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00406dff FB |
1 | /* |
2 | NetWinder Floating Point Emulator | |
3 | (c) Rebel.COM, 1998,1999 | |
4 | (c) Philip Blundell, 1999 | |
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" | |
00406dff FB |
24 | #include "softfloat.h" |
25 | #include "fpopcode.h" | |
26 | #include "fpa11.inl" | |
27 | //#include "fpmodule.h" | |
28 | //#include "fpmodule.inl" | |
29 | ||
00406dff FB |
30 | void SetRoundingMode(const unsigned int opcode); |
31 | ||
32 | unsigned int PerformFLT(const unsigned int opcode); | |
33 | unsigned int PerformFIX(const unsigned int opcode); | |
34 | ||
35 | static unsigned int | |
36 | PerformComparison(const unsigned int opcode); | |
37 | ||
38 | unsigned int EmulateCPRT(const unsigned int opcode) | |
39 | { | |
40 | unsigned int nRc = 1; | |
41 | ||
42 | //printk("EmulateCPRT(0x%08x)\n",opcode); | |
43 | ||
44 | if (opcode & 0x800000) | |
45 | { | |
46 | /* This is some variant of a comparison (PerformComparison will | |
47 | sort out which one). Since most of the other CPRT | |
48 | instructions are oddball cases of some sort or other it makes | |
49 | sense to pull this out into a fast path. */ | |
50 | return PerformComparison(opcode); | |
51 | } | |
52 | ||
53 | /* Hint to GCC that we'd like a jump table rather than a load of CMPs */ | |
54 | switch ((opcode & 0x700000) >> 20) | |
55 | { | |
56 | case FLT_CODE >> 20: nRc = PerformFLT(opcode); break; | |
57 | case FIX_CODE >> 20: nRc = PerformFIX(opcode); break; | |
3b46e624 | 58 | |
00406dff FB |
59 | case WFS_CODE >> 20: writeFPSR(readRegister(getRd(opcode))); break; |
60 | case RFS_CODE >> 20: writeRegister(getRd(opcode),readFPSR()); break; | |
61 | ||
62 | #if 0 /* We currently have no use for the FPCR, so there's no point | |
63 | in emulating it. */ | |
64 | case WFC_CODE >> 20: writeFPCR(readRegister(getRd(opcode))); | |
65 | case RFC_CODE >> 20: writeRegister(getRd(opcode),readFPCR()); break; | |
66 | #endif | |
67 | ||
68 | default: nRc = 0; | |
69 | } | |
3b46e624 | 70 | |
00406dff FB |
71 | return nRc; |
72 | } | |
73 | ||
74 | unsigned int PerformFLT(const unsigned int opcode) | |
75 | { | |
76 | FPA11 *fpa11 = GET_FPA11(); | |
3b46e624 | 77 | |
00406dff FB |
78 | unsigned int nRc = 1; |
79 | SetRoundingMode(opcode); | |
80 | ||
81 | switch (opcode & MASK_ROUNDING_PRECISION) | |
82 | { | |
83 | case ROUND_SINGLE: | |
84 | { | |
85 | fpa11->fType[getFn(opcode)] = typeSingle; | |
86 | fpa11->fpreg[getFn(opcode)].fSingle = | |
20495218 | 87 | int32_to_float32(readRegister(getRd(opcode)), &fpa11->fp_status); |
00406dff FB |
88 | } |
89 | break; | |
90 | ||
91 | case ROUND_DOUBLE: | |
92 | { | |
93 | fpa11->fType[getFn(opcode)] = typeDouble; | |
94 | fpa11->fpreg[getFn(opcode)].fDouble = | |
20495218 | 95 | int32_to_float64(readRegister(getRd(opcode)), &fpa11->fp_status); |
00406dff FB |
96 | } |
97 | break; | |
3b46e624 | 98 | |
00406dff FB |
99 | case ROUND_EXTENDED: |
100 | { | |
101 | fpa11->fType[getFn(opcode)] = typeExtended; | |
102 | fpa11->fpreg[getFn(opcode)].fExtended = | |
20495218 | 103 | int32_to_floatx80(readRegister(getRd(opcode)), &fpa11->fp_status); |
