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1 | /* |
2 | NetWinder Floating Point Emulator |
3 | (c) Rebel.COM, 1998,1999 |
4 | (c) Philip Blundell, 1999, 2001 |
5 | |
6 | Direct questions, comments to Scott Bambrough <scottb@netwinder.org> |
7 | |
8 | This program is free software; you can redistribute it and/or modify |
9 | it under the terms of the GNU General Public License as published by |
10 | the Free Software Foundation; either version 2 of the License, or |
11 | (at your option) any later version. |
12 | |
13 | This program is distributed in the hope that it will be useful, |
14 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
15 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
16 | GNU General Public License for more details. |
17 | |
18 | You should have received a copy of the GNU General Public License |
19 | along with this program; if not, write to the Free Software |
20 | Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. |
21 | */ |
22 | |
23 | #include "fpa11.h" |
24 | #include "fpopcode.h" |
25 | #include "fpa11.inl" |
26 | #include "fpmodule.h" |
27 | #include "fpmodule.inl" |
28 | #include "softfloat.h" |
29 | |
30 | unsigned int PerformFLT(const unsigned int opcode); |
31 | unsigned int PerformFIX(const unsigned int opcode); |
32 | |
33 | static unsigned int PerformComparison(const unsigned int opcode); |
34 | |
35 | unsigned int EmulateCPRT(const unsigned int opcode) |
36 | { |
37 | |
38 | if (opcode & 0x800000) { |
39 | /* This is some variant of a comparison (PerformComparison |
40 | will sort out which one). Since most of the other CPRT |
41 | instructions are oddball cases of some sort or other it |
42 | makes sense to pull this out into a fast path. */ |
43 | return PerformComparison(opcode); |
44 | } |
45 | |
46 | /* Hint to GCC that we'd like a jump table rather than a load of CMPs */ |
47 | switch ((opcode & 0x700000) >> 20) { |
48 | case FLT_CODE >> 20: |
49 | return PerformFLT(opcode); |
50 | break; |
51 | case FIX_CODE >> 20: |
52 | return PerformFIX(opcode); |
53 | break; |
54 | |
55 | case WFS_CODE >> 20: |
56 | writeFPSR(readRegister(getRd(opcode))); |
57 | break; |
58 | case RFS_CODE >> 20: |
59 | writeRegister(getRd(opcode), readFPSR()); |
60 | break; |
61 | |
62 | default: |
63 | return 0; |
64 | } |
65 | |
66 | return 1; |
67 | } |
68 | |
69 | unsigned int PerformFLT(const unsigned int opcode) |
70 | { |
71 | FPA11 *fpa11 = GET_FPA11(); |
72 | struct roundingData roundData; |
73 | |
74 | roundData.mode = SetRoundingMode(opcode); |
75 | roundData.precision = SetRoundingPrecision(opcode); |
76 | roundData.exception = 0; |
77 | |
78 | switch (opcode & MASK_ROUNDING_PRECISION) { |
79 | case ROUND_SINGLE: |
80 | { |
81 | fpa11->fType[getFn(opcode)] = typeSingle; |
82 | fpa11->fpreg[getFn(opcode)].fSingle = int32_to_float32(&roundData, readRegister(getRd(opcode))); |
83 | } |
84 | break; |
85 | |
86 | case ROUND_DOUBLE: |
87 | { |
88 | fpa11->fType[getFn(opcode)] = typeDouble; |
89 | fpa11->fpreg[getFn(opcode)].fDouble = int32_to_float64(readRegister(getRd(opcode))); |
90 | } |
91 | break; |
92 | |
93 | #ifdef CONFIG_FPE_NWFPE_XP |
94 | case ROUND_EXTENDED: |
95 | { |
96 | fpa11->fType[getFn(opcode)] = typeExtended; |
97 | fpa11->fpreg[getFn(opcode)].fExtended = int32_to_floatx80(readRegister(getRd(opcode))); |
98 | } |
99 | break; |
100 | #endif |
101 | |
102 | default: |
103 | return 0; |
104 | } |
105 | |
106 | if (roundData.exception) |
107 | float_raise(roundData.exception); |
108 | |
109 | return 1; |
110 | } |
111 | |
112 | unsigned int PerformFIX(const unsigned int opcode) |
113 | { |
114 | FPA11 *fpa11 = GET_FPA11(); |
115 | unsigned int Fn = getFm(opcode); |
116 | struct roundingData roundData; |
117 | |
118 | roundData.mode = SetRoundingMode(opcode); |
