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