1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
|
/*
NetWinder Floating Point Emulator
(c) Rebel.COM, 1998,1999
(c) Philip Blundell, 1999
Direct questions, comments to Scott Bambrough <scottb@netwinder.org>
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
#include "fpa11.h"
#include "softfloat.h"
#include "fpopcode.h"
#include "fpa11.inl"
//#include "fpmodule.h"
//#include "fpmodule.inl"
extern flag floatx80_is_nan(floatx80);
extern flag float64_is_nan( float64);
extern flag float32_is_nan( float32);
void SetRoundingMode(const unsigned int opcode);
unsigned int PerformFLT(const unsigned int opcode);
unsigned int PerformFIX(const unsigned int opcode);
static unsigned int
PerformComparison(const unsigned int opcode);
unsigned int EmulateCPRT(const unsigned int opcode)
{
unsigned int nRc = 1;
//printk("EmulateCPRT(0x%08x)\n",opcode);
if (opcode & 0x800000)
{
/* This is some variant of a comparison (PerformComparison will
sort out which one). Since most of the other CPRT
instructions are oddball cases of some sort or other it makes
sense to pull this out into a fast path. */
return PerformComparison(opcode);
}
/* Hint to GCC that we'd like a jump table rather than a load of CMPs */
switch ((opcode & 0x700000) >> 20)
{
case FLT_CODE >> 20: nRc = PerformFLT(opcode); break;
case FIX_CODE >> 20: nRc = PerformFIX(opcode); break;
case WFS_CODE >> 20: writeFPSR(readRegister(getRd(opcode))); break;
case RFS_CODE >> 20: writeRegister(getRd(opcode),readFPSR()); break;
#if 0 /* We currently have no use for the FPCR, so there's no point
in emulating it. */
case WFC_CODE >> 20: writeFPCR(readRegister(getRd(opcode)));
case RFC_CODE >> 20: writeRegister(getRd(opcode),readFPCR()); break;
#endif
default: nRc = 0;
}
return nRc;
}
unsigned int PerformFLT(const unsigned int opcode)
{
FPA11 *fpa11 = GET_FPA11();
unsigned int nRc = 1;
SetRoundingMode(opcode);
switch (opcode & MASK_ROUNDING_PRECISION)
{
case ROUND_SINGLE:
{
fpa11->fType[getFn(opcode)] = typeSingle;
fpa11->fpreg[getFn(opcode)].fSingle =
int32_to_float32(readRegister(getRd(opcode)), &fpa11->fp_status);
}
break;
case ROUND_DOUBLE:
{
fpa11->fType[getFn(opcode)] = typeDouble;
fpa11->fpreg[getFn(opcode)].fDouble =
int32_to_float64(readRegister(getRd(opcode)), &fpa11->fp_status);
}
break;
case ROUND_EXTENDED:
{
fpa11->fType[getFn(opcode)] = typeExtended;
fpa11->fpreg[getFn(opcode)].fExtended =
int32_to_floatx80(readRegister(getRd(opcode)), &fpa11->fp_status);
}
break;
default: nRc = 0;
}
return nRc;
}
unsigned int PerformFIX(const unsigned int opcode)
{
FPA11 *fpa11 = GET_FPA11();
unsigned int nRc = 1;
unsigned int Fn = getFm(opcode);
SetRoundingMode(opcode);
switch (fpa11->fType[Fn])
{
case typeSingle:
{
writeRegister(getRd(opcode),
float32_to_int32(fpa11->fpreg[Fn].fSingle, &fpa11->fp_status));
}
break;
case typeDouble:
{
//printf("F%d is 0x%" PRIx64 "\n",Fn,fpa11->fpreg[Fn].fDouble);
writeRegister(getRd(opcode),
float64_to_int32(fpa11->fpreg[Fn].fDouble, &fpa11->fp_status));
}
break;
case typeExtended:
{
writeRegister(getRd(opcode),
floatx80_to_int32(fpa11->fpreg[Fn].fExtended, &fpa11->fp_status));
}
break;