119 | roundData.precision = SetRoundingPrecision(opcode); |
120 | roundData.exception = 0; |
121 | |
122 | switch (fpa11->fType[Fn]) { |
123 | case typeSingle: |
124 | { |
125 | writeRegister(getRd(opcode), float32_to_int32(&roundData, fpa11->fpreg[Fn].fSingle)); |
126 | } |
127 | break; |
128 | |
129 | case typeDouble: |
130 | { |
131 | writeRegister(getRd(opcode), float64_to_int32(&roundData, fpa11->fpreg[Fn].fDouble)); |
132 | } |
133 | break; |
134 | |
135 | #ifdef CONFIG_FPE_NWFPE_XP |
136 | case typeExtended: |
137 | { |
138 | writeRegister(getRd(opcode), floatx80_to_int32(&roundData, fpa11->fpreg[Fn].fExtended)); |
139 | } |
140 | break; |
141 | #endif |
142 | |
143 | default: |
144 | return 0; |
145 | } |
146 | |
147 | if (roundData.exception) |
148 | float_raise(roundData.exception); |
149 | |
150 | return 1; |
151 | } |
152 | |
153 | /* This instruction sets the flags N, Z, C, V in the FPSR. */ |
154 | static unsigned int PerformComparison(const unsigned int opcode) |
155 | { |
156 | FPA11 *fpa11 = GET_FPA11(); |
157 | unsigned int Fn = getFn(opcode), Fm = getFm(opcode); |
158 | int e_flag = opcode & 0x400000; /* 1 if CxFE */ |
159 | int n_flag = opcode & 0x200000; /* 1 if CNxx */ |
160 | unsigned int flags = 0; |
161 | |
162 | #ifdef CONFIG_FPE_NWFPE_XP |
163 | floatx80 rFn, rFm; |
164 | |
165 | /* Check for unordered condition and convert all operands to 80-bit |
166 | format. |
167 | ?? Might be some mileage in avoiding this conversion if possible. |
168 | Eg, if both operands are 32-bit, detect this and do a 32-bit |
169 | comparison (cheaper than an 80-bit one). */ |
170 | switch (fpa11->fType[Fn]) { |
171 | case typeSingle: |
172 | //printk("single.\n"); |
173 | if (float32_is_nan(fpa11->fpreg[Fn].fSingle)) |
174 | goto unordered; |
175 | rFn = float32_to_floatx80(fpa11->fpreg[Fn].fSingle); |
176 | break; |
177 | |
178 | case typeDouble: |
179 | //printk("double.\n"); |
180 | if (float64_is_nan(fpa11->fpreg[Fn].fDouble)) |
181 | goto unordered; |
182 | rFn = float64_to_floatx80(fpa11->fpreg[Fn].fDouble); |
183 | break; |
184 | |
185 | case typeExtended: |
186 | //printk("extended.\n"); |
187 | if (floatx80_is_nan(fpa11->fpreg[Fn].fExtended)) |
188 | goto unordered; |
189 | rFn = fpa11->fpreg[Fn].fExtended; |
190 | break; |
191 | |
192 | default: |
193 | return 0; |
194 | } |
195 | |
196 | if (CONSTANT_FM(opcode)) { |
197 | //printk("Fm is a constant: #%d.\n",Fm); |
198 | rFm = getExtendedConstant(Fm); |
199 | if (floatx80_is_nan(rFm)) |
200 | goto unordered; |
201 | } else { |
202 | //printk("Fm = r%d which contains a ",Fm); |
203 | switch (fpa11->fType[Fm]) { |
204 | case typeSingle: |
205 | //printk("single.\n"); |
206 | if (float32_is_nan(fpa11->fpreg[Fm].fSingle)) |
207 | goto unordered; |
208 | rFm = float32_to_floatx80(fpa11->fpreg[Fm].fSingle); |
209 | break; |
210 | |
211 | case typeDouble: |
212 | //printk("double.\n"); |
213 | if (float64_is_nan(fpa11->fpreg[Fm].fDouble)) |
214 | goto unordered; |
215 | rFm = float64_to_floatx80(fpa11->fpreg[Fm].fDouble); |
216 | break; |
217 | |
218 | case typeExtended: |
219 | //printk("extended.\n"); |
220 | if (floatx80_is_nan(fpa11->fpreg[Fm].fExtended)) |
221 | goto unordered; |
222 | rFm = fpa11->fpreg[Fm].fExtended; |
223 | break; |
224 | |
225 | default: |
226 | return 0; |
227 | } |
228 | } |
229 | |
230 | if (n_flag) |
231 | rFm.high ^= 0x8000; |
232 | |
233 | /* test for less than condition */ |
234 | if (floatx80_lt(rFn, rFm)) |
235 | flags |= CC_NEGATIVE; |
236 | |
237 | /* test for equal condition */ |
238 | if (floatx80_eq(rFn, rFm)) |
239 | flags |= CC_ZERO; |
240 | |
241 | /* test for greater than or equal condition */ |
242 | if (floatx80_lt(rFm, rFn)) |
243 | flags |= CC_CARRY; |
244 | |
245 | #else |
246 | if (CONSTANT_FM(opcode)) { |
247 | /* Fm is a constant. Do the comparison in whatever precision |