00406dff FB |
104 | } |
105 | break; | |
3b46e624 | 106 | |
00406dff FB |
107 | default: nRc = 0; |
108 | } | |
3b46e624 | 109 | |
00406dff FB |
110 | return nRc; |
111 | } | |
112 | ||
113 | unsigned int PerformFIX(const unsigned int opcode) | |
114 | { | |
115 | FPA11 *fpa11 = GET_FPA11(); | |
116 | unsigned int nRc = 1; | |
117 | unsigned int Fn = getFm(opcode); | |
3b46e624 | 118 | |
00406dff FB |
119 | SetRoundingMode(opcode); |
120 | ||
121 | switch (fpa11->fType[Fn]) | |
122 | { | |
123 | case typeSingle: | |
124 | { | |
125 | writeRegister(getRd(opcode), | |
20495218 | 126 | float32_to_int32(fpa11->fpreg[Fn].fSingle, &fpa11->fp_status)); |
00406dff FB |
127 | } |
128 | break; | |
129 | ||
130 | case typeDouble: | |
131 | { | |
26a76461 | 132 | //printf("F%d is 0x%" PRIx64 "\n",Fn,fpa11->fpreg[Fn].fDouble); |
00406dff | 133 | writeRegister(getRd(opcode), |
20495218 | 134 | float64_to_int32(fpa11->fpreg[Fn].fDouble, &fpa11->fp_status)); |
00406dff FB |
135 | } |
136 | break; | |
3b46e624 | 137 | |
00406dff FB |
138 | case typeExtended: |
139 | { | |
140 | writeRegister(getRd(opcode), | |
20495218 | 141 | floatx80_to_int32(fpa11->fpreg[Fn].fExtended, &fpa11->fp_status)); |
00406dff FB |
142 | } |
143 | break; | |
3b46e624 | 144 | |
00406dff FB |
145 | default: nRc = 0; |
146 | } | |
3b46e624 | 147 | |
00406dff FB |
148 | return nRc; |
149 | } | |
150 | ||
3b46e624 | 151 | |
00406dff FB |
152 | static unsigned int __inline__ |
153 | PerformComparisonOperation(floatx80 Fn, floatx80 Fm) | |
154 | { | |
20495218 | 155 | FPA11 *fpa11 = GET_FPA11(); |
00406dff FB |
156 | unsigned int flags = 0; |
157 | ||
158 | /* test for less than condition */ | |
20495218 | 159 | if (floatx80_lt(Fn,Fm, &fpa11->fp_status)) |
00406dff FB |
160 | { |
161 | flags |= CC_NEGATIVE; | |
162 | } | |
3b46e624 | 163 | |
00406dff | 164 | /* test for equal condition */ |
20495218 | 165 | if (floatx80_eq(Fn,Fm, &fpa11->fp_status)) |
00406dff FB |
166 | { |
167 | flags |= CC_ZERO; | |
168 | } | |
169 | ||
170 | /* test for greater than or equal condition */ | |
20495218 | 171 | if (floatx80_lt(Fm,Fn, &fpa11->fp_status)) |
00406dff FB |
172 | { |
173 | flags |= CC_CARRY; | |
174 | } | |
3b46e624 | 175 | |
00406dff FB |
176 | writeConditionCodes(flags); |
177 | return 1; | |
178 | } | |
179 | ||
180 | /* This instruction sets the flags N, Z, C, V in the FPSR. */ | |
3b46e624 | 181 | |
00406dff FB |
182 | static unsigned int PerformComparison(const unsigned int opcode) |
183 | { | |
184 | FPA11 *fpa11 = GET_FPA11(); | |
185 | unsigned int Fn, Fm; | |
186 | floatx80 rFn, rFm; | |
187 | int e_flag = opcode & 0x400000; /* 1 if CxFE */ | |
188 | int n_flag = opcode & 0x200000; /* 1 if CNxx */ | |
189 | unsigned int flags = 0; | |
190 | ||
191 | //printk("PerformComparison(0x%08x)\n",opcode); | |
192 | ||
193 | Fn = getFn(opcode); | |
194 | Fm = getFm(opcode); | |
195 | ||
196 | /* Check for unordered condition and convert all operands to 80-bit | |
197 | format. | |
198 | ?? Might be some mileage in avoiding this conversion if possible. | |
199 | Eg, if both operands are 32-bit, detect this and do a 32-bit | |
200 | comparison (cheaper than an 80-bit one). */ | |
201 | switch (fpa11->fType[Fn]) | |
202 | { | |
5fafdf24 | 203 | case typeSingle: |
00406dff FB |
204 | //printk("single.\n"); |
205 | if (float32_is_nan(fpa11->fpreg[Fn].fSingle)) | |
206 | goto unordered; | |
20495218 | 207 | rFn = float32_to_floatx80(fpa11->fpreg[Fn].fSingle, &fpa11->fp_status); |
00406dff FB |
208 | break; |
209 | ||
5fafdf24 | 210 | case typeDouble: |
00406dff FB |
211 | //printk("double.\n"); |
212 | if (float64_is_nan(fpa11->fpreg[Fn].fDouble)) | |
213 | goto unordered; | |
20495218 | 214 | rFn = float64_to_floatx80(fpa11->fpreg[Fn].fDouble, &fpa11->fp_status); |
00406dff | 215 | break; |
3b46e624 | 216 | |
5fafdf24 | 217 | case typeExtended: |
00406dff FB |
218 | //printk("extended.\n"); |
219 | if (floatx80_is_nan(fpa11->fpreg[Fn].fExtended)) | |
220 | goto unordered; | |
221 | rFn = fpa11->fpreg[Fn].fExtended; | |
222 | break; | |
3b46e624 | 223 | |
00406dff FB |
224 | default: return 0; |
225 | } | |
226 | ||
227 | if (CONSTANT_FM(opcode)) | |
228 | { | |
229 | //printk("Fm is a constant: #%d.\n",Fm); | |
230 | rFm = getExtendedConstant(Fm); | |
231 | if (floatx80_is_nan(rFm)) | |
232 | goto unordered; | |
233 | } | |
234 | else | |
235 | { | |
236 | //printk("Fm = r%d which contains a ",Fm); | |
237 | switch (fpa11->fType[Fm]) | |
238 | { | |
5fafdf24 | 239 | case typeSingle: |
00406dff FB |
240 | //printk("single.\n"); |
241 | if (float32_is_nan(fpa11->fpreg[Fm].fSingle)) | |
242 | goto unordered; | |
20495218 | 243 | rFm = float32_to_floatx80(fpa11->fpreg[Fm].fSingle, &fpa11->fp_status); |
00406dff FB |
244 | break; |
245 | ||
5fafdf24 | 246 | case typeDouble: |
00406dff FB |
247 | //printk("double.\n"); |
248 | if (float64_is_nan(fpa11->fpreg[Fm].fDouble)) | |
249 | goto unordered; | |
20495218 | 250 | rFm = float64_to_floatx80(fpa11->fpreg[Fm].fDouble, &fpa11->fp_status); |
00406dff | 251 | break; |
3b46e624 | 252 | |
5fafdf24 | 253 | case typeExtended: |
00406dff FB |
254 | //printk("extended.\n"); |
255 | if (floatx80_is_nan(fpa11->fpreg[Fm].fExtended)) | |
256 | goto unordered; | |
257 | rFm = fpa11->fpreg[Fm].fExtended; | |
258 | break; | |
3b46e624 | 259 | |
00406dff FB |
260 | default: return 0; |
261 | } | |
262 | } | |
263 | ||
264 | if (n_flag) | |
265 | { | |
266 | rFm.high ^= 0x8000; | |
267 | } | |
268 | ||
269 | return PerformComparisonOperation(rFn,rFm); | |
270 | ||
271 | unordered: | |
272 | /* ?? The FPA data sheet is pretty vague about this, in particular | |
273 | about whether the non-E comparisons can ever raise exceptions. | |
274 | This implementation is based on a combination of what it says in | |
275 | the data sheet, observation of how the Acorn emulator actually | |
276 | behaves (and how programs expect it to) and guesswork. */ | |
277 | flags |= CC_OVERFLOW; | |
278 | flags &= ~(CC_ZERO | CC_NEGATIVE); | |
279 | ||
280 | if (BIT_AC & readFPSR()) flags |= CC_CARRY; | |
281 | ||
20495218 | 282 | if (e_flag) float_raise(float_flag_invalid, &fpa11->fp_status); |
00406dff FB |
283 | |
284 | writeConditionCodes(flags); | |
285 | return 1; | |
286 | } |