default: nRc = 0;
}
return nRc;
}
static unsigned int __inline__
PerformComparisonOperation(floatx80 Fn, floatx80 Fm)
{
FPA11 *fpa11 = GET_FPA11();
unsigned int flags = 0;
/* test for less than condition */
if (floatx80_lt(Fn,Fm, &fpa11->fp_status))
{
flags |= CC_NEGATIVE;
}
/* test for equal condition */
if (floatx80_eq(Fn,Fm, &fpa11->fp_status))
{
flags |= CC_ZERO;
}
/* test for greater than or equal condition */
if (floatx80_lt(Fm,Fn, &fpa11->fp_status))
{
flags |= CC_CARRY;
}
writeConditionCodes(flags);
return 1;
}
/* This instruction sets the flags N, Z, C, V in the FPSR. */
static unsigned int PerformComparison(const unsigned int opcode)
{
FPA11 *fpa11 = GET_FPA11();
unsigned int Fn, Fm;
floatx80 rFn, rFm;
int e_flag = opcode & 0x400000; /* 1 if CxFE */
int n_flag = opcode & 0x200000; /* 1 if CNxx */
unsigned int flags = 0;
//printk("PerformComparison(0x%08x)\n",opcode);
Fn = getFn(opcode);
Fm = getFm(opcode);
/* Check for unordered condition and convert all operands to 80-bit
format.
?? Might be some mileage in avoiding this conversion if possible.
Eg, if both operands are 32-bit, detect this and do a 32-bit
comparison (cheaper than an 80-bit one). */
switch (fpa11->fType[Fn])
{
case typeSingle:
//printk("single.\n");
if (float32_is_nan(fpa11->fpreg[Fn].fSingle))
goto unordered;
rFn = float32_to_floatx80(fpa11->fpreg[Fn].fSingle, &fpa11->fp_status);
break;
case typeDouble:
//printk("double.\n");
if (float64_is_nan(fpa11->fpreg[Fn].fDouble))
goto unordered;
rFn = float64_to_floatx80(fpa11->fpreg[Fn].fDouble, &fpa11->fp_status);
break;
case typeExtended:
//printk("extended.\n");
if (floatx80_is_nan(fpa11->fpreg[Fn].fExtended))
goto unordered;
rFn = fpa11->fpreg[Fn].fExtended;
break;
default: return 0;
}
if (CONSTANT_FM(opcode))
{
//printk("Fm is a constant: #%d.\n",Fm);
rFm = getExtendedConstant(Fm);
if (floatx80_is_nan(rFm))
goto unordered;
}
else
{
//printk("Fm = r%d which contains a ",Fm);
switch (fpa11->fType[Fm])
{
case typeSingle:
//printk("single.\n");
if (float32_is_nan(fpa11->fpreg[Fm].fSingle))
goto unordered;
rFm = float32_to_floatx80(fpa11->fpreg[Fm].fSingle, &fpa11->fp_status);
break;
case typeDouble:
//printk("double.\n");
if (float64_is_nan(fpa11->fpreg[Fm].fDouble))
goto unordered;
rFm = float64_to_floatx80(fpa11->fpreg[Fm].fDouble, &fpa11->fp_status);
break;
case typeExtended:
//printk("extended.\n");
if (floatx80_is_nan(fpa11->fpreg[Fm].fExtended))
goto unordered;
rFm = fpa11->fpreg[Fm].fExtended;
break;
default: return 0;
}
}
if (n_flag)
{
rFm.high ^= 0x8000;
}
return PerformComparisonOperation(rFn,rFm);
unordered:
/* ?? The FPA data sheet is pretty vague about this, in particular
about whether the non-E comparisons can ever raise exceptions.
This implementation is based on a combination of what it says in
the data sheet, observation of how the Acorn emulator actually
behaves (and how programs expect it to) and guesswork. */
flags |= CC_OVERFLOW;
flags &= ~(CC_ZERO | CC_NEGATIVE);
if (BIT_AC & readFPSR()) flags |= CC_CARRY;
if (e_flag) float_raise(float_flag_invalid, &fpa11->fp_status);
writeConditionCodes(flags);
return 1;
}
|