248 | Fn happens to be stored in. */ |
249 | if (fpa11->fType[Fn] == typeSingle) { |
250 | float32 rFm = getSingleConstant(Fm); |
251 | float32 rFn = fpa11->fpreg[Fn].fSingle; |
252 | |
253 | if (float32_is_nan(rFn)) |
254 | goto unordered; |
255 | |
256 | if (n_flag) |
257 | rFm ^= 0x80000000; |
258 | |
259 | /* test for less than condition */ |
260 | if (float32_lt_nocheck(rFn, rFm)) |
261 | flags |= CC_NEGATIVE; |
262 | |
263 | /* test for equal condition */ |
264 | if (float32_eq_nocheck(rFn, rFm)) |
265 | flags |= CC_ZERO; |
266 | |
267 | /* test for greater than or equal condition */ |
268 | if (float32_lt_nocheck(rFm, rFn)) |
269 | flags |= CC_CARRY; |
270 | } else { |
271 | float64 rFm = getDoubleConstant(Fm); |
272 | float64 rFn = fpa11->fpreg[Fn].fDouble; |
273 | |
274 | if (float64_is_nan(rFn)) |
275 | goto unordered; |
276 | |
277 | if (n_flag) |
278 | rFm ^= 0x8000000000000000ULL; |
279 | |
280 | /* test for less than condition */ |
281 | if (float64_lt_nocheck(rFn, rFm)) |
282 | flags |= CC_NEGATIVE; |
283 | |
284 | /* test for equal condition */ |
285 | if (float64_eq_nocheck(rFn, rFm)) |
286 | flags |= CC_ZERO; |
287 | |
288 | /* test for greater than or equal condition */ |
289 | if (float64_lt_nocheck(rFm, rFn)) |
290 | flags |= CC_CARRY; |
291 | } |
292 | } else { |
293 | /* Both operands are in registers. */ |
294 | if (fpa11->fType[Fn] == typeSingle |
295 | && fpa11->fType[Fm] == typeSingle) { |
296 | float32 rFm = fpa11->fpreg[Fm].fSingle; |
297 | float32 rFn = fpa11->fpreg[Fn].fSingle; |
298 | |
299 | if (float32_is_nan(rFn) |
300 | || float32_is_nan(rFm)) |
301 | goto unordered; |
302 | |
303 | if (n_flag) |
304 | rFm ^= 0x80000000; |
305 | |
306 | /* test for less than condition */ |
307 | if (float32_lt_nocheck(rFn, rFm)) |
308 | flags |= CC_NEGATIVE; |
309 | |
310 | /* test for equal condition */ |
311 | if (float32_eq_nocheck(rFn, rFm)) |
312 | flags |= CC_ZERO; |
313 | |
314 | /* test for greater than or equal condition */ |
315 | if (float32_lt_nocheck(rFm, rFn)) |
316 | flags |= CC_CARRY; |
317 | } else { |
318 | /* Promote 32-bit operand to 64 bits. */ |
319 | float64 rFm, rFn; |
320 | |
321 | rFm = (fpa11->fType[Fm] == typeSingle) ? |
322 | float32_to_float64(fpa11->fpreg[Fm].fSingle) |
323 | : fpa11->fpreg[Fm].fDouble; |
324 | |
325 | rFn = (fpa11->fType[Fn] == typeSingle) ? |
326 | float32_to_float64(fpa11->fpreg[Fn].fSingle) |
327 | : fpa11->fpreg[Fn].fDouble; |
328 | |
329 | if (float64_is_nan(rFn) |
330 | || float64_is_nan(rFm)) |
331 | goto unordered; |
332 | |
333 | if (n_flag) |
334 | rFm ^= 0x8000000000000000ULL; |
335 | |
336 | /* test for less than condition */ |
337 | if (float64_lt_nocheck(rFn, rFm)) |
338 | flags |= CC_NEGATIVE; |
339 | |
340 | /* test for equal condition */ |
341 | if (float64_eq_nocheck(rFn, rFm)) |
342 | flags |= CC_ZERO; |
343 | |
344 | /* test for greater than or equal condition */ |
345 | if (float64_lt_nocheck(rFm, rFn)) |
346 | flags |= CC_CARRY; |
347 | } |
348 | } |
349 | |
350 | #endif |
351 | |
352 | writeConditionCodes(flags); |
353 | |
354 | return 1; |
355 | |
356 | unordered: |
357 | /* ?? The FPA data sheet is pretty vague about this, in particular |
358 | about whether the non-E comparisons can ever raise exceptions. |
359 | This implementation is based on a combination of what it says in |
360 | the data sheet, observation of how the Acorn emulator actually |
361 | behaves (and how programs expect it to) and guesswork. */ |
362 | flags |= CC_OVERFLOW; |
363 | flags &= ~(CC_ZERO | CC_NEGATIVE); |
364 | |
365 | if (BIT_AC & readFPSR()) |
366 | flags |= CC_CARRY; |
367 | |
368 | if (e_flag) |
369 | float_raise(float_flag_invalid); |
370 | |
371 | writeConditionCodes(flags); |
372 | return 1; |
373 | } |
374 |
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