root / target-arm / nwfpe / fpa11_cprt.c @ ea785922
History | View | Annotate | Download (7.6 kB)
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" |
24 |
#include "softfloat.h" |
25 |
#include "fpopcode.h" |
26 |
#include "fpa11.inl" |
27 |
//#include "fpmodule.h"
|
28 |
//#include "fpmodule.inl"
|
29 |
|
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; |
58 |
|
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 |
} |
70 |
|
71 |
return nRc;
|
72 |
} |
73 |
|
74 |
unsigned int PerformFLT(const unsigned int opcode) |
75 |
{ |
76 |
FPA11 *fpa11 = GET_FPA11(); |
77 |
|
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 = |
87 |
int32_to_float32(readRegister(getRd(opcode)), &fpa11->fp_status); |
88 |
} |
89 |
break;
|
90 |
|
91 |
case ROUND_DOUBLE:
|
92 |
{ |
93 |
fpa11->fType[getFn(opcode)] = typeDouble; |
94 |
fpa11->fpreg[getFn(opcode)].fDouble = |
95 |
int32_to_float64(readRegister(getRd(opcode)), &fpa11->fp_status); |
96 |
} |
97 |
break;
|
98 |
|
99 |
case ROUND_EXTENDED:
|
100 |
{ |
101 |
fpa11->fType[getFn(opcode)] = typeExtended; |
102 |
fpa11->fpreg[getFn(opcode)].fExtended = |
103 |
int32_to_floatx80(readRegister(getRd(opcode)), &fpa11->fp_status); |
104 |
} |
105 |
break;
|
106 |
|
107 |
default: nRc = 0; |
108 |
} |
109 |
|
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); |
118 |
|
119 |
SetRoundingMode(opcode); |
120 |
|
121 |
switch (fpa11->fType[Fn])
|
122 |
{ |
123 |
case typeSingle:
|
124 |
{ |
125 |
writeRegister(getRd(opcode), |
126 |
float32_to_int32(fpa11->fpreg[Fn].fSingle, &fpa11->fp_status)); |
127 |
} |
128 |
break;
|
129 |
|
130 |
case typeDouble:
|
131 |
{ |
132 |
//printf("F%d is 0x%" PRIx64 "\n",Fn,fpa11->fpreg[Fn].fDouble);
|
133 |
writeRegister(getRd(opcode), |
134 |
float64_to_int32(fpa11->fpreg[Fn].fDouble, &fpa11->fp_status)); |
135 |
} |
136 |
break;
|
137 |
|
138 |
case typeExtended:
|
139 |
{ |
140 |
writeRegister(getRd(opcode), |
141 |
floatx80_to_int32(fpa11->fpreg[Fn].fExtended, &fpa11->fp_status)); |
142 |
} |
143 |
break;
|
144 |
|
145 |
default: nRc = 0; |
146 |
} |
147 |
|
148 |
return nRc;
|
149 |
} |
150 |
|
151 |
|
152 |
static unsigned int __inline__ |
153 |
PerformComparisonOperation(floatx80 Fn, floatx80 Fm) |
154 |
{ |
155 |
FPA11 *fpa11 = GET_FPA11(); |
156 |
unsigned int flags = 0; |
157 |
|
158 |
/* test for less than condition */
|
159 |
if (floatx80_lt(Fn,Fm, &fpa11->fp_status))
|
160 |
{ |
161 |
flags |= CC_NEGATIVE; |
162 |
} |
163 |
|
164 |
/* test for equal condition */
|
165 |
if (floatx80_eq(Fn,Fm, &fpa11->fp_status))
|
166 |
{ |
167 |
flags |= CC_ZERO; |
168 |
} |
169 |
|
170 |
/* test for greater than or equal condition */
|
171 |
if (floatx80_lt(Fm,Fn, &fpa11->fp_status))
|
172 |
{ |
173 |
flags |= CC_CARRY; |
174 |
} |
175 |
|
176 |
writeConditionCodes(flags); |
177 |
return 1; |
178 |
} |
179 |
|
180 |
/* This instruction sets the flags N, Z, C, V in the FPSR. */
|
181 |
|
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 |
{ |
203 |
case typeSingle:
|
204 |
//printk("single.\n");
|
205 |
if (float32_is_nan(fpa11->fpreg[Fn].fSingle))
|
206 |
goto unordered;
|
207 |
rFn = float32_to_floatx80(fpa11->fpreg[Fn].fSingle, &fpa11->fp_status); |
208 |
break;
|
209 |
|
210 |
case typeDouble:
|
211 |
//printk("double.\n");
|
212 |
if (float64_is_nan(fpa11->fpreg[Fn].fDouble))
|
213 |
goto unordered;
|
214 |
rFn = float64_to_floatx80(fpa11->fpreg[Fn].fDouble, &fpa11->fp_status); |
215 |
break;
|
216 |
|
217 |
case typeExtended:
|
218 |
//printk("extended.\n");
|
219 |
if (floatx80_is_nan(fpa11->fpreg[Fn].fExtended))
|
220 |
goto unordered;
|
221 |
rFn = fpa11->fpreg[Fn].fExtended; |
222 |
break;
|
223 |
|
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 |
{ |
239 |
case typeSingle:
|
240 |
//printk("single.\n");
|
241 |
if (float32_is_nan(fpa11->fpreg[Fm].fSingle))
|
242 |
goto unordered;
|
243 |
rFm = float32_to_floatx80(fpa11->fpreg[Fm].fSingle, &fpa11->fp_status); |
244 |
break;
|
245 |
|
246 |
case typeDouble:
|
247 |
//printk("double.\n");
|
248 |
if (float64_is_nan(fpa11->fpreg[Fm].fDouble))
|
249 |
goto unordered;
|
250 |
rFm = float64_to_floatx80(fpa11->fpreg[Fm].fDouble, &fpa11->fp_status); |
251 |
break;
|
252 |
|
253 |
case typeExtended:
|
254 |
//printk("extended.\n");
|
255 |
if (floatx80_is_nan(fpa11->fpreg[Fm].fExtended))
|
256 |
goto unordered;
|
257 |
rFm = fpa11->fpreg[Fm].fExtended; |
258 |
break;
|
259 |
|
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 |
|
282 |
if (e_flag) float_raise(float_flag_invalid, &fpa11->fp_status);
|
283 |
|
284 |
writeConditionCodes(flags); |
285 |
return 1; |
286 |
} |