212
213 }
214
215 /*
216 -------------------------------------------------------------------------------
217 Returns the result of converting the canonical NaN `a' to the double-
218 precision floating-point format.
219 -------------------------------------------------------------------------------
220 */
221 static float64 commonNaNToFloat64( commonNaNT a )
222 {
223
224 return
225 ( ( (bits64) a.sign )<<63 )
226 | LIT64( 0x7FF8000000000000 )
227 | ( a.high>>12 );
228
229 }
230
231 /*
232 -------------------------------------------------------------------------------
233 Takes two double-precision floating-point values `a' and `b', one of which
234 is a NaN, and returns the appropriate NaN result. If either `a' or `b' is a
235 signaling NaN, the invalid exception is raised.
236 -------------------------------------------------------------------------------
237 */
238 static float64 propagateFloat64NaN( float64 a, float64 b )
239 {
240 flag aIsNaN, aIsSignalingNaN, bIsNaN, bIsSignalingNaN;
241
242 aIsNaN = float64_is_nan( a );
243 aIsSignalingNaN = float64_is_signaling_nan( a );
244 bIsNaN = float64_is_nan( b );
245 bIsSignalingNaN = float64_is_signaling_nan( b );
246 a |= LIT64( 0x0008000000000000 );
247 b |= LIT64( 0x0008000000000000 );
248 if ( aIsSignalingNaN | bIsSignalingNaN ) float_raise( float_flag_invalid );
249 if ( aIsNaN ) {
250 return ( aIsSignalingNaN & bIsNaN ) ? b : a;
251 }
252 else {
253 return b;
254 }
255
256 }
257
258 #ifdef FLOATX80
259
260 /*
261 -------------------------------------------------------------------------------
262 The pattern for a default generated extended double-precision NaN. The
263 `high' and `low' values hold the most- and least-significant bits,
264 respectively.
265 -------------------------------------------------------------------------------
266 */
267 #define floatx80_default_nan_high 0xFFFF
268 #define floatx80_default_nan_low LIT64( 0xFFFFFFFFFFFFFFFF )
269
270 /*
271 -------------------------------------------------------------------------------
272 Returns 1 if the extended double-precision floating-point value `a' is a
273 NaN; otherwise returns 0.
274 -------------------------------------------------------------------------------
275 */
276 flag floatx80_is_nan( floatx80 a )
277 {
278
279 return ( ( a.high & 0x7FFF ) == 0x7FFF ) && (bits64) ( a.low<<1 );
280
281 }
282
283 /*
284 -------------------------------------------------------------------------------
285 Returns 1 if the extended double-precision floating-point value `a' is a
286 signaling NaN; otherwise returns 0.
287 -------------------------------------------------------------------------------
288 */
289 flag floatx80_is_signaling_nan( floatx80 a )
290 {
291 //register int lr;
292 bits64 aLow;
293
294 //__asm__("mov %0, lr" : : "g" (lr));
295 //fp_printk("floatx80_is_signalling_nan() called from 0x%08x\n",lr);
296 aLow = a.low & ~ LIT64( 0x4000000000000000 );
297 return
298 ( ( a.high & 0x7FFF ) == 0x7FFF )
299 && (bits64) ( aLow<<1 )
300 && ( a.low == aLow );
301
302 }
303
304 /*
305 -------------------------------------------------------------------------------
306 Returns the result of converting the extended double-precision floating-
307 point NaN `a' to the canonical NaN format. If `a' is a signaling NaN, the
308 invalid exception is raised.
309 -------------------------------------------------------------------------------
310 */
311 static commonNaNT floatx80ToCommonNaN( floatx80 a )
312 {
313 commonNaNT z;
314
315 if ( floatx80_is_signaling_nan( a ) ) float_raise( float_flag_invalid );
316 z.sign = a.high>>15;
317 z.low = 0;
318 z.high = a.low<<1;
319 return z;
320
321 }
322
323 /*
324 -------------------------------------------------------------------------------
325 Returns the result of converting the canonical NaN `a' to the extended
326 double-precision floating-point format.
327 -------------------------------------------------------------------------------
328 */
329 static floatx80 commonNaNToFloatx80( commonNaNT a )
330 {
331 floatx80 z;
332
333 z.low = LIT64( 0xC000000000000000 ) | ( a.high>>1 );
334 z.high = ( ( (bits16) a.sign )<<15 ) | 0x7FFF;
335 z.__padding = 0;
336 return z;
337
338 }
339
340 /*
341 -------------------------------------------------------------------------------
342 Takes two extended double-precision floating-point values `a' and `b', one
343 of which is a NaN, and returns the appropriate NaN result. If either `a' or
344 `b' is a signaling NaN, the invalid exception is raised.
345 -------------------------------------------------------------------------------
346 */
347 static floatx80 propagateFloatx80NaN( floatx80 a, floatx80 b )
348 {
349 flag aIsNaN, aIsSignalingNaN, bIsNaN, bIsSignalingNaN;
350
351 aIsNaN = floatx80_is_nan( a );
352 aIsSignalingNaN = floatx80_is_signaling_nan( a );
353 bIsNaN = floatx80_is_nan( b );
354 bIsSignalingNaN = floatx80_is_signaling_nan( b );
355 a.low |= LIT64( 0xC000000000000000 );
356 b.low |= LIT64( 0xC000000000000000 );
357 if ( aIsSignalingNaN | bIsSignalingNaN ) float_raise( float_flag_invalid );
358 if ( aIsNaN ) {
359 return ( aIsSignalingNaN & bIsNaN ) ? b : a;
360 }
361 else {
362 return b;
363 }
364
365 }
366
367 #endif
Linux® is a registered trademark of Linus Torvalds in the United States and other countries.
TOMOYO® is a registered trademark of NTT DATA CORPORATION